Tiagra Crankset Replacement Question

[Russellwells777]

Hi Guys,

I picked up an older Raleigh RC3000, and I am busy fixing it up. I want to replace the crank set and BB (as the BB is quite old). 
What type of BB is on this bike, i am guessing this is an Octalink Bottom Bracket (but I could be wrong), which crankset and Bottom bracket would be the best to replace these ones with? 

Sorry if this is a stupid question, Bottom Brackets and Cranks are quite intimidating to figure out. 

[Martin PJ]

It's Octalink, I have an Ultegra crank like this, uses Octalink BB6600 or BB7700 Bottom Bracket, they are expensive and hard to find. Normally about R900 or so. Better to replace everything. The BB shell is English BB 68 mm, which is the most common Shimano type.

[Russellwells777]

Just now, Martin PJ said:

It's Octalink, I have an Ultegra crank like this, uses Octalink BB6600 or BB7700 Bottom Bracket, they are expensive and hard to find. Normally about R900 or so. Better to replace everything. The BB shell is English BB 68 mm, which is the most common Shimano type.

Thanks Martin, So If I pickup a newer Tiagra Crankset and replace the BB with a 68mm thread i should be good to go?

Obviously I'd just need a new bottom bracket tool for the Hollowtech bracket?

[Martin PJ]

Yes, you would be good to go. Both types of Bottom Brackets need a special tool. The right side is clockwise to remove it. Left is counter clockwise (i.e. normal).

[Russellwells777]

4 minutes ago, Martin PJ said:

Yes, you would be good to go. Both types of Bottom Brackets need a special tool. The right side is clockwise to remove it. Left is counter clockwise (i.e. normal).

Thanks for your help Martin, much appreciated

[David Marshall]

Bit late to the party but here is my 2c.  That is a 9 speed so any 9 speed crank with a English threaded bb will fit.  You could even get away with an 8 or 10 speed crank.  If you buy new the current 9 speed would be a Sora.

Number one prize is an outboard bearing Shimano  bb with a crank having a 24 mm axle.

Cheapest (if new) would be a square taper bb with something like a Suntour square taper crank.  Note the bbs come in a few axle lengths so you would need the right one.

Steer clear of the splined type bbs (Octolink, ISIS drive etc) as they have specific lengths for different frame/crank combinations and as mentioned are scarce and expensive.