Hello all! So currently I have 145mm cranks on my triathlon bike and 165mm cranks on my road and gravel bike. In short, is this good or bad? Should I go down to 160mm cranks on the road and gravel bikes? Or even 145mm? I can feel that their is an adjustment period when switching between bikes. I’m not worried about hurting myself, I just want to train as effectively as possible.
Note: I cannot and should not go above 145mm cranks on the Tri-Bike per my bike fitter and a minor back injury.
Hello all! So currently I have 145mm cranks on my triathlon bike and 165mm cranks on my road and gravel bike. In short, is this good or bad? Should I go down to 160mm cranks on the road and gravel bikes? Or even 145mm? I can feel that their is an adjustment period when switching between bikes. I’m not worried about hurting myself, I just want to train as effectively as possible
If it feels fine to you then you will be fine. I went from 175mm to 165mm on my road bike. I still have 175mm on my MTB. While I do kind of want 165mm on my MTB I’m probably not going to spend the money, and it is totally fine.
I’ve heard of experiments in which adult athletes went all the way down to ~85mm before any noticeable loss in power output. I’d have to dig around to find it though. My only concerns (& this is my bro-science thinking so not to be relied upon) would be possibility of losing flexibility & reduction in capacity to output power at the extremities of your range of motion if the tri is your main training bike, where those more extended & more contracted muscle positions are not being used, which may become a problem on the bikes with longer cranks. Ignore all that if you do regular stretching exercises.
A lot of people do go to shorter crank lengths on a tri bike to help with running off of the bike.
Some things to consider:
165 to 145 is a pretty substantial jump. That sounds like it might be difficult to adjust from one to the other. I have 172.5 on my road bike and 167.5 on my tri bike.
The people that are moving to shorter cranks might not necessarily be keeping the same crank length on the road bike that they ride. So if someone moves from a 175 mm to a 172.5 mm that might make the change for both the road and tri bike.
If you feel it’s working for you, I don’t know if I’d switch things up.
Has your fitter given an opinion on if moving to a different size crank length for a road bike would impact your back injury too?
In my 17-year-old-self’s experience of switching back & forth between my mountain bike’s 115mm cranks (there’s a story to that) & the 170s on my road bike, the change felt weird for only about 5 minutes if I rode both bikes multiple times per week.
I ride 155s on my TT bike having moved down from the 170s it came with, quickly to 165, then 160 and now 155s, I have ridden 165 on my winter bike since the early 2000s, and 170s on my normal road bike from a similar time. I have been happy to swap across these as and when. Oddly my old MTB bought c2000 had 175s and I did not notice until a few years ago.
I am about to change the road bike 170s to 165s. However I think people adapt and swap with little difference,e specially when tucked in on a TT position.
It’s all about fit, so if your other bikes are well fit even with much longer cranks then you’re okay. If you have significant flaws in your ride position on those other bikes then you’re not okay.
