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  1. #1
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    Road tires moving to even sizes reason?

    I noticed Bontrager and Specialized road tires are now 24 and 26x700c instead of previous 23 and 25’s
    Does anyone know why they changed?
    Change just to change?

    RC

  2. #2
    What the what???
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    Maybe they're finally getting around to accurately measuring them.
    The Law of Headwinds states: If the ride out is easy... wait.

  3. #3
    Adorable Furry Hombre
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    Quote Originally Posted by Opus51569 View Post
    Maybe they're finally getting around to accurately measuring them.

    Especially with wider-format rims making hitherto tire sizes even more of a wild guess.
    "Refreshingly Unconcerned With The Vulgar Exigencies Of Veracity "

  4. #4
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    I really don't like the Specialized 26mm Turbo. They're simply too wide on a HED Belgium Plus. 25mm wide tire on 25mm wide rim is my cut off point. Anything wider feels sluggish

  5. #5
    changingleaf
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    There's a trend for wider tires. The sizing is relative and somewhat arbitrary though, just like clothing sizes can be. I have a set of the 26mm Specialzed Turbo tires on Boyd Altamont rims and they measure 28.5mm wide. These rims are almost 20mm wide on the inside. The same tires measure about 27 on Reynolds Assault rims with a 17mm inner width. They are probably down to 26mm wide on 15mm inner width rims.

    On the Altamont rims with the tires perfectly centered they barely fit in the frame of a 2016 Cannondale Supersix.

    Note, 25mm Schwalbe pro one tires don't fit in the Cannondale and measure just over 29mm with the Altmaont rims.

    So these 25mm Schwalbe tires are actually wider than the 26mm Specialized tires.

  6. #6
    gazing from the shadows
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    Quote Originally Posted by changingleaf View Post
    There's a trend for wider tires. The sizing is relative and somewhat arbitrary though, just like clothing sizes can be.
    Yep. Somewhat arbitrary is a good way to put it.

    So it seems now they round up instead of down, since people are more likely to look for bigger rather than smaller (lighter) tires.

    There is data on the site on this, btw:

    http://forums.roadbikereview.com/whe...ad-363087.html Table in this one.

    http://forums.roadbikereview.com/whe...-306276-2.html No table, but some numbers.

    I am sure there are others out there as well, RBR and otherwise.
    .
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  7. #7
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    Quote Originally Posted by aclinjury View Post
    I really don't like the Specialized 26mm Turbo. They're simply too wide on a HED Belgium Plus. 25mm wide tire on 25mm wide rim is my cut off point. Anything wider feels sluggish
    That's quite a generalization.

    For the OP: Bontrager is making their TLR tires in 24 and 26mm, the regularu clinchers are still 23 and 25mm. I've yet to mount a 25mm clincher and a 26mm TLR on the same wheel but I'm betting they're the same size.
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  8. #8
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    I purchased an old Bontrager AW2 in 25 while some new tires were in 24 and 26. The funny thing was the old stock 25 had a smaller profile then previous AW2 25’s. I know this because the previous AW2 would barely clear my 07 Buenos Aires stays at the brakes. They must have started making 24’s.
    BTW cx do you believe in the “aero wings” to reduce drag on these tires? I fall for marketing .
    RC

  9. #9
    Russian Troll Farmer
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    I'm betting it's because a lot of older 'racing' frames are quite tight, and people need the in-between sizes. I'd love to try a 25 on my old Cannondale, but unfortunately, 24's are the widest that will fit.
    "L'enfer, c'est les autres"

  10. #10
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    Somebody try and convince me the difference between 23 and 25mm tires is significant enough to be of real value. I think it's not even worth considering.

    If manufacturers offered 3mm size choices, then I'd take note.

  11. #11
    'brifter' is a lame word.
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    Quote Originally Posted by RoadCube View Post
    I purchased an old Bontrager AW2 in 25 while some new tires were in 24 and 26. The funny thing was the old stock 25 had a smaller profile then previous AW2 25’s. I know this because the previous AW2 would barely clear my 07 Buenos Aires stays at the brakes. They must have started making 24’s.
    BTW cx do you believe in the “aero wings” to reduce drag on these tires? I fall for marketing .
    RC
    If the 'wings' had a big effect everyone would do them.
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  12. #12
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    Quote Originally Posted by Peter P. View Post
    Somebody try and convince me the difference between 23 and 25mm tires is significant enough to be of real value. I think it's not even worth considering.

    If manufacturers offered 3mm size choices, then I'd take note.
    So you think that being able to drop your tire pressure 10 psi is meaningless for comfort, traction, and tire wear? Most would disagree.

  13. #13
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    Quote Originally Posted by Peter P. View Post
    Somebody try and convince me the difference between 23 and 25mm tires is significant enough to be of real value. I think it's not even worth considering.

    If manufacturers offered 3mm size choices, then I'd take note.
    I definitely feel there's a real difference.

    I'm not trying to convince you of anything but if you think there wouldn't be a difference then you should have nothing to lose by trying 25 yourself so why not find out for yourself instead of guessing.
    If they feel the same as you speculate, nothing lost there as same is same.
    Last edited by Jay Strongbow; 1 Week Ago at 10:20 AM.

  14. #14
    changingleaf
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    Well 2mm is certainly more than the flex between different wheels.

    Anyway if 2mm is not enough, then go to 28mm or if it doesn't matter then why not use 20mm for that matter.

  15. #15
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    I'm going with the Unobtainium tire in size 24.5mm front for aero and 25.5mm rear for longetivity.

  16. #16
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    Quote Originally Posted by Kerry Irons View Post
    So you think that being able to drop your tire pressure 10 psi is meaningless for comfort, traction, and tire wear? Most would disagree.
    I don't feel 2mm is significant enough of a size increase to exercise or gain the benefits you suggest.

  17. #17
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    Quote Originally Posted by changingleaf View Post
    Anyway if 2mm is not enough, then go to 28mm or if it doesn't matter then why not use 20mm for that matter.
    I did that many years ago with Micheline Hi-lite tires. Their advertised 23mm tire actually measured 19 or 20mm, I forget what I measured. All I know is I kept getting pinch flats at 100psi. for my 130lbs. and it wasn't worth the harsh ride of pumping them up harder to avoid the pinch flats.

    I DO intend to try 25mm tires when my current tires wear out.

  18. #18
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    Quote Originally Posted by Peter P. View Post
    I don't feel 2mm is significant enough of a size increase to exercise or gain the benefits you suggest.
    I love it when people doubt Kerry Irons.

    The issue is not width, it is volume. 2mm different width between 23s and 25s yields an 18% greater volume.

    Is 18% significant enough in your eyes?
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  19. #19
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    Quote Originally Posted by Peter P. View Post
    Somebody try and convince me the difference between 23 and 25mm tires is significant enough to be of real value. I think it's not even worth considering.

    If manufacturers offered 3mm size choices, then I'd take note.
    I'm way late here, but this is just an odd post.

    You say that 2mm is not worth considering, but then say that 3mm is worth taking note in a thread that talks about 26mm tires, which is 3mm off from 23mm. So are you taking note?

    I know math can be hard, but tires dont come in a straight line. The volume difference is significant, as has been pointed out.

    I can't try and convince you of anything. I can, however, try *to* convince you of something.

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