Today in adventures in 11-speed:
I wanted to shoot some more pictures of what you can run into when using these cranks with modern 11-speed gearing.
Now these are modern
Spécialités TA Pro 5 chainrings, one of which I still had lying around the other I ordered because I wanted a smaller inner chainring. The cranks were originally a triple and came with the mounting bolts for a triple. So I ordered a bolt set for double chainrings and this is what happened:
Essentially the way the chainrings mount means there is slightly too much room between them and the 11-speed chain can (but not always) drop between them. Damn.
Now for those not familiar with it, all deraileur chain from the past 30-40 years or so fits on "
3/32-inch chainrings" but with denser cassettes in the rear the chain has become narrower.
So where 6 to 9-speed chain is all about
7mm (
9/32″) wide, modern 11-speed is often
5.5mm (
7/32″) wide and newer 12-speed chain is even
5.3mm (
13/64″) or even
4.9mm (
3/16") for 13-speed Campagnolo.
(
and don't get me started on the weird numbers this makes in inches. My first instinct is to convert it all to 18/64", 14/64", 13/64" and 12/64" for ease of comparison.)
Now if you think this means the chain must be getting weaker because it's so thin... think again. Modern
12-speed chain lasts twice as long in testing compared to it's 11-speed counterparts and three times as long as the 9-speed versions.
Then again, it better be. A
€90 MSRP chain (
$108) versus a Shimano HG95 Ultegra chain that's available for less than €30 (
$36) is a big difference in price. Even though the 12-speed last three times longer.
This is all down to modern materials engineering, metal hardening and coating treatments. You could argue we could get similar longevity if they applied that knowledge to 9-speed chain... but AFAIK nobody makes those.
Source: CyclingAbout.com & Zerofrictioncycling.com
Anyway, I'm getting off-track here. So my 11-speed chain is 1.5mm narrower than the chainrings were designed for so it drops inbetween. So how thick are those spacers? As it turns out;
3.6mm.
It doesn't help that they are a weird ř12mm x 7.15mm x 3.6mm size.
I mean I can easily find
-a2/din-125a-[-]-a2-[-]-m6]M6 rings, which are 12mm x 6.4mm and a
7.1mm drill bit but if two of those stacked are 3.2mm it doesn't make a lot of difference.
Perhaps the easiest way is to simply sand down the aluminum spacer rings to a thickness just over 2.1mm and see what that does. The ones I got are from
Velo Orange so if I mess up they aren't that expensive and offer bigger 10mm stainless steel bolts.
Expect an update in the future.
