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| Newly-mounted WickWerks 50/34 compact road double chain rings |
I clamped a laser to the downtube and spun the empty crank, and if it's out of flat it's by a very small amount. This is pretty strictly down to me pushing too darn hard at this point in time.
There's a 50/34 set of Surly stainless steel rings coming for the Experiment, since I have some hope those will last without bending. (They will likely also shift like urgh, but everything is tradeoffs.) And the Experiment is what I'd be riding if the particular horror of being sixty kilometres into a planned three hundred kilometre tour when the big front ring goes non-serviceable happens. (And, hey, last time took out the small ring, too, nearly; enough top ring bend to interfere with any gear but least and next-least.)
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7 comments:
I'm kind of in awe of your ability to bend chainrings. I'm neither very large nor very powerful. I simply can't imagine the force it would take to do that!
Of course, I'm still riding a 1991 Trek hybrid with almost all original equipment. It's getting a little ramshackle and noisy, but still shifts and brakes well. ::knock wood::
I don't feel like I'm powerful; I haven't been decently strong since my middle twenties. It's more that I'm not in the design space.
I'm, well, I'm increasingly middle-aged, but (as I understand it) bike stuff is mostly designed for people who are 150 pounds, maybe a bit more; I'm a hundred pounds heavier than that and I can still do the one-foot-on-a-high-thing-and-step-up, so I've got to be able to generate a kilonewton or so of downforce per foot. Into longer than normal cranks. Nobody seems to make shifts-nicely rings that are meant to deal with this.
(I am starting to dream about getting one of those electron-beam 3D printers that do complex metal parts and making chain rings in really robust aerospace nickel-cobalt alloys.)
Long may your Trek shift and brake well! and the rattles are usually subject to a bit of tightening here and there, or getting a good mechanic to be nice to the bearings.
Maybe switch to a 130 bcd crankset so there's more spider and less ring there? (possibly a 130/74 triple with the outer ring replaced by a bashguard -- you could get a 50/30 double out of that and a < 1:1 alpine gear.)
That's a much more practical suggestion than my desire to get a serious metal parts additive machining device (at a mere quarter million or so the each) and start making robust 110BCD rings.
I suspect it would work, too, especially if I could solve the shifting issues. I've been trying to avoid 130BCD because that means junking two custom cranksets. Certainly it's the tabs down to the spider that fail with the decent (Praxis, WickWerks, Carbon-Ti) rings. (Blacks pure and the SRAM rings just folded.)
Sigh. "Blackspire", of course. Not "Blacks pure", which is at best some kind of dire blended whiskey.
Don't let the sunk cost fallacy drag you down, though; at the amount of money you've put into getting custom rings you can get a 130/74 crankset and see if it works better.
If a 130/74 does work better, you can store the custom cranksets for a rainy day (or the day you decide you want to put a 42/34 alpine double on one of your bikes and spin your way up the bluffs around Lake Ontario.
The problem is the 195mm crank arms; I know that works. I know with great confidence that I go faster and hurt less. (Leg cramps two hours after getting home when I forget to take ibuprofen, lie there and stiffen, and then move abruptly is *way* better than leg cramps that happen while riding and make getting home seem highly unlikely.)
So, yes, I could try the standard 175mm cranks in 130/74 pretty easily, but I more or less already know that crank arm length doesn't work, and indeed hurts. So trying 130/74 means a High Sierra order, a long wait, and exceeds prudence with present cash flow even more than the last couple ring purchases have.
So, yeah, something I should try. But it'd be nice to keep some >50km bike capability in the meantime.
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