Crank length

A.J.T.73 said:

I have a giant scr 3.0, with a 175mm crank. I was wondering what would happed if i changed it down to a 160? as i would get better turning and better saddle height.
Thanks
Alex

Where will you buy 160mm Road cranks? 😕

You must have very short legs to need 160mm, how tall are you?

OK, i agree now after looking thats quite silly.
You can get 165mm and loads of 170's. I am 5 foot 8 inchs.
What are the pros and cons of getting shorter crank arms?
thanks

A.J.T.73 said:

OK, i agree now after looking thats quite silly.
You can get 165mm and loads of 170's. I am 5 foot 8 inchs.
What are the pros and cons of getting shorter crank arms?
thanks

There is a correct length crank for each leg, it is part of bike sizing and bike fit. You will be 172.5 or 175mm depending on leg length.
http://www.giant-bicycles.com/en-AU/technology/compactroad_new

Unless you are having your legs re-sized, shortened, there is no point in going for shorter cranks. :eek:

George, looked at the link you provided, couldn't see anything on crank length...

I'm curious because I have very long legs considering I too am 5'8" and have been considering going to a 175 instead of 172.5.

One of the links down the bottom talks about component choice and rider size: http://www.giant-bicycles.com/en-AU/technology/fivepoint_new_2/

Quoted post said:

5. Are the specifications and features suitable to the level and type of performance required?

In our COMPONENT selection, we are certain to choose the right parts to deliver an unparalleled experience. Everything on our (women’s) bikes, from handlebar width to crank length, has been specially selected.

There are many crank length calculators available on the net. I use the one on the Greenspeed page.

gclark8 said:

There is a correct length crank for each leg, it is part of bike sizing and bike fit. You will be 172.5 or 175mm depending on leg length.
giant-bicycles.comcompactroad newOpen ↗

Unless you are having your legs re-sized, shortened, there is no point in going for shorter cranks. :eek:

Correction...

There is a standard recommendation for crank length... 😉

Look at any sizing site, and if it says anything about their numbers being right for everyone, then find another site. Any online fitting is a recommendation to get you into the right ballpark, and a site should be clear about that.

Shorter cranks can be beneficial for spinners (higher RPM possible due to less pedal movement per revolution) where longer may be better for mashers (lower RPM, but higher leverage).

Read other forums, and you will find some people ride different crank lengths depending on bikes usage. Usually shorter for road riding than mountain biking for example.

You will also find riders that have different crank lengths on different road bikes and feel comfortable on all of them.

I just had a bike built with 105 and the shop asked my inseam and suggested 172.5... Looking at my metric ruler, I find it hard to believe that 2.5 mm is going to matter much compared to the 170's I have been riding. But I don't expect to be able to tell a difference, so I went with their recommendation.

30 years ago, the majority of riders had no idea that there was a rule concerning crank lengths, and rode whatever their bikes came with. And we still had fun riding. 🙂

Quoted post said:

I just had a bike built with 105 and the shop asked my inseam and suggested 172.5... Looking at my metric ruler, I find it hard to believe that 2.5 mm is going to matter much compared to the 170's I have been riding. But I don't expect to be able to tell a difference, so I went with their recommendation.

Thank You! :p

A.J.T.73 said:

I have a giant scr 3.0, with a 175mm crank. I was wondering what would happed if i changed it down to a 160? as i would get better turning and better saddle height.
I'm 5'8"

in my opinion, 175 would be way too long for you, unless you have freakishly long legs. Definitely worth looking at shorter cranks

As you say, the big advantage is a better saddle position.

I'm 6ft with long legs, and I went down the 'long crank' obsession for a while, ending up with 180s for about a year. I gave it up as a bad joke; went back to trying 175, 172.5 and 170s, and have pretty much settled on 172.5s because I like the position they put me in. I feel like I can get nice and high over the pedals with the 172.5s and pound the [censored] out of them. I sometimes ride 175s, but they feel a little long for me now.

531Aussie said:

in my opinion, 175 would be way too long for you, unless you have freakishly long legs. Definitely worth looking at shorter cranks

As you say, the big advantage is a better saddle position.

I'm 6ft with long legs, and I went down the 'long crank' obsession for a while, ending up with 180s for about a year. I gave it up as a bad joke; went back to trying 175, 172.5 and 170s, and have pretty much settled on 172.5s because I like the position they put me in. I feel like I can get nice and high over the pedals with the 172.5s and pound the [censored] out of them. I sometimes ride 175s, but they feel a little long for me now.

I'm 6'3" and 175 is perfect for me.