DIY tyre sealant update

28 12 2009

A while ago i blogged about some DIY tyre sealant I was cooking up. It turns out that was nearly 4 months ago and I have been completely problem free up unto this point.

As a refresher, I have been running Mavic 819 rims (UST ready) with 2.25 Racing Ralphs in UST with a small amount of sealant (about 60 mls per end) to prevent leaks and increase puncture resistance.

I have put about 1000km’s onto this combo and haven’t had to perform any maintenance whatsoever.

Lately, the front tyre has developed a slow leak so that it will be flat when left overnight. There was no weep through so I guessed the sealant had probably gone off. I am still seeing weep through on the rear tyre so I know that sealant is still liquid, although I might top it up just to be on the safe side.

I dismounted the front tyre to see how things were looking in there – bone dry. Not really a surprise. There were obvious green balls of sealant all over the place which you can see in the pic, but there was also an almost invisible fine layer of latex coating the entirety of the inside of the tyre – the camera doesn’t really show it.

So i cleaned up the dreggs, added another 60 mls of sealant and re-inflated the tyre. Getting the Ralph to seat and inflate with nothing more than a track pump is a bit of an art form. The trick is to tilt and rotate the rims so that a swirl of sealant contacts the beads. This helps to prevent the air escaping while you go crazy with the pump. This proved quite successful and as soon as the full length of the bead was wet on both sides, it inflated quite easily.

Interestingly, the batch of sealant that I had made 4 months ago and stored in a milk bottle was still as fresh as the day it was made. I have noticed it tends to seperate into layers if you leave it standing – I don’t know if that is a good or bad thing? It goes back into suspension readily as soon as it is shaken however.

Now that I have a tyre with a known leak, it will be an actual test for the sealant. Before this, running UST tyres, it might not have been doing anything at all! The tyres should be airtight anyway so all it might have been doing is adding weight.

I will report back in a week or so when I see whether the leaking tyre is cured.

Dry DIY sealant




2 responses

5 01 2010
DIY tyre sealant: Update # 2 « the unknown rider

[…] Update #1 […]

16 01 2010
cycling trivialities – update « hunter women ride

[…] fernleigh on his way back from a glenrock ride with the boys. his rear tubeless tyre (check out his blog on DIY tyre sealant if you are interested) had a massive gash in the side wall, and was out for the count. we slowly […]

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