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I have a new road bike that has a triple crankset. But I wanted to try double on it. When I replaced it. I found out that my standard square tapered double cranks won't fit with the bike's frame. Can I just instead use a double crank that is Hollowtech capable for me to able to do so? Because, correct me if I'm wrong, but it raises the crankset up a bit away from the frame right? Thanks I really appreciate any info.

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    Its possible all you need is a new BB with a longer shaft. As always, the answer will be here.... www.sheldonbrown.com/chainline.html – mattnz Mar 21 '16 at 5:53
  • May I ask why you want to drop from a triple to a double? The only advantage is a small decrease in bike weight, and the loss of low gearing would not make up for it. You may also need a replacement 2 position front derailer, or adjust the three place FD so one position doesn't work. – Criggie Mar 21 '16 at 9:20
  • Narrower cranks, weight, ability to use shorter rear derailleur cage, shorter chain, style points. Triples kind of suck, unless you really need one. – ojs Mar 21 '16 at 18:17
  • @ojs as I said - minimal differences and no real gain. What are "style points" ? Triples are awesome, I wouldn't buy a bike without one. – Criggie Mar 21 '16 at 22:33
  • I own a bike with triple, and the smallest chainwheel is useless. Like, not useful even for 20% climb with two week's baggage in panniers. – ojs Mar 22 '16 at 19:35
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The simple solution will probably be a longer bottom bracket. Square taper BB's come in a variety of lengths specifically for this reason.

Switching to hollowtech might work, but if your frame isn't built to that spec you could well have the same interference problems... only now you have new hollowtech BB and cranks.

This is one of those times it can be worth paying a bike shop. Not for the skill of the mechanic, but for the shelf of parts. They can try different sized BB's until they find one that fits, and all it costs you is labour and a single BB. Doing it at home you could end up with 3 or 4 BB's that are not quite right.

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