cranks 175mm vs 180mm

alibabameister

Hi
Replacing a chainset and almost worth getting a chainset with cranks and wondering if I should get the longer armed cranks and what benefits I would see?

Cheers

AL

coulddobetter

If 175 now suits stick with it . Moving up could actually cause biomechanical I.e knee problems . You would potentially have a slightly lower gearing effectively ( don't ask me to explain the physics ) . There's a greater risk of pedal catching obstacles . You would be spinning at at a lower cadence ( not always efficient .

cooldad

I doubt you'd even notice the difference.

mac-cos

Isnt 180mm seriously long ie for super long legs ? You might need to give more info to help the info givers. ie leg lenght, use , bike? I understand from my internet wanderings that the (road) pros are moving to shorter cranks and if off road use shorter cranks may help avoid pedal strikes. Id agee on the potential knee issues it may bring as your knees will have to rotate around a larger circumference which will also put more acute angles into the hip and knee joints as your saddle should be lower to compensate for the lower pedal.

alibabameister

Rider = 98kg 6' 2" with a 34" inside leg
Bike = 2008 specialized enduro large frame used for everything from xc to trails in wales

nicklouse

why do you think you might want longer cranks?

what has made you think about it?

alibabameister

I need to replace the drivetrain (sprockets chain etc) and can get a crankset with a bottom bracket for not a lot more than the cost of the front chainrings

alibabameister

I need to replace the drivetrain (sprockets chain etc) and can get a crankset with a bottom bracket for not a lot more than the cost of the front chainrings and just saw different options available so was wondering if it would be worth changing things

YeehaaMcgee

What crankset are you looking at? you can get 3 chainrings, for about £40-£50.

welshkev

YeehaaMcgee wrote:

What crankset are you looking at? you can get 3 chainrings, for about £40-£50.

superstar have them on offer at the minute for £30 for the 3 (obviously depending what size he wants)

nicklouse

alibabameister wrote:

I need to replace the drivetrain (sprockets chain etc) and can get a crankset with a bottom bracket for not a lot more than the cost of the front chainrings and just saw different options available so was wondering if it would be worth changing things

OK but what makes you think 180mm cranks? why would you?

most people on Spesh bikes claim they need shorter cranks as the BBs are so low. (which is just poor pedaling).

if you saw some cranks at 170mm would you be asking about them?

crank length does not matter too much on an MTB unless you are someone who sits down all the time just spinning the cranks. (Roadie).

alibabameister

I've been looking around and have seen some deore ones for 60 to 70, but really like the xt ones for about 120.

I just thought the longer cranks would give more leverage and be easier to pedal, currently have 175mm ones and don't really have any issues regularly hitting stuff with the cranks.

What are the superstar or trailbright or middleburn ones like, are they as good as shimano and should I really have a steel centre chainring and will it be ok to mix different makes of chainrings? currently got 22, 32, 44 seen 24, 32, 42 will this be ok?

Tallbikeman

I'm 1.95 meters tall and have ridden 180mm cranks for decades. Even when I raced road I used 180mm cranks because I felt best while riding this size crank. I tried 190mm cranks one time but they hurt my hip joint. 175mm cranks also work well but that 5mm does make a difference for me. This is such an individual experience topic. Go ahead and try some 180mm cranks and see if you like them. If not try some other length. The one thing a longer or shorter crank won't do is make you faster. Only proper physical conditioning and training are going to make you faster. I've heard all kinds of stories about pros using shorter cranks for more power. Like a car engine more rpm equals more horsepower and I guess the same is true to some extent for human "engines". As far as ground strikes with the cranks or pedals while mountain biking I never had issues with that and I raced for about 4 years here in Northern California. My racing mountain bicycle had a low bottom bracket and 180mm crankset and I never hit anything. At the mountain bicycle races I've seen cranks and crank axles torn out of frames by a rock strike but I was lucky and always timed my pedaling to the objects. It has been a long slow process getting bicycles to represent what I want to ride and the end target is always changing.

tom_howard

My racing mountain bicycle had a low bottom bracket and 180mm crankset and I never hit anything.

Hardtail or full suss?

(Holy thread resurrection etc)

JBA

Tallbikeman wrote:

Go ahead and try some 180mm cranks and see if you like them. If not try some other length.

I suspect the OP may have got new cranks during the last 6 years!

robertpb

In other news Mafeking has been relieved