Seems like the advantages of riding a Disc wheel are overwhelming. I’ve pretty much decided that if I get some aero wheels the rear must/should be a disc but I have a few last questions. When is riding a disc a disadvantage? Why aren’t more people riding a disc instead of an deep aero wheel. Are disc wheels uncomfortable to ride for long periods of time, i.e. Ironman distances.
I have a Zipp disc and love it. I used to road race and I would use it in crits a lot. If it is very windy it would probably be best if you didn’t have it on. Make sure you have good brake pads cause if they are wet, they seem to not work as good when wet. You will notice how they will sorta carry you the faster you go. Also, don’t skimp on tires. Spend the $$$ and get something good like a conti GP19 or soemthing (tubular).
Have fun
RTD
The only time disc wheels are slower is up very steep hills. I have no idea why more top racers aren’t on disc wheels, possibly the cost.
Just a note on the previous post: disc wheels are illegal in ALL mass start road races, both UCI and USCF, and have been for as long as I can remember. DO NOT show up at a crit and expect to be able to ride your disc, you won’t be allowed to.
MH
Most top racers are sponsored! Campy might not be too happy if their sponsored athletes were riding Zipps! :),
Would you drop 30 secs per 40K for, say, a new Cervelo P3, with full DA or Campy? :), Of course, you’d probably make it up, and some, with the Cervelo P3…
–Robert
Don’t understand why anybody would run a disc at a road race. They would be negated by the aerodynamics of riding in a pack.
Just a note on the previous post: disc wheels are illegal in ALL mass start road races, both UCI and USCF
I can’t speak for UCI, but as to USCF, disk wheels most certainly are legal in all mass start events. In fact rule 1J1b) provides an explicit exception to the no-fairing rule to allow spoke covers on wheels. This has been the case as long as I can remember (12 years).
Why use them in a mass start race? If you plan on winning, you’re going to have to leave the pack sometime.
Tony Geller
"Don’t understand why anybody would run a disc at a road race. They would be negated by the aerodynamics of riding in a pack. "
I couldn’t agree with you more, and on top of this, discs are sketchy in a group - you never know when you are going to get hit with a cross wind. Gust. Swerve. Chop. Crunch. Ouch.
MH
To answer why one would ride a disk in a crit or road race, they are usually much more stiff and responsive to a regular spoked wheel. In a sprint there is no wheel flex whatsoever. Try one sprinting one day and you’ll se what I mean.
Can’t say that they are heavier either. A Zipp disc weighs around 900 to 950 grams. Some so called “race wheels” weigh just as much if not more. The Campy carbon Eurus weighs 954 g, Mavic Ksyrium SSC SL rear weighs 940g. Spynergy Tillium Carbon rear is 850g.
Also, disks have always been legal in USCF road races. I’ve used one and so have many others that I have known.
Rusty
No, disc wheels are not legal in USCF races. As you correctly point out, spoke COVERS are legal; discs however are not. You can run a J-disc, or a homemade kevlar contraption, or anything that constitutes a fairing on a spoked wheel, but you can’t ride a solid or structural disc wheel. Totally stupid, but that’s the rule.
MH
I should have quoted rule 1J1c)
“Wheels may be made with spoked or solid construction. No wheel may contain special mechanisms to store and release energy.”
This comes in the general rules section. There are no exceptions made in the road, circuit or criterium sections to alter this.
I went back and read the rule, and you are correct about 1J1c, however, 1J1B says “there may be no protective shield, fairing or other device on any part of the bicycle that has the effect of reducing air resistance, except that spoke covers may be used.”
On re-reading the rule, I agree that your interpretation of it may well be valid, however, I have on more than one occasion seen riders excluded from races because they were riding discs, and the official was interpreting the rule to mean “covers OK, discs not.” In fact, at a 'cross nationals race a couple of years ago, the head ref used this rationale to dismiss a contested finish argument - the rider in question was running a J-disc.
The rule, as it is written, may well be ambiguous - “solid construction” is allowed, but fairings “other than spoke covers” are not. If a disc wheel is seen as both structural and a fairing, under the letter of the rule, it would not be allowed, but it may be (allowed) under the spirit of the rule. Interpretation by the head official is the key here.
My take is, technically, I think you are incorrect, but in the spirit of the rule you may well be correct - but I wouldn’t want to bank my race on that.
MH
Just did a duathlon with some very steep hills…I think I was the only one out there with a disc wheel. I only had a couple of people pass me uphill, but on the downhills, I was able to coast as fast as some others pedaled; sometimes passing pedalers while I coasted…if the hill was steep enough, and never had anyone that caught or passed me on the flats or downhills. As for the riders I tended to swap places with, I’d leave them on any flat or downhill, or even slight uphill. If I got caught, it would be near the top of very steep walls. I don’t know if this difference is simply because I weigh 20-40 lbs. more than them, or if it was partly due to the disc wheel. It could also be because I’m 10-20 years older than them!
I rode this 30K course over 6 minutes faster than last year, but, I certainly don’t think it was all because of a disc wheel…mostly it’s because my power is better. One guy said he drafted off of me whenever I’d go by him, then he’d reach the next summit ahead of me and catch the draft again as I came by on the next downhill/flat. I suspected he was drafting at least sometimes, because at the speed I was passing him I didn’t see how he could catch up to me on some of those uphills. Nothing I could do about it, I was racing clean and never looked back to see how close he was. However, he said he’d use a disc next year after seeing one ridden on this course.
Unless you’re small or not real strong, I don’t think riding a disc on a net-zero climb race course would hurt you uphill as much as it helps downhill or on the flats…unless the downhills are so technical that you’d have to brake…that would negate some of the disc’s benefits.
I have a Zipp disc and love it. I used to road race and I would use it in crits a lot.
Have fun
RTD
Rusty D,
Is this a mistake? Discs have never been allowed in crits to my knowledge.
I don’t doubt you have seen disks excluded from races but this is a clear misinterpretation of the rules. 1J1c) explicitly allows wheels of solid construc tion (disks). 1J1B) excludes protective fairings “on any part of the bicycle.” that is added onto the bike. Therfore structural components are allowed (think Trek y-foil). The wheel cover excception was added to 1J1b) to allow people the benefit of structural disk wheels without the great expense (at the time) through the use of wheel covers.
This is not my personal opinion but is what I was taught in getting my officials license here in new Mexico.
Tony Geller
Back in the day I used a disc numerous times in crits and RRs. That was my race wheel of choice. The down side to it is when you are gonna jump everybody knows cause it can be heard.
Hey,
As far as disc wheels go in the comfort dept. I have used them in IM distance races and felt no adverse feelings above and beyond the feelings you get from sitting your butt on a saddle for that long (no small issue there). As far as mass start events, there has never been a time that they were not allowed (except on the front of the bike). If you want a real good example of how effective they are, check out pictures from national and world championship velodrome racing, particularly the match sprint. You will see, almost without fail, a trispoke on the front and disc on the back. In match sprint there are 2 things most important, acceleration and top end. If a disc wasn’t the best wheel for the back, they wouldn’t use them. In tri’s and TT’s and bike races, acceleration and top end are all factors we have to deal with every pedal stroke. A hill has to be very steep for a spoked wheel to be an advantage, because the speed would have to be very slow for moment of inertia of the hooped wheel to cease being as much of a factor. I took physics a long time ago, but I remember that the moment of inertia of a disc is something like 1/3 that of a hooped wheel in the most simple of settings (equal diameter and mass). Granted, there are a ton of other factors that influence MOI beyond this simple generalization (discs are usually heavier for the same diameter), but for the most part a disc will be faster. On a hilly course, consider how much of the time you will be descending and riding flats or rollers. If the majority of your time is spent climbing (really climbing, like a time trial up Mt. Ventoux) then really light spoked wheels should be the ticket (watch the tour, see what they ride) but do you really see this happening often enough to pass up the advantages of riding a disc all the other times you race? Good luck, race well, and get a good disc. You’ll love the cool noise (yes it is energy being wasted, but not alot). Oh yeah, MOI is loosely defined as the amount of energy requied to impart a change in the rotational velocity…sort of. If anyone disagrees with me, please let me know, I would love to hear your thoughts. I think I am right on this, but I could be wrong.