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-   -   tire question (http://www.bikeforums.net/track-cycling-velodrome-racing-training-area/747662-tire-question.html)

mcafiero 06-29-11 04:41 PM

tire question
 
currently I'm riding some conti 23's on my old Gios Pista and I have less than 1mm clearance between the tire and the bridge near the top of my seat stays.

I have been encouraged to seek out a smaller tire. I see that the Conti GP Attack tires come in a 22, but on the web site, it refers to that as the front wheel size.

Any ideas? As crazy as it looks to have such little clearance, I don't see what sort of danger that could put me in. After all, it IS clearing.

carleton 06-29-11 05:16 PM

What model tire are you using?

Will you provide a photo of the problem?

mcafiero 06-29-11 11:13 PM

Quote:

Originally Posted by carleton (Post 12858238)
What model tire are you using?

Will you provide a photo of the problem?

Ya I'll try to do that tomorrow

TejanoTrackie 06-30-11 05:35 AM

Rear tire clearance at the seatstay bridge varies with the wheel position in the dropouts. As long as the tire clears the bridge when the wheel is all the way forward in the dropouts you are ok. Does the tire clear the back of the seatube with the wheel fully forward in the dropouts?

mcafiero 06-30-11 09:19 AM

Quote:

Originally Posted by TejanoTrackie (Post 12860147)
Rear tire clearance at the seatstay bridge varies with the wheel position in the dropouts. As long as the tire clears the bridge when the wheel is all the way forward in the dropouts you are ok. Does the tire clear the back of the seatube with the wheel fully forward in the dropouts?

I pushed the wheel forward to the very front of the dropouts and no it does NOT clear the bridge on the seat stays. But if it did, it would also not touch the seat tube. So good on seat tube, bad on seat stays :/

I should probably give up and just get one of these: http://www.pinarello.com/eng/xtrack_451.php

mcafiero 06-30-11 09:23 AM

1 Attachment(s)
here's a pic http://bikeforums.net/attachment.php...hmentid=208702

mcafiero 06-30-11 09:24 AM

oh and the current tire are conti gatorskins

chas58 06-30-11 10:20 AM

Not all frames are going to allow the tire to go all the way forward. In general, if there is no rubbing (no missing paint near the wheel/frame interface) you may be OK.

The risk is that one day you will crank down hard on acceleration, the nut will slip and your tire will jerk forward against the frame, and basically lock up. That could be nasty.

20mm Conti supersonics may be an option. Another option may be to add an extra link to your chain to get your tire away from the frame (if you are already forward in your dropouts). Another option would be to get one of those doohickeys for your drop outs to lock the wheel in place.

mcafiero 06-30-11 11:01 AM

Quote:

Originally Posted by mcafiero (Post 12860991)
oh and the current tire are conti gatorskins

Any sort of disadvantage of running a 700x20 tire?

Kayce 06-30-11 11:35 AM

As long as the fit is good on the rim, and you take care of them its just fine. But you wont really gain that much more clearance. If you were to go tubie and get some 20s or even 19s you would be much better off. Another option to avoid what chas was talking about is to get a chain tug. A cheap crappy bmx style one would work just fine, and avoid that problem all together.

Ray R 06-30-11 02:42 PM

Conti Sprinters are 22mm, but you'd have to switch to tubulars. Italian track bikes often have very little clearance between forks/stays and tires. I couldn't use a 23mm tire on my Colnago Master Pista. The tire would just clear the stay brace in back, but wouldn't clear the fork crown in front.

bitingduck 07-02-11 12:18 PM

Quote:

Originally Posted by chas58 (Post 12861298)
The risk is that one day you will crank down hard on acceleration, the nut will slip and your tire will jerk forward against the frame, and basically lock up. That could be nasty.

I don't think I've ever seen this happen mid-race- it's usually pulling off the rail or in a standing start when you're putting out a lot of force for the initial acceleration. And in any case, whenever I've seen it the wheel gets pulled all the way to the chainstay and rubs there, making clearance at the seat tube moot.

Quote:


20mm Conti supersonics may be an option. Another option may be to add an extra link to your chain to get your tire away from the frame (if you are already forward in your dropouts). Another option would be to get one of those doohickeys for your drop outs to lock the wheel in place.
Extra link is a nice solution if you're worried about it-- It's generally not too hard to pick a chain length that will let you use the full range of gears you want to use for training and racing. The original Felt Tk2 had short dropouts, so two chains might be required for covering the full range on those. Chaintugs can be a pain for quick wheel changes, but they will keep you from slipping.


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