Installing New Crank On Square Taper BB

nicklouse

kurth wrote:

There's no info on this crank anywhere......it does appear on that sheldon thing but doesn't really say much

The chainline is 55mm :?

The crank definatley won't go on no more.....that's as far as I can get it! :x

then you would be better replacing the BB with a 110mm version.

55mm is too wide

kurth

I can't get in all the gears,its a bit of a nightmare. Got a mate coming around later to see if we can get it on any further......if not, I'm going to write it off as a bad job and put the old crank back on.....and upgrade to a new bike in a year or so!

*AJ*

It just needs a shorter BB axle, like Nick said above.

Rockhopper

Have you had the bottom bracket to pieces? Might the axle be in the wrong way around?

The Rookie

TuckerUK wrote:

We (that's me as an engineer, and three professional sources) will have to just agree to disagree with you then, make no odds to me. Vive la difference!

As an engineer I would disagree, greasing will encourage movement and fretting, dry increases the contact friction making both less likely.

Mini A-series crank, run them dry, usually fine, run the taper 'wet' and they frequently end up seized solid.

Simon

TuckerUK

The Beginner wrote:

TuckerUK wrote:

We (that's me as an engineer, and three professional sources) will have to just agree to disagree with you then, make no odds to me. Vive la difference!

As an engineer I would disagree, greasing will encourage movement and fretting, dry increases the contact friction making both less likely.

Mini A-series crank, run them dry, usually fine, run the taper 'wet' and they frequently end up seized solid.

Simon

You really need to read the whole thread, and the links. No harm in disagreeing, but there is empirical evidence to support the greasing notion.

TuckerUK

Andy B wrote:

How far along the taper the crank arm goes depends on the crank arm itself, tolerances and differences between manufacturers all play a part

Just because your son's goes that far along the taper does not mean that the cranks in question on this thread go on as far as your son's

Nor does it mean that the crank arm in question should be as close to the BB shell as your son's are.

I'm washing my hands of this thread now, as obviously I know nothing, nor do any of the other contributors to this thread who haven't got engineering degrees, built several race cars, hundreds of cycles, work for major car manufacturers in their engineering departments or worked as professional cycle mechanic for years...

Where did I even imply that you or any poster 'knew nothing'? Perhaps you can start a 'who has the most impressive CV' thread that we can all contribute to? I'll pass, I have nothing to prove (about myself) to anyone here.

You may well be far more experienced and knowledgeable than me, I don't claim to be an expert...but are you more experienced and/or knowledgeable than Sheldon Brown, Harris Cyclery, or Jobst Brandt? Either way, as I said, each to their own.

Incidentally, the picture shown was a Shimano MTB crankset (requiring a 110-113mm BB axle) on a 110mm BB axle. Be no point showing a photo of anything else really would there? Sorry, perhaps I should have said that, I presumed it was a given. Yes the 110mm as opposed to 113mm axle BB would account for a 1.5mm discrepancy, but as you can see from the photos we are talking way more than a 1.5mm discrepancy.

OP, be interesting to learn what the problem is when you finally get it sorted. Good luck.