The joy of se…..lf sealing innertubes

There’s nothing more satisfying than making a successful change to your bicycle. Well actually there are a few thing but then this a cycling blog so we’ll stay with that theme! I’ve taken an educated guess and it worked. My “puncture proof” inner tubes have chalked up a couple of scores!

So far I’ve had two rear punctures but got home without even knowing it. Only to find the tube flat when I’ve come to use the bike again. Now to me this is a huge win! Who wants to actually have to stop and change a tube? Especially in a wheels that is arse deep in crud, then risking pinching the tube removing or remounting, and causing ingress of more crap into the tyre.

The first puncture I had on this setup I decided to fix, but I did so at my leisure and after I had cleaned the bike. After removing the flint from the tyre it was a small simple hole easily patched. Fitted back up and inflated.

You can just about see the flint hole.

The second puncture I haven’t actually mended yet. I haven’t needed to. I found the offending flint, plucked it from the tyre, and re-inflated the tyre to 60psi. Turned the wheel so that the sealant could run to the flat. Two rides later I still haven’t had to pump it up! Smug points at full effect.

Fairly big cut in the tyre would have probably required a tubeless plug.

Whilst I’m not looking forward to getting punctures, I am looking forward to seeing how many punctures they prevent… or to describe it better, how many times I get home without a puncture!

The reason I’ve put together the self healing tube setup is because I believe it to be best all round solution for a gravel bike. Yes there is additional weight of a tube and a sealant, yes there is a loss in supple feel over a tubeless setup, and yes you can’t run your tyres at as low a pressure. But when taking those points into consideration, gravel bikes aren’t performance hunting machines like a road bike. Weight of a tube and sealant is marginal, maybe 150g per wheel? Supple feel is again a marginal gain. Can you really tell the difference when you are rattling down a gravel track? And the grip really won’t change much. Now tyre pressures, this really isn’t limited by not going tubeless. Tyre pressures are decided predominantly by riders weight, terrain, and tyre type. Yes tubeless probably allows you to run the tyre of your choice ever so slightly lower, being as there’s no risk of pinch flats, but would you really be running that low a pressure on a gravel bike anyway? It would just be slow! And on a bike with no suspension, likely to damage rims. The other factor to take into account is rim width, low pressures on narrower rim just don’t mix that well. You get a lot of tyre roll.

When it comes to punctures on tubeless tyres, they can be a faff to fix. Something that is enough to put a hole in a tubeless tyre, or tyre in general, will likely put less of a hole in a tube being that it is further away from the point of puncture and is able to stretch away from the intruding object. That hole in the tubeless tyre probably won’t seal with sealant as it will be too large and require a plug, or worse case scenario a tube to be fitted. Inside a slimy tubeless tyre filled with sealant, great.

Tubeless tyre repair kit

I’m not anti tubeless by any means. I run tubeless on my winter road bike and haven’t had a puncture in two years (just cursed myself). But it’s under very different circumstances. Flint on gravel tracks is a real threat to your tyres, simply not a consideration on well maintained road surfaces. The tyres I run also have very close matching rim to tyre width dimensions, allowing lower pressures to be run without tyre roll. And as far as suppleness and grip goes, road tyres and gravel tyres deliver grip and comfort in different ways. Gravel tyres use a tread to physically grip and press into the ground (think tractor tyre) and a large volume to increase comfort, whereas road tyres rely on maximum contact on a smooth surface (think f1 car) and a lower volume to reduce weight and tyre roll, so increases suppleness is easily noticed when run on a lower volume tyre on a hard and more consistent surface.

The back end of my vintage gravel bike…. so to receive upgrades!

So there goes my recent result of my experiment! Don’t be too quick to discredit the good old innertube. Tubes and sealants are the most common way to prevent punctures in off road vehicles, so why not apply it to your bike! It might just stop all that faffing!

Want to see what setup I put together to prevent punctures? Visit my previous post HERE. Good luck with your puncture reduction program!


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