Shimano compact crank + BB compatibility

Cusp said:

Hello,

Been searching and can't seem to find the info I need.

Shimano sells 3 compact cranks: R700, R600, R4550s

R700 is supposely ultegra/DA quality for 10 speeds.

R600 is 105 quality for 10 speeds

R4550 is tiagra/105 quality for 9 speeds.

(NOTE: Apparantly the parts for r600 and r4550 are the same. So probably same crank just one is MEANT for 9 speed and the other 10 speed).

NOW MY QUESTIONS ...

For ALL cranks you need an 'outboard' BB. According the the shimano website - the r600 and r4550 cranks should use the tiagra level 4500 BB and the r700 crank should use the ultegra level 6600 BB.

Sure, fine ... ok ... I want to get the 4550 crank for my 9 speed bike ... BUTTT ... the 4500 BB is SOOOOO hard to find on the internet and the ones that are found are priced HIGHER than the ultegra level 6600 BB. Weird!!!

Sooo - are all these Hollowtech II, outboard BB interchangable? I am not gonna spend $45 for a tiagra if I can find an ultegra 6600 for $36 or EVEN LESS on ebay!!!

So for the lucky ones with the Shimano compacts (r700, r600, r4550) what BB are you using?

Thanks!

The Shimano external BBs & FSA Mega-Exo BB are interchangeable. I think the MSRP for the various Shimano BBs are very close ... and, there doesn't seem to be any appreciable difference in the BBs, themselves. So, buy what is readily available from your LBS/whomever.

The R4550 & R600 have SOLID, FORGED arms like the FSA alloy/Gossamer cranks ... nothing wrong with that ... and, fabricated in Malaysia.

The R700 has Hollowtech arms.

The chainrings on the R700 are much better than the "Tiagra" grade chainrings.