Sulliotti Posted March 16, 2017 Report Share Posted March 16, 2017 Hey! I have a question, but also I want to understand the "why" of this. Bike: Play KII (20') with Jitsie components Cranks: 172mm - I have this lenght of cranks in my bike and i used them since 4 years.. But, upon checking new complete bikes I noticed that all the mod bikes used 160 or 165mm. What is the best choice for this bike? And why is better to use shorter instead of the172mm? Those this make a big difference? Thanks! I'm the only Mod rider in my country so I have discover this things by myself hahaha Cheers Quote Link to comment Share on other sites More sharing options...
jeff costello Posted March 16, 2017 Report Share Posted March 16, 2017 i'm not really qualified to speak on the ups and downs, but i run 170mm ones on my mod too. no problems & i like them. i chose the longer ones, because i like to ride a pretty high gearing. Quote Link to comment Share on other sites More sharing options...
Herbertlemon102 Posted March 16, 2017 Report Share Posted March 16, 2017 in general, 175mm is for stock to match the ratio of the gearing and wheel size, whereas mod are 165mm for the same reason, just a smaller wheel and thus smaller cranks. 170/175mm cranks on a standard setup mod (18:12 gearing) will feel "light" and some prefer that feeling of a bit more leverage. but you wont be going any faster. haha Quote Link to comment Share on other sites More sharing options...
ItsMatt Posted March 16, 2017 Report Share Posted March 16, 2017 here's what roadies use. I like to stick with 175's on my road bike and 24", I'm 6ft 1" and I feel like it gives me a bit more room to move around. Quote Link to comment Share on other sites More sharing options...
bing Posted March 17, 2017 Report Share Posted March 17, 2017 It's personal preference. There are no rules for it. I ride a mod now, and on all the mods I've had in the past I've had 170mm cranks on, got 170mm cranks on my mtb, and got 172.5 on my roadie, so can't really tell the difference. 160mm cranks on a mod feel too short for me, I'm 5' 10" tall 1 Quote Link to comment Share on other sites More sharing options...
ogre Posted March 17, 2017 Report Share Posted March 17, 2017 i've currently got 170s in my 20" and 26", but i'm 6ft tall and tend to choose the longer/bigger options. i'd guess they usually spec a shorter crank for a mod cause they're usually aimed at smaller riders. the normal rules for cranks go out the window for trials though... 2 Quote Link to comment Share on other sites More sharing options...
Sulliotti Posted March 17, 2017 Author Report Share Posted March 17, 2017 7 hours ago, ogre said: i've currently got 170s in my 20" and 26", but i'm 6ft tall and tend to choose the longer/bigger options. i'd guess they usually spec a shorter crank for a mod cause they're usually aimed at smaller riders. the normal rules for cranks go out the window for trials though... Yeah, I'm actually 5.5ft tall, maybe I should use the 165cm... just to see how they feel if not I'll sell them, Thanks for the help everybody! Quote Link to comment Share on other sites More sharing options...
kevind Posted March 17, 2017 Report Share Posted March 17, 2017 Again not to qualified on this. when the riders are younger longer cranks mean easier leverage? and a by product that its easier to get the pedal down to rest? Older riders can gain more strength and therefore can lever a smaller crank over a shorter distance to get more power/lift.? by product that it is less easier to get a pedal down? Quote Link to comment Share on other sites More sharing options...
Greetings Posted March 17, 2017 Report Share Posted March 17, 2017 Long cranks on a mod feel a bit like pedaling in a pair of wellingtons. It's a matter of preference but short cranks suit small bikes much better IMO. To give you some idea, I've been running short cranks (158-160) and a light gear ratio (17:16) on a 26" bike for ages, know of a few very powerful riders who use 160 cranks on 26" bikes with an 18:16 ratio to great results. If you have a lot of strength, a short crank will turn that into more power because the movement will be quicker. With longer cranks, you can make up for strength with speed. Another thing is stability. If you pedal quickly on short cranks, you're going to maintain balance much easier especially if you're short. I guess that doesn't apply nowadays when trials is pretty much static. But any rolling moves will feel more comfortable on short cranks than they will on long ones. Also, match the length to how tall you are. I'm slightly under 180cm, have short legs and never got on with long (170 or over) cranks. Come to think of it, all the riders mentioned above are short too. So perhaps their choice of short cranks is not so much a matter of excessive strength, as it is of being vertically impaired. This doesn't apply to mods where the gear ratio is pretty much fixed but on a side note, I spent a lot of time playing around with various ratios and crank lengths and found that this gives you endless possibilities in fine tuning the bike to your strengths and weaknesses. You can go from relying on your drivetrain (heavy ratio and long cranks) to relying entirely on body movement via medium length cranks and a 1:1 ratio, or anything in between. You can generate power through fast light movement or through short powerful bursts. The alternative is to just man up, go to the gym and ride more But I'd still recommend that anyone who has the opportunity and feels stiff on the bike to ride a 1:1 ratio (or 18:14 on a mod) for a month or two. You find that kicking the pedal does absolutely nothing, it's all about the body movement and speed. 1 Quote Link to comment Share on other sites More sharing options...
Rebelistic Posted March 21, 2017 Report Share Posted March 21, 2017 (edited) I'm not sure why mods tend to have shorter cranks, probably more down to convention and aesthetics than anything else (makes the 18/12 gearing acceptable whereas with 175mm cranks it's a bit light). I've decided to run 19/12 with 170 cranks on my Alias that gives me an equivalent gearing very slightly higher than normal as I wanted a more streety setup. Thinking more about it, the crank length kind of changes riding position too (feet closer together or further apart) and range of movement. Edited March 21, 2017 by Rebelistic remove waffle 1 Quote Link to comment Share on other sites More sharing options...
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