Looks like you should be easily go to 28T and there is an 11-28 cassette.

Ditto above. I routinely do more than 3K' total climbing with my 36/25 max gearing on my TT bike. Going to 28 would be no problem. For reference, I did 12K' total climbing century with my TT bike on a 34/28 max. That had several >12% climbs that were brutal, but take those out, and the gearing was no problem.

Thank you.

Sounds like the 28 is a safe bet. You guys think if I tried to get a 30 on there I could do it without having to swap anything else out (other than adjusting the Di2 of course)? Don't know if that is overkill but it seems like those two extra gears might come in handy.

I looked into an 11-32 for Whistler but it required a new RD. Sticking w/ 11-28.

This is my home course and I run a 55/42 x 11-28 on my P5. There is only one section on the course that you would need a 28 with your compact gearing. This section is called Sparks grade and is roughly going to be 6'-9' of climbing at about an 8% average grade.

The main climbing comes over a 11.5 mile section from Elk Lake to Sunrise Lodge. Strava has me riding this segment 36 times with my top 10 times between 39'-42'. The average gradient is only 2% over this stretch but that is deceptive as 931ft of climbing comes over the last 4.5 miles. From Elk Lake to Sunrise lodge it plays out like this - 5 x 1:00-2:30 stair-steps, 2 short rollers as you pass Devil's Lake, an 5'-7' flat lead-in to Sparks grade, 9'-16' climb to Todd Lake, then two short gradual climbs to Sunrise lodge. The last 4.5 miles averages 4% with the first mile at 8% average. My average top 10 time on 42 strava attemps is roughly 19:00 and ranges from 17:20-21. 98%+ of riders will ride both of these sections slower than me but this should help you get a better time frame.

Lastly, the Sunriver Cutoff descent is roughly 14 miles back to T2 with 7 miles of fast decending and 7 miles of 0 - (2%). Even with a 55 I run out of gears in spots on top, but for the most part I'm pedaling. This descent is basically straight the whole time and is safe and on nice roads. It's about 60-40 on headwind vs. tailwind for this section. If there is a headwind I would fuel up on the steep section and be as aero as possible over the last 7 miles of gradual DH. Averge time for steep 7 miles is 11'-12' at 36-38mph. Average time for 10 miles of descent (I rarely ride the final 3 miles into Sun River) is 17'-19' at 32-35mph.

Elk Lake To Sunrise Lodge Climbing Segment https://www.strava.com/...sults&gender=all
DH Segment https://www.strava.com/...sults&gender=all

Massive intel. Thank you.

I'll go with the 11-28, but now I wonder if I should swap to 53/39. I'll think it over.

Thanks again.

How does what was just posted above in times and distances climbing equate to a "total of about 3k feet" in 56 miles? I think the post about the times/distances was great. I'm questioning the OP's total elevation.

Sounds like a lot more to me than 3000 feet. I climb at about 75ft a minute from 5-8%, cruising. Those times posted it appears every single of the 3000 feet is in that one section. Or, the total elevation is a lot more than 3000ft.

I say that because in 45ish minutes I'd be up all 3000, or if it's not all up during that time, at least close to it.

You could probably go to a 30 as Shimano is pretty conservative with their capacity ratings. People regularly exceed capacity and report that it works. I don't know if Di2 programming has to know the cassette and would not work or not.

You are right-I should have been more clear. Total ascent is ~3K (start at ~4300 to around ~7K altitude), but total climbing is higher.

Maybe MtnMikeLars can weigh in...

Haven't used one myself, but I've heard good things about this Wolf Tooth extender:
https://www.wolftoothcomponents.com/products/roadlink


Supposedly lets you go up to a 40 tooth cassette with a regular road derailleur.


For $20, it's certainly cheaper than a new RD....