Foo
A couple of months ago, I replaced the crankset on the mclm with a somewhat more modern unit with external bearings and everything. Today, after two months of increasingly unhappy knees and legs after reasonably long loops (the Codename:UGB210 loop last Saturday was instructive, but not in the way I wanted,) I finally snapped, took the new crankset off and put the old one back on.
The Sram Apex crankset I’d installed had 172.5mm crankarms, and a tread of ~150mm. The old crankset has 170mm crankarms and (on a 113mm bottom bracket) a ~140mm tread. It doesn’t seem like very much, but the final straw today was when I came back from the store (after one short loop on the mlcm and another on the trek,) sat down, then listened to my knees going “pop!” “ping!” and “klunk” every time I moved my legs. I’m fond of my legs, and I managed to ride – with the old crankset – a collection of loops up to 600km this year without any knee or leg discomfort at all.
So I ripped the Sram crankset out, threw it away (not really; I’m going to try and sell it, but it’s not usable for me), took the old mlcm crankset off the trek and moved it back to the mlcm (with a brief intermission to swap chainrings,) dug out one of my old Biopaced cranksets and the loose-bearing bottom bracket that used to be on the trek, put them onto the trek, tried to tighten up all the nuts and bolts, and collapsed into a heap.
I’ve discovered that the spiffy Sram hex-socket-on-both-sides chainring bolts have one fatal weakness to them, in that it’s really easy to destroy them, even if I tighten them with short wrenches. When I swapped the alpine double chainrings over to the Sram crankset, I thought I was carefully tightening the bolts to spec, but apparently my torque wrench is measuring low because I ripped one of the bolts in half when bringing it up to spec. And then I ripped another one in half when I was paranoiacally tightening it with a very short wrench :-(
I hope that putting back the old crankset(s) (and I’m going to have to retune my saddle and handlebar position, but I need to do that anyway because my parents gave me some money as a birthday present and I used a bit of that to get some Salsa cowbell handlebars which are going to play merry hell with the front end configuration of the mlcm) makes my legs happier when I go out for my next reasonably long loop.
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Well, that sucks.
I recall reading an account of the guy who completed first in some 1200 km randonneur ride in BC; 2mm of new padding in a shoe was giving him severe leg pain. (and gods know I’ve been finding that it’s not enough to get the shoe cleats close, and I ride what are by your standards short distances.)
In terms of torque wrenches, the nice folks at Warren & Brown make what are alleged to be (and I know of no reason why they are not) the best ones: http://www.warrenandbrown.com.au/PrecisionTools/ProductTree.aspx?From=Cat&ProductId=61 I certainly like mine to pieces.
(3/8 instead of ¼ because if you ever get the next up bottom-brackets-and-old-style-cranks size, it’s in 3/8 drive only, and it’s only one set of hex sockets that way.)
It’s amazingly hard to find posted widths on cranksets.