I’m on the fence about buying either a disc-cover,e.g. from Wheelbuilders, or buying a used rear disc wheel, e.g. HED Jet disc, which can be had for as low as $600. I don’t have PT (and probably won’t b/c I’m in the process of buying an SRM). The disc-cover would probably go on my Reynolds DV66T.
Any thoughts? What have been your experiences with either of these options?
Cover costs about $100 and provides the same aerodynamics of a true disc. Flexibility of removing the cover if you need to. Cover can be easily added to a PT hub wheel. I have absolutely no idea why anyone buys a true disc. I think it’s because people believe if it’s more expensive it must be faster, but not true. I’ve been using home made disc covers for 20 years and never had a problem.
As you’ll hear over and over, and you’ll find if you search the forum for your thread title, it depends.
Do you do UCI governed Time Trials?
Do you fly to your races (have luggage/weight/space restrictions)?
Do you have the budget for the disk as well as your current wheels?
I’ve used a Wheelbuilder Aerojacket wheel cover for many races with my Zipp 808 rear. I love the fact that I have options on race day if it’s windy, and I don’t have to travel with 2 rear wheels to get that flexibility.
The Aerojacket cost me USD99 and doesn’t cost me any more to travel with to races o/s.
The HEDs is kinda a covered spoked wheel. In that that case you can do it your own. Aero are all.
He big difference is the weight ( if that matters) the dough and the sound.
I’m asking me the same question right now, off season boredom I guess.
Economics aside, has there ever been an objective study done comparing the aerodynamics of a wheel cover versus a true disc? Specifically, I was wondering how the dishing of a conventional wheel with a cover compares to the narrower flat sidewall profile of a true disc.
Mark
A real carbon disc (e.g. Zipp) looks better, is lighter and more importantly sounds amazing compared to a wheelcover. Notice I didnt say faster.
Economics aside, has there ever been an objective study done comparing the aerodynamics of a wheel cover versus a true disc? Specifically, I was wondering how the dishing of a conventional wheel with a cover compares to the narrower flat sidewall profile of a true disc.
Mark
The wheelbuilder site has a chart with wind tunnel results for a number of combinations. A covered 30 mm deep wheel didn’t do quite as well as a real disk at low yaw, but did well at high yaw. A covered Zipp 808 was the fastest combination they tested. I’d imagine the results depend on how well the cover mates to your rim, and how well it’s installed. A sloppy fit with a gap probably won’t do as well as a real disk, a tight fit on the right rim will be just as good.
Wheelbuilder looks like they are having a sale on their aerojackets for $69 and I was thinking of picking one up. Problem I have is I don’t have the typical wheelset that is listed on their wheel selection when ordering, I’ll have to pick “Other” in the “Please select wheel type” drop down. My wheel choice to work with is the Felt TTR3 or the Mavic Aksium. Has anyone ordered an aerojacket for either of these wheels and if so what has your experience been?
One here:
http://www.wheelbuilder.com/aerodisc-data.html
biketechreview.com has another that you can pay for.
In both cases those tests were done with the plastic bolt method of attachment. The electrical tape method might be a hair faster still.
Economics aside, has there ever been an objective study done comparing the aerodynamics of a wheel cover versus a true disc? Specifically, I was wondering how the dishing of a conventional wheel with a cover compares to the narrower flat sidewall profile of a true disc.
Mark
If I’m reading this right though, at lower yaw angles, the disc cover would reduce drag by 30g on a standard box rim.
If I go by Flo cycling’s data, the Flo 30s save more than that at low yaw over a standard box rim. Does that mean that in that case, a disc cover would actually be slower?
One here:
http://www.wheelbuilder.com/aerodisc-data.html
biketechreview.com has another that you can pay for.
In both cases those tests were done with the plastic bolt method of attachment. The electrical tape method might be a hair faster still.
Economics aside, has there ever been an objective study done comparing the aerodynamics of a wheel cover versus a true disc? Specifically, I was wondering how the dishing of a conventional wheel with a cover compares to the narrower flat sidewall profile of a true disc.
Mark
It probably just means wheelbuilder used a more aero baseline wheel.
Yeah, Flo used a Mavic Open Pro vs a ‘30mm alloy’ on the wheelbuilder test.
Some 30mm alloy wheels are not bad, the Mavic Open Pro is especially bad.
If I’m reading this right though, at lower yaw angles, the disc cover would reduce drag by 30g on a standard box rim.
If I go by Flo cycling’s data, the Flo 30s save more than that at low yaw over a standard box rim. Does that mean that in that case, a disc cover would actually be slower?
One here:
http://www.wheelbuilder.com/aerodisc-data.html
biketechreview.com has another that you can pay for.
In both cases those tests were done with the plastic bolt method of attachment. The electrical tape method might be a hair faster still.
Economics aside, has there ever been an objective study done comparing the aerodynamics of a wheel cover versus a true disc? Specifically, I was wondering how the dishing of a conventional wheel with a cover compares to the narrower flat sidewall profile of a true disc.
Mark
Wheelbuilder looks like they are having a sale on their aerojackets for $69 and I was thinking of picking one up. Problem I have is I don’t have the typical wheelset that is listed on their wheel selection when ordering, I’ll have to pick “Other” in the “Please select wheel type” drop down. My wheel choice to work with is the Felt TTR3 or the Mavic Aksium. Has anyone ordered an aerojacket for either of these wheels and if so what has your experience been?
I’ve never ordered one for either rim but I would think the TTR3 would be easier to work with since it’s quite a bit deeper, so the fit doesn’t need to be as precise. And the deeper rim would allow you to use tape which might be a bit more aero as Jack says.
Thats a good point that I didn’t consider. I was considering weight being my biggest concern, but that may be a pretty big factor to consider as well.
Wheelbuilder looks like they are having a sale on their aerojackets for $69 and I was thinking of picking one up. Problem I have is I don’t have the typical wheelset that is listed on their wheel selection when ordering, I’ll have to pick “Other” in the “Please select wheel type” drop down. My wheel choice to work with is the Felt TTR3 or the Mavic Aksium. Has anyone ordered an aerojacket for either of these wheels and if so what has your experience been?
I’ve never ordered one for either rim but I would think the TTR3 would be easier to work with since it’s quite a bit deeper, so the fit doesn’t need to be as precise. And the deeper rim would allow you to use tape which might be a bit more aero as Jack says.
I made my own for the TTR3. Easy to do. patersonpaul is selling ABS sheets pretty cheap.** **
