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PostPosted: Wed Feb 14, 2007 10:49 am 
Social Secretary
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Location: Kent
Morning all,

I have a set of Topline cranks 130 BCD and 170mm length that I want to use for a single speed project, I think I can get a 36t chain ring so does anyone see any issues with this. I know most MTB’s have the longer crank length (175) and that basically these are road cranks but is there any reason why I shouldn’t try them ??

I also read somewhere that the shorter crank length is only useful on a mountain bike for people of hobbit stature, is this going to cause me issues being quite tall ??

Cheers


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PostPosted: Wed Feb 14, 2007 11:17 am 
Gold Trader / PoTM Winner / RB Rider
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main problem you are going to have is that the cranks are probably going to touch the frame .
one way to sort this out is to use a longer BB , but you might have a problem with the chain line .
MTB frames are wider at the BB for bigger tyre clearance , so road cranks do touch the frame .

and IMO 170 is top small for you .


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PostPosted: Wed Feb 14, 2007 11:19 am 
Retro Guru
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I can't imagine 5 mm being of noticeable difference, It's only 1/5" in old money!

I guess that you'll have to put the tiniest amount of extra effort in as you'll have less leverage from the cranks and also you'll have to spin in slightly smaller circles.

Your knees won't come up as far when your at TDC.

You'll have more crank/ground clearance.

Anything else.....?


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PostPosted: Wed Feb 14, 2007 11:21 am 
BoTM Winner
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well , i have some lx cranks on the pine mountain , been using them since 95

and i only noticed they were 170 last year :roll:

and i am 6`2"

not noticed any problems :D


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PostPosted: Wed Feb 14, 2007 11:25 am 
Retro Guru
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Just a thought.... How long are your legs?

When your cranks are pointing forward the front of your knee is supposed to be over the axle of the pedal, this might not be right for you with shorter cranks.


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PostPosted: Wed Feb 14, 2007 11:32 am 
Pumpy's Bear
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I've read that all your bikes should be set up to within 2mm all round but doubt that this is critical (or even necessary) unless you are a super serious athlete and probably not even then.

As above, doubt that you'll even notice 5mm difference unless you are very sensitive to the set up of your bike. Just adjust your saddle slightly and off you go.


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PostPosted: Wed Feb 14, 2007 11:32 am 
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I'm 6"2 and my inside leg is about 33" ...

I'm going to have to speak to the LBS about the rear wheel anyway as I haven't got a clue what I'm doing so I'll check about the BB and Cranks at the same time I guess...


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PostPosted: Wed Feb 14, 2007 11:36 am 
BoTM Winner
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as i said 170 on the pine , 175 on all the others

never noticed any difference ???


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PostPosted: Wed Feb 14, 2007 11:41 am 
Gold Trader / PoTM Winner / RB Rider
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it is all in the head guys . :lol:

I dont even know how long my cranks are . :oops:


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PostPosted: Wed Feb 14, 2007 11:46 am 
Mr Darcy
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..or how long my legs are, how thick my cleats are, how high my seat is etc

Its all set up perfectly, but by feel :D


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