Losing watts with a pair of bora ones

[ArizonaPie]

Hi everyone,

I've been riding a pair of yoeleo C50s for the last few years and bought a set of Bora One 50 to upgrade them at the end of 2020. I only tested them quickly at the end of the season last year, but on a hill climb segment I usually train in, I noticed I needed around 10 more watts to do the same time. I thought it was just different weather conditions, didn't think too much about it and stored them for the winter/spring. But now that the weather is better I have put them back on the road bike and I have still noticed the same thing. While riding with a mate two weeks ago, I had the Yoeleos on and we were doing the same watts up hills (between 0 and 2watts difference judging from strava); whereas last week end, when I took out the Boras and rode with the same mate, I was putting out 10 more watts than he did on each climb (between 8 and 13 watts difference).

I wanted to do one more test today, so I checked the Bora Ones prior to going out: my rear hub seems pretty fine, the bearings are very smooth which contrasts a lot with the Yoeleo's that are actually pretty worn out at the moment, I even swaped the quick release skewers just in case. The only thing I did not swap was the cassette which is an 11-30 on the boras and 11-28 on the yoeleos but I suppose it should not affect the results when climbing to watts (I might be wrong though).
I then went out 3 times up the hill climb of my training segment and compared the results with previous climbs, I estimated that I lose between 8 and 17 watts for the same climb time with the Boras (the faster I go, the more I lose). I might do one more attempt tomorrow with the yoeleos just to confirm everything, as the weather condition will be very similar, but it really doesn't look good for the BO 50s (especially when considering that the bearings of the yoeleos are close to dead).

I don't really see what could be wrong on this pair of wheels tbh. I bought the pair of Bora One 50s from a shop that got them out of a pro team after a few races. They said they checked everything and I can't see anything wrong esthetically nor mechanically, but maybe they've just been worn out too much or something like that. The only thing I can think of otherwise is that they somehow don't work well with my bike (a Canyon Aeroad), but that would be strange as well. If anyone has pointers to what I could check, that'd be very much appreciated.

[spdntrxi]

tires ?

[pdlpsher1]

The Bora One has a 17mm internal rim width. If the Yoeleo wheel has a wider width then you must increase the tire pressure on the Bora so that both wheels have the same tire casing tension. You must adjust the air pressure for wheel/tire width differences or else the comparison would be invalid. Since you're comparison is done on a climb the only contributing factors to any power differences would be the tire's rolling resistance. The bearing drag loss are too small to be in the picture.

I have two sets of pre-WTO Boras, one set of Ones and one set of Ultras. These are fantastic wheels with very low bearing drag due to the angular contact bearings used.

[Alexandrumarian]

fastest vs average tires and tubes, or clincher vs tubular can easily make a 10-15W difference, but on the flat...
When climbing that reduces to 1/3, maybe 1/2 if you climb fast, but still not very obvious.

I wonder if the preloads are too tight. I like mine just close enough that they do not have any obvious play, but if i really yank on the axle i feel a little bit of give. And if unsure, the final test can be on the road. Ride a bit, check if wheel developed a bit of play. If yes, tighten the ring a tiny bit, go for a bit more etc. Stop when no play or go back a little. Only small 1-2mm ring advancements. Do not overtighten the lock screw, only enough to close the slit shut. I find my boras, in the hand, feel faster and easier to spin, but also noisier and "grittier" compared to the cartridge bearing hubs. Those are more silent, smooth, but slow in the hand. I have 240 too, stops much faster. All pretty meaningless on the road where rr and aero take over...

[TobinHatesYou]

Don't do a climb for your wheel test. Do a rolldown test on a gentle descent that flattens out.

[Hexsense]

Since the tests are so far apart. And it's climbing.
Have you check your body weight scale accuracy? Ignoring that people weight fructuate 1-2kg easily pre and post ride lost by sweat.
Even if it say the same number but you may accidentally gain/lost a few kg. That easily require a lot more power to climb.

Also, brake rub?

[ArizonaPie]

Thanks for the answers.
Regarding weight I'm generally around the same weight +/-1 kg during the season so it shouldn't affect the results a lot especially on short climbs. I don't think the brakes rub during the ride (they don't for sure when I checked statically) and I'm climbing mostly seated, plus the boras are stiffer than the yoeleos, I'll pay attention during the next ride just in case though.

I use the same type of tubulars on both wheelsets (Conti sprinters in 25mm). Pdlpsher1 pointed out that if one rim is thinner than the other one there is a need for a change in pressure. It might be just that because the boras are 24mm wide when the yoeleos are 25. And just by looking at the tyre when I'm on the bike I felt it was more flattened on the road compared to what I'm used to on the yoeleos. I pump them up to the same pressure on both pairs usually (9 bars) so I'll try to add 1 to 1.5bars and see if it changes things up.

[Alexandrumarian]

I think he was talking about clinchers. 24 vs 25mm (Bora is actually 24.5) tubular rims...really zero need to change pressures imho. You could consider trying more like 7.5-8 bar instead of 9, for comfort if anything, unless you are 230 pounds. I am 210 and use 8bar for 23mm front tubular, 8 rear for 25mm. Can go as low as 6.5 with a 28mm on a bad road. I never found any speed gain (backed by careful power meter testing) when using super high pressure, just a lot of handlebar buzz...

Either way, 1 kilo or 1 bar of difference never makes 10W of difference....

[ArizonaPie]

So I have been able to ride with the same mate again two days in a row. I tried pumping up my tubulars a notch at 10bars this week end and on two 1h30 climbs we got exactly 7w difference each time (I was at 8 bars actually last time we rode together, which might explain the 3w improvement compared to the previous test). There's definitely something less efficient with the boras. I'm still wondering if it'd perform better with 23-24mm tubulars, but gaining 10w like that would be very surprising.

[smokva]

So I have been able to ride with the same mate again two days in a row. I tried pumping up my tubulars a notch at 10bars this week end and on two 1h30 climbs we got exactly 7w difference each time (I was at 8 bars actually last time we rode together, which might explain the 3w improvement compared to the previous test). There's definitely something less efficient with the boras. I'm still wondering if it'd perform better with 23-24mm tubulars, but gaining 10w like that would be very surprising.

I don't understand why are you comparing your power with someone elses. Also 7W doesn't mean much if we don't know what is this number relative to total power.
For example if your effort was average 270W (this number looks resonable) than 7W/270W = 2,59% Most powermeters have accuracy +/- 2%. So if you and your riding mate were on oposite range of accuracy you can have difference of up to 4% on powermeters only.

You should try both wheelsets yourself with same tires and tubes, on the same bike (with same powermeter), same road (or same indor trainer) and on the same time (same part of the day with same conditions). Use the same average power for both tries (try not to vary much from average power and go with sustainable power) and see your times. When you do this you'll eliminate most of the other reasons that might explain power differences:
- different riders (weight, body position)
- different bikes (different equipment, efficiency and maintenance of parts)
- different powermeters (accuracy and consistency of each powermeter is different)
- different day (humidity, temperature, air pressure...change in the weight and fitness of rider....change in the performance of bike parts with time).

When you do this test you will have test results that support your claim and than you will know that there are no other factors which contribute to it.
If you do this test on static trainer have in mind that front wheel is not contributing with losses since it is not spinning, so if there is no difference in measurment its either there is no difference or the whole diference comes from the front wheel....so you might want to repeat test on the road

[ArizonaPie]

So I have been able to ride with the same mate again two days in a row. I tried pumping up my tubulars a notch at 10bars this week end and on two 1h30 climbs we got exactly 7w difference each time (I was at 8 bars actually last time we rode together, which might explain the 3w improvement compared to the previous test). There's definitely something less efficient with the boras. I'm still wondering if it'd perform better with 23-24mm tubulars, but gaining 10w like that would be very surprising.

I don't understand why are you comparing your power with someone elses. Also 7W doesn't mean much if we don't know what is this number relative to total power.
For example if your effort was average 270W (this number looks resonable) than 7W/270W = 2,59% Most powermeters have accuracy +/- 2%. So if you and your riding mate were on oposite range of accuracy you can have difference of up to 4% on powermeters only.

I'm comparing to someone else because he's riding at the same time with the same condition and I already have several points of comparison with him: as stated in my original post, when we rode a few weeks ago with the Yoeleos we had the exact same wattage on climbs. When changing my wheels - and only my wheels, same bike, same power meters, same guys pretty similar weight - I had +10w at 8.5-9bars and +7w at 10bars 2 days in a row.

I was around 230w during the climbs (and he was around 220w obv) and we both have assiomas btw which are +-1%. But it's not relevant to the result. He's just my point of comparison, the power numbers do not really matter. I should be able to ride with someone who outputs 100w more I'd still see the difference between the two wheelsets.

[themidge]

Not sure about the wheels, maybe they're just less aero?

But I have to ask, what on earth are you doing putting 8.5-10bar (~120-145psi) in your tyres??? Unless the roads are like a billiard table you'll be faster with lower pressure, no matter which wheels you ride.

[TobinHatesYou]

Perform a rolldown test already, or stop posting useless anecdotes. Do several runs with each setup as well.

[ArizonaPie]

Not sure about the wheels, maybe they're just less aero?

But I have to ask, what on earth are you doing putting 8.5-10bar (~120-145psi) in your tyres??? Unless the roads are like a billiard table you'll be faster with lower pressure, no matter which wheels you ride.

It's possible they're lacking in aero as they have different shapes (V for the boras U for the yoeloes).

10bar was just for this test and it was an actual billiard table. I've used 8.5-9bar since I've switched to 25mm tubulars and I don't find it uncomfortable (I used to put 7bar in 23mm clinchers prior), but the roads are indeed in quite good conditions around me.

[Steve Curtis]

Maybe the campagnolo marketing BS is more advanced than their technical capabilities.