A Few Questions on Rims

[The Saint]

Other than the obvious differences of weight and price what makes a deep cut rim or a disk rim better than you normal stock standard rim?

 

Also from my limited experience in cycling why is it that the pros ride with a disk wheel in a time trial but not in a normal stage?

 

I would also imagine that a disk wheel would be difficult to ride with if you had a strong cross wind, but the pros still seem to prefer this type of wheel in the time trial - why?

[pastapouch]

You don't wanna ride in normal races(you;re not alowed to) , because of safety. Its designed to cut throught the wind, and makes control difficult, reducing wind resistance. And TT rules would not allow you to use a disk if there's very strong cross winds. A deep section rim is just more aero dynamic than standard section rims. All in all, in SA where there isn't any notible hills, I'd go for deep section rims for the aero adv oppsed to superlight rims. do a search on rims/disk wheels etc, there was a discussion on the site a while ago...

[Spinnekop]

Other than the obvious differences of weight and price what makes a deep cut rim or a disk rim better than you normal stock standard rim? 

 

Well.  You have more aerodimanics on the deep section rims.

Secondly' date=' most deep sections are what the call Tubbies.  It is a lighter wheelset and uses different tyres to your normal Clinchers

 

Also from my limited experience in cycling why is it that the pros ride with a disk wheel in a time trial but not in a normal stage?

 

Elite riders are, as far as I know, not allowed to use a disk in a normal race.  Only in TT.

 

 

I would also imagine that a disk wheel would be difficult to ride with if you had a strong cross wind' date=' but the pros still seem to prefer this type of wheel in the time trial - why?

[/quote']

 

Last time I heard, disk wheels are heavy.  And if there is a cross wind, you get blown off.   I think it was Darren Lill that was blown of last year or the previous in the Giro.

 

The aerodynamic advantage the disk wheel gives you, is amazing!!  Every second to win........
But if the wind blows, no one will use it.

 

Hope this helps.

[The Saint]

Thank you, yes it does help.

[ZippIt]

the disc wheels they make now are pretty similar in weight to normal wheels -eg Zipp disc = 930g

I think the campy one is even lighter..

 

The legal rim depth limits for road races are 808 (= 81mm) on the rear and 404 (= 58mm) on front (i think)

 

The main advantage with deep section wheels is that the spokes are shorter and the part of the spoke that is moving fastest is closer to the hub - so in effect the fastest moving part of the wheel is also the most aero being solid. Also the fact that the air entering the the front wheel is not disturbed as much and the are leaving the rear wheel is smoother

 

Not sure about the Darren Lill thing because the only TT in the giro is a hill climb