Another MTB --> commuter conversion. Questions

Lot of myths floating around about crank lengths on bikes........... It's a subject that is actually worth researching properly rather than just quoting others who haven't actually looked into it properly (or who don't understand the system.)

I'm beginning the change to 165 on everything (7 or 8 bikes to change). As there is no actual downside to going shorter (power, cadence, leg speed, climbing, TTs, all either unaffected or improved, unless you do something daft like 100mm cranks......), but longer can cause issues.

https://www.trainingpeaks.com/blog/the- ... nk-length/

And there is nothing about MTBs that stops you spinning a high cadence, i'll happily hit 130+ on my HTs. FS or longer travel makes it a little trickier unless it's locked out......

Re: Re:

hamster":3uydi21a said:

Cranks need to be fitted to leg length, then gears do the rest.

Click to expand...

Yes agreed and also your assertion about mechanical advantage via gears. Reason for my statement about longer cranks aiding climbing as a response to your '175s are a no no' is not - as someone has impolitely suggested - being due to not looking into it properly, but rather because i had a particular experience where it made sense to fit 175s and insodoing gained a bit. The bike in question had the chainset ring sizes i wanted and i'd already fitted the largest possible cassette which the original short cage mech could accomodate, i didn't want to swap out the mech for a mid cage to accomodate a larger cassette wanting to maintain a certain originality in the look of this particular bike. So the bike was geared as low as i could get it without 'spoiling' it's originality, as i saw it. It had 170 cranks. I could ride those, no big deal but by swapping to 175 (similar design) which i know i can ride without any problem, i was able to gain extra leverage via crank length. Hence my comment that longer cranks can help in climbing isn't as 'unresearched' as it might sound, however modest the gains may be (175 is 3% longer than 170).

165s being great for higher cadences on the track is valid for sure, not sure how relevent that would be for an MTB commuter though.

People suggesting others don't know what they are talking about may be advised to excerise a little more restraint. There can be good reasons for going shorter and good reasons for going longer, depending on circumstances. Positive discussion is healthy.