Swapping groupsets: Ultegra and 105

[grellboy]

Seen a second hand bike I want to buy with 105 on it. (52/36 front, 28 - 11 rear, BB 30). If I bought it I would sell my current bike to partially pay for it. Current bike has Ultegra: (50/34 front, 11 -32 rear, BB not sure!). Was thinking that if I bought the other bike second hand, even though the frame is far superior maybe I should swap the trousers around, because of superior level of Ultegra and the fact that the 105 running gear must be at least three years old, whereas my ultegra has had about six months use. So what I want to know is how easy is it to swap from one to the other, would it have to be a whole swap and would you bother!?

 

[grellboy]

Btw, groupsets- not trousers!!!

 

[I like Skol]

Yes..... but it may not be straightforward due to the BB compatibility?

 

[Drago]

Assuming like for like with number of gears, its probably easy.

I wouldn't bother myself, but its your call.

Service your new purchase thoroughly, cables will make a bigger contribution to shift feel and quality than notional changes between selected components from adjacent level group sets.

 

[Ajax Bay]

Seen a second hand bike I want to buy with 105 on it. (52/36 front, 28 - 11 rear, BB 30). . . . Current bike has Ultegra: (50/34 front, 11 -32 rear, BB not sure!). Was thinking that. . . maybe I should swap the trousers (sic) around, because of superior level of Ultegra and the fact that the 105 running gear must be at least three years old, whereas my ultegra has had about six months use. So what I want to know is how easy is it to swap from one to the other, would it have to be a whole swap and would you bother!?

It wouldn't have to be a whole swap and I would bother. The resale value of your current bike would be reduced (with 105 on, far less than the benefit of Ultegra on your 'new' bike which (you know) is less than a year old.
I'm assuming these are both 11 speed. To give you a better answer you'd need to share the version of Ultegra and 105 (eg 6800 and 5800). Also be sure to know before purchase whether the bike you're buying has full 105 trousers or if the chainset is pants.

 

[I like Skol]

the bike you're buying has full 105 trousers or if the chainset is pants.

 

[Cycleops]

Also be sure to know before purchase whether the bike you're buying has full 105 trousers or if the chainset is pants.

Look for skid marks.

Sorry @grellboy you're never going to live this one down .

 

[roadrash]

well, if we are talking trousers then perhaps you could replace the chain for a belt drive

 

[HLaB]

With my old 52/38 FSA crank with with 105 I had to change to Shimano outboard BB when I changed to Ultegra its quite straightforward. If your 105 already uses the shimano outboard BB format it'll be even more straight forward.