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Old 07-03-14, 09:34 AM
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tetonrider
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Thanks, Hida!
Originally Posted by Hida Yanra
Alloy bolts are fine- they have a shorter service life because of getting rounded out (metal is too soft for consistent install/removal), but for this they'd be fine. They'll take the torque no problem.
Good to know. I wasn't aware of that as the reason.

Originally Posted by Hida Yanra
I'd probably go with a 39t or 38t myself, and if you can get one there in time, a wide-narrow tooth chainring. They are SO NIFTY, and seem to fix just a whole mess of problems.
What BCD are you using? (I think you probably have options for both 130 and 110, but checking to be safe)
So funny you mention this. Before checking back in on this thread I was thinking about the MTB 1x solutions (wide/narrow) and learned that they now have 110 & 130BCD rings. I know they still have some problems, esp with mud, and they work better with an RD with a clutch, but this isn't bumpy or muddy terrain.

You're right, I could run either; 110 would be slightly easier.


Originally Posted by Hida Yanra
34x14 isn't a bad gear- but big/big gears do have better efficiency (since we are working the tiny %s here), so 38/39 is preferable.
Agreed.

Originally Posted by Hida Yanra
How does the start play out? Is it a CX style thing where making that first group off the line is critical? How often will you need to react to surges during the race? (in reference to the 550w stuff you mentioned)
It's a mass start race, but it's not super insane at the start. It is important to be at the front but not so difficult to get there. I.e., it's not like there are 1,000 riders on a narrow road. I'll start in the first row and be fine there. Here's an idea of what the surges look like (yellow). I was in the first few wheels for the first mile. At ~1.5 miles, a rider took off, and I decided instead to settle into my rhythm, guessing that he was doing something unsustainable. (He was; I passed him for good at about 2.25 miles in, probably where that little bump is.

Cadence is in green. That dotted line is at 81rpm (my average for the climb). Speed is in blue. It ranged from 8mph to 19.3 (blue dotted lines @ 8 & 18).

Originally Posted by Hida Yanra
How likely is a sprint at the end of the climb? What are your gearing plans for that?
I put in a little dig at the end. The 32:00 marker was approaching, but I finished at 32:08. In theory, I should not have been able to surge that hard.

Last year I ran 50/34 + 11-25. I'm not sure I used the 25 at all. The way I'd typically ride is to start in the big ring for the first 60", then shift down. After 2' in there's a flat/fast spot. I'd normally shift to the big ring for a minute. I then settle into something like 34/21-25. At ~5 miles in there's a short dip. I'll usually shift to the big ring here, but I also usually need the little break. Every second may count, so I'll need to push here, but I get less bang for the buck in this section. There are a couple steep bits at the end.

I used a gear calculator; 39x13 = 19.25mph @ 82rpms. @90rpms, 39x14=19.7. On the lower end, though, 39x25=9.7mph @ 82 (what I averaged on the steeper, consistent middle section).... I'd have to drop cadence a bit more vs what I prefer. Actually, a 39T wide narrow isn't possible, I think, so it would be 38 or 40.

36Tx12 would be 19.25 @ 82rpm and 36x25 @ 80=9mph.

34x11 = 19.8 @ 82 and 34x25=8.5 @ 80.

I didn't want to go 11-28 (bigger sprad in the back = longer chain = slightly higher chance of a drop.


Originally Posted by Hida Yanra
What cassette are you going to use? The Recon stuff works quite well in my experience, and they are both light and cheap (compared to DA/Record cassettes)
I have 1190 11-25 and 11-28 available. An aluminum cassette scares me a bit, esp as this could involve shifting under heavy load. 124g claimed (recon 11-28) vs 154 (for 11-25; few grams more for the 11-28). Hm.

Wide/narrow rings are a 30g penalty vs a DA inner ring, but the alternative is a chain watcher + outer guide. Weight savings for no FD & no big ring = 1/2 a pound for me -- more when I factor in no front shifter.

Thanks for the thoughts. Obv geeking out on the gearing
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