Guys who race, do crits etc or know about stuff
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- maggierose
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I rode 80 miles on Saturday; the first part being a fast group ride and then I rode additional miles afterwards. During the group ride, Strava estimated my wattage to be 312 avg @ 25.2mph; during my solo portion Strava estimated my wattage at 204 watts @ 21.2 mph avg. My historical PM data tells me that the group ride estimate is probably 50 - 60 watts high. And my solo miles were 10 - 20 watts low. Hope that helps.
Yeah, Strava's power estimates are not great. Just did a somewhat hilly 70 mile ride last week with 20 mph winds. I was pulling at the front for probably two thirds of the ride (because I knew the route and I provide a good draft ). One of the ladies who rode with us had a power meter. Her average power for the ride was 170 W. Strava estimated mine at 190 W. That might have been fine if I didn't weigh an extra 100 lbs (me at 225 lbs), she took more than two pulls the whole ride, or if it wasn't windy.
@maggierose That's perfect thanks, exactly what I was looking for!
@fab63 Wouldn't really be so hard for Strava to pull weather info from a major aggregator and factor in wind values. I wonder if it's something they've considered. Bet they're at least looking into it..
@fab63 Wouldn't really be so hard for Strava to pull weather info from a major aggregator and factor in wind values. I wonder if it's something they've considered. Bet they're at least looking into it..
Shrike wrote:@fab63 Wouldn't really be so hard for Strava to pull weather info from a major aggregator and factor in wind values. I wonder if it's something they've considered. Bet they're at least looking into it..
That math gets somewhat complicated, though it could be done.
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- in the industry
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I think pulling in more data would not make the numbers more real, the numbers would still be wrong.
Most road races I average 220ish watts in a crit it will be higher due to more sprinting. If I use a bike without a power meter like I did in one race recently I averaged according to strava 360W. I can't average that. So strava in a bunch is not even in the same ball park. In fact the estimated power data should be taken of as it simply misleading.
Most road races I average 220ish watts in a crit it will be higher due to more sprinting. If I use a bike without a power meter like I did in one race recently I averaged according to strava 360W. I can't average that. So strava in a bunch is not even in the same ball park. In fact the estimated power data should be taken of as it simply misleading.
^Exactly this. In my local weekly circuit races I typically average between 235 and 260 watts. Last week it chucked it down and I rode my rain bike with no PM; the dynamics of the race and average speed etc. were broadly similar to previous weeks but Strava's estimate was 381 watts!
I've seen it the other way, as well. A friend and I did the same segment, and our times were similar, but it estimated his power about 40W lower than mine. Problem is he weights about 10kg more than me! My data was actual (from my P2M), and we figure he was most likely 40W higher than mine, or a complete 80W higher than Strava's estimate.
It's rubbish.
It's rubbish.
"Deserve's got nothing to do with it." William Munny
My brother and I did the same rolling-terrain segment with a strong tailwind last weekend. We were not together, but at about the same time. Solo, no drafting.
His time: 24:38; My Time 24:39; so basically about the same.
His average Stravawatts: 209
My actual average watts on a power meter: 119
...and I outweigh him by at least 30 pounds.
Stravawatts might work in some situations, but Strava can't possible know wind conditions or if you are in a pack, so they are basically a wild guess. I don't see how there could be a consistent offset factor unless you rode exactly the same criterium at the same speed in the same pack situation a few times to analyze the data.
His time: 24:38; My Time 24:39; so basically about the same.
His average Stravawatts: 209
My actual average watts on a power meter: 119
...and I outweigh him by at least 30 pounds.
Stravawatts might work in some situations, but Strava can't possible know wind conditions or if you are in a pack, so they are basically a wild guess. I don't see how there could be a consistent offset factor unless you rode exactly the same criterium at the same speed in the same pack situation a few times to analyze the data.
- bearsdidit
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Strava is fairly accurate on climbs but worthless for group rides. There is no way for the software to account for drafting and wind.
Interesting, didn't realise how badly off Strava numbers were compared to a power meter. I didn't expect accuracy, but didn't think it could be as much as 40% off or whatever in normal conditions i.e.. riding solo, not too windy, rolling terrain..
Might have to bite the bullet and get a Stages.. not super expensive, and has decent reviews it seems.
Might have to bite the bullet and get a Stages.. not super expensive, and has decent reviews it seems.
Similar to riding in a pack: Strava doesn't understand how aero a TT bike and TT position can be and will calculate TT watts as if you'd be riding a regular road bike (and in a regular riding position).
Chains to the right!
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