Carbon wheels? What’s the ride and weight advantage
06-27-20, 11:53 AM
#51
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Radial front, 2x rear on both wheels. The DT350 hubs on my LB have a slightly narrower flange width, specifically on the NDS side. Probably to keep the tension higher on the NDS side. So that could potentially be a reason why. But I highly doubt that the lauded 350 hub would feel that much worse than a cheapo bitex RAR12. Initially I thought it was the bearing seals, but the feeling never went away. Felt like I was suffocating uphill. Mine are the AR56 btw
It’s less about material and more about depth IMO. The deeper the rim, the bigger the “lever arm” that is acting upon the hinge point (the spoke/rim intersection) and the stiffer the rim needs to be to compensate. The AR56 is insanely light for how deep and wide it is, so I’m not super surprised.
It’s less about material and more about depth IMO. The deeper the rim, the bigger the “lever arm” that is acting upon the hinge point (the spoke/rim intersection) and the stiffer the rim needs to be to compensate. The AR56 is insanely light for how deep and wide it is, so I’m not super surprised.
06-27-20, 11:58 AM
#52
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Very interesting. I did some google and found this article that explains what you're describing pretty well. I guess now the question is whether the aero benefit of the deeper rim is enough to compensate for the additional springiness of the wheel. Did you notice that you were slower on the climbs?
06-30-20, 01:17 PM
#53
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Weight savings, aero and aesthetics.
Practically speaking, there difference is quite minor, actually. I just got my 10.2kg steel bike serviced, upgraded to 105 and clad with 25mm r on Mavic tires wheelsets (royal porkers, at nearly 2000gm a pair) and took it out for today's scheduled 60' recovery spin. I compared it to the same ride from 2 weeks ago with my Dura Ace Di2 Venge with 35mm wide-rim, mid-depth wheels, which clocked in at 7.3kg.
Ride 1 is the Venge
Ride 2 is the steel bike.
Both are out and back rides along a pancake-flat coastal road that runs near my house. Admittedly, the Venge is a little hampered because the headwinds on the way out were a fair bit stronger that day, but the difference is still quite minor (looking at other rides, about 10W less for these sort of constant-effort rides).
Admittedly, the difference increases when you faster, but I have no idea where people "gain 1-2mph by changing wheels".
Practically speaking, there difference is quite minor, actually. I just got my 10.2kg steel bike serviced, upgraded to 105 and clad with 25mm r on Mavic tires wheelsets (royal porkers, at nearly 2000gm a pair) and took it out for today's scheduled 60' recovery spin. I compared it to the same ride from 2 weeks ago with my Dura Ace Di2 Venge with 35mm wide-rim, mid-depth wheels, which clocked in at 7.3kg.
Ride 1 is the Venge
Ride 2 is the steel bike.
Both are out and back rides along a pancake-flat coastal road that runs near my house. Admittedly, the Venge is a little hampered because the headwinds on the way out were a fair bit stronger that day, but the difference is still quite minor (looking at other rides, about 10W less for these sort of constant-effort rides).
Admittedly, the difference increases when you faster, but I have no idea where people "gain 1-2mph by changing wheels".
06-30-20, 02:12 PM
#54
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06-30-20, 04:14 PM
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Yeah, that was a bit of a hyperbole. At least this guys result implies that on a flat ride, a major difference in wheel and bike weight does not impact speed much.
07-01-20, 11:59 AM
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Just the wheels? Well under 1kph, IMO - you'd be lucky if it is 0,5kph. Even on climbs, a 250gm difference between wheels on a 80kg bike + rider is.. what, a 0.3% weight difference?
That said, all my bikes have carbon wheels on them. They just look bad-ass
Last edited by guadzilla; 07-01-20 at 12:09 PM.
07-01-20, 12:45 PM
#57
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i guess some folks think they look really cool.. but idunno.. i like the OPEN PRO CDs i had from colorado cyclist the best of any wheel set i have ever used... i dont think the weight savings is that big a deal unless you are fighting for seconds in a stage race... club cyclist dont really earn true bragging rights for winner of the limit sign world championships..or at least they never seem to last that long. but i guess they look cool... to some..
07-02-20, 10:45 AM
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250g on a 300m climb is 75kJ, and at 20km/h equates to 3.75W. I would expect to notice that if you're already sitting at or near FTP. Even if the speedo doesn't show a lot, it could easily be the difference between normal heading up the hill and "man, why is it so hard today"...
07-02-20, 02:12 PM
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Maybe you have a different CdA than i do, because 10W most definitely doesnt get me an additional 1mph.
As for your assertion that you can "feel" an extra 0.3% system weight when climbing at FTP, and that this extra 0.3% weight is the difference between feeling normal and "why is it so hard": if I am riding at FTP, I am riding at FTP and it is going to feel very hard no matter what - the only thing that will change is the speed - by about 0.3% (let's assume a linear W/kg math for now). Maybe that is the sort of difference that you can notice, but i sure as hell cannot.
As for your assertion that you can "feel" an extra 0.3% system weight when climbing at FTP, and that this extra 0.3% weight is the difference between feeling normal and "why is it so hard": if I am riding at FTP, I am riding at FTP and it is going to feel very hard no matter what - the only thing that will change is the speed - by about 0.3% (let's assume a linear W/kg math for now). Maybe that is the sort of difference that you can notice, but i sure as hell cannot.
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07-02-20, 03:12 PM
#61
Senior Member
On a road bike, maybe for a very small cyclist on a very efficient setup. For a typical rider, 10W will buy around half a mph at 18.5mph.
(Also, 10W from wheelset differences alone at 18.5mph would be very much at the extreme end of the spectrum.)
Watts to raise a mass through gravity on Earth's surface is roughly (mass in kg)*(rate of ascent in m/s)*9.8. To get 3.75W from a .25kg load, you'd need to be ascending at about 1.53m/s. If you're ascending at 1.53m/s while riding 20kph (which is 5.55m/s), it means that you're going up a 27.5% gradient.
Doing 20kph on a 27.5% gradient is going to be somewhere in the neighborhood of a 17-18W/kg effort. That's not "FTP" for anybody.
Professional climbers sometimes have FTPs in the vague ballpark of 6W/kg. In realistic situations, that's good enough to buy an ascent rate of up to around half a meter per second. 250g ascending at half a meter per second is about 1.2W.
And for a typical person on a road bike, the power impact of 250g on a threshold climb is well under a watt.
(Also, 10W from wheelset differences alone at 18.5mph would be very much at the extreme end of the spectrum.)
Doing 20kph on a 27.5% gradient is going to be somewhere in the neighborhood of a 17-18W/kg effort. That's not "FTP" for anybody.
Professional climbers sometimes have FTPs in the vague ballpark of 6W/kg. In realistic situations, that's good enough to buy an ascent rate of up to around half a meter per second. 250g ascending at half a meter per second is about 1.2W.
And for a typical person on a road bike, the power impact of 250g on a threshold climb is well under a watt.
