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  1. #1
    Senior Member chas0039's Avatar
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    Mismatched tire sizes....OK or not?

    I want to use a 700x23 on the front and a 700x25 on the rear. Is there any safety or other issue I should be aware of?

    Thanks

  2. #2
    Senior Member MrCjolsen's Avatar
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    Nope. None at all.

  3. #3
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    None whatsoever.

  4. #4
    Mr. Dopolina Bob Dopolina's Avatar
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    Check out the Continental Attack/Force combination.

  5. #5
    Senior Member chas0039's Avatar
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    Thanks guys. I kind of figured that was the case, but it never hurts to check with the pros.

  6. #6
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    Quote Originally Posted by Bob Dopolina View Post
    Check out the Continental Attack/Force combination.
    I'm not real happy with mine, not because of the mixed sizes but because of the way they ride and handle. They seem to have a hard rubber compound and feel a bit unstable. I use them on my time trial aero wheels but don't like them for hard cornering.

  7. #7
    Mr. Dopolina Bob Dopolina's Avatar
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    Quote Originally Posted by Al1943 View Post
    I'm not real happy with mine, not because of the mixed sizes but because of the way they ride and handle. They seem to have a hard rubber compound and feel a bit unstable. I use them on my time trial aero wheels but don't like them for hard cornering.
    These tires are designed for racing and aggressive cornering. The black ones will have the new "Black Chili" compound. Go to the Conti site and check it out. I'm not sure where you feeling of instability comes from. (your mother I know mine does) Are you talking about traction or do you feel flex in the sidewalls?

  8. #8
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    Quote Originally Posted by Bob Dopolina View Post
    These tires are designed for racing and aggressive cornering. The black ones will have the new "Black Chili" compound. Go to the Conti site and check it out. I'm not sure where you feeling of instability comes from. (your mother I know mine does) Are you talking about traction or do you feel flex in the sidewalls?
    I don't have the newer "Black Chili" compound. I think the tires are OK, they just don't seem to have near the grip that my Michelin Pro2 Race tires have. They feel harder and seem to chatter more on rough pavement. Maybe they would feel better with less air pressure but I bought them for time trials and like to run 120 psi in time trials.

  9. #9
    cab horn
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    Quote Originally Posted by chas0039 View Post
    I want to use a 700x23 on the front and a 700x25 on the rear. Is there any safety or other issue I should be aware of?

    Thanks
    Your bike will instantly explode the second the tires hit pavement.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  10. #10
    Sir Fallalot wroomwroomoops's Avatar
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    I've built up a ****bike (you have nice bikes, bikes, beaters and ****bikes, and this is it) to test a chain tensioner and to maybe keep it to run around in the parks around my home. I had two spare tires (both used, but still "alive") that I could throw onto it: one semi-slick and the other a knobby XC/DH. I decided to put the knobby tire in the back and the semislick in the front. Is that the correct idea, what do you guys think? It should have good grip and cornering in gravel, and I didn't want to use new tires, just these two used ones (it's a ****bike), so my only choice is knobby in front/semislick in the back or knobby in back/semislick in the front.

  11. #11
    Mr. Dopolina Bob Dopolina's Avatar
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    I'd put the knobby on the front. You can handle the rear wheel sliding out a bit but if the front goes...OUCH!

  12. #12
    Sir Fallalot wroomwroomoops's Avatar
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    You are right, but I was hoping the grips on the side of the semislick would keep it from sliding - I guess it would only slide while cornering, and the thread on the semislick is supposed to prevent just that, on loose?

  13. #13
    Sometimes knows stuff. rmfnla's Avatar
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    Quote Originally Posted by Bob Dopolina View Post
    I'd put the knobby on the front. You can handle the rear wheel sliding out a bit but if the front goes...OUCH!
    This doesn't really apply to a road bike unless you will be riding in dirt or wet.

    Slick tires give the best traction on dry roads; treads and knobs are there to make people feel more secure.

    You have more weight on the rear tire (which is why you get more flats back there) so the additional air cushion of the larger tire will do the most good there. Again, this applies to a road bike on the road.

    Riding in the dirt requires a larger contact patch up front for better traction on turns; in that case the larger tire goes up front (not that 2mm would make that much difference in this case).
    Last edited by rmfnla; 07-26-07 at 04:57 PM.
    Today, I believe my jurisdiction ends here...

  14. #14
    Mr. Dopolina Bob Dopolina's Avatar
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    I think the OP was talking about riding on mixed surfaces, road, dirt paths, gravel etc. In that case I'd stick with the knobs on the front. I do agree that a slick tire gives better traction on the road and if it were a strictly road application, I'd put the slick on the front..

  15. #15
    Sir Fallalot wroomwroomoops's Avatar
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    It's not slick, it's a semi-slick. As I said:
    Quote Originally Posted by wroomwroomoops View Post
    You are right, but I was hoping the grips on the side of the semislick would keep it from sliding - I guess it would only slide while cornering, and the thread on the semislick is supposed to prevent just that, on loose?
    which was an answer to:
    Quote Originally Posted by Bob Dopolina View Post
    I'd put the knobby on the front. You can handle the rear wheel sliding out a bit but if the front goes...OUCH!

  16. #16
    Senior Member
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    Quote Originally Posted by Bob Dopolina View Post
    I think the OP was talking about riding on mixed surfaces, road, dirt paths, gravel etc.
    The OP was talking about mixing a 700 X 23c road tire with a 700 X 25c road tire. Nothing to do with slicks or knobbys.

  17. #17
    Sir Fallalot wroomwroomoops's Avatar
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    Quote Originally Posted by Al1943 View Post
    The OP was talking about mixing a 700 X 23c road tire with a 700 X 25c road tire. Nothing to do with slicks or knobbys.
    Sorry, it's all my fault...

  18. #18
    Mr. Dopolina Bob Dopolina's Avatar
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    Quote Originally Posted by wroomwroomoops View Post
    Sorry, it's all my fault...
    AHA! The Finn hijacked the thread!

    As a reply about the semi-slick/knobby combo, I think it would come down to what KIND of knobs were on each tire. In the end, I'd go with whichever tire looks like it will give the best cornering on mixed surfaces and loose stuff like gravel. THAT tire, I'd put on the front.

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