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[Mudsimus]

How big is the differance between 172,5 and 175 cranks?

Is there a website with all the pros and cons? I'm 1,8m and if the cranks wont work.....make me a offer...105 10sp cranks with bb

[wannabepro]

How big is the differance between 172' date='5 and 175 cranks?[/quote']

 

 

 

Ammmmmmmmm ammmmmm.........2.5??????????

[nellie]

Let me see...175-172,5 = 2,5????

[nellie]

Wannabepro:

[bikemonster]

The difference is erm, 2.5mm. 

 

That makes for a 5mm difference in diameter, and a 22/7 * 5mm increase in radius.

 

FWIW, when my latest bike had 172.5mm cranks instead of 170mm, my cadence dropped.  I am 1.7m tall. 

 

Pro of going to longer cranks is that you get more leverage.

 

The cons are that you may make your knees and hips work a bit more to accommodate the larger radius that your feet will be travelling.

 

Neither pro nor con, but a difference, is that cadence can be expected to go down with longer cranks.  If you are a spinner, you are prolly better off with the shorter cranks, if you are a power rider you are prolly better off with longer cranks.

 

 

[Thyolo]

Thanks you 2 - made me laugh out loud and attract strange looks 

[Mudsimus]

You are all a bunch of clowns.....better of asking my dog..

[nellie]

You talk to animals??? Cool!!! Can you talk to cats and pigs too??

[bikemonster]

You talk to animals??? Cool!!! Can you talk to cats and pigs too??

 

Talking to animals is very easy Nellie.

 

 

 

It's understanding the replies that gets a little tricky.

 

[nellie]

that's what i meant okay!!! (...'n goeie begrip het 'n halwe woord nodig!)

[DRIVETRAIN]

 

I am too in the process of upgrading from 170 to 172.5 cranks 10sp...(not fitted as yet)

 

I posted some concerns I had as well but the most positive thing to come out of the replies was that guys who have gone from 170 - 172.5 feel good about the upgrade---providing I stay with the 52 ring...

 

The cons are that you may make your knees and hips work a bit more to accommodate the larger radius that your feet will be travelling.

 

Bike max would you then say it will have an adverse affect on my knees & hips ??? I do enjoy "spinning" & not grinding big gears..

 

"DT"

 

 

[Mudsimus]

Thanks DT.

[Gumpole]

I went from 170 to 175 and the difference is hardly apparent, although short power climbs are much better!

[bikemonster]

That's bikemonster you're quoting, not bikemax!

 

Anyhoo...

 

"Adverse" effect is prolly overstating. 

 

For me, I had a really pleasing summer of cycling last year, so I was reluctant to change my bike set up.  The new bike arrived with 172.5 but I did not worry too much 'cause I knew I was planning on upgrading the gruppo anyway.  I rode maybe 300km with 172.5, and always felt sluggish with it.  There were no issues with discomfort or lack of flexibility.

 

When I duly upgraded and went back to 170 the pedalling circle felt "small" at first, but I have been pleased that I did.  My cadence came back up (usually average around 100 rpm according to my Polar) and I am satisfied that I made the right decision.

 

Like everything in cycling, there is a hefty dose of "fashion" in crank length size, and some of the references that I googled gave me the impression that 10 - 15 years ago cyclists were riding 2.5mm shorter cranks across the board than they now do.  The prevalence of MTBing may have something to do with that, as MTB cranks are typically longer than road cranks for increased leverage.  I guess (and it is just a guess) that people decided that they would prefer the same crank length for road and dirt.

 

The effect of the chainring is negligible.  If you are looking at the difference between a 53 and 52 tooth ring, that is a difference of less than 2%.  If you're a spinner, I do not believe that you could feel the difference between spinning at 99rpm and spinning at 101rpm at a given road speed.