Switching from 5700 triple to 5800 mid-compact

DasBike

Hello. I'm riding a cube peloton race 2013 with shimano 105 5700 groupset including triple chainset with 11-28 cassette.
I'm interested in switching to a 36-52 105 5800 chainset. I've read elsewhere about setting up the brifter to work on a compact chainset. Also I think the bottom bracket will be compatible. Is there anything else I would need to change to make this work? Eg rear mech or derailleurs?
Thanks in advance!

keef66

Front mech will need to be raised a tiny bit.

Make sure you get good advice about setting up your triple shifter for a double chainset.

With the first generation of 10 speed 105 (5600) Shimano used a single model of LH shifter for both double and triple setups. They had a significant number fail when used with doubles, possibly due to incorrect setup, possibly incorrect use. Mine actually failed on a triple setup :roll:

So for the next generation 5700 they produced double and triple specific LH shifters.

DasBike

Thanks. I assume the front mech raise is to accommodate the 52 teeth big chain ring vs current 50 teeth version. Would gear changes work better with a front mech for double chainsets rather than the triple one I have?

I was going to follow advise on this thread for the LH brifter setting: http://forums.roadbikereview.com/compon ... 84590.html

My cables are internally routed so won't have the barrel adjuster for front mech to help on this.

keef66

Correct re raising the front mech.

I think a double front mech may work a little better. The alignment and limit screws will be right.

I installed inline cable adjusters on my CR1 which has unthreaded cable stops; especially useful when setting up the front mech.

DasBike

Any thoughts on the ultegra vs 105 crankset. Looks like the 105 (5800) is around £85 and the ultegra (6800) is around £160. Same question on front mech, 105 vs others. Having read http://blog.artscyclery.com/ask-a-mecha ... our-money/ it seems to suggest that ultegra crankset and dura ace front mech are worth the extra cost but I think that could bring the cost of my upgrades up significantly for marginal benefit over 105 upgrades.

keef66

Think with your eyes shut you'd be hard pressed to tell a 105 crankset from Ultegra. For nearly double the cash you're getting a slight weight saving, possibly a bit more machining on the teeth of the big chainring, and it arguably looks a bit nicer.

Not worth it to me.

And a front mech is a pretty simple thing, so I doubt there's any performance gain to be had there either.

Your money at the end of the day...

Bordersroadie

I did the same a while back, Cube Streamer (old name for Peleton), went from 5700 triple to a 6800 compact.

Keep the same levers and mech, they have been fine for me, no issues at all. I would buy the Ultegra crankset over the 105 for two reasons. One, it's lighter and looks nicer and two, if you look at the reverse of a 5800 crankset it has been designed with a lovely grid perfect for collecting crud and making cleaning a bit of a bugger, unlike the smooth, flat back to the 6800 version.

For set up. I used the "big/middle" part of the left hand gear selection and made the old "granny ring" click redundant just by using the stop limiting screw on the front derailleur.

No need for any other changes, it should all work beautifully!

DasBike

Bordersroadie wrote:

No need for any other changes, it should all work beautifully!

Did you keep the same chain length? I have a long RD cage to take up the slack in the triple and I'm hoping this should accommodate a 52 tooth big chain ring compared to the 50 tooth on the triple.

keef66

Unless your chain's been shortened to the bare minimum you will probably be OK.

With a long cage rear mech I've swapped between a 50/39/30 triple and a 53/39 standard chainset without changing the chain.