Anyone care to guess how many watts I would save upgrading by old Shimano 7900 C50 aero wheels with Grand Prix 20 on front and 23 on rear vs Hed 6+ wheels with 23 Grand Prix tires both with latex tubes?
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Re: How many watts saving old wheels vs new [pokey]
[ In reply to ]
pokey wrote:
Anyone care to guess how many watts I would save upgrading by old Shimano 7900 C50 aero wheels with Grand Prix 20 on front and 23 on rear vs Hed 6+ wheels with 23 Grand Prix tires both with latex tubes?How fast do you typically race at?
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Re: How many watts saving old wheels vs new [Thomas Gerlach]
[ In reply to ]
FTP about 3.7 if that helps, looking at Ironman Whistler this year most other races are also quite hilly, I also have a set of older Easton EC90TT wheels.
Re: How many watts saving old wheels vs new [pokey]
[ In reply to ]
At low yaw, probably 5-6 watts at 40kph. Probably considerably more in the 10-15* yaw range, but, if you can ride @ 40kph, you probably won't be spending all that much time at yaw's beyond 10*
That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
"They're made of latex, not nitroglycerin"
That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
"They're made of latex, not nitroglycerin"
Re: How many watts saving old wheels vs new [gary p]
[ In reply to ]
gary p wrote:
At low yaw, probably 5-6 watts at 40kph. Probably considerably more in the 10-15* yaw range, but, if you can ride @ 40kph, you probably won't be spending all that much time at yaw's beyond 10* That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
At low yaw, I wouldn't be confident of any saving at all.
Re: How many watts saving old wheels vs new [Ai_1]
[ In reply to ]
Yes, that's why I asked the question, when I read FLOs web site it said something like we spend about 2/3rds of the time at 0-5%, and looking at various comparisons of wheels there appears to be very little differences in aero wheels at low yaw.
Re: How many watts saving old wheels vs new [pokey]
[ In reply to ]
That sounds more realistic.
Older style aero wheels were okay at low yaw. It's drag and stability at higher yaw angles that had lots of room for improvement. I'd be very surprised if there was large gains to be made at low yaw with relatively narrow tyres. Wider tyres may benefit more from a move to more modern aero rims.
Older style aero wheels were okay at low yaw. It's drag and stability at higher yaw angles that had lots of room for improvement. I'd be very surprised if there was large gains to be made at low yaw with relatively narrow tyres. Wider tyres may benefit more from a move to more modern aero rims.
Re: How many watts saving old wheels vs new [Ai_1]
[ In reply to ]
Ai_1 wrote:
gary p wrote:
At low yaw, probably 5-6 watts at 40kph. Probably considerably more in the 10-15* yaw range, but, if you can ride @ 40kph, you probably won't be spending all that much time at yaw's beyond 10* That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
Do you have a source for those figures?
At low yaw, I wouldn't be confident of any saving at all.
No direct source (i.e. Jet6+ & 7900C50 in the same test), thus the qualification "probably." I inferred that from the ProCycling aero wheel velodrome test in which the Roval CLX64 needed ~6.5 watts less to maintain 40kph than the Dura Ace C50 alloy/carbon composite wheel (and most other wheels in the test). Tom A's wind tunnel tests seems to show that the CLX64 and Jet6+ are very close in performance, and I'm making an assumption that the 7900 C50 won't perform considerably different than the DA C50 composite. That last assumption is the biggest leap in my conclusion.
[EDIT] I attempted to upload a .pdf of the test, but the file size exceeds the forums limits. I've been unable to find a link to the test online since I downloaded it. The original link I used was on the Swiss Side website, but it's now gone. [/EDIT]
"They're made of latex, not nitroglycerin"
Re: How many watts saving old wheels vs new [gary p]
[ In reply to ]
gary p wrote:
Ai_1 wrote:
gary p wrote:
At low yaw, probably 5-6 watts at 40kph. Probably considerably more in the 10-15* yaw range, but, if you can ride @ 40kph, you probably won't be spending all that much time at yaw's beyond 10* That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
Do you have a source for those figures?
At low yaw, I wouldn't be confident of any saving at all.
No direct source (i.e. Jet6+ & 7900C50 in the same test), thus the qualification "probably." I inferred that from the ProCycling aero wheel velodrome test in which the Roval CLX64 needed ~6.5 watts less to maintain 40kph than the Dura Ace C50 alloy/carbon composite wheel (and most other wheels in the test). Tom A's wind tunnel tests seems to show that the CLX64 and Jet6+ are very close in performance, and I'm making an assumption that the 7900 C50 won't perform considerably different than the DA C50 composite. That last assumption is the biggest leap in my conclusion.
[EDIT] I attempted to upload a .pdf of the test, but the file size exceeds the forums limits. I've been unable to find a like to the test online since I downloaded it. [/EDIT]
Re: How many watts saving old wheels vs new [Ai_1]
[ In reply to ]
Ai_1 wrote:
gary p wrote:
Ai_1 wrote:
gary p wrote:
At low yaw, probably 5-6 watts at 40kph. Probably considerably more in the 10-15* yaw range, but, if you can ride @ 40kph, you probably won't be spending all that much time at yaw's beyond 10* That's just the aero. Don't have an answer for you on the .crr difference between the 20 an 23 tire.
Do you have a source for those figures?
At low yaw, I wouldn't be confident of any saving at all.
No direct source (i.e. Jet6+ & 7900C50 in the same test), thus the qualification "probably." I inferred that from the ProCycling aero wheel velodrome test in which the Roval CLX64 needed ~6.5 watts less to maintain 40kph than the Dura Ace C50 alloy/carbon composite wheel (and most other wheels in the test). Tom A's wind tunnel tests seems to show that the CLX64 and Jet6+ are very close in performance, and I'm making an assumption that the 7900 C50 won't perform considerably different than the DA C50 composite. That last assumption is the biggest leap in my conclusion.
[EDIT] I attempted to upload a .pdf of the test, but the file size exceeds the forums limits. I've been unable to find a link to the test online since I downloaded it. [/EDIT]
Do you know what tyres were used?
23c Conti GP TT
"They're made of latex, not nitroglycerin"
Re: How many watts saving old wheels vs new [pokey]
[ In reply to ]
Probably not enough for you to notice. The ride might be a little more forgiving with newer wheels as you will have better stability in crosswinds.