I got a mountainbike from wich the back wheel completely bent. I can't fix it with a spoke wrench. The tire is a v-brake tire and I had a spare v-brake rim laying in my shed only problem is that it had a road tire on it.

So my question is: could I just put a mtb outer tire on that v-brake rim with the road tire on it and succesfully use it on the trails?


Assuming the new rim is about the same width as the bent one, then the tyre and tube should transfer over okay.

You need to check the valve hole in the rim - there are two common sizes, and the wrong one won't fit or risks punctures at the base of the valve.

I suggest you fit the tyre, and inflate it to a relatively high pressure, whatever's maximum on the sidewall. Then leave it overnight and check again in the morning. If it holds air and hasn't blown off the rim then deflate a little to riding pressure, and go for a test ride

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    It's probably worth also mentioning that a wide tire on a narrow rim may feel quite different cornering and is slightly more prone to rolling off during hard cornering. Might also need to adjust brakes to account for the narrower rim. – Andrew Apr 12 at 0:33
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    Despite @Andrew's (correct) point, mtb manufacturers use rather narrow rims, narrower than in the compatibility tables you'll often see. So my hardtail came with 2.1" tyres on 17mm rims,narrower than the 19mm rooms on my tourer (with 35mm stock tyres) – Chris H Apr 12 at 6:33
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    @Chris H With everything you mention about your hardtail I suspect it’s got some fairly dated specs - most MTBs I see are coming with 25-35mm rims nowadays. 30mm with a 2.5” tire seems to be the happy medium. Heck, road bike rims are all in the 19-25mm range now. – MaplePanda Apr 12 at 7:00
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    @MaplePanda you're right. It's a 2017 model, but honestly more like a 2017 paint job on an earlier design. It's capable enough for me (biggest issue probably the max 2.1" rear tyre) but then I like triple chainrings. You've given me an idea though - I'm thinking about a spare wheelset for the tourer and hardtail (both 9-speed, 160mm disc brakes). Maybe the current hardtail wheels should be the spare and I should put better ones on that frame. – Chris H Apr 12 at 7:49
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    @Chris H I imagine you’ll run into lateral clearance issues if you go to a wider rim. With a max 2.1 at 17mm, you’re going to be limited to 2.0 with even a 21 or something. Narrower still for even wider rims. – MaplePanda Apr 12 at 14:57

It sounds like you're asking if you can put a mountain bike tire directly over the wheel + tire of a road bike.

(please correct me if I am wrong)

There are a few things to account for.

  1. It is not very safe to put a tire over another tire, as most tires are slick and the inner tire may not gain traction on the inner tire.

  2. It is not likely that the mountain bike tire will even fit over the road bike tire, as even the largest mtb tire will most likely not fit over even the smallest road bike tire size.

In the end, it seems that doing this is not possible and even if it worked, it would still be unsafe.

Edit - It seems I have missintepreted the question. with the diameter and width of mountain bike tires, it is practicaly impossible to fit even a 29er on a road wheel, not because of the diamter, but instead the thickness of it.

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    I think you’re misreading it. I assume he means replace the road tire with an MTB tire – Andrew Apr 11 at 23:08
  • oh okㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤ – DumBum Apr 11 at 23:50
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    A 29er tire will go perfectly on a modern road rim. People aren’t riding 14mm rims any more. – MaplePanda Apr 11 at 23:58
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    I've heard of people putting an old tyre's tread inside a new tyre to add thickness and act as additional puncture protection, but that means cutting the bead wires off the old tyre, basically slicing around the sidewalls on both sides. – Criggie Apr 12 at 2:59
  • Schwalbe’s Procore system is an interesting rendition of this idea though. Seems to work pretty well! – MaplePanda Apr 12 at 6:57

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