neptronix said:
I can see that liner destroying inner tubes the same way my stop flats and mr tuffy's did.
Mine would consistently destroy the tube within 50-100 miles.
As I've noted before in threads about flats, to stop this tube damage, all you really need to do is provide a sacrificial surface for the liner to wear, by taking an old tube (preferably a thick one) and cutting out it's valve stem along with the thicker area immediately around the stem on the inner circumference. Then slit this tube along it's inner circumference, and slip it over your actual tube that will be inflated. Install the tire liner inside the tire, then install this layered tube assembly.
The disadvantage is that you have one more flexy layer in the tire which eats up energy as it rolls, and the tire is heavier.
But this combination does work, and is what I've used on CrazyBike2 and SB Cruiser (both heavy cargo bike/trike) for years, with the only problems typically being valve stem failures from crappy tubes (fixed on 20" wheels by using MC tubes with threaded stems (TR-4) that secure to the rims, and on 26" wheels by using CST brand tubes and another one I can't remember the name of now).
The wear on the sacrifical layer (which also acts as additional tube thickness vs punctures even along the sidewalls) is not noticeable before I wear a tire tread out (1-2000 miles ish, a year or two, depending on usage and tire; I use soft compounds for better grip (CST City in front for the last several years, Shinko SR714 in back) vs harder that would last longer).
I don't use a liner anymore on the rear ones; it hasn't been necessary, as the tires themselves are so thick they stop msot things, and have actually deflected nails to the side on their own when it's near the edge of the tread anyway. Plus, the wider the tire is with more surface area at the contact patch, the less likely it is the liner *could* deflect something anyway--the liners work better the skinnier the tire is, and/or the rounder the contact patch is, to help it do the deflecting.
But I do still use the extra "old tube as liner" method.
As Eastwood says, you may also be able to smooth the end-edges of the liner so they aren't sharp, but I never had any success with that with the Slime brand liners I used at the time.
.. i really think it would be worth experimenting with gluing a liner or another tire to the inside of another tire using RTV. It would prevent the inner slip issue.
Don't do this with a liner.
I already did this years ago on DayGlo Avenger, for this same reason, with terrible results, using the Slime brand liners of the time. It will prevent the liner from being able to flex in a way that deflects stuff that's hard and sharp enough to puncture the liner and long enough to go thru it. Normally the liner works on these things by letting the sidewall edges lift up slightly and slide the tip of the pointy thing toward the sidewall instead of thru it and into the tube.
It did stop the liner from doing the snake thing and ending up "sinewaved" back and forth across the tread area (leaving unprotected areas of center tread), and from moving around and cutting the tube.
It did still stop goatheads and certain thorns and some small irregular road debris from puncturing the tube, however some of these would now be stuck in the RTV and tire (which never happened before gluing the liner down) and those not ground up by the action (glass and metal bits, etc) would be able to wiggle around and shred the tire itself until it herniated the area open by cutting the internal threads of the carcass, and then the tire could split up the sidewall and let teh tube hang out and be ripped open by the frame or the center kickstand mount or rim brakes, etc.
The worst, though was that it could not stop some nails (primarily roofing nails) and glass shards and mesquite thorns (usually those still attached to a piece of branch) and whatnot anymore--instead they would now go right thru the liner and the tube and the *back* of the tube and (in the case of nails) the RIM! actually now being stuck in or even thru the middle of the rim itself. The tube would be so damaged that it couldn't even be patched, so I'd be stuck walking if I didn't have a spare tube with me, along with a way to sand down and / or securely cover the rim damage (which could leave sharp edges on the hole or the deep scratch if it didn't actually puncture the rim).
I tried just gluing the ends of the liner together (without gluing it to the tire) so it couldn't change length or move the ends' edges against the tube, but the liner didnt' stay stuck to any glue I tried, including the RTV (though it did stick really well to the RTV on the tire itself; I don't know why...when I had to remove a liner from a destroyed tire I could pretty easily pull it out off the RTV).
I have used old *tires* as liners, but not glued them down because there was no need to. Just cutting off the bead (not the sidewall) and sometimes sanding the inner edges of the cut, then installing the tires inside the other tires, then installing the tube, then putting this mess on the rim and inflating, was sufficient. The inner tire would not shift around or damage the tube, unlike liners. IF you don't remove the bead, then the bead will wear and possibly release it's wire and THAT will take out your tube (and sometimes the actual tire!) but that's the only problem I ever had.
The catch is you have to use an inner tire that has a slightly smaller outer circumference than the inner circumference of the actual tire, just small enough to fairly closely fit against the inner walls and tread of the tire, or else it won't seat well even under inflation, and sometimes can roll badly until the actual tire's inner (usually) or outer (sometimes) circumference wears and exposes threads inside and then those can start breaking, and then the tire can come apart. (since you have an inner tire surface that's not catastrophic, but it will ride like crap (THunk thunk thunk on the rupture in the carcass) until you can change the tire).
You would also want to use as smooth a tread as possible on the inner tire (vs something like a knobby with knobs cut off, etc), for the closest smoothest fit against the inside of the other tire.
It might work fine to glue this inner tire against the outer tire, and perhaps it would help with rolling resistance. Never tried the experiment.
I've also never tried gluing the "old tube as a liner" onto either the tire or the tube (if I were going to do it I'd probably glue it to the tube, not the tire, then immediately inflate the system as an assembled wheel).
The best way to ensure the tire didn't have any imperfections would be to cure the RTV while the wheel is spinning continuously against a roller. IE, inflate the tube, set the cruise control to a slow speed, and let it spin on a bike trainer for at least 4 hours of the curing process.. and the rolling would likely even out imperfections.
I didn't have any issues with imbalance (well, not any more than the overlapped liner ends already caused), so you don't really have to worry about that. Not that I was going more than around 15mph on that bike, maybe 20 for short peaks here and there, but I don't think the RTV itself, if properly applied, will cause balance issues. Only a very thin layer needs to be applied to the liner, then stick it inside the tire and press it down, then insert the tube and inflate that, while it's all installed on the rim as normal--the inflated tube will apply even pressure around the tire for you.
The reflectors on the spokes, the valve stem, the not-very-balanced-manufacturing of the tires, etc, all made far more of a difference than the liner or the RTV did. Especially the tires, and especially the Kenda brand ones (which for me always had problems with the sidewalls, and with there being thicker tread rubber on some areas of every tire), and Innova (same imbalance problems), and another I can't recall at the moment. The CST and Maxxis didnt' have the imbalance problems to a significant degree, though they were not perfect either.