What are the pros and cons of 170mm cranks pls?

Specifically versus 175mm cranks.

Just noticed the cranks I took off my new S/M sized freeridey bike are 170mm, but the cranks I was about to fit are 175mm (like on all my bikes).

I'm guessing they help prevent pedal strikes, but any other advantages?

Better for short-arses? Might stick them on my wife's bike if so.

I think the general consensus was that they make **** all difference to most folk

more mechanical advantage. Only a bit but most times i go out i feel like i need all i can get. Would be forever blaming the cranks if they were 170s.

Had some 170's on for a while, assumed they were 175's, never bothered to check, did'nt notice any difference at all, only found out when cleaning the 170's for sale purposes some 1 1/2 years later.

Nickc has it.

Somthing for folk to think makes a difference.

They seem to come on small bikes and ladies bikes. They're on my good ladies – personally I cant see the difference. If you dont notice then why worry?

170mmshorter arm which gives you more control at connering in DH runs and when you do drops
however its depends on what kinda stuff you doing and your how high your bb is on your frame
I use 170mm on road, jump and DH/FR bike and 175mm arms on my xc/trail bike

The original purpose is shorter riders = shorter cranks, taller riders = longer cranks. If you have short legs you don't want to be spinning in a big circle. If you ride an MTB that fits & has correct length cranks that are 175mm, a road bike that fits is likely to have 170mm. Reason being, I would think, is that shorter is also better for spinning fast, longer is better for leverage that you need more of on a MTB. They come in other sizes too. But years back I had some 170mm coz they were on sale, really couldn't tell any difference at all. I guess there's a point to slightly better clearance, but avoiding pedal strikes is more about technique, in that if you clout pedals all the time, 5mm less isn't going to solve it!

Best excuse I've heard from an ex roadie avoiding a MTB ride – "I can't hire a bike because I need 175mm cranks", not realising that they're pretty much standard on a MTB. Real reason? Ultra competitive Aussie who didn't want hi lack of fitness to be seen by all! Not that anyone cared!

That 5mm must make sooooo much diferance 😕

Ask a female friend about the said 5mm.

I've got mid to long legs (6ft 2 or so tall) and I've used cranks between 180 and 165mm. Difference is just noticaeble (TINY bit harder to turn a gear as they go shorter and correspondingly a TINY bit easier to spin a lower gear faster) but unimportant to me

Search Function Broke? 😉

Crank length is, or isn't, a big deal for you depending on the person… Some people notice it, some don't. If you do, you'll know about it, if you don't, I wouldn't worry.

But on a long travel full sus bike you're more likely to hit your pedals on the ground/rocks with longer cranks…

I fit them on my downhill bike and don't notice any difference when pedalling

yesq they are a massive improvement… for your wallet

170s save the planet, by using less metal.