Road Bike Racing - Wheel covers on "mass start bike" TT

I am told that discs and TT helmets (US CPSC approved) are allowed. But I can't figure out about wheel covers. Any thoughts? The bike and ride must comply with mass start road bike requirements. Just to clarify this is a TT (not a mass start TT) where mass start legal road bikes are required.

I think wheel covers must be allowed if disks are allowed. Just my $.02

My general thought was also that they should be allowed.

What are you allowed to put on the front wheel? Tri spokes? or standard wheel?

Can't imagine why a disk would be okay but wheel cover not.

What are you allowed to put on the front wheel? Tri spokes? or standard wheel?

Can't imagine why a disk would be okay but wheel cover not.

Wheel covers aren't structural.

Right. There is some USAC exemption for wheel covers but I haven't found it to figure out if it's specifically for TTs. The front wheel is anything mass start road race legal. I don't know about the legality of a 3 spoke, pretty sure at least some of them are mass start legal(??) but I have a ZIPP 404 :)

If you're already running 404s, is the hassle worth it?

Zipp says at 300 watts over 40km, 404/404 vs 808/disk is 20 seconds, about 8 of which is the difference between the 404 and the 808 on the front. So that leaves you 12 seconds for the back, and that assumes the cover is just as good as the disk.

http://www.zipp.com/Portals/0/Technology/Documents/ZippAeroEdgeFlyer_2.pdf

Would I do it? Sure, more out of my natural desire to screw around with my bike if nothing else. But if there are wind issues out there, I might decide not to.

[I think I just convinced myself not to buy a disk.]

Right. There is some USAC exemption for wheel covers but I haven't found it to figure out if it's specifically for TTs. The front wheel is anything mass start road race legal. I don't know about the legality of a 3 spoke, pretty sure at least some of them are mass start legal(??) but I have a ZIPP 404 :)

http://www.usacycling.org/forms/RdTrkCx_rulebook.pdf 1J specifically sections b and c.

But if there are wind issues out there, I might decide not to.

Putting more surface area behind the steering axis makes a bike more stable in a crosswind, not less.

http://www.usacycling.org/forms/RdTrkCx_rulebook.pdf 1J specifically sections b and c.

So "except that spoke covers may be used" ... sounds like I am OK.

Good luck at GMSR! Looks like a fun course, they have switched it around a bit last minute but still looks sweet. I cannot make it but will watch the crit on Monday.

What cat are you with?

Good luck at GMSR! Looks like a fun course, they have switched it around a bit last minute but still looks sweet. I cannot make it but will watch the crit on Monday.

What cat are you with?

Thanks! I am in 4B. They took away the hill climb but thats OK. Saturday and Sunday are each 10 miles longer than last year, I think. The ITT without a TT bike kills me. I just finished putting together a TT bike when they sent out an e-mail saying "Oh btw, no TT bikes allowed" but what can you do. Obviously I am doing everything I can do be aero and I think a lot of guys will NOT have wheel cover + TT helmet + skinsuit + removed water cages. Now if I can just get the motor started!!!

Putting more surface area behind the steering axis makes a bike more stable in a crosswind, not less.

Not sure I'm getting that. If you hold surface area constant, I'm sure it's true that having more behind axis is better than having it in front, but putting a wheel cover on is going to increase the surface area (maybe cross section is better phrase) exposed to the wind.

Not sure I'm getting that. If you hold surface area constant, I'm sure it's true that having more behind axis is better than having it in front, but putting a wheel cover on is going to increase the surface area (maybe cross section is better phrase) exposed to the wind.

No, not holding area constant, adding more surface area. Adding more area behind the axis increases the ratio of area behind the steering axis to in front of it. This results in a more stable ride. Though the total side force may increase, that is not what makes a bike unstable. Instability is caused by the wind acting on the front wheel.