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Tight tires, grind down tight rim to decrease diameter?

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Tight tires, grind down tight rim to decrease diameter?

Old 12-05-19, 12:43 PM
  #26  
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previously noted, but still good tire jack

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Old 12-05-19, 11:31 PM
  #27  
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Originally Posted by Snikerdoodlz View Post
I'm using Schwalbe Marathon road tires. Those tires are already tighter than usual, so the combination was brutal. I used to use Maxxis Gypsies, which were still unreasonable.

People are saying to guide the bead into the central depression. Does it not do that automatically when you pull on it when flipping tire levers?
Yes and no. As above, thicker tires and sidewalls are harder to keep pushed into the center well. With a lighter standard bicycle tire it's easy to get the beads to stay there. The heavier tire just requires more effort to maintain the slack in the bead that's needed to pull it over the rim's wall.

If you watch them change car tires at a auto shop you'll see that the principal is the same- they just have big hydraulic machines to do the prying and lifting of the bead.
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Old 12-06-19, 02:38 AM
  #28  
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The trick I use is to put the bead in the center channel as suggested but then to do the last difficult bit at 90 degrees from the stem, not 180. This way the opposite side sit entirely in the channel. Tires that I couldn't otherwise get on have slipped right on this way.
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Old 12-06-19, 05:29 AM
  #29  
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Originally Posted by Jeff Wills View Post
Yes and no. As above, thicker tires and sidewalls are harder to keep pushed into the center well. With a lighter standard bicycle tire it's easy to get the beads to stay there. The heavier tire just requires more effort to maintain the slack in the bead that's needed to pull it over the rim's wall.
.
This is my understanding, that the strap/toe clips force a really stiff sidewall tire down and into the depression a and holds it in place.
I've seen some continental touring plus tires that are like this, very stiff sidewalls, throw in a certain rim combo and its been a real bugger.
decades ago I had some specialized city nimbus something tires that were like this also.
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Old 12-08-19, 10:01 PM
  #30  
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Originally Posted by Snikerdoodlz View Post
I'm using Schwalbe Marathon road tires. Those tires are already tighter than usual, so the combination was brutal. I used to use Maxxis Gypsies, which were still unreasonable.

People are saying to guide the bead into the central depression. Does it not do that automatically when you pull on it when flipping tire levers?
Which Schwalbe Marathon, and what size? They come in several models and widths.

26x2.00 is a wide rim so your tire choices are limited.
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Old 12-08-19, 10:49 PM
  #31  
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Originally Posted by WizardOfBoz View Post
Second, there is no way to do the grinding with sufficient precision, without removing the rim and mounting it on a lathe face plate. Precision metal cutting requires tools and jigs and fixtures that are exceptionally rigid and a spoked bike wheel doesn't qualify.

So, I suspect that you'd end up with an aesthetically unsatisfactory wheel with really uneven grinding marks that would break prematurely.


If one trued the wheel, very true, say 1/4mm wobble/hop, then one might be able to use the wheel as a lathe of sorts. And, build a jig to do the work.

Where to take the material off? In the bead seat, or the valley between bead seats, and it severely reduces the strength of the wheel, and a E-Bike wheel at that!!!

One could grind off the hooks. It might help with mounting slightly, but risk blowouts. Or, the hooks may also contribute strength to the sides of the rims.

Aestetics won't be an issue as the grinding would be mostly hidden.

Anyway, I agree that this is a very bad idea, and one needs to further diagnose the problem/solution.
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Old 12-08-19, 11:11 PM
  #32  
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Originally Posted by dsbrantjr View Post
If your rim has a thick cloth tape such as Velox, you could try a thinner tape such as Continental Easy Tape or a layer of filament-reinforced packing tape or Kapton tape. The thinner tape should make tire mounting easier by allowing you to get the bead deeper into the center of the rim channel.
Yes, the shape of the rim above, it appears to be a standard rim, without the new tubeless shelf that causes so many people problems.

I'd also look at the tape.

Another option are veloplugs. On occasion, I've gone over the veloplugs with a thin layer of tape like electrical tape (or stronger tape).



The veloplugs provide the strength, and the tape keeps them from moving, and keeps the tube inside.
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Old 12-08-19, 11:26 PM
  #33  
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Originally Posted by CliffordK View Post
If one trued the wheel, very true, say 1/4mm wobble/hop, then one might be able to use the wheel as a lathe of sorts. And, build a jig to do the work.
I grew up working in a machine shop. Modern metalworking doctrine is that you use an extremely rigid machine to cut metal, with a rigid fixture holding the workpiece. Else you get chatter, grabbing and gouging, the workpiece breaking, or (worse of all) the workpiece or parts of it flying off the lathe and killing someone. Thus, you'd use a lathe with the rim fastened to a faceplate. Given the rim diameter, you'd need a pretty massive lathe (a 30" swing). The pic below is a 42 inch lathe with a propeller mounted to the faceplate.

A spoked wheel has a very high strength to weight ratio, but is not nearly as rigid as a faceplate that is 2 inches thick and made of heat-treated tool steel. For one thing, transmitting adequate power from a hub to the wheel rim would likely break spokes. A bike hub has superb strength for handling a cyclist's weight, but bike bearings don't really come anywhere near the rigidity of that lathe spindle which are gonna have perhaps 6 inch id, tapered roller bearings in double sets fore and aft.

Not saying it couldn't be done with some clever McGyvering and by suspending normal rules of safety and risk avoidance. But we agree:

Originally Posted by CliffordK View Post
Anyway, I agree that this is a very bad idea, and one needs to further diagnose the problem/solution.
Your advice is IMHO golden and is really what the OP should be doing. Observe, think, and test different methods of solving the problem before getting out the angle grinder, I always say.


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