Guestimating sustainable output for a 200 mile ride in the mountains...

What's the dealio on calculating very long sustainable power outputs, taking into account that most of the ride is over 7,000ft?

I know what I'm comfortable at over several hours at lower elevations upto 2,600ft but not at what I sustain for 198miles, at altitude where you're spending most of the day climbing.

Most of the older schedules I've looked at for 12+ hour events (RTTC 12 and 24 hour events on flat courses) have been based around pacing schedules from 50 mile and 100 mile TT events and extrapolating from that as well as pacing from heart rate.

I looked at the Monod spreadsheet, popped my old test results in there and extended it out over 12 hours and it told me that I'd be riding on the rivet all day... 290 watts all day. Yeah right. LOL

Yeah, Monod is pretty useless much over an hour. It just doesn't have a way to account for fatigue and assumes you can sustain CP forever. Pretty good to an hour or perhaps an hour and a half, but not very useful beyond that.

Tough call as you've got both a very long ride to estimate and then the altitude factor.

FWIW, I've managed about .75 for ten hours on the bike at altitude, but then I live at altitude so my FTP already reflects acclimitization.

As a swag I'd expect at least a 5% decrease in FTP from sea level to over 7000' maybe more and then sustaining something like 70% to 75% of that over the course of such a long ride depending on how you pace. Just guesses, but you've probably got some idea of how much your FTP will drop based on previous rides as a starting point.

Good luck,
-Dave

I've never done either a long ride (6 hours or more) or a ride at altitude since I bought my PowerTap. Previous rides in the mountain, such as the 129 mile Deathride, were all done using HR but to be honest, apart from a sore back, the legs were still pretty good at the end. Of course there's going to be a couple of long rides to "test the water" - especially when the weather starts to heat up a little, but that's about it.

I have some calculated data, using the Polar CS600 "lap times" that I marked, Google Earth and analytical cycling, from the climb of Monitor Pass which is used on this ride. On last years Deathride when I was feeling pretty grim due to health issues (and really shouldn't have been riding) the first 7.5miles of the climb from 395/Topaz side I was around 210 to 220 watts in autopilot mode. I didn't count the last 2 miles as it's basically a false flat that only climbs ~300ft.

Appendic C, page 60 of Charles Howe's little treatise here would suggest a 5-10% drop up to 5000 feet., 10-15% at 7000 feet, etc.

I live at sea level. I was in North Carolina about a month ago and rode from Asheville (~2000 feet) up to Mount Mitchell (~6600 feet at the top). It was about 40 miles uphill all the way to the mountain and rode it basically at tempo. I tried to drill it for the actual access road to the mountain (~30 minutes) but could only manage high tempo/low threshold power, about 85% of FTP.

I'm sure that the 3 hours before this had something to do with it and I was holding back a little since I still had to ride 40 miles back to Asheville (though mostly downhill) but it's not like I could have gone a lot harder on the mountain either. The whole ride was ~6 hours with IF at 73% of FTP. That reference would suggest that I was 5-10% diminished over the course of the ride due to altitude. I can't argue.Then again, I spent ~48 hours at 2000 feet before doing this ride. I don't know if that counts for acclimatization or not.

The last time I flew to New Mexico, I spent the first night in my hotel room in Santa Fe (~7000 feet) unable to sleep well because I was wheezing and had an elevated heart rate. No signs of that at 6600 feet last month though. Maybe I was slightly acclimated before that ride.

Just my "FWIW" story.

Thanks guys for the info.

Steve, even though you only managed "high tempo/low threshold" did you feel like you could maintain that effort for as long as you could at sea-level or were you left feeling like you'd done a threshold workout?

I'm just wondering if there's a correlation between riding tempo, say 230 watts, at sea-level and riding what feels like low threshold at altitude but is still 230watts - or does the body not care about what you perceive to be the effort and just deals with 230 watts being well, 230 watts over 12 or so hours?
From what I understand about riding at altitude, you either try and get there as close to the event as possible, within 24 hours of the start if the logistics allow, or you get there 4 or more days before hand. The grey period inbetween is 'supposed' to be a time of reduced performance.

This wouldn't be the Alta Alpina by chance, would it? If so, be aware the best time on the test ride was 13:55, so it will be a long day, more or less equivalent to Devil Mountain.

I would suggest getting there 4 days ahead rather than the <24 hour option.

I tried the sub 24 hour method for a ride in the Dolomites when I lived in Germany and while I rode well (I was fitter in those days), my PE and HR were through the roof, with 4 out of 6.5 hours spent at 90% MHR (180+) and went straight to get some oxygen after the finish. I didn't have a PM then, but the elevated HR shows I was working much harder than normal for the same pace due to altitude. A few days later my HR dropped signficantly.

In terms of power, mine drops as the day goes on. Putting out tempo watts over Coleman Valley after 8 hours felt like high L4, and I just had to back off after 11 hours going up Sierra Road last weekend, but I would imagine you are fitter than I am. My best 9 hour ride was at 0.775 IF, I will update after Central Coast on May 9, which should be more like 11.5-12.5 ride time (I hope).

Good luck!

Yeah, it's the Alta Alpina Challenge. I dig the scenery up there so having an excuse to ride and get fed and watered en route is an opportunity I'm not going to miss.

I aint going up there and burning 4 days of vacation just to do a ride. I'm a contractor, so that's 3 more days of good money lost. LOL

I'm expecting it to take a while longer than 12 hours - especially given the last 100 miles but at least I won't have my friends from England with me that normally come over for the Deathride. They like to stop and all the rest stops and "gasbag" (chat) to anyone and everyone. I think between the top of Monitor and Ebbetts we spent about 2 hours last year sitting around, eating, checking out the ladies etc etc...

I basically just want to be off Ebbetts before the shadows of the evening sun start making the descent any trickier at warp speed than it already is. I don't mind being on Monitor when it's still pretty dark as it's a "real road" with modern stuff like lane markings, warning signs, reflective road markers etc

Don't assume that I'm fitter than you. I'm the one who's being asked by their Doc/pulmonologist whether I'm having problems climbing the stairs at home after they listen to my chest.

Well, you know, there's a side story here. You know what they say about the weather changing quickly in the mountains? Perfect example: Nice "warm" spring day all the way up there (~50 F/10C, sun was out, blue sky). Got going on the mountain proper and about 10 minutes into the 30 minute ascent, the clouds start rolling in from the side of the mountain that I just rode along for 3 hours. Gets cold fast, visibility drops, result: I was not a happy camper. But, I was riding threshold which at least kept me warm. It added to the difficulty though. I froze my ass off coming down the mountain too, even wearing all the extra clothing I brought.

I spent all winter riding threshold indoors (and a little outdoors) so I was well acquainted with the sensation. The answer is "yes", it did feel like a threshold effort.In fact, I tried to ride at FTP for a a few sections but couldn't hold it. Again, 3 hours of tempo beforehand had something to do with it too.
That's what I don't know. The tables would suggest that your threshold would, in effect, drop, but does that just diminish everything "down the line", i.e. at power levels less than threshold? My assumption is "yes", it sort of "derrates" everything you do and if you could do 300 W for 60 minutes at sea level, you can now do it for only 60*X minutes, where X is how much the table says your threshold dropped.
I've never felt well when I first arrive at altitude (7000 feet or more) from sea level so I don't think that the first approach would work for me. It always takes a couple of days before I feel like a human again.

How long and at what altitude?

Swampy,

My ride this weekend (218 miles, 14,000 feet elevation gain) was not at altitude (and I cracked a bit in the heat during the second half when I ran out of Endurloytes (there were none at lunch ...)); however, I had an IF of 0.74 for 12.5 hours ride time, so just below tempo range.

I have done low end tempo (0.775 IF) for rides of up to 9 hours, so those are two totally anecdotal data points ...

Thanks Watoni.

~210 miles in less than 9 hours at altitude?

Thanks y'all for the info provided - it worked very well on the ride.

Despite freezing my ass off for ~150 of the 198 miles it was the funnest ride I've ever ridden. Less bodyweight is already on the agenda, but it was nice to see that my time up Ebbetts Pass was 15 minutes quicker today despite hitting the climb at 130 miles rather than 42 miles as with previous climbs up it in the Death Ride.

Congratulations (belated)!

I would be interested what percentage drop you think was due to altitude, since I am considering the Alpina and the Everest Challenge for next year (less weight on the agenda here as well).

My last double was Mt. Tam on August 1, where I averaged 192 watts and had an NP of 230 ~(0.8) for 11:51 of riding (12:37 total). That was a good day (and I might need to bump up my FTP by a few watts?), but I would imagine I could expect a drop of at least 5% at the Alpina or EC

I don't have the numbers to hand (at work and the data is at home ) but I kept the power between 190 and 210 all day. Having that climb up Monitor from Topaz as the last climb with only about 15 miles to go from the top I was taking it somewhat easy. Towards the end I was getting sleepy and the power dropped of down to between 170 to 200.

As far as the Alpina ride goes - the Alta Alpina club had a meeting last month as to whether they're going to do it again next year. The feedback from all the riders was awesome. If the ride does happen and you chose to have an early start all I can say is get a really good front light - the kind that will burn your retinas out at 1500yards. Going through those backroads at o'dark 30 it's next to impossible to see with a regular lights and with the cloud cover (no moonlight) and the nearest street light being about 10 miles away, it easy to play 'find the potholes' by feel *ouch* rather than sight.