Any disadvantages to short cranks?

They feel less stable.

yeah, you'll have a harder time keeping good balance front to back because your feet are closer together.

170mm is what i find the best, they are shorter still stable and they give u a noticable amount of extra clearence belive it or not, i made the mistake of switching from 170 to 175 last season and im just dieing to go back

I have 165mm cranks on my Trail-or-Park and they work great for me. They don't feel unstable at all.

I would consider less torque a big con. I don't know what kind of bike you are putting them on, but why would you a want a bike that takes longer to get up to speed? Also, I personally don't think it would play to much of a role in pinching the seat. Shorter cranks for full grown people is just another dumb fad.

Shorter cranks do NOT equal less torque except for singlespeeds. Most people will compensate for shorter cranks by pedalling in a gear or two lower, which gives you the same torque (power is unchanged in either case). You should choose crank length based on either rock clearance (which is why 165mm is popular for DH) and the length of your legs (taller riders usually prefer longer cranks).

I've always ridden 180's (bmx) but my new buildup i'm running 175, not a big difference.

for fun for awhile i had a crap bike that i had kids cranks on, it was ... different lol, they must have been 140mm or so ,, they bent every time I'd bunnyhop, but i learned switch foot bunnyhops that way too, ( having to bend them back )..lol

5mm in between cranks really won't make a huge difference in the leverage or balance point, but if you really find yourself smashing your cranks to pieces, you'll need all the help you can get. 170 is the way to go.

Binaural said:

Shorter cranks do NOT equal less torque except for singlespeeds. Most people will compensate for shorter cranks by pedalling in a gear or two lower, which gives you the same torque (power is unchanged in either case). You should choose crank length based on either rock clearance (which is why 165mm is popular for DH) and the length of your legs (taller riders usually prefer longer cranks).

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Less leverage (shorter arms) equals less torque you can output, the gearing doesn't matter.

If you have a shorter crank arm you have less torque to start off from a dead stop, but you can spin faster because you you have less of a diameter to spin.

With DH the shorter arms are convenient for clearance, but really you don't need a lot of torque to make it down the hill, but you do need to spin fast when you hit those flat areas.

With DJ/Park I prefer a little bit longer arm (175-180) to allow for "snappier" take off.

To each their own

cheers

they dont feel unstable i rujn 165's the only thing i dont like is when i jump on other peoples bikes im always liie wtf's up with ur cranks, otherwise no real disadvantages

opjones said:

Less leverage (shorter arms) equals less torque you can output, the gearing doesn't matter.

If you have a shorter crank arm you have less torque to start off from a dead stop, but you can spin faster because you you have less of a diameter to spin.

With DH the shorter arms are convenient for clearance, but really you don't need a lot of torque to make it down the hill, but you do need to spin fast when you hit those flat areas.

With DJ/Park I prefer a little bit longer arm (175-180) to allow for "snappier" take off.

To each their own

cheers

Click to expand...

Of course the gearing matters - the reason bikes have gears is to allow riders to choose high-torque/low-speed combinations while accelerating and low-torque/high-speed combinations once up to speed. You accelerate faster in low gears due to the higher torque, but the speed you can reach is limited. At higher speeds you don't need to accelerate as hard but you need the higher speed, so you select a higher gear. This has less torque but even accelerating more slowly you will still achieve a higher speed than you could in the lower gear.

Your problem is that you are confusing power and torque. If a crank is a bit shorter then you can achieve the same torque by running a slightly lower gear. Power is the rate at which you can put energy into the drivetrain, and is independent of the gearing you have selected.

Binaural said:

Your problem is that you are confusing power and torque. If a crank is a bit shorter then you can achieve the same torque by running a slightly lower gear. Power is the rate at which you can put energy into the drivetrain, and is independent of the gearing you have selected.

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Nothing is confused...changing gearing is unrelated to the torque provided by cranks. Shorter cranks provide less torque. Gearing is a way to compensate for less torque...if the OP wants to buy new cranks and rings.