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Posted

Hi Guys

 

According to ergofit i need a 172.5 crank length for my road bike, i currently have a 175.

 

Is this significant or should i not worry about it? it obviously affects the drop as my seat should then be set 2.5 cm lower?

 

My crank is the brand new shimano 105 (black) which has done 240ks (ok dont shhot me for using "brand new". Should i sell and get a 172.5 or keep?

Posted

gosh im far from the pro? but really, is it gonna make that much of a diff? and do you really want to break the bank when you have a brand new like 105 there mate?

Posted

Dude I ride a 175 crank on the tandem and a 172.5 on the single - I didn't even know the tandem had a 175 on it until I re-did my seat height calculation - no difference as far as I am concerned.

Posted

You will not feel the difference. I bought a bike and only after a year I found out that my crank arm lengths differ, the one was 175 and the other 172.5. I bought the bike like that did not even notice

Posted

I've ridden with a 170 a 172.5 and with a 175and I honestly can't tell you the difference.

Don't think that 5mm can make such a difference.

 

Rather spend the money on steak..........

Posted

Closest way to calculate your seat height is the following. Measure your inseam - push the tape into the bone between your hol and your nuts :blink: and down to the floor (no shoes on)

 

Take the measurement multiply by 109% and then minus your crank arm length (17.5 in your case)

 

That will give you a measurement as close a dammit from the top of your saddle to the middle of the BB. From there it is mm adjustments to get your seat height correct.

 

Hope this helps

Posted

Closest way to calculate your seat height is the following. Measure your inseam - push the tape into the bone between your hol and your nuts :blink: and down to the floor (no shoes on)

 

Take the measurement multiply by 109% and then minus your crank arm length (17.5 in your case)

 

That will give you a measurement as close a dammit from the top of your saddle to the middle of the BB. From there it is mm adjustments to get your seat height correct.

 

Hope this helps

 

or just multiply the inseam by 0.883 = center BB to top of seat height. Makes sense that you have another calc that takes crank arm length into account... kinda ;)

Posted

Closest way to calculate your seat height is the following. Measure your inseam - push the tape into the bone between your hol and your nuts :blink: and down to the floor (no shoes on)

 

 

That is called your taint.

 

'Cos it ain't your hol and it ain't your nuts...

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