I am looking to build up a bike for travelling. Trips will vary between road rides and gravel bikepacking. I will need to remove the handlebars and fork in order to pack the bike in the bag I intend to travel with. For bikepacking, I currently have a Salsa Cutthroat with 100mm of suspension and that suspension makes such a difference that I think for gravel riding I would like to use the Fox 32TC suspension fork.
Looking at the best geometry for the bike, current wisdom suggests that I want suspension corrected geometry so that I can swap the Fox 32TC suspension fork with a fork like the No.6 Gravel Correct fork for when riding on the road. However, would it not be better to have suspension anticipated geometry (or similar branding) so that I have different geometries between road and gravel mode? So a frame with an 80mm BB drop, 72.5 degree HTA, 75 degree STA and ca.60mm trail with a rigid 398mm A2C fork in road mode will have something like (relying on AI here so could be wrong) a 70mm BB drop, 71.2 degree HTA, 73.6 STA and ca. 70mm trail with a 40mm suspension fork, which has a longer 435mm A2C.
What do people think? Anyone tried this? Thanks
I’d suggest consider what setup you’ll use for the majority of the miles and go from there. Because optimizing for both setups ends up with a bike that is not great at either.
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A 20mm increase in A2C fork length will decrease head and seat tube angles by 1 degree, increase BB drop by 7mm, and decrease reach by 13mm. So your head angle, for example, would decrease by 1.85 degrees going to a suspension fork, to 70.65, and so forth with the rest of the calculations. I think it’s not plausible to go back and forth as you would have to adjust your seat position and angle and your position on the bike would change significantly. I’d just pick a setup for what you’re going to be doing most of the time and go with that. If you have a diverse biking need, like for more of an XC experience, you could get a second bike if that would fit your space and budget restrictions.
Unlike others here, I think your idea has potential, provided you are comfortable with your saddle being slightly nose-up or nose-down in one or both modes or you are happy to twiddle the angle every time.
Road set-ups lean towards forward, long and low nowadays while I prefer off-road/ gravel handlebar positions that are higher and a touch closer. Changing fork length does both of those things. The current fashion for super-steep seat angles in the dirt puts too much weight on my hands for distance riding, so a more rearward saddle is my preference. YMMV
Thanks Bruce - definitely at risk of over-thinking this…!
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Thanks Ronan - I was actually thinking that I would have two seatposts/saddles and two stems. I’m taking them out/off to pack anyway, so seems relatively simple to just select the right set-up and not have to worry about re-dialling in the fit each time.
Thanks Dave. I think perhaps designing the bike to work really well for one use case (endurance road for me) is likely the best idea and then it is relatively low risk (compared to the price of a frame) to see how it performs with the longer fork in. It does seem possible on paper, but an expensive mistake if it just makes for a bad bike in both set-ups, so dialling in one set-up and experimenting from there seems lower risk. I suspect most people don’t go this route because taking the fork out is likely too much hassle for people to be regularly switching, but with a travel bike I’ll be taking the fork out anyway. With zeno couplers, it should be a really easy swap.