Shimano 105 5750 10 speed & Shimano Ultegra 6800 11 Speed, same spec/dimensions?

russboy

I've probably not worded my question very well.

If I removed my 105 5750 10 speed would the Ultegra 6800 11 speed slot straight into place, i.e using the existing BB that is in there?

I'm not actually going to do the above but rather remove the 105 chainset from my old bike, poss with the BB as well & trial fit to my new bike. If that works or I think it can work buying a new compatible BB (if needed) then I will go on to buy the Ultegra 6800.

LBS not been too helpful saying what will/wont work, but then that was Evans & not always been impressed with their workshop skills in the past.

trailflow

All Shimano Hollowtech 2 chainsets use a 24mm spindle,so it will fit fine.

russboy

trailflow wrote:

All Shimano Hollowtech 2 chainsets use a 24mm spindle,so it will fit fine.

Cheers, just what I was looking for.

As it happens stripped the cranks off both bikes this morning & I will need a new BB on the new bike for a Shimano crankset as the existing BB has a 24mm spindle on the drive side but reduces to 22mm on the none drive side.

dj58

Bear in mind that the latest Shimano threaded bottom bracket SM-BBR60 have a smaller O.D. housing and you may need the adaptor (TL-FC25) to use with you existing tool.

russboy

Worked out what I need to get Ultegra on the new bike, no joy on the existing BB as it BB has a 24mm spindle on the drive side but reduces to 22mm on the none drive side. Took both bikes apart to have a look.

Removed the BB on the new bike to get the details of it:



So basically I need exactly the same but not reducing to 22mm on the non drive side.

As you'd expect the width of the frame at the BB is 68mm, as here:



With the opening at 42mm as here:



So it looks like this would do the trick:

http://www.sjscycles.co.uk/kcnc-bb30-bo ... prod33009/