Bottom bracket question

[SuperBob]

I'm installing a double crank by Sugino on my bike. I've tried both 68X110 and 68X107 bottom brackets and the crank arm don't seem to be just right. Is this normal? My assumption is that the cranks should be equally spaced from the centre of the bike.

The bike previously had a Truvativ triple Touro crank with TruVativ 68x113 BB, BUT with a washer on the drive side. I assume that this washer was used to correct the chainline.

Perhaps I should try the washer with one of the new BBs and crankset. Your thoughts are appreciated! :)

[531Aussie]

I've tried both 68X110 and 68X107 bottom brackets and the crank arm don't seem to be just right. Is this normal? :) what do you mean by "don't seem to be just right"?
Not centered?

can you post a picture?

A roughly even distance between the cranks and the chain-stays is probably a more accurate way of assessing the centering

[Retro Grouch]

What kind of bike? Could you possibly have a 73mm wide bottom bracket shell?

[SuperBob]

By "not right" I meant that the left crank was farther from the left chainstay than the right crank was from the right chainstay. Sorry, I had pics last night but my computer kept crashing on me.

So last night I took the washer from the stock BB and put it on the right/drive side of the BB and the crank arms now appear to be equally spaced from the chainstays. The removeable ring is recessed a bit into the BB shell but the cranks are secure without any play that I can notice. I guess the company that manufactured the bike used the washer as a correction for some error in the shell position.

The front derailler seems to match the chainring positions pretty well so I will proceed and put the new chain on.



To Retro Grouch: The bike is a 2004 Norco entry-level road bike. I was at the local coop bike shop and we measured the shell to be 68mm. It's an aluminum frame with an odd compact geometry.

[serpent950]

Should have measured the old bottom bracket in the frame from tip to tip with calibers.......When you replace it with the new one try to hit that measurement from the center of the bottom bracket frame:)