Shimano 105 upgrade compatibility query

[littleandy0410]

My 2008 Boardman Road Comp is long due some TLC, as it is my daily commuter, and is still on its original cables, shifters, front and rear mech, etc. It is also in need of new brake blocks, and the chain and cassette have done a fair few thousand miles since they were last changed too.

Then last week, the front mech split across the top bridge, causing me to be stuck in the top ring. So some man-maths has taken place, and I have decided the best thing would be an upgrade to a full Shimano 105 5800 groupset.

I also own a 13 Bikes Intuition Beta, which has 5800 gears, but with an FSA Gossamer PF30 chainset. I was thinking of changing the chainsets over, putting the FSA one on the Boardman, and getting the 36/52 chainset and fitting that to the Intuition.

So what I need to know is:

1. Will the 36/52 chainset fit the Intuition frame, bearing in mind the front mech is braze on, not band on fit, and currently has a compact 34/50.
2. The Boardman has a GXP bottom bracket, the Intuition has a PF30 bottom bracket. Is there going to be compatibility issues? The 5800 bundles come with a choice of BBs.
3. Then I need to measure the frame to work out which size band-on front mech I need for the Boardman!

Sorry for the rambling thread! Thanks in advance if you've read this far, and can help me!

[Barchettaman]

1) yes
2) you'll need an adaptor but it'll work (BBright wouldn't work, it's too wide I think)

[upsidedownmark]

1) yes - but a shimano crank requires reducer shims, or a different set of bearings to go in a PF30 shell - shimano cranks are 24mm axles, not 30mm (unless they're now doing a 30mm axle which I'm pretty certain they don't)

2) NO. If the fsa gossamer crank is PF30 (actually labelled BB30), it has a 30mm axle. GXP is much smaller - nearer the 24mm shimano std. Megaexo would be the 24mm version.

GXP bottom brackets come in press fit and threaded. If it's press fit gxp, I'm not sure - I don't know about the standard, and whether that shell will also take a 30mm sized bottom bracket. If it is a threaded external cup, I'm pretty sure there's no way to get a 30mm bearing into a standard english/italian threaded bottom bracket shell.
[ETA - 99% certain even if it's pressfit gxp - BB86, you can forget getting a 30mm crank in there]

Short version, you're probably better buying the right cranks for the right bikes. It's a bit of a minefield.. but shimano cranks will fit in pretty much anything, with appropriate extra parts.

Edited by upsidedownmark on Tuesday 10th March 01:03

[Dammit]

Use the 5800 cranks - they are very good, both sets of cranks you have are not going to perform (primarily shifting) anywhere near as well as the 105 ones would.

[Matt_N]

Will your rear wheel take an 11spd cassette?

You may need to man maths some new wheels into the Boardman too if it won't.

[bakerstreet]

Matt_N said:

Will your rear wheel take an 11spd cassette?

You may need to man maths some new wheels into the Boardman too if it won't.

2008 suggests that it won't.

If you want an upgrade path with out resorting to changing the wheels, then Ultegra 6700 (10sp) is worth a look. Quite cheap now as people are moving to 11 speed thinking it will make them instantly faster

[Matt_N]

bakerstreet said:

2008 suggests that it won't.

Was my thinking too but he may have upgraded the wheels.

At £300 for the 5800 groupset and £200ish for some wheels you're on the border of just getting a new bike with some man maths

[bakerstreet]

Matt_N said:

Was my thinking too but he may have upgraded the wheels.

At £300 for the 5800 groupset and £200ish for some wheels you're on the border of just getting a new bike with some man maths

Agreed. I spent a fortune upgrading my 2010 Defy 2. Looking back, I wish I had just put that money towards a new bike.

[littleandy0410]

Ok, seems like it's as much of a minefield as I expected, certainly BB-wise! Obviously I could just use the 105 cranks on the Boardman, but just thought my "best" bike should have the better components!

I have upgraded the wheels previously.......however, they are Shimano R501 wheels, which I foolishly thought were 9/10 speed. But they're 8/9/10 speed, which (it would appear) are not compatible with 11 speed.

So now, the options are:

1. Replace the front mech, for about £15. Boring!
2. Upgrade to 5800, with some shiny new wheels.
3. Upgrade to 10 speed 105, or as suggested above, 10 speed Ultegra
4. Rutland Cycles have a Giant Defy with 10. Speed 105 down to £675.......I could probably get close to £200 for the Boardman if I fixed the mech......

Man-maths at work here! Broken Tiagra front mech = new bike? Maybe, if I can get it past the Long-haired General!