# Tire clearance: how close is too close?



## FuelForThought (May 13, 2012)

Just installed some brand new Michelin Pro4 SC 700 x25 on my Look 585. The new tires dwarf the Veloflex Master 23 that were previously on the bike. Very quick spin tells me that the volume increase will provide a much cushier ride. The Michelin Pro4 measure 26.00mm wide on my Fulcrum racing zero wheels (~21mm wide rim). So far so good.

Now the issue is with the seat stay clearance. Laterally no problem. But those tires are really tall (at least on the Fulcrum rims) and the top of the tire is within ~1 to 2 mm of the seatstay arch. Should I be worried? Is the tire more likely to become less tall as it ages (sidewalls soften?)?

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## chudak (Jul 28, 2012)

I had a similar problem when I switched from the stock vittorias and then conti gator skins to conti gp4000S on my Felt. The gp's were much bigger than either of the other two. My clearance may be slightly better than yours but not much...maybe another mm. I figured if they weren't rubbing they were fine. Once you wear a little rubber off the tread it will increase the clearance a bit.

Seems like a lot of manufacturers are building their frames with silly dimensions. I checked my buddy's brand new Fuji SST 2.0 and there is no way he could put 25mm tires on that thing. They have about the same clearance as yours does with the stock 23's.


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## Camilo (Jun 23, 2007)

Yea, I don't know why the frames have to be built so tight as to make 25's difficult, let alone 28's. Maybe there's an advantage to pure racers and it's just our fault for not being discriminating enough to choose frames that have the extra clearance.

So I guess we enthusiasts, even amateur racers, should use market forces to show the high end frame manufacturers that what they should be doing is making frames that easily fit 25's, even 28's. I don't think that would be much of a design change either functionally or aesthetically.


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## MR_GRUMPY (Aug 21, 2002)

Tire clearance: how close is too close? 

That is too close.

You need to go back to 23's.

A broken spoke, and you'll have a long walk.
.
.


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## FuelForThought (May 13, 2012)

MR_GRUMPY said:


> A broken spoke, and you'll have a long walk.


Care to elaborate? How would tire rubbing on seat stay break a spoke?

I was more worried about frame abrasion when I posted the question but would be happy to learn something new.


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## bigbill (Feb 15, 2005)

FuelForThought said:


> Care to elaborate? How would tire rubbing on seat stay break a spoke?
> 
> I was more worried about frame abrasion when I posted the question but would be happy to learn something new.


If you break a spoke, the wheel goes out of true and the tire can rub the frame. Might not even turn if it's bad enough.


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## Randy99CL (Mar 27, 2013)

What I see is that you don't have much clearance for stones or gravel sticking to the tread of the tire. Hopefully that won't be a problem.


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## bigbill (Feb 15, 2005)

Randy99CL said:


> What I see is that you don't have much clearance for stones or gravel sticking to the tread of the tire. Hopefully that won't be a problem.


That's about the clearance I have from the top of the tire to my rear Chorus brakes when I run a 25mm. There's more side to side but I do scrape some gravel and rocks off the tire with my brakes, especially when it's hot outside. In the OP picture, there isn't much room for a tire to wobble.


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## MisterMike (Aug 12, 2004)

Randy99CL said:


> What I see is that you don't have much clearance for stones or gravel sticking to the tread of the tire. Hopefully that won't be a problem.


+1 
That clearance is just one (not completely cured) chip sealed road from shredding that frame.


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## FuelForThought (May 13, 2012)

bigbill said:


> If you break a spoke, the wheel goes out of true and the tire can rub the frame. Might not even turn if it's bad enough.


Ah, got it. Fulcrum Racing Zero rear is laced 21 spoke triplet so if I break a spoke, chances are I walk home no matter what tire I am running.


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## FuelForThought (May 13, 2012)

bigbill said:


> In the OP picture, there isn't much room for a tire to wobble.


There is about 3.5mm between the sides of the tire and the side of the seatstays. 

BTW, I love the new tires. Just went for a ride and the extra cushioning is very welcome. Much easier to stick to a line on technical descent. A bit less "lively" than the Veloflex or more muted. But for my use, the perfect tire.

One option would be to keep the 25 in front and switch to a 23 in the rear. Anyone does that?


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## Tachycardic (Mar 31, 2013)

FuelForThought said:


> There is about 3.5mm between the sides of the tire and the side of the seatstays.
> 
> BTW, I love the new tires. Just went for a ride and the extra cushioning is very welcome. Much easier to stick to a line on technical descent. A bit less "lively" than the Veloflex or more muted. But for my use, the perfect tire.
> 
> One option would be to keep the 25 in front and switch to a 23 in the rear. Anyone does that?


Sure, you can do that. But that 25 in the rear is real tight. Too tight for comfort. I wouldn't chance it.


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