Had a funny crash today, over the bars and ended up with a broken finger. During this debacle, and I think as a result of the angle the front wheel was turned to, the front tyre spunked some of its latex out with a corresponding sound of relief. Is this fairly normal if the tyre gets a lot of pressure on the side? I’m new to tubeless, so anything to check for other than put a bit of latex back in the tyre (maybe?). No obvious damage to the rim or sidewall.

While I’m asking, the front tyre, a HR2, wobbles side to side when the wheel spins (did this from new so not a result of crashing today). The wheel is true, and the tyre bead even in the rim as best I can see – going by the uniformity of the hatched bit. Is this common? Tyre fitted wonky or a duff tyre? Back one is fine.

Many thanks.

Should t have any latex coming out. I’d say they weren’t seated. I assume this isn’t a ghetto setup? Did you pump the tyre up to 40psi and hear it crack into position, then leave it over night before deflating? Somethings not right. I run HR II 2.3 never had that happen. I run the at 20 psi front 22 psi rear.

Came with the bike, I’ve not done anything to them. Didn’t even check the pressures to be honest, they felt about right 🙂

This happens any time the tyre burps IME.

“Burping” can happen with tubeless at lower pressures..

Not had a HR 2 burp on me. If they did it would mean something’s wrong.

When I fit new tyres I make sure everything’s clean. Old dried latex on rim removed etc
Slap on tyre and leave small bit open
Put in two generous cups latex and fully fit tyre
Spin tyre around to coat the inside
Pump to 40 psi, you will hear loud crack as it seats fully
Leave over night
Deflate to ride pressure @ 20 psi front 25 psi rear is a good start
Top up latex every six months
Ride and never puncture or burp

You burped. It happens. Moar pressurz next time 😉

Hope the finger heals up ok.

Burping is fairly normal, as long as it’s not happening often and as long as it’s just burping not coming off entirely. You crashed hard enough to break a human, can’t complain too much if your tyre also had a moment to itself 😉

As long as the bike’s ok…

It was definitely during the crash rather than immediately before it, so I guess some unorthodox and particularly sideways pressure was applied. Ill check the pressures and see what they are – the back will still be as it came.

What sort of pressures for the larger gent? I used to have 40 in my old bike, which seemed ok, but that wasn’t tubeless.

I am about 100kg and run about 35psi out back and a shade less up front. Any less and its just too squirmy.

Burping should not be regular but it does happen.

burped. more pressure

Ok, that’s easy enough. More latex in there too, or maybe just give it a shake and see if there’s still some in?

This is the best explanation that I have come across http://www.pinkbike.com/news/Tech-Tuesday–Wider-Rims-Are-Better-and-Why-Tubeless-Tires-Burp-.html

Decent read on pink bike there, but in summary if you put enough lateral force through the tyre bad things will happen. If it only happens during these times when your crashing/screwing up there may be nothing wrong with your set-up (set up for 90% of your riding not the 10% when it goes wrong – like lugging round a 38lb 7″ bike because you do something steep in the alps once a year)

The more people who adopt tubeless the more questions, there is a bit of a magic bullet associated with it and generally when it works it works far better than tubes, people forget all the stupid pinch flats etc or having to run super heavy tyres or high pressures to avoid flats but then get annoyed when they have 1 tubeless fail in a year.

Thanks JoeG, I like that sort of article

First time I used tubeless was when I went over to Spain a few years ago.
I had a fairly high speed crash when traversing a large piece of off camber rock and my front tyre burped. I think I’d got a few thorn punctures earlier in the ride that had sealed, but dropped the tyre pressure quite a bit & I hadn’t really noticed. The angle of the rock was enough to drag the bead from the rim slightly causing it to burp and because the pressure was already low it flattened completely.

I had a similar incident a few days later. Not had any problems since though.

Did you pump the tyre up to 40psi and hear it crack into position, then leave it over night before deflating

Overnight? Seriously? I’ve ridden on tyres 30 seconds after fitting them! I much prefer pumping to 20psi and then pulling the bead about by hand where necessary. 40psi is beyond the max for some light rims!

Decent read on pink bike there, but in summary if you put enough lateral force through the tyre bad things will happen.

I think that’s the crux of it – you side loaded the tyre massively, stands to reason the bead will give. You can up the pressure, but if it’s not happened in the course of normal riding I’d not worry too much about it.

Well, 19psi in the rear tyre, which was quite a surprise because it didn’t feel that squishy, but I guess that’s the calibration of my squeeze being off. Measured with a Topeak digital gauge.

19psi – that’s what I run. I’m about 10st, so if you are heavier then suggest a bit more. Something like your weight in lb/7 = starting psi, then vary from there.

I’m 10 stone but if I put 19psi in my tyres, my wheels become a pleasing percussion section, greeting every rock and root with a cheerful bong.

I’m 10.5 stone, but rarely go below 25psi. In fact I tend to run 25psi.

Hmmmm, never hit rim on rocks or roots. 25psi and it’d be v hard and I’d be pinging off into the bushes.

Guessing my ’19psi’ read off the trackpump may well be different measured on something else.

I have put 35 in, so I’ll see how that goes. I am touch over 10 stone….

Regarding the wonkiness in the tyre, if you reinflate it (I go for 60psi to seat it, then let it down to normal pressure) and it’s still doing it then the tyre is a duff. It happens, the shop should swap it. If not then it wasn’t seated and it might well be why your tyre burped.

I’m 11.5st and run high 20’s pressure wise.

^ 60psi is way too high and could blow off / damage the rim ?

managed to burp a cx tyre at 45psi the other week, interesting, off camber and turning back up the hill, just soft enough for plenty of grip, slight loss of pressure but rode home ok and topped up then.

Run full tubeless on CX and SS but I’ve been reticent to run it on the front my gnarpoon (which naturally is suspended in a continual state of gnar shreddery) due to worries about burpage. Was nervous first time I ran CX but apart from the other week they’ve been fine, guess it’s just a trust thing (that and I don’t get many front flats so not sure it’s worth the faff/worry)

They feel so hard with 35/32psi in (R/F) – but I’m measuring it with a Topeak Smartgauge so I’m not sure I can measure it any more accurately?

Hmmmm, never hit rim on rocks or roots. 25psi and it’d be v hard and I’d be pinging off into the bushes.

That’ll depend on the tyres etc – if you’re running wide tyres it’ll feel different to narrow ones.

They feel so hard with 35/32psi in (R/F) – but I’m measuring it with a Topeak Smartgauge so I’m not sure I can measure it any more accurately?

I wouldn’t get hung up on it, you massively sideloaded the tyre, it’s unsurprising it burped. If you’d done it as part of normal riding then I’d be looking to up your pressures, but not when it’s happened as it has.

^ 60psi is way too high and could blow off / damage the rim ?

Meh, never had a tyre blow off for the 10 or so seconds I have them at 60psi to seat the tyre, even on Stans rims. I let them down as soon as everything’s pinged into place.

Fair enough, I’ll see how they go next ride and then maybe go down a bit if necessary.

Meh, never had a tyre blow off for the 10 or so seconds I have them at 60psi to seat the tyre, even on Stans rims. I let them down as soon as everything’s pinged into place.

I have, just a little bit more air to push-that-last-bit-of-bead-in then <<kaboom>>, temporary loss of hearing, shock and pebble dashed with jizz… it also went next to my thumb which was quite character building too and the tyre was ruined.

Badger?