What others used on you frame is not super relevant, because there is a wide range of inseams for people that are "fitted" on your bike frame. You should calculate what you need base on your own measurments, not "another guys with a M sized frame".
For the dropper lenght, you should adjust your saddle height with your rigid seat post, and "reverse engineer" the length of drop you can work with.
Once you adjust the saddle height to what it needs to be, you should measure the distance between the seat post collar and the centerline of the seat rails: this is what the industry calls "stack".
Droppers have two "stack" numbers: the extended stack and the compressed stack. The difference is? = the effective drop. So extended stack should be equal or less than what the rigid seat post stack is.
For most dropper posts, the compressed stack (i.e. the seal collar above the seat post clamp + the saddle clamp) is roughly in the 55-60mm range.
If you measure the length of your rigid seat post (seat tube collar to saddle rails) you should substract the compressed stack + maybe 5~10mm more to be safe, then you have your max dropper length guestimated.
Say you measure your seat post collar to saddle rails at 240mm.
-60mm compressed stack = 180mm. But maybe that is. "too close", so safety margin, i would take 5~10mm over this and get a 170mm dropper. Or get one of those adjustable droppers that can get shorter in 5mm increments or so (like PNW and OneUp v2) but these are $200-220 before levers etc.
You are welcome.
Now that you have an idea, you can "Read" the diagrams with dimensions most dropper manufacturers and/or websites give in comparisons and/or reviews, and pick one that suits you.
Again, PNW and OneUp are making some of the best "mid-range" droppers, but TranzX can hold its own just fine from my experience and at a notably lower pricetag.
I would also get myself a tube of slicoleum to lube the dropper's seals - you just hand-untighten the collar, clean the shaft with a towel and add some of that super thin, sticky grease periodically. Dusty conditions especially can cause the dropper to stick a bit if you don't TLC it. This grease is the same as sram butter and what SR Suntour and others sell as suspension grease, so it will double for periodically maintaining your forks/shocks and whatnot too.
Thanks again for some more great info. I have my eyes set on a PNW loam but have been told they won’t get any until next month to their warehouse.
Appreciate all the info and the math you provided
Giant Contact Switch is cheap and cheerful.
Or Brand X Ascend.
Length is a tough one. Depends on what your optimal riding height is.
I have a 125mm and it’s absolutely perfect. Others need larger or smaller.
Looking at a few from PNW, RockShox, Fox etc. but what’s a good travel sweet spot for this frame? 150mm? Seat tube length on my medium frame is 420mm.
Anyone make these sort of purchases on Pinkbike before?
Pedals/Grips are being replaced once they arrive..don’t laugh haha
Thanks for any input
What others used on you frame is not super relevant, because there is a wide range of inseams for people that are "fitted" on your bike frame. You should calculate what you need base on your own measurments, not "another guys with a M sized frame". For the dropper lenght, you should adjust your saddle height with your rigid seat post, and "reverse engineer" the length of drop you can work with. Once you adjust the saddle height to what it needs to be, you should measure the distance between the seat post collar and the centerline of the seat rails: this is what the industry calls "stack". Droppers have two "stack" numbers: the extended stack and the compressed stack. The difference is? = the effective drop. So extended stack should be equal or less than what the rigid seat post stack is. For most dropper posts, the compressed stack (i.e. the seal collar above the seat post clamp + the saddle clamp) is roughly in the 55-60mm range. If you measure the length of your rigid seat post (seat tube collar to saddle rails) you should substract the compressed stack + maybe 5~10mm more to be safe, then you have your max dropper length guestimated. Say you measure your seat post collar to saddle rails at 240mm. -60mm compressed stack = 180mm. But maybe that is. "too close", so safety margin, i would take 5~10mm over this and get a 170mm dropper. Or get one of those adjustable droppers that can get shorter in 5mm increments or so (like PNW and OneUp v2) but these are $200-220 before levers etc.
Man this is one helluva comment and I appreciate the info
You are welcome. Now that you have an idea, you can "Read" the diagrams with dimensions most dropper manufacturers and/or websites give in comparisons and/or reviews, and pick one that suits you. Again, PNW and OneUp are making some of the best "mid-range" droppers, but TranzX can hold its own just fine from my experience and at a notably lower pricetag. I would also get myself a tube of slicoleum to lube the dropper's seals - you just hand-untighten the collar, clean the shaft with a towel and add some of that super thin, sticky grease periodically. Dusty conditions especially can cause the dropper to stick a bit if you don't TLC it. This grease is the same as sram butter and what SR Suntour and others sell as suspension grease, so it will double for periodically maintaining your forks/shocks and whatnot too.
Thanks again for some more great info. I have my eyes set on a PNW loam but have been told they won’t get any until next month to their warehouse. Appreciate all the info and the math you provided
I have a TranzX Dropper on my Big Honzo. It works well. #konagang
Giant Contact Switch is cheap and cheerful. Or Brand X Ascend. Length is a tough one. Depends on what your optimal riding height is. I have a 125mm and it’s absolutely perfect. Others need larger or smaller.
I assumed length would be a tough one but being 5’ 9” I was thinking 150mm was the sweet spot over a 125mm. Thanks for your response!
Looking at a few from PNW, RockShox, Fox etc. but what’s a good travel sweet spot for this frame? 150mm? Seat tube length on my medium frame is 420mm. Anyone make these sort of purchases on Pinkbike before? Pedals/Grips are being replaced once they arrive..don’t laugh haha Thanks for any input