Gearing advice for IM Canada

[wintershade]

Hello all. First post alert!

I'm an early-30s San Francisco, CA based MOP triathlete and recreational road rider. Strong swimmer/runner and relatively weak rider (3.0 watts/kg weighing 70kg) with mediorce bike handling skills (like most triathles).

I'm looking for some gearing advice as I enter the final stages of training for IM Canada this July, which is generally regarded as a hilly/challenging bike course. This is my second IM, with previous being IM Louisville at 6.5 hour bike leg. Consensus on slowtwitch is a compact + 11/28 is ideal for most riders in Whistler.

My bike (Ultimate 9 SLX Pro) is Campy Record 36/52 x 12-27 running Bora 50s.

So question is: easiest fix is dropping on 12 x 29 casettee. I presume I'll need a new chain? Alternatively, I could swap to a compact and run the 12-29 (or perhaps an 11-29 to get back some of my top end), but that's obviously a bigger upgrade. One other option I considered was just adding a 34 small ring (for a Franken 34/52) but I worry about front shifting performance.

At the end of the day, cost isn't really an issue, especially since I could recoup much of the cost of a new new crank by selling my old one. I do worry that for shorter course races and bombing down SF hills a 50x11 might have me spinng out early as I generally feel more comfortable desending if I can "feel" my pedals. But honestly, I'm pretty rarely in the little cogs despite doing lots of lower candence training to prep for Whistler.

IMCA bike course: http://www.ironman.com/triathlon/events ... z5CrUfNPn9

Thanks!

[dricked]

11-32 on the rear? Gives you the bailout gear and with a 52-36 upfront it might be the easiest solution.

[wintershade]

I’m pretty sure my Campy Record 11 RD doesn’t support an 11-32, but I could be wrong. I’m pretty sure I have the short cage post-2015 RD. I’d probably rather swap cranks than RD.

[dricked]

Well I think you have your answer then.

[wintershade]

Hmm, maybe.

I guess it really comes down to how much of a difference is there really between the 34/11-29 vs 36/12-29, if conventional wisdom is 34/11-28.

[wintershade]

Also, while I presume I'd need a new chain if I swap to compact + 11/29, would I likely need one going up to the 12/29 with my 36/52? It's just adding 2 teeth, rather than 4.

[Antoine]

I would go for 12-29, 36x29 is almost the same as 34x28.
Not necessarry to change the chain if it's in good condition, unlike it's already too short for your current 52x27. Just check how it goes on 52x29.

[Bigger Gear]

I have ridden all of those roads, as I live not too far away. The climb up to Whistler Olympic park is the obviously toughest part. It has an early stretch at 6% average then levels for a bit then finisheds at 5-6%. The climb on the highway back to Whistler Village is not steep but can be windy. The parts around Alta Lake are very rolling with lots of punchy pitches, some that are probably over 10% but not for very long.

I think 52x36 with a 12-29 would be more than enough. I've ridden all of that with 39x25 when I've been fit, and rarely touching the 25. If you want a bit more gear for the descending you could use the 11-29 cassette.