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  1. #1
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    Tire tread too rounded?

    I installed a Bontrager XR2 front tire recently. From the attached picture does the tread look too rounded. I rode through some wet dirt, on a flat fireroad, and noticed the contact patch looked really narrow. Thoughts?
    Attached Thumbnails Attached Thumbnails Tire tread too rounded?-dnmyiiogsmybrkeo%25nziqa.jpg  


  2. #2
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    "too rounded"?

    Bontrager tires typically have a rounded profile.
    This is not a bad thing, just the style of the tire. I like rounded profile tires. In my opinion they turn in better, and they transition more predictably.

  3. #3
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    Quote Originally Posted by DethWshBkr View Post
    "too rounded"?

    Bontrager tires typically have a rounded profile.
    This is not a bad thing, just the style of the tire. I like rounded profile tires. In my opinion they turn in better, and they transition more predictably.
    Here is a picture of the rear Maxxis tire. The "mud" coverage extends all the way across the tread vs. the XR2 which covers a narrow band.
    Attached Thumbnails Attached Thumbnails Tire tread too rounded?-ll0ml57ys4s8z2%257l8mukg.jpg  


  4. #4
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    They look similarly rounded to me. More weight on the back means the rear tire will sink into mud more. If you never lean into turns, you might prefer a flatter profile.

  5. #5
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    Did the patch on the road look that thin or did the dirt just fall off tire edges? If it was that thin you can probably air down a little more.

  6. #6
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    I would say the profile looks very familiar to the picture on Trek's website. If you are using this for muddy cond. it may not be the best choice. XR2 is for loose over hard pack cond..

  7. #7
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    Were you running it on the 60mm rims it was made for?

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    What rim size and psi?

    I run them on 40 & 50 mm rims at 12 psi and the center knobs are not as tall as what your picture shows.
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  9. #9
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    I need a rounded tire profile up front to be able to lean the bike from side to side. With too much "edge", it creates a "pivot point" where the bike doesn't seem to want to get to and at that point, traction is usually very sketchy.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  10. #10
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    Quote Originally Posted by azjonboy View Post
    What rim size and psi?

    I run them on 40 & 50 mm rims at 12 psi and the center knobs are not as tall as what your picture shows.
    I thought this would have been a primary question asked and that is why I omitted it from my post. The rim width in 25mm ID. - yep narrow. Running @ 18 psi.

  11. #11
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    Does it not do something you want it to do?

  12. #12
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    Quote Originally Posted by keen View Post
    I thought this would have been a primary question asked and that is why I omitted it from my post. The rim width in 25mm ID. - yep narrow. Running @ 18 psi.
    I think the 40-50 and 60mm comments were meant to be sarcastic. I use 100mm.

  13. #13
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    Quote Originally Posted by keen View Post
    I thought this would have been a primary question asked and that is why I omitted it from my post. The rim width in 25mm ID. - yep narrow. Running @ 18 psi.
    Like was said, the mud band in your picture is mostly related to load f/r.
    What pressures are you using? Try dropping the front my 10psi and see what happens to the mud band.
    If you feel like you need a squarer profile on the front, then there are several tires that would work on a 25mm rim, for example DHF 2.3.

  14. #14
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    You also happened to leave out what width it is, which will make a big difference on what rim width will work better for you. For me 25-30mm IW works best with most brands 2.3-2.5" tyres, but Bontrager tyres are always a bit rounder and can handle wider rims to get say a similar profile to a Maxxis fo similar width. One thing I'll note is the what I consider weird tyre combo you've got going on.

    Quote Originally Posted by keen View Post
    I thought this would have been a primary question asked and that is why I omitted it from my post. The rim width in 25mm ID. - yep narrow. Running @ 18 psi.
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    Quote Originally Posted by One Pivot View Post
    Does it not do something you want it to do?
    I have 1/2 dozen tame XC rides so I have not been able to put it to the test. From a visual standpoint, staring @ the front tire, has me questioning the grip strength in turns - mental thing thus far.

  16. #16
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    Quote Originally Posted by LyNx View Post
    One thing I'll note is the what I consider weird tyre combo you've got going on.
    Agreed. If you're gonna mix square and round profiles put the round tire in the back.

    Round tires like that work best on hardpack, loose over hard, or rock. Or flat trails. Surfaces where tall cornering knobs aren't going to hook up, so they just feel skate-y.
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  17. #17
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    Quote Originally Posted by LyNx View Post
    You also happened to leave out what width it is, which will make a big difference on what rim width will work better for you. For me 25-30mm IW works best with most brands 2.3-2.5" tyres, but Bontrager tyres are always a bit rounder and can handle wider rims to get say a similar profile to a Maxxis fo similar width. One thing I'll note is the what I consider weird tyre combo you've got going on.
    Yes that would help - 2.6". Yep wide tire on a narrow rim.

  18. #18
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    Quote Originally Posted by fsrxc View Post
    Like was said, the mud band in your picture is mostly related to load f/r.
    What pressures are you using? Try dropping the front my 10psi and see what happens to the mud band.
    If you feel like you need a squarer profile on the front, then there are several tires that would work on a 25mm rim, for example DHF 2.3.
    I agree the rear is loaded. Tried 16 psi bit it felt a little mushy especially on the local hardpack.

  19. #19
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    Quote Originally Posted by scottzg View Post
    Agreed. If you're gonna mix square and round profiles put the round tire in the back.

    Round tires like that work best on hardpack, loose over hard, or rock. Or flat trails. Surfaces where tall cornering knobs aren't going to hook up, so they just feel skate-y.
    Mostly hardpack terrain. Definitely a tread mismatch going on. The rear is an Ardent LUST 2.25. For some reason I go through different tires and end up putting the LUST Ardent back on. I can handle shallow tread up front it grips the hardpack. If I run similar tread in the rear I loose traction on the climbs.

  20. #20
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    Quote Originally Posted by keen View Post
    I have 1/2 dozen tame XC rides so I have not been able to put it to the test. From a visual standpoint, staring @ the front tire, has me questioning the grip strength in turns - mental thing thus far.
    Get some proper rides in and push the tires till they let go. There is no other way to tell for sure if they're going to work for you. If they work to your satisfaction, great. If not, you'll have an idea of where and how they come up short, and from there you can start working out potential solutions.

  21. #21
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    I run an XR2 on my XC race bike.
    I think very good traction for the terrain it's designed for. Very fast rolling too.
    I am 200 lb, and I run 25 psi front and rear on an XR2 with I think 26mm internal rims.
    In the mud, the XR2 is a horrible tire. XR4 then!
    Tires are designed for certain applications, keep that in mind!

  22. #22
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    I'd go completely against this, a back tyre washing is one thing, but have the front loose traction and nasty things happen. Unless you're getting paid to ride, not worth it IMHO, get a tyre with bigger/better side knobs and take the very minuscule, if any rolling resistance and have confidence you won't get slammed unexpectedly.

    Quote Originally Posted by aerius View Post
    Get some proper rides in and push the tires till they let go. There is no other way to tell for sure if they're going to work for you. If they work to your satisfaction, great. If not, you'll have an idea of where and how they come up short, and from there you can start working out potential solutions.
    One day your life will flash before your eyes, will it be worth watching??

  23. #23
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    Quote Originally Posted by LyNx View Post
    I'd go completely against this, a back tyre washing is one thing, but have the front loose traction and nasty things happen. Unless you're getting paid to ride, not worth it IMHO, get a tyre with bigger/better side knobs and take the very minuscule, if any rolling resistance and have confidence you won't get slammed unexpectedly.
    Having the front wheel slide is almost normal for me, and I'm not even close to getting paid to ride. Having the front tire slide isn't a big deal, it's how the front tire lets go and what it does after it breaks traction that matters. The tires I ride are pretty well behaved in those respects, they break traction predictably and after they let go there's still a decent amount of resistance to push against which gives you time to control the slide and regain control of the bike.

    Modern bikes are also pretty forgiving when it comes to losing grip on the front end, my Enduro bike will practically ride itself out of a front wheel slide as long as I don't panic, it's not like the old days where you're quickly dumped on your face unless you take heroic actions.

  24. #24
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    Quote Originally Posted by LyNx View Post
    I'd go completely against this, a back tyre washing is one thing, but have the front loose traction and nasty things happen. Unless you're getting paid to ride, not worth it IMHO, get a tyre with bigger/better side knobs and take the very minuscule, if any rolling resistance and have confidence you won't get slammed unexpectedly.
    The short knobbed Ikon (my previous tire) worked fine on local hardpack. I have tried a few tires w/ more pronounced side knobs and have experienced a little "squirm". I went w/ the 2.6 XR2 to add some volume but wasn't expecting such a rounded casing.

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