# Cross Tires on Road Bike



## hardcorebeaverpeasant (Dec 20, 2010)

Is anyone familiar with a cross tire that will fit well on a road bike with no modification to the current brakes. I have a Trek 1.2 with Sora brakes and would like to put some cross tires on it that would be good for gravel roads. I have looked into putting some old school center pull brakes on to fit bigger tires but if there is a bigger tire that will work with the current set up that would be great.
Thanks


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## krisdrum (Oct 29, 2007)

Not sure a "cross" tire is the answer. Typically the narrowest of those are 30mm, which I doubt you'd have clearance for, especially with the addition of "knobs". Probably your best bet is a 28mm road tire with a bit of tread to it. You really don't need a knobby tire for gravel unless there is mud/loose dirt involved as well.


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## simonaway427 (Jul 12, 2010)

I'd be less concerned about brake clearance and more worried about rubbing on the stays.


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## ZoomBoy (Jan 28, 2004)

As Krisdrum said why not just run some 27/28s instead of a knobbied cross tire? I doubt you will find a true CX tire, clincher or tubular, that will fit.


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## Mike T. (Feb 3, 2004)

As a rider of a kazillion miles on gravel roads I have an opinion for you. As we know, or should know, gravel conditions come in as many types as there are snow conditions in winter. My local roads range from unrideable even on a mountain bike with 2.1" tires to packed dirt that is as fast as asphalt and ok for 23mm tires. About twice yearly they "grade" our dirt/gravel roads and they are unrideable on any bike until the vehicles have them somewhat packed down.

I've used everything from mountain bike tires to 32mm cyclocross knobbies, to file tread cyclocross tires to 28 and 25mm road tires.

As a general statement, the enjoyment of dirt/gravel road riding is in proportion to tire width and in inverse proportion to tire pressure. But tire width is dictated more by frame and fork clearances than by brake clearance as, depending on the brake, not much more than 26mm will pass through a rim brake without tire deflation. That's very true with my DuraAce and Campagnolo rims brakes anyway. My current dirt road bike - a '90s vintage Masi road frame - won't take anything more than 26mm wide tires and is not a fun bike on dirt/gravel with anything more than about 80psi and when the roads are not packed and fast.

I'm not aware of any true 'cross tires narrow enough to fit a normal road bike but my current Continental 28mm 4-Season tires have some tread (their actual width is 25mm - ahemm). As a comparison, my smooth 25mm Michelin Pro measure 26.3mm. Ahemm x2. I just measured those tires with calipers.

Choose wisely and use the right tool for the job.


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## Kerry Irons (Feb 25, 2002)

*Frame clearance*



hardcorebeaverpeasant said:


> Is anyone familiar with a cross tire that will fit well on a road bike with no modification to the current brakes. I have a Trek 1.2 with Sora brakes and would like to put some cross tires on it that would be good for gravel roads. I have looked into putting some old school center pull brakes on to fit bigger tires but if there is a bigger tire that will work with the current set up that would be great.


Your issue will most likely be frame and fork clearance rather than brake clearance. Look at how much clearance there is between the top of the tires and the bottom of the fork crown arch and the rear brake bridge. That will tell you how much larger a tire you can fit. 

For example, if you have 25 mm tires now and you have 5 mm space between the tire and the frame, then the biggest tire you could realistically run would be 28 mm (leaving 2 mm clearance).

Tread would be a secondary consideration compared to just tire size - the bigger the better.


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