wroomwroomoops

Hey all,


I have a rim made of a material that seems rather slippery, and the tire's compound (Schwalbe Ice Spiker) seems kind of slippery, too, no matter how much I clean it with ethanol or light paraffin ("turpetine"). I believe I need to increase the friction/adhesion between this tire and the rim, in order to avoid further relative slippage of the two.

Anyone with some constructive ideas? I would like to avoid actually gluing one bead to the rim.

Thanks in advance.

Kimmo

Latex?

wroomwroomoops

Tell me more.

bradtx

Hooked tire bead into a non hooked rim ot the other way around? Good luck.

Brad

pmt

Clean them both with acetone or equivalent. That'll certainly make the rubber tire less slick.

dabac

There's a type of rubber filler/repair gunk called liquisole. I have used it on occasion on folding tyres with a tendency to slip on the rim. Apply a thin layer on the bead surface, allow to cure, then mount tire.

Kimmo

https://en.wikipedia.org/wiki/Latex - Latex is used in many types of clothing. Worn on the body (or applied directly by painting) it tends to be skin-tight, producing a "second skin" effect.

A bit of that stuff on the rim would do it

wroomwroomoops

Hooked into hooked (if I understand the jargon correctly).

wroomwroomoops

Thanks guys. I think I'll try acetone, first, as it is readily available. Then I'll try to find latex, and then liquisole (if I can get a hold of it).
Note, however, that contact glue has very low adhesion to the rubber compound of this tire. If liquisole is similar, it might not work.

silver_ghost

What exactly is the problem you're experiencing? Is the tire blowing off the rim? Is the tire slipping around the rim under braking, causing your valve stem to end up crooked?

FBinNY 

Exactly my question.

Retaining the tire doesn't depend on friction, but on the relative diameter of the tire bead and/or a mechanical interlock of the edge of the bead under a hooked edge in the rim, with the pressure keeping it trapped.

Tire creep of properly inflated tires is rare, but it does happen especially in front wheels.

Don't worry about how slippery things are unless/until you find you have a creep issue. Then you might try a very light tack like 3Ms Post-it Note glue stick. You can try other adhesives, but keep in mind that you want the ability to move the tire to seat it properly, so only light tack adhesives are called for.

Al1943

Have you been riding under-inflated?

wroomwroomoops

Both of those happened. The tire blowing off the rim might have happened because of residual contact glue in the rim, though. I got rid of that, now.

wroomwroomoops

Yes, I experience (also) that creep. The rim is a bit narrow compared to the tire, but I have an even wider tire on the same (a second) front tire, and on that combo (of tire and rim) I have no problems whatsoever.

I will look into that post-it note glue. That sounds like it could actually work.

And no, I do NOT ride under-inflated. I gave up on that.

FBinNY 

The tire blowing off (undamaged) is purely a seating problem, since mechanical forces and not friction is what keeps them on.

It is possible that on some flat sided rims the tire might have crept enough to shift off the seat and accumulate enough slack in one place to blow off, but that's a slow process (except maybe in Colorado descents) and I'd hope you'd feel the out of roundness in plenty of time.

fietsbob

For very low pressure to gain maximum contact patch for winter traction

The Makers of Snow Cat Rims [all weather sports] recommend using sew up tire glue
and using it on just one bead.

to mend a puncture you take the unglued tire bead off the rim, leave the other be.

This is to prevent rotational creep, which shears off inner tube stems,
as tube and tire move, together, but hole in rim does not.

silver_ghost

So you've glued your tires to your rims before? I'd think that any foreign material in the rim hook (even mislayed rim tape, in my experience) would cause seating issues, possibly leading to a blow out.

I can't figure how a light adhesive would have more "sticking power" than the mechanical force of a properly inflated tire pushing against the rim. Maybe with the crazy low pressures run on those snowcat style rims (<5-10psi), but not with a "regular" tire.

I sometimes run sub-reccomended pressures in the winter time. I keep an eye on my valve stems and deflate, then scoot the tire back into place when required (no more than once or twice a season).

I don't mean to sound argumentative, I've just never heard of someone having to use glue on a clincher, and can't help but think it'll do more harm than good.

wroomwroomoops

FWIW: the blow-off happened as I was inflating the tire while off the fork. So no, it wasn't the creep that caused the blow-off. I can't get my head around this, as the other, perfectly identical rim, has none of the problems. The only difference is the tire, which in this case (I'm talking about the Schwalbe) has this really slippery rubber compound. The other tire is a Nokian Extreme - good tire but without any puncture protection, and the rubber compound is definitely a more traditional one.

wroomwroomoops

It's not the one vs. the other. That is, mechanical force/pressure all by itself doesn't hold anything in place. You need some friction, too. I guess the two should be multiplied to obtain that "sticking power" you mention. If you made your tire from teflon, you would have a hard time preventing it from rotating in the rim, even if you inflate it to a high pressure.


OK, this sounds very interesting, as the blow-out happened after I partially succeeded in gluing one bead to the rim. There was some contact glue that solidified somewhat randomly and instead of contributing to the adhesion, was clogging the hook channel (or whatever the thing where the bead lies, is called). I am guessing I should clean that glue out as perfectly as possible.

DannoXYZ 

Well, friction is a function of normal-force f=uN. The more force you have pressing two things together, the more friction you have. Slide a tyre across a cement floor, easy huh? Now have someone stand on the tyre and try to slide it from under their feet; it's not possible without pushing them off the tyre first. Now multiply that by the inner surface-area of the tyre at the bead times air-pressure and you've got thousands of pounds of force pushing the tyre against the hook-edge of the rim.

There are two opposing forces at work:

1. air-pressure along inside-edge of casing will try to expand the tyre casing outwards.

2. bead resists stretching and translates expansion of casing into lateral movement sideways (the two beads move wider apart).

The bead material is very important for #2. High-pressure tyres with kevlar-beads should always be used with hook-edge rims due to the flexible bead. In which case, the pressure of the tube pushing on the bead underneath the hook generates extreme friction between the tyre and rim.

With straight-edge rims, a steel-bead can pretty much hold any pressure you put into the tyre. You're not going to be actually using any kind of pressure close to where it can stretch a steel-bead; the casing will probably blow through first. Kevlar-beads on straight-edge rim is another matter and would depend upon the size of the tyre (larger tyres have more casing surface-area and generates more stretching and pulling force on the bead).


I think in this case, you may have some issues with pinching the tube under the bead or a tyre that's slightly oversized at the bead-seat or foreign matter under the hook-edge of the rim.

operator

This is ******** people. Just ********.

Increasing rim friction IS NOT GOING to work. Either the tyre is the wrong size for the wheel, or the tyre or wheel are both oversized/undersized enough to cause a seating issue. If that is the case NO friction compound is going to work.

1) Verify that the tyre is the correct bead set diameter for the rim
2) If 1 is true and tyre is blowing off, then either the tube is being pinched or the tyre really is just oversized, or the OP is overinflating it like crazy.

and YOU SHOULD NOT USE IT. It is DANGEROUS. No amount of friction increasing compound (seriously what the ****?) is going to solve this problem.

Kimmo

Go tubeless - just try it on the front.

wroomwroomoops

That's what I have stated, as well. Force by itself is not enough to keep the tire from rotating inside the rim. The tribological properties of the tire's and the rim's surface are important as well, and are represented by that multiplicative factor (called coefficient of friction) in the RHS of the equation you posted.

Thank you for the detailed account on how the normal force is obtained in a rim-tire system. You and others seem to assume that this force is not enough in my case. That may or may not be so. I understand why some people may have come to this conclusion: because I mentioned the blow-out I had at one point. But that blow-out happened once I have identified the problem of the too little friction between tire and rim. Since I identified this problem, I tried fixing it by gluing one bead to the rim. Since my gluing was messy, random sized pieces of hardened glue have been deposited in the rim groove (hook), and that might have been the reason for the blow-out which happened immediately after my gluing attempt.

(the following is not directed to Danno in particular):

If you look at the chronological order of the events above described, you could make the assumption, as I did, that increasing the friction (as in, friction coefficient) between my tire and rim is a sensible approach to prevent the rotation of the tire in the rim. The reasoning, in short, is:
Increase friction coefficient --> increase friction (friction force) --> reduce chance of tire rotation in rim, for a given tire pressure.

An element that reinforces this assumption, in my eyes, is the fact that an identical rim (actually, identical wheel) with a different tire in it, had never any problems with the tire rotating (creeping) in the rim, and the only difference is the tire, that is, the tire compound, which does feel much more "sticky" than the one in the problematic wheel-tire combo.


If you feel you disagree with the logic here exposed, please do voice your concerns, but abstain from from histrionic expressions of outrage.

LarDasse74

I have installed thousands of tires over the years on bikes ranging from old roadsters and folders and baloon tire cruisers up to modern multi-thousand $$ wonderbikes, and I can only recall one tire (about 20 years ago) that chronically blew off - and that one was a kevlar beaded tire on a straight-wall rim. I remember that one instance because we blew so many tubes trying ot get it seated that my boss threatened to make us pay for the next one we blew. It only now occured to me that it was a folding-bead X straight-wall problem.

This is not to say I have never blown another tire off a rim - I have done that plenty of times... more times than I want to admit. But with each and every one I was able to partially inflate the tire, work my way around the rim pushing the bead in with my thumb to look for improperly seated sections, then continue inflation to correctly reach the reccomended pressure. Maybe there is something wrong with your tire/rim combo making this impossible, but without seeing it I still believe it can be done without any extrordinary efforts, rim or tire mods, or super glues.

wroomwroomoops

^^Well, I had one blow-off, so this is not a case of chronic blowing-off, like you had 20 years ago. My main problem still remains to avoid the sliding/creeping of the tire in the rim. I realize now that it would have been wiser just not mention that one blow-off. It has arisen a lot of speculation and avoidance of reading.