Bottom Bracket

kincsem

I am doing a bit of work on my 2006 Specialized Allez (base model). It has a Shimano Sora triple. I have taken off the square taper cranks. The bottom bracket bearings feel a bit rough (probably grit), but I have not yet taken off the crank cups as I don't have the proper tool (Park Tool BB Tool BBT22).

I'm going to order the BBT22 and a new Bottom Bracket.

My question is which square taper Bottom racket. I'm going to get this one but do not know what size to get.

http://www.chainreactioncycles.com/Models.aspx?ModelID=17473


I measured the bike with a Vernier calliper and got the following:
Outside edge to outside edge of the square taper BB is 114 mm
Outside edge to outside edge of the bottom bracket crank cups is 76.5 mm (the cups are still in the bike; the frame / shell would be a few mm less).

The Park Tool blue book says usually 68mm for road bikes and 73mm for MTB. The Shimano website says 68mm-70mm for the 2010 Sora triple.

My guess is the 68-113mm.

Any help would be much appreciated. I emailed CRC but no reply.

redmaxi

For the size '68 - 113'. The '68' refers to the width of the BB of the frame.
The '113' refers to the width of the crank (the one you want obviously).

68mm denotes English/French or 73mm ISO thread.
70mm denotes Italian thread.

It's no good measuring the outer diameter at the cups because some will screw in farther or less than others giving varying measurements.

Measure the width at the frame it'll either be a clear 68mm or 70mm.

kincsem

Thanks for the reply.

A few minutes ago I ordered the tool needed to remove the cups.

When I remove the BB next week I can measure the frame, and also probably read the part number / dimensions off the old BB when I get it out. Then I can order the correct Bottom Bracket. No sense in rushing and ordering the wrong part.

rottenhat

The likelihood of the bb shell on a Specialized being Italian threaded is vanishingly small but I imagine you could confirm this by checking on their website.

redmaxi

kincsem wrote: »

when I get it out. Then I can order the correct Bottom Bracket. No sense in rushing and ordering the wrong part.

Wise man, just remember of course if:

it's british (68mm): Right cup = Left hand thread
Left cup = Right hand thread

Its' Italian (70mm): Right cup = Right hand thread
Left cup = Right hand thread

Greyspoke

To measure the bottom bracket shell just turn the bike upside down and measure across the shell with an ordinary tape measure/ruler.