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Replacing crank arms
#1
Haven't rode in years, just bought a new MTN Bike and the pedals are a longer distance apart than I was used to.....I want to replace the crank arms w/shorter ones and are the fittings universal? and where can I purchase them?
  Reply
#2
No fittings are not universal. Amazon, bike shop, and many other places.

Are you saying the pedals are too far apart side to side; or the length of the crank arms are too long?

Crank arms are normally 170mm long, 175mm is the next most common size, and there are many others. There are several interfaces between the cranks and the bottom bracket, most common being square, but within square there is diamond with the points lined up with the arm, and square with the flats lined up with the arm (45° rotation). Then there is Octalink and ISIS, and ......

Before anyone can assist you, we need to have pictures and a great deal of information about the bike you purchased.

The obvious question is: why did you purchase it if it doesn't fit you? And why can't you take it back?
Nigel
  Reply
#3
(07-04-2014, 11:33 PM)nfmisso Wrote:  No fittings are not universal. Amazon, bike shop, and many other places.

Are you saying the pedals are too far apart side to side; or the length of the crank arms are too long?

Crank arms are normally 170mm long, 175mm is the next most common size, and there are many others. There are several interfaces between the cranks and the bottom bracket, most common being square, but within square there is diamond with the points lined up with the arm, and square with the flats lined up with the arm (45° rotation). Then there is Octalink and ISIS, and ......

Before anyone can assist you, we need to have pictures and a great deal of information about the bike you purchased.

The obvious question is: why did you purchase it if it doesn't fit you? And why can't you take it back?

I have always had racing style bike (Raleigh 1971 model) so I am used to a smaller top to bottom distance, meaning smaller crank arms-The bike purchase is a Mountain style and every bike I tested has longer crank arms and I prefer a shorter pedal distance, thus smaller crank arms
  Reply
#4
I assume by racing you mean a road bike. Road bikes almost always had 170mm crank arms. Your mountain bike may have 175mm. If you aren't familiar with the metric system that is a difference of about .2 inches. As Nigel noted we need more info before any suggestion can be made as to different arms. The proper solution would have been to mention your concern when purchasing the bike so that the shop could trade out for shorter arms at probably a reduced price.
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