[notfastenough]

Hey folks, I fancy upgrading the non-series stock chainset for my chistmas present on my Trek Madone (BB86). The rest of the shifting/drivetrain is Ultegra 6700. The cost difference between crank/chainset for Ultegra 6700 and 105 5800 is negligible, so I’ve got a few questions:

1. The 5800 chainset is described as ’11-speed’ – is it any different to 10-speed, are they compatible?

2. The 5800 chainset now includes the hollowtech bits (as does 6700) and the 4-arm spider (which 6700 lacks) – any thoughts on comparison of performance/weight? I know the 4-arm look is a bit marmite, but I like it.

3. The review for 6700 on this site said:

“Shimano have been fiddling with the spacing between the two rings and they’ve added an extra millimetre of space between the rings on the doubles. That doesn’t sound a lot but it means you get a greater range of gears available in the small ring without having to worry about chain rub. The only possible downside of that extra millimetre is that it means you need to buy a double- or triple-specific STI lever, which makes changing from one to the other a costly job.”

Would this apply when switching from non-series compact chainset to 6700 compact? Not so keen on buying a new shifter.

Thanks in advance.

Topic

[Scrufftie]

I’d go for the new 105 over
I’d go for the new 105 over the old Ultegra. You’ll get the same quality but greater choice of rings if you decide to change size or need to replace worn ones. I think all the new Shimano 4 arm chainsets are cross compatible so should ensure reasonable availability of new rings. The new chainsets allows for greater choice of the number of teeth so you could switch from 50 to 52 more easily

[MattT53]

11 speed chainsets work just
11 speed chainsets work just fine with 10 speed groups, I’ve been running an 11 speed ultegra chainset on a 10 speed ultegra group (inc 10 speed chain) for a year with no issues

[joemmo]

11speed chains are
11speed chains are fractionally narrower than 10 speed and although the chances are it will work ok it could be an expensive experiment if the spacing change turns out to be an issue, even in some marginal cases. Ultegra 6700 chainsets can be had for a decent price so maybe just stick to what you know will work.

[Author]

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