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Question about tyre

CROMERBOY's picture

By CROMERBOY - Posted on 06 October 2010

Hi guys I am after some advise.
Last night I tried to convert my non UST Nobby Nic to tubeless using Stans rim strips and sealant.
To cut a long story I got the tyre to bead up and inflate but when it hit about 20psi it spewed sealant from a hole in the tyre (not sidewall).
Eventually the hole sealed (it is about 5mm long) and so I started inflating again - once again at 20psi it spewed out sealant and eventually sealed.
This contuinued a couple of more times so I left it a couple of hours and tried again - no joy. Left it overnight and again no joy.
My question is -
should I give up on this tyre as far as tubeless is concerned?
should I throw a tube back in and forget that this ever happended?
should I put a patch internally on the tyre and throw a tube in?
should I retire the tyre as an emergency (and expensive) spare?

hawkeye's picture

You could try applying a glue-on tube patch over the hole from the inside of the tyre, but you'll need to clean off the sealant first or the glue won't take.

However, 5mm is perhaps pushing it for a casing cut. My criteria is this: if the casing bulged/bulges around the cut when inflated, then the tyre is shot and for the sake of safety should be replaced.

Might be expensive to throw away a $80 tyre, but medical expenses cost more. You can always zip tie a length of it it to your saddle for some wet weather grip like Peaty does. So it won't be wasted. Eye-wink

CookPassBartridge's picture

Hey Hawkeye,

I'm not very clever, nor have any good advice other than: "I freaking love mountain biking. The worse thing I can imagine (apart from alien invasion) is to get amped up for a big trip out only to get let down by equipment (something that has happened in my personal life all to often)."

QuikStep's picture

I would also try the patch and see how that goes. I tried to set up some non-UST tyres on non-UST rims with a Caffe Latex kit and after not being able to get a seal with leaks around spokes and on the bead I gave up, after trying everything for a week. I then invited some mates over to help and give advice but when they arrived I pumped up the tyres to show them how it doesnt work and from that time on they have stayed up for a 3 months now!
So either take it to the LBS or get some mates to have a look and it will make you look stupid by working.
going tubeless is the best mod I have made to my bike.

hawkeye's picture

I was assuming folks would join the dots. My bad. Sad

The risk from a casing cut where the casing around the cut bulges is expansion of the tear and sudden blowout failure. Depending on which tyre it is, some might argue it might be less of a problem on the trail, but it's definitely a potential biggie if it happens on the road with traffic on the way to the trail.

As most of my riding hours are in traffic while commuting that comes into sharper focus for me than it might for others.

If I got a cut like that on the trail I'd patch/tape/cable tie/whatever the tyre to get to the end of the ride, but the tyre would definitely be replaced before the next ride. I've hurt myself too much from stupid riding mistakes in the last year and a half to want to take avoidable risks with compromised tyres.

But if the casing doesn't bulge around the cut, a tube patch over the cut will seal it up fine and you should be OK to ride. Just give your tyres a periodic close look-over to make sure there are no changes and it is still safe and you should be good to roll.

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