Avoiding flats

So somehow I managed to go 7 months without a flat tire while riding 5-6 times a week, only to suffer two flat tires on the same day yesterday. One was due to a blackberry thorn. The other was likely the same thing, but since it was on my 36er with a Foss tube I did not bother looking to find out as I currently have no way to repair it.

So I’m thinking now that the blackberries around here are growing like mad, (we have particularly nasty blackberries in the pacific NW), I should be taking some measure to try and prevent this in the future. My inclination is to add a thin layer of tire slime between my tube and tire, a thin layer around the bead of the tire and a small amount inside the tube.

Years ago I set up a bike to be thorn proof using tire liners, heavy duty tubes and a generous amount of slime inside the tubes and it genuinely was thorn proof after that. It was also sluggish and felt like pedaling a paddle boat with a dragging anchor.

This time around I want a little better thorn resistance, but at the lowest cost in performance possible. Anybody have any better ideas on how to achieve this?

I’m using: Vee tire 36", tubeless, sealant, Vittoria Airliner. I ride at 25 PSI dampening every kind of bump, protected from flats and also able to ride a bit completely flat. The added weight is someway less important than the dampening effect over roots.

However it is a trail setup

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For a 36er you can buy a 29" tube off the shelf with tire slime already in the tube. Many riders including me use 29" tubes in a 36" tire at a substantial cost saving.

I don’t know if tire slime would do any good on the outside of the tube. For it to work it has to be in the pressurized area.


I’m not sure myself. I think it might help seal things in a couple ways though. I first noticed this last leak when my tire started burping while jumping. It seems the tube was leaking into the space between the tire and the tube and this was evident as when I would push inward on the valve or wiggle it side to side air would audibly come out around the valve hole. Also, when I broke the bead free from the rim air noticeably escaped, so to some extent, my tubed tire was behaving in the same manner as a tubeless.

I’ve also seen similar behavior with Big Apple tires on my bike. When I finally had to replace one of my tubes I looked for leaks in my old tube and instead of finding one, I found several. Somehow the compound they used or something seemed to seal itself to the tube? I don’t know. I just know the 26x2.35 Big Apples I have on that bike seem to be extremely flat resistant.

I’ll look into the airliners. The only tire inserts I have ever used were plastic puncture guards.

Slime makes a 29er tube.

The hesitation I have with slime is that they recommend 4 ounces of it in a bicycle tube. That’s 100g of liquid sloshing around near the outer edge of your tire.

I used a small fraction of that in my 27.5 tube yesterday and put a thin layer along the bead and surrounding the tube. I’ll see how it works. So far I haven’t noticed the dampened feeling I had with it the last time I used it in a bike.

How well do the pre slimed tubes work? I would be interested to know if anybody has used one and whether one may stretch a 29 slime tube onto a 36 rim.

I have not tried a slimed one but the 29" tube should be the same and they work fine. At cost of $7 for a slimed 29" tube maybe someone that needs the puncture protection should try it and report back.

So those 29" tubes you get, are those mountainbike tubes or still unicycle tubes. I mean are unicycle tubes thicker than mountainbike tubes? I can understand that a mountainbike tube is cheaper than a unicycle tube, but shouldn’t the price of a 29" unicycle tube be so close to a 36" tube that the difference is negligible ?
Personally I’ve tried patching my 36" tube a few times, but it keeps losing air. And I hate patching tires. In the LBS they said they don’t patch tires anymore, because it is so much easier for them to just put in a new tube. But new tubes are often more expensive than having them patched, at least so many years ago when they still patched them.

I think this is like with tires. A 36" is not a standard size, so it requires a different machine.

Yeah, no difference between unicycle and bicycle tubes. The 29” tubes are cheaper than 36” due to economies of scale.

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Or possibly it’s more accurate to say there’s no such thing as a unicycle tube.

Even if it says Foss on it. :stuck_out_tongue:

I’ve got the big bottle of slime. It’s great stuff for things like garden tractors where efficiency is not a factor and it really does seem to seal up small leaks. My experience with bicycles in the past however is it can create a very sluggish feeling bike. I think the effect of having liquid in your tire is even more significant than a similar fixed amount of weight would be.

On the bottle of slime that I have, it recommends 4 oz per tire. That’s 113 grams right where you want it least! On the Slime website they recommend 3-4 oz, so still at least 85 grams, and they don’t list the weight of their tubes with the slime preinstalled.

When I treated my tire two days ago I probably used about 1.5 oz, with most of that being around the bead of the tire and between the tube and the tire and maybe 0.5 oz inside the tube. I have no idea how effective this will be at preventing flats, but I could not feel any difference when riding it.