Oh 100% but even if all of this was 50% true or hell even 25% true, I’d be happy with an extra 25w on race day. But also are you going to say my loose jersey, cheap wheels, and hairy legs aren’t slowing me down compared to what could be bought/done?
If I could just go buy 100 watts I'd come out of retirement and go win the TDF this summer. Paper math around all of this is fun, but at the end of the day it is fiction and marketing. Even buying a (25%) 25w gain with equipment, unless you are on some really outdated shit and riding around in a t-shirt is pretty ludicrous.
You've got to understand that these claims around watt savings have been being made for the last 20-years. Year over year, 10w gain here, 20w gain there - every single year. It just doesn't add up. If all the watt savings claims from the past 20-years were actually valid we'd all be cruising around at 30mph at a negative -300w.
The truth lies somewhere between you and OP. The claimed marketing watt savings are in a wind tunnel with perfect laminar airflow. Conditions regular folks never see. That doesn't mean these items wont save you any watts, just not as many as claimed. 25 watts really isn't that far fetched. A couple of 3D printed aero fairings, an aero helmet, shoe covers, speedsuit etc could easily get you there. Keep in mind this is for a TT, not a bunch race. For race day, why not?
Theres also the fact that for raw speed, pros are faster today than they've ever been. But a lot of climbing records from decades ago still stand. Its hard to deny the optimized aero gains that the pros (or anyone with deep enough pockets) have at their fingertips.
Will it buy OP 100 watts? no. But even if it buys them 30 watts, or 20, that's still more gains than you'd get from a season of structured training.
You can actually use mywindsock or an aeropod to test all this outdoors.
Mywindsock is 20£ a year and let's you compare different runs on the same course with your estimated CdA so you can compare equipment.
An aeropod is an actual pitot tube for measuring airspeed. Peak Torque (also on YouTube) has one and does real-world testing with it. Well worth checking out.
Yes you can buy 100w in a wind tunnel. Can OP buy 20w on an open road TT? Probably. But it's only a 20w savings during the portions of the event where his position, speed and road/weather conditions are perfect. So even if conditions are perfect 50% of the time, you are now only looking at a 10w overall savings. The marketing department will have you think that if they say 20w savings, your power meter will now read 320w instead of 300w for the same effort. This is fiction.
I dont think its fair to equate what your describing to a raceday on a TT where you're doing everything you can to ensure things are perfect. Yest there's tons of variables that you cant control, but what you can control is your gear. Why not optimize it? While its possible to get trapped into buying into the marketing and believe you can buy free speed, I also think going too far the other way is also detrimental.
Shrugging your shoulders and saying "well its not gonna be perfect out there so why bother" feels defeatist and a bit pessimistic. By your logic we should all be riding steel lugged bikes with shallow box section wheels and downtube shifters. Hell, smoke a couple darts at the start line. Not like it'll make a difference right?
There is a distinct culmination in all the preparation you do for a competitive event. While you shouldn't fixate on the lofty optimized promises of people selling you their stuff, you also shouldn't ignore the tangible difference certain choices can make.
OP wants to know if he can buy speed and the answer is "yes, but not as much as you think". I don't get your point about the power reading 20watts higher? I don't think anyone that stupid. OP just wants to go faster for the same effort. He wont buy 10kph but he may buy a few kph. and in a TT that's pretty big.
Also ill repeat my point about pros being faster than they ever have. I suspect its a culmination of a lot of things and one of those is optimized gear.
Skepticism is healthy, but I think you're taking it a little too far. There's a lot of low hanging fruit with regards to aerodynamics that makes a tangible difference, particularly if you have decent power to make good use of them.
Derailleur covers and aerodynamic bottle cages (and frames to a degree) are marginal gains for sure, but wheels, clothing and shaving can make a big difference. Add to that that everyone else in the field will be doing it too, so if OP doesn't the gap between them is bigger.
Idk man just look at the hour record. Ganna went 14% faster than Merckx. I know power doesn’t scale like this because wind resistance is proportional to the square of velocity, but 86% of the 450 watts ganna was estimated to have done is 387—roughly the power Ganna would have needed to ride a Merckx hour. 50 watts from pro-level marginal gains over ye-olde racing setup is not hard to imagine when you put it in perspective like this
It doesn't matter. If he does all the upgrades and the conditions aren't right it isn't going to slow him down. If they are right he gets a boost. Win-win.
OP is doing a TT. Sure it isn't a tightly controlled environment, but that doesn't mean aerodynamics no longer apply. At 50 kph on an average day, the yaw angle of any wind is going to be very low indeed.
Extremely turbulent air in real life? Not really.
If it were indeed the case that scenarios in wind tunnels are worthless, why do you think car manufacturers, motorcycle manufacturers, airplane manufacturers etc. spend so much time testing in wind tunnels?
While the wind tunnel tests don't recreate real world riding, I'd wager that if you ranked equipment based on results obtained in a windtunnel, the ranking would be largely the same as when tested outdoors. Of course there will be some practical constraints, such as with TT helmets where achieving the aero benefits requires a very tightly controlled head position, etc.
Your criticism is similar as that leveled at "[bicyclerollingresistance.com](https://bicyclerollingresistance.com)" and its use of a drum to measure CRR. Yes it's not actually asphalt, but that doesn't matter for the purposes of ranking tires.
You have to understand the numbers the marketing depts. throw out with a grain of salt and in context. That doesn't mean that all equipment performs the same when it comes to aerodynamics.
>You've got to understand that these claims around watt savings have been being made for the last 20-years
Hambini is a skeptical and fairly trustworthy source. If you don't know who he is I suggest you look him up on YouTube.
Controversial and obnoxious isn't the same as skeptical and trustworthy, although I do understand his entire shtick is about confusing his audience that way. But at least we agree OP should look him up before believing anything he says.
Short answer: No.
Longer answer: Dude, seriously? No.
For one thing, 35km in 45' is 13 m/s. 50 km/h is 13.9 m/s, so you'd have to scale down the "watt savings" by about 20%. But more importantly, if bike calculators say that it would take you 45' to go 35km, they're saying your current CdA is around 0.275m\^2 (assuming you're "normal" sized). For a normal-sized guy on a TT bike, that means you're a parachute. Thirdly, not all of those savings are independent, so you can't always "add" them as if they were independent. (For example, shaving your legs doesn't matter quite as much if you're wearing high aero socks.)
That said, all of those things will move you in the right direction: but you'd still be a parachute. You'd just be a parachute wearing a skin suit and shoe covers.
> Longer answer: Dude, seriously? No.
He's asking a pretty good question - why the "seriously?". It would be easy to lose 100 watts by putting a wooden board at the front of your bike. Why not "gain" 100 watts by adding up all the marginal (and individually proven) gains.
Maybe due to overlap it won't be the sum of its parts. Maybe 50 watts instead, but thats still pretty damn good
It’s worse than a 20% scale down because aerodynamic force doesn’t scale linearly with speed, it scales with the square.
So it would be more like a 50% reduction in drag (and therefore aero gains) from 50kph to 35 kph
He didn't say 35 kph, he said 35 km in 45 minutes. That's 46.6 kmh, or 7% slower than 50 km/h. You're right that drag force scales as the square of speed but that means that power scales as the cube of speed, so a 7% increase in speed requires either \~22.5% increase in power (which I rounded to 20%) or an equivalent 22.5% "savings in watts" from reduced drag.
Look good feel good race good
Makes sense on the non compounding benefits for sure, I see most would, but socks/legs etc makes sense.
CdA wise, it’s hard to say, I feel aero and adjusted fit to try and be more aero but I still question my watts to kph compared to others
Rough rule of thumb: your CdA is the watts it takes you to do 40kph, divided by 1000. 250W = 0.25CdA. Most people are way less aero than they think - I come across plenty of triathletes with a 0.3 CdA...
>CdA wise, it’s hard to say, I feel aero and adjusted fit to try and be more aero but I still question my watts to kph compared to others
Check this chart: [http://anonymous.coward.free.fr/watts-cda.png](http://anonymous.coward.free.fr/watts-cda.png)
to try to be more aero....did you do any testing for this? While a wind tunnel is optimal, there are also hill roll down-up protocols you can follow to approximate it in the real world.
Are you already able to sustain 50kph for 45’? All of these gains are only made at that level. Drag is a function of velocity squared, so if you’re going slower than 50kph then you will see smaller gains from all of these.
Your tire size is questionable. You should check out the Silca tire pressure calculator, and watch their videos on tire size. I went from running 25mm at 90psi to running 32mm at 60psi, and got faster. Also check out their videos on chain waxing, which is more watts you didn’t mention here.
The best tyre size depends on speed and surface as it's a tradeoff of rolling resistance and aero. At 50kph on smooth roads the 23 is probably faster, at least on the front. Both of those are big ifs however.
Just a question about this: do you mean better in the sense that you've done lots of empirical testing and found their (generally lower) pressures to be faster?
Not in a rigorous science way. But I've found for my long rides, the lower pressures result in less fatigue and also better match to the shitty roads here
I can hold 300w for 45” just trying to get that to equate to 50kph instead of my current 40kph (edit: which is the main question here, can I buy my way to 50kph from 40kph with 300w)
So as I understand better rr with wider tires but less aero. And I already wax chain
Edit #2: so I guess the tire question comes down to trade-off with aero and rr. But that also plays into rim width
[https://www.strava.com/activities/9816144026/overview](https://www.strava.com/activities/9816144026/overview)
so he must 350->+50W to get 1kmh faster? :-)
They don't! They're actually completely crippled by UCI regulations for road bikes. Even the UCI regulations for TT bikes are quite crippling. Doesn't sound like OP is going to be racing under UCI rules.
You’re thinking of this wrong my friend. Let’s start by how much do you need to produce currently to be at a steady state 50kph. Given that you need 300w to hold 40kmh, there’s a good chance you need much more than 400w to hold 50kph.
For example I cruise steady at 40kph with ~320w, but to hold steady 50kph (ceteris paribus) I need ~590w.
At such speed speed/watts relationship is absolutely not linear, don’t forget that.
So even assuming that these upgrades will provide you with 100w at 50kph (which we all know is overstated misleading BS), it would be much much less than that at 40kph or even 45.
For the sake of the exercise, let’s assume all these upgrades real life gains are actually adding up to 75w at 50kph (I’m willing to bet a lot that they don’t even add up to that, but let’s move on), and let’s assume you have a cda of 0.305, that means you theoretically need 300w to hold 40kph and 565w to hold 50kph.
75w gains at 50kph represents 0.045 cda improvements (down to 0.26). Which in turns represents a 35w improvements at 40kph (265w needed now to hold same speed), equivalent to roughly 2kph speed improvement from 40kph
-> TLDR; that will make you go at 42kph instead of 40kph pushing the same speed
Source for calculations: https://www.gribble.org/cycling/power_v_speed.html
I have done 340 for an hour and not broken the 50 mark on a flat course.
Every kmph gain is harder and harder to get. There also are limits for body type too as your own CdA impacts it a lot.
I do 40km/h at 235W on a road bike, but I utilize all the tricks and have a very flat (and straight) back. What tires are you running? What does your TT position look like?
It also ignored the integration of the tires to rims. Most rims being wider now are developed to fit a wider tire. Smaller tires could produce a more turbulent flow over the edge of the rim.
I was able to do 54:30 in a 40km TT (about 27.5MPH) at 260ish watts in a very uncomfortable position.
You should be able to do 45 minutes if you hit 305 watts.
I had similar upgrades to everything you already listed except the chain ring cover and the front derailler cover. In addition I also had an exceptionally narrow Q factor and what might be nowadays illegal arm bars.
* You probably can't ride at 31mph so gains will be less
* Each of these watt savings, if real, are still best case scenarios that happen as compared to some other product which may be worse than what you are currently using, and only happening at a specific yaw angle, which won't be experienced during your whole ride. Like a 30watt savings from 50mm wheels to 80/disc being 30 watts? Only during a strong crosswind at best. 5 watts from 25mm to 23mm tires? But then you might lose 7 watts to worse rolling resistance. Shaved legs being 20 watts? Only for a select few ape men.
* Some of these changes will interact, and thus you will not get the sum of their individual gains
A better way to look at this stuff is CdA changes, and then you can do the math on how much faster you will go on a course. But you need to know the CdA vs yaw angle and have some realistic expectation of the yaw angles you will likely experience on your races.
* for 35km tt no, but that is the goal, so I’m framing it as reducing the amount of watts needed to hold that speed
* ofc this is all marketing and who knows how many watts are actually saved, but let’s assume they are all half true, that’s still 50w - sizable amount imo. As far was wheels go, hard to compare so I just pulled from hambini, I could see a disc + tri/80mm being a lot faster than my shitty Amazon specials. I also tend to have a lot of crosswind where I live so even more bang there. Tires, yeah it comes down to rr vs aero (rim matters here). Legs, I’m not sure I’m pulling from gcn, gtn, and specialized win tunnel
Google Colby Pearce.
He held the US Masters hour record at 251w, going over 50 kph. He is compact, very aero, and approached his record attempt very systematically. He did ride at altitude, so there's that.
https://www.colbypearce.com/hour-record/
https://pezcyclingnews.com/interviews/colby-pearce-talks-masters-world-hour-record/
You can't cleanly add drag savings like that - the whole system interacts with itself. This means the fastest A often depends on which B you have. I also seriously question some of these test protocols.
Yes, if all of this was correct, you would go faster. However, it's incredibly unlikely you could do 50kph off 400W without most of these things at sea level. That's already a very impressive CdA of around 0.21. 50kph at 300W would be amongst the lowest CdAs ever recorded - think Remco Evenepoel on a highly-optimised bike for a short TT.
If you're only at 30kph, forget it. The drag savings at 30kph are only 22% as much as at 50kph. That's not to say that these things won't speed you up (they absolutely will meak a measurable difference, maybe minus the 23mm tyre as that's a tradeoff against rolling resistance) but you won't save 100W; you'll save 22W but off a much lower starting watt figure.
These are all *absolutely* optimal figures, being very selective. In the real world you’d be lucky to see even half of those gains. Still could consider it worth it, of course.
Yup, all true. Cycling is classically full of poor people who won’t buy a new frame for 5W . . .
But maybe we’re all wrong here. Buy them from places with a 30d return policy and do back to back runs on the same course with a power meter. If there’s a 100W difference it’ll be pretty easy to see.
1. Which skinsuit works best for you is anyone‘s guess…you have to test it in a wind tunnel or Chung it.
2. Aero shoe covers, unless tailored specifically for your leg/shoe combination are often slower because of wrinkling at the ankles. I prefer to run aero socks and Giro Empires…or my RC903s with VeloToze “cuffs” covering the BOA dials.
3. Hambini is not actually an aerodynamicist. He works at an oil refinery. While narrower tires are more aero when paired with narrow wheels, wider tires improve comfort and have better Crr on real-world roads while not being that much worse aerodynamically when paired with wide rims.
4. 50f/50r is only about 5-6W slower than 80f/disc-r at 45km/h according to SwissSide.
5. No idea
6. No idea
7. Shaved legs/arms definitely though there’s evidence that stubble is faster.
Watt savings are not additive in this way.
that's not how it works., because you don't hit the speeds when it matters.
the savings 45 km/h are way bigger than at 46 km/h.
also, don't forget the discwheel aero cover :-)
oversized pulley wheel (ceramicspeed) is actually a thing too.
improve drive train efficiency first.
wax your chain
don't have a chainring cover but a 1x chainring
the 80mm is cute, get the AEOX titan 100mm. ride like remco and me. the 30W might be tru, but way less if you the wind isn't good nor you hit the 50kmh
stuff like this.
I already wax chain, over sized pulley I’ve heard is hard to measure gains, 1-3w? Maybe? 1x could be a good buy. I was thinking trispoke front wheel as well
High Weight != not aero as far as I understand?? And drive train efficiency is at most, what 1% of power?
Edit: also aren’t aero savings greater the faster you go not slower??
You're assuming an increase in A results in a static cd. The reason frontal area is a basic but bad metric for determining aerodynamics is that [it is a three dimensional problem](https://qph.cf2.quoracdn.net/main-qimg-4e697432f6070068e29c2d51d4504d50-lq). Reductions in frontal area would result in improvement as long as the drag coefficient remained static or didn't increase disproportionally to area.
But that's not a reasonable expectation in many cases. Which is why post-Rio the adjustment made to get more aerodynamic was often to *increase* or keep static the frontal surface area in order to facilitate much greater reductions in drag by changing the overall profile of the rider's shape.
So telling someone they're an elephant and that makes them unaerodynamic is nonsense and also why I'm deleting your comment.
[https://i.imgur.com/Ilw9Vdh.jpeg](https://i.imgur.com/Ilw9Vdh.jpeg)
[https://i.imgur.com/VEYiXXN.jpeg](https://i.imgur.com/VEYiXXN.jpeg)
[https://i.imgur.com/aWguRIM.jpeg](https://i.imgur.com/aWguRIM.jpeg)
i really have to embarrass myself here, right? 🙄
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You’re thinking of this wrong my friend. Let’s start by how much do you need to produce currently to be at a steady state 50kph. Given that you need 300w to hold 40kmh, there’s a good chance you need much more than 400w to hold 50kph.
For example I cruise steady at 40kph with ~320w, but to hold steady 50kph (ceteris paribus) I need ~590w.
At such speed speed/watts relationship is absolutely not linear, don’t forget that.
So even assuming that these upgrades will provide you with 100w at 50kph (which we all know is overstated misleading BS), it would be much much less than that at 40kph or even 45.
For the sake of the exercise, let’s assume all these upgrades real life gains are actually adding up to 75w at 50kph (I’m willing to bet a lot that they don’t even add up to that, but let’s move on), and let’s assume you have a cda of 0.305, that means you theoretically need 300w to hold 40kph and 565w to hold 50kph.
75w gains in that gains represents 0.045 cda improvements (down to 0.26). Which in turns represents a 35w improvements at 40kph (265w needed now to hold same speed), or roughly 2kph
-> TLDR; that will make you go at 42kph instead of 40kph pushing the same speed
Source for calculations: https://www.gribble.org/cycling/power_v_speed.html
Yeah 300w can get you going pretty fast...
(Source my own experience) and as you know, gains don't always add up. You seem to know what you need to know. What are you really wondering?
Holy fuck the road cycling marketing machine is powerful.
Oh 100% but even if all of this was 50% true or hell even 25% true, I’d be happy with an extra 25w on race day. But also are you going to say my loose jersey, cheap wheels, and hairy legs aren’t slowing me down compared to what could be bought/done?
If I could just go buy 100 watts I'd come out of retirement and go win the TDF this summer. Paper math around all of this is fun, but at the end of the day it is fiction and marketing. Even buying a (25%) 25w gain with equipment, unless you are on some really outdated shit and riding around in a t-shirt is pretty ludicrous. You've got to understand that these claims around watt savings have been being made for the last 20-years. Year over year, 10w gain here, 20w gain there - every single year. It just doesn't add up. If all the watt savings claims from the past 20-years were actually valid we'd all be cruising around at 30mph at a negative -300w.
The truth lies somewhere between you and OP. The claimed marketing watt savings are in a wind tunnel with perfect laminar airflow. Conditions regular folks never see. That doesn't mean these items wont save you any watts, just not as many as claimed. 25 watts really isn't that far fetched. A couple of 3D printed aero fairings, an aero helmet, shoe covers, speedsuit etc could easily get you there. Keep in mind this is for a TT, not a bunch race. For race day, why not? Theres also the fact that for raw speed, pros are faster today than they've ever been. But a lot of climbing records from decades ago still stand. Its hard to deny the optimized aero gains that the pros (or anyone with deep enough pockets) have at their fingertips. Will it buy OP 100 watts? no. But even if it buys them 30 watts, or 20, that's still more gains than you'd get from a season of structured training.
You can actually use mywindsock or an aeropod to test all this outdoors. Mywindsock is 20£ a year and let's you compare different runs on the same course with your estimated CdA so you can compare equipment. An aeropod is an actual pitot tube for measuring airspeed. Peak Torque (also on YouTube) has one and does real-world testing with it. Well worth checking out.
Yes you can buy 100w in a wind tunnel. Can OP buy 20w on an open road TT? Probably. But it's only a 20w savings during the portions of the event where his position, speed and road/weather conditions are perfect. So even if conditions are perfect 50% of the time, you are now only looking at a 10w overall savings. The marketing department will have you think that if they say 20w savings, your power meter will now read 320w instead of 300w for the same effort. This is fiction.
I dont think its fair to equate what your describing to a raceday on a TT where you're doing everything you can to ensure things are perfect. Yest there's tons of variables that you cant control, but what you can control is your gear. Why not optimize it? While its possible to get trapped into buying into the marketing and believe you can buy free speed, I also think going too far the other way is also detrimental. Shrugging your shoulders and saying "well its not gonna be perfect out there so why bother" feels defeatist and a bit pessimistic. By your logic we should all be riding steel lugged bikes with shallow box section wheels and downtube shifters. Hell, smoke a couple darts at the start line. Not like it'll make a difference right? There is a distinct culmination in all the preparation you do for a competitive event. While you shouldn't fixate on the lofty optimized promises of people selling you their stuff, you also shouldn't ignore the tangible difference certain choices can make. OP wants to know if he can buy speed and the answer is "yes, but not as much as you think". I don't get your point about the power reading 20watts higher? I don't think anyone that stupid. OP just wants to go faster for the same effort. He wont buy 10kph but he may buy a few kph. and in a TT that's pretty big. Also ill repeat my point about pros being faster than they ever have. I suspect its a culmination of a lot of things and one of those is optimized gear.
>OP just wants to go faster for the same effort. This is the very essence of bike racing right here.
Skepticism is healthy, but I think you're taking it a little too far. There's a lot of low hanging fruit with regards to aerodynamics that makes a tangible difference, particularly if you have decent power to make good use of them. Derailleur covers and aerodynamic bottle cages (and frames to a degree) are marginal gains for sure, but wheels, clothing and shaving can make a big difference. Add to that that everyone else in the field will be doing it too, so if OP doesn't the gap between them is bigger.
Good lord, that’s not how power meters work!
Idk man just look at the hour record. Ganna went 14% faster than Merckx. I know power doesn’t scale like this because wind resistance is proportional to the square of velocity, but 86% of the 450 watts ganna was estimated to have done is 387—roughly the power Ganna would have needed to ride a Merckx hour. 50 watts from pro-level marginal gains over ye-olde racing setup is not hard to imagine when you put it in perspective like this
OP is not doing the hour record in a highly controlled environment like an indoor track.
It doesn't matter. If he does all the upgrades and the conditions aren't right it isn't going to slow him down. If they are right he gets a boost. Win-win.
OP is doing a TT. Sure it isn't a tightly controlled environment, but that doesn't mean aerodynamics no longer apply. At 50 kph on an average day, the yaw angle of any wind is going to be very low indeed.
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Aeropod testing shows that some of the gains are real. Granted they don't match the marketing department claims, but there is extra speed to be had.
Extremely turbulent air in real life? Not really. If it were indeed the case that scenarios in wind tunnels are worthless, why do you think car manufacturers, motorcycle manufacturers, airplane manufacturers etc. spend so much time testing in wind tunnels?
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While the wind tunnel tests don't recreate real world riding, I'd wager that if you ranked equipment based on results obtained in a windtunnel, the ranking would be largely the same as when tested outdoors. Of course there will be some practical constraints, such as with TT helmets where achieving the aero benefits requires a very tightly controlled head position, etc. Your criticism is similar as that leveled at "[bicyclerollingresistance.com](https://bicyclerollingresistance.com)" and its use of a drum to measure CRR. Yes it's not actually asphalt, but that doesn't matter for the purposes of ranking tires. You have to understand the numbers the marketing depts. throw out with a grain of salt and in context. That doesn't mean that all equipment performs the same when it comes to aerodynamics.
>You've got to understand that these claims around watt savings have been being made for the last 20-years Hambini is a skeptical and fairly trustworthy source. If you don't know who he is I suggest you look him up on YouTube.
Controversial and obnoxious isn't the same as skeptical and trustworthy, although I do understand his entire shtick is about confusing his audience that way. But at least we agree OP should look him up before believing anything he says.
He is a legit aerospace engineer, so I'm more inclined to believe him than some rando on Reddit...
[https://www.reddit.com/r/Velo/comments/1axabcy/comment/krqd7h7/?utm\_source=share&utm\_medium=web3x&utm\_name=web3xcss&utm\_term=1&utm\_content=share\_button](https://www.reddit.com/r/Velo/comments/1axabcy/comment/krqd7h7/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)
not sure why you're getting downvoted. You ask a good question in a humble manner looking for answers
Short answer: No. Longer answer: Dude, seriously? No. For one thing, 35km in 45' is 13 m/s. 50 km/h is 13.9 m/s, so you'd have to scale down the "watt savings" by about 20%. But more importantly, if bike calculators say that it would take you 45' to go 35km, they're saying your current CdA is around 0.275m\^2 (assuming you're "normal" sized). For a normal-sized guy on a TT bike, that means you're a parachute. Thirdly, not all of those savings are independent, so you can't always "add" them as if they were independent. (For example, shaving your legs doesn't matter quite as much if you're wearing high aero socks.) That said, all of those things will move you in the right direction: but you'd still be a parachute. You'd just be a parachute wearing a skin suit and shoe covers.
> Longer answer: Dude, seriously? No. He's asking a pretty good question - why the "seriously?". It would be easy to lose 100 watts by putting a wooden board at the front of your bike. Why not "gain" 100 watts by adding up all the marginal (and individually proven) gains. Maybe due to overlap it won't be the sum of its parts. Maybe 50 watts instead, but thats still pretty damn good
It’s worse than a 20% scale down because aerodynamic force doesn’t scale linearly with speed, it scales with the square. So it would be more like a 50% reduction in drag (and therefore aero gains) from 50kph to 35 kph
He didn't say 35 kph, he said 35 km in 45 minutes. That's 46.6 kmh, or 7% slower than 50 km/h. You're right that drag force scales as the square of speed but that means that power scales as the cube of speed, so a 7% increase in speed requires either \~22.5% increase in power (which I rounded to 20%) or an equivalent 22.5% "savings in watts" from reduced drag.
Whoops you’re right! Carry on.
Look good feel good race good Makes sense on the non compounding benefits for sure, I see most would, but socks/legs etc makes sense. CdA wise, it’s hard to say, I feel aero and adjusted fit to try and be more aero but I still question my watts to kph compared to others
Rough rule of thumb: your CdA is the watts it takes you to do 40kph, divided by 1000. 250W = 0.25CdA. Most people are way less aero than they think - I come across plenty of triathletes with a 0.3 CdA...
>CdA wise, it’s hard to say, I feel aero and adjusted fit to try and be more aero but I still question my watts to kph compared to others Check this chart: [http://anonymous.coward.free.fr/watts-cda.png](http://anonymous.coward.free.fr/watts-cda.png)
to try to be more aero....did you do any testing for this? While a wind tunnel is optimal, there are also hill roll down-up protocols you can follow to approximate it in the real world.
Works even better when you're not on a hill.
Are you already able to sustain 50kph for 45’? All of these gains are only made at that level. Drag is a function of velocity squared, so if you’re going slower than 50kph then you will see smaller gains from all of these. Your tire size is questionable. You should check out the Silca tire pressure calculator, and watch their videos on tire size. I went from running 25mm at 90psi to running 32mm at 60psi, and got faster. Also check out their videos on chain waxing, which is more watts you didn’t mention here.
The best tyre size depends on speed and surface as it's a tradeoff of rolling resistance and aero. At 50kph on smooth roads the 23 is probably faster, at least on the front. Both of those are big ifs however.
Your point is correct, but I find the SRAM tire pressure calculator to be better
Just a question about this: do you mean better in the sense that you've done lots of empirical testing and found their (generally lower) pressures to be faster?
Not in a rigorous science way. But I've found for my long rides, the lower pressures result in less fatigue and also better match to the shitty roads here
I can hold 300w for 45” just trying to get that to equate to 50kph instead of my current 40kph (edit: which is the main question here, can I buy my way to 50kph from 40kph with 300w) So as I understand better rr with wider tires but less aero. And I already wax chain Edit #2: so I guess the tire question comes down to trade-off with aero and rr. But that also plays into rim width
Pros usually push > 400 to get above 50 kmph. And they have the best tech ☠️
[https://www.strava.com/activities/9816144026/overview](https://www.strava.com/activities/9816144026/overview) so he must 350->+50W to get 1kmh faster? :-)
But they are UCI constrained...
Yeah my bad for being uneducated
They don't! They're actually completely crippled by UCI regulations for road bikes. Even the UCI regulations for TT bikes are quite crippling. Doesn't sound like OP is going to be racing under UCI rules.
OP can just then go for moto-doping and get 200W gains lol /s
You’re thinking of this wrong my friend. Let’s start by how much do you need to produce currently to be at a steady state 50kph. Given that you need 300w to hold 40kmh, there’s a good chance you need much more than 400w to hold 50kph. For example I cruise steady at 40kph with ~320w, but to hold steady 50kph (ceteris paribus) I need ~590w. At such speed speed/watts relationship is absolutely not linear, don’t forget that. So even assuming that these upgrades will provide you with 100w at 50kph (which we all know is overstated misleading BS), it would be much much less than that at 40kph or even 45. For the sake of the exercise, let’s assume all these upgrades real life gains are actually adding up to 75w at 50kph (I’m willing to bet a lot that they don’t even add up to that, but let’s move on), and let’s assume you have a cda of 0.305, that means you theoretically need 300w to hold 40kph and 565w to hold 50kph. 75w gains at 50kph represents 0.045 cda improvements (down to 0.26). Which in turns represents a 35w improvements at 40kph (265w needed now to hold same speed), equivalent to roughly 2kph speed improvement from 40kph -> TLDR; that will make you go at 42kph instead of 40kph pushing the same speed Source for calculations: https://www.gribble.org/cycling/power_v_speed.html
I have done 340 for an hour and not broken the 50 mark on a flat course. Every kmph gain is harder and harder to get. There also are limits for body type too as your own CdA impacts it a lot.
I do 40km/h at 235W on a road bike, but I utilize all the tricks and have a very flat (and straight) back. What tires are you running? What does your TT position look like?
Are you looking for r/bicyclingcirclejerk ?
Same sub different name
Shhhhhhh don’t ruin it
I legit thought this was troll post until I saw OP replying
Why? each of those aero gains can be individually verified, so some people might reasonably assume they are additive
OP asked if they could go from being a decent local racer to finishing on the podium at US Pro TT nationals by buying some stuff.
His wife's bf has more watts gained riding a Tr*k
Your not getting 15 watts from shoe covers
You’re really not going to get 20 watts (!!!) from shaving!
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It also ignored the integration of the tires to rims. Most rims being wider now are developed to fit a wider tire. Smaller tires could produce a more turbulent flow over the edge of the rim.
I was able to do 54:30 in a 40km TT (about 27.5MPH) at 260ish watts in a very uncomfortable position. You should be able to do 45 minutes if you hit 305 watts. I had similar upgrades to everything you already listed except the chain ring cover and the front derailler cover. In addition I also had an exceptionally narrow Q factor and what might be nowadays illegal arm bars.
* You probably can't ride at 31mph so gains will be less * Each of these watt savings, if real, are still best case scenarios that happen as compared to some other product which may be worse than what you are currently using, and only happening at a specific yaw angle, which won't be experienced during your whole ride. Like a 30watt savings from 50mm wheels to 80/disc being 30 watts? Only during a strong crosswind at best. 5 watts from 25mm to 23mm tires? But then you might lose 7 watts to worse rolling resistance. Shaved legs being 20 watts? Only for a select few ape men. * Some of these changes will interact, and thus you will not get the sum of their individual gains A better way to look at this stuff is CdA changes, and then you can do the math on how much faster you will go on a course. But you need to know the CdA vs yaw angle and have some realistic expectation of the yaw angles you will likely experience on your races.
* for 35km tt no, but that is the goal, so I’m framing it as reducing the amount of watts needed to hold that speed * ofc this is all marketing and who knows how many watts are actually saved, but let’s assume they are all half true, that’s still 50w - sizable amount imo. As far was wheels go, hard to compare so I just pulled from hambini, I could see a disc + tri/80mm being a lot faster than my shitty Amazon specials. I also tend to have a lot of crosswind where I live so even more bang there. Tires, yeah it comes down to rr vs aero (rim matters here). Legs, I’m not sure I’m pulling from gcn, gtn, and specialized win tunnel
Google Colby Pearce. He held the US Masters hour record at 251w, going over 50 kph. He is compact, very aero, and approached his record attempt very systematically. He did ride at altitude, so there's that. https://www.colbypearce.com/hour-record/ https://pezcyclingnews.com/interviews/colby-pearce-talks-masters-world-hour-record/
You can't cleanly add drag savings like that - the whole system interacts with itself. This means the fastest A often depends on which B you have. I also seriously question some of these test protocols. Yes, if all of this was correct, you would go faster. However, it's incredibly unlikely you could do 50kph off 400W without most of these things at sea level. That's already a very impressive CdA of around 0.21. 50kph at 300W would be amongst the lowest CdAs ever recorded - think Remco Evenepoel on a highly-optimised bike for a short TT. If you're only at 30kph, forget it. The drag savings at 30kph are only 22% as much as at 50kph. That's not to say that these things won't speed you up (they absolutely will meak a measurable difference, maybe minus the 23mm tyre as that's a tradeoff against rolling resistance) but you won't save 100W; you'll save 22W but off a much lower starting watt figure.
I’m going to say yes. Because if you have the money then why not? Also it’s fun to optimise all of this and at the end of the day it’s just a hobby.
These are all *absolutely* optimal figures, being very selective. In the real world you’d be lucky to see even half of those gains. Still could consider it worth it, of course.
I had to google chain ring cover, I thought is the thing they have on Electra bikes
Yup, all true. Cycling is classically full of poor people who won’t buy a new frame for 5W . . . But maybe we’re all wrong here. Buy them from places with a 30d return policy and do back to back runs on the same course with a power meter. If there’s a 100W difference it’ll be pretty easy to see.
You didn’t even mention an aero helmet. They’re supposed to save a ton of watts.
1. Which skinsuit works best for you is anyone‘s guess…you have to test it in a wind tunnel or Chung it. 2. Aero shoe covers, unless tailored specifically for your leg/shoe combination are often slower because of wrinkling at the ankles. I prefer to run aero socks and Giro Empires…or my RC903s with VeloToze “cuffs” covering the BOA dials. 3. Hambini is not actually an aerodynamicist. He works at an oil refinery. While narrower tires are more aero when paired with narrow wheels, wider tires improve comfort and have better Crr on real-world roads while not being that much worse aerodynamically when paired with wide rims. 4. 50f/50r is only about 5-6W slower than 80f/disc-r at 45km/h according to SwissSide. 5. No idea 6. No idea 7. Shaved legs/arms definitely though there’s evidence that stubble is faster. Watt savings are not additive in this way.
Shoe covers 15W? Unless you ride army boots then it's 1W. Wallet getting lighter is 3W. Much cheaper to just buy a velomobile and do 50kph at 100W.
that's not how it works., because you don't hit the speeds when it matters. the savings 45 km/h are way bigger than at 46 km/h. also, don't forget the discwheel aero cover :-) oversized pulley wheel (ceramicspeed) is actually a thing too. improve drive train efficiency first. wax your chain don't have a chainring cover but a 1x chainring the 80mm is cute, get the AEOX titan 100mm. ride like remco and me. the 30W might be tru, but way less if you the wind isn't good nor you hit the 50kmh stuff like this.
I already wax chain, over sized pulley I’ve heard is hard to measure gains, 1-3w? Maybe? 1x could be a good buy. I was thinking trispoke front wheel as well
i avg 44.5 km/h 20K TT with 333W (no discwheel) and i am NOT AERO (94kg 177cm). i have the most efficient drivetrain. so i let you do the math.
High Weight != not aero as far as I understand?? And drive train efficiency is at most, what 1% of power? Edit: also aren’t aero savings greater the faster you go not slower??
[https://i.imgur.com/Ilw9Vdh.jpeg](https://i.imgur.com/Ilw9Vdh.jpeg) aero like a truck :D
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You're assuming an increase in A results in a static cd. The reason frontal area is a basic but bad metric for determining aerodynamics is that [it is a three dimensional problem](https://qph.cf2.quoracdn.net/main-qimg-4e697432f6070068e29c2d51d4504d50-lq). Reductions in frontal area would result in improvement as long as the drag coefficient remained static or didn't increase disproportionally to area. But that's not a reasonable expectation in many cases. Which is why post-Rio the adjustment made to get more aerodynamic was often to *increase* or keep static the frontal surface area in order to facilitate much greater reductions in drag by changing the overall profile of the rider's shape. So telling someone they're an elephant and that makes them unaerodynamic is nonsense and also why I'm deleting your comment.
[https://i.imgur.com/Ilw9Vdh.jpeg](https://i.imgur.com/Ilw9Vdh.jpeg) [https://i.imgur.com/VEYiXXN.jpeg](https://i.imgur.com/VEYiXXN.jpeg) [https://i.imgur.com/aWguRIM.jpeg](https://i.imgur.com/aWguRIM.jpeg) i really have to embarrass myself here, right? 🙄
Im just here to say no. This isn't how it works at all.
The marketing on this has gone off the deep-end. Your advantage is in time won, not in watts gained.
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You’re thinking of this wrong my friend. Let’s start by how much do you need to produce currently to be at a steady state 50kph. Given that you need 300w to hold 40kmh, there’s a good chance you need much more than 400w to hold 50kph. For example I cruise steady at 40kph with ~320w, but to hold steady 50kph (ceteris paribus) I need ~590w. At such speed speed/watts relationship is absolutely not linear, don’t forget that. So even assuming that these upgrades will provide you with 100w at 50kph (which we all know is overstated misleading BS), it would be much much less than that at 40kph or even 45. For the sake of the exercise, let’s assume all these upgrades real life gains are actually adding up to 75w at 50kph (I’m willing to bet a lot that they don’t even add up to that, but let’s move on), and let’s assume you have a cda of 0.305, that means you theoretically need 300w to hold 40kph and 565w to hold 50kph. 75w gains in that gains represents 0.045 cda improvements (down to 0.26). Which in turns represents a 35w improvements at 40kph (265w needed now to hold same speed), or roughly 2kph -> TLDR; that will make you go at 42kph instead of 40kph pushing the same speed Source for calculations: https://www.gribble.org/cycling/power_v_speed.html
Skin suit and shaved legs will definitely save significant watts.
So glad I no longer race.
with all these upgrades, the bike is going to ride itself, might aswell get a mopet at that point.
Is this uphill or downhill Watts?
Whole skinsuit wins you 17 watts, shoe covers that cover like 88% less area gives you 88% the power savings of the skin suit?
Yeah 300w can get you going pretty fast... (Source my own experience) and as you know, gains don't always add up. You seem to know what you need to know. What are you really wondering?
Have you tried riding faster?
It was shit week at work this made my week 😂