Bottom Bracket Replacement - Shimano?

[dhd.evans]

My BB is knacked on my B'Twin 700 Ultra AF - I suppose 3,000mi in all conditions is fair play to it.

The chainset/cranks are a Shimano RS500 52/34 but i can't quite work out what the BB should be. Hesitant to take it out without having a replacement to hand. I think it's either this one but could be this one?

Can anyone lend a hand?

 

[si_c]

The first one.

 

[Cycleops]

You'll need one of these to remove and install:

http://www.wiggle.co.uk/park-tool-hollowtech-ii-bb-and-crank-arm-tool-1/

Make a note of any spacers on the BB.

 

[dhd.evans]

You'll need one of these to remove and install:

http://www.wiggle.co.uk/park-tool-hollowtech-ii-bb-and-crank-arm-tool-1/

Make a note of any spacers on the BB.

Got the tools just not the BB!

 

[dhd.evans]

Thanks @si_c , @Cycleops - ordered and on its way. Kinross Sportive (88mi) a week on Saturday so bike has to be in tip-top condition!

 

[dhd.evans]

I took the crank off over the weekend once I'd got the BB. Turns out it's a pressfit BB (confirmed through Decathlon) and not this one. No bike today!

For information it's a Shimano BB71-41B bottom bracket.

 

[Cycleops]

Oh dear, sorry. You'll need a different set of tools.

 

[dhd.evans]

Oh dear, sorry. You'll need a different set of tools.

No need to apologise, i appreciate someone stepping up and answering what i considered to be a dumb question! I've only dealt with threaded BBs so pressfit seems like a whole new ballgame...

 

[smutchin]

I replaced a pressfit BB recently (exactly the same model - Shimano BB71). It's not a difficult job at all but you do need the right tools.

I bought a Park BB90 removal tool, which is essentially just a steel tube with a splayed end. You could improvise but the purpose of the splayed end is to apply force equally around the whole BB so you knock it out straight. It does make the job very easy.

I already had a bearing press which I used to fit the new BB. The removal tool came with bearing press adapters the right size for a Shimano BB71. Again, the bearing press makes installation of the new BB extremely easy. And it's best not to improvise a tool for that job because you risk the bearings not going in straight, which isn't good for either the bearings themselves or the frame.