I’ve bought a pro capra, one ride in and having trouble with the tubeless set up. I’m using the stock tyres (mavic roam rear and charge front).
I found the rear tyre went flat twice on the first ride and this seems to have been a result of burping.
I’m at home now investigating and and it seems that the tyres burp really easily at lower pressures. Put the wheel in the bath and press down and air clearly escapes each time its loaded.
I’m used to running low pressures with stans crest and flow rims, never had an issue before.
Am i missing something? Or are these wheels shite?

The wheels aren’t shite, it’s generally down to user error when setting them up. I had the same issue with my Crossmax SX wheel set but that was due to me rushing them and not putting enough sealant in the tyres and also running them at too low a psi. I upped the psi and put in a bit more sealant, I’d never had a single issue with them again!

Burping is all about how well retained the tyre is on the rim- not really something the user can cause, other than too-low pressures or inappropriate tyres. What psi are you using?

A good read on tubeless http://www.pinkbike.com/news/Tech-Tuesday–Wider-Rims-Are-Better-and-Why-Tubeless-Tires-Burp-.html

Are you using sealant ?

Northwind – Member

Burping is all about how well retained the tyre is on the rim- not really something the user can cause, other than too-low pressures or inappropriate tyres. What psi are you using?

Or they weren’t inflated enough to ping them into place before going back down again to the chosen pressure?

That’s a good point! Yes, that too. Though I’d be surprised if they stayed up long enough to go riding at all, like that

How low pressures are you running?!? I’ve run my ST/dampfs down at 14psi and had no issues with burping. if you can physically push down hard enough with just the wheel in your hand to cause a leak, you’re either running ridiculously low pressures or the bead isn’t properly seated!

I’m no stranger to tubeless, been running tubeless for several years. I’ve never burped a tyre on a stans rim and I run very low pressures because I like the grip that gives, for me thats the whole point.
Aaaaaanyway, just been out for a ride again, the front burped a few times but nothing too catastrophic, however the rear went flat in no time. After several flats, I ended up having to pump the rear tyre up hard. It was ok then, but might as well have run a tube.

I used a compressor to inflate the tyres, held them at 70psi so thought that would have seated them but maybe not. I’ll have to try again and make sure I fully tyre soap the beads, maybe they aren’t seating right. I really hope thats the case because the Stans set up seems so much better right now and its half the price.

Have any of you successfully used these wheels tubeless with low pressures?

Yes, but how low are you talking? The lowest ive had them set at 18psi with no problems, I normally run just over 20

yeah no lower than that, actually they were probably at about 25 today. It seems its likely to be a tyre seating issue then. Have you used the mavic charge and roam tyres?

Nope never used them, I was using a Schwalbe Hans Dampf/Magic Mary combo

I’m going to tackle them again later, see if I can seat it correctly, thats got to be it I suppose. Perhaos they are trickier to seat than stans.
These are mavic tyres suggested for their own tubeless system, theyve got to work surely?! I’ll update how I get on.

Have you used the mavic charge and roam tyres?

Not sure if it’s possible in this case, but are they definitely the proper versions as you would buy from a shop? Just in case they’re some kind of oem crap (would be surprised though)

I’ve got a knackered old set of crossmax xl’s that have spent the last year wearing a tubeless dampf and Nic. I’ve got sealant in, but they were happy without and went straight up.

At one point Mavic were supplying tubeless wheelset and tyres on oem bikes with tubes fitted and a separate bag of rape and valve. Obviously that’s not the case here, but there isnt anything else silly they’ve started doing?

Only other thing is rim width… Are they still 19mm? Is the bead unseating at low pressure with wide carcass on narrow rim? Flows are a fair bit wider.

My SXs burp below 25psi off camber with 17 stone plus loading on them if I land on a rock………
To me it is what it is, 30 psi no burps….adjust the air pressure to a level that they don’t for your specific rim/ tyre set up.

Sure, but burping in use is one thing, burping when tested in the bath?

vincienup – Member

bag of rape

Not buying these wheels

Maybe Mavic rims simply aren’t as good as Stans then. I could run 15psi and not burp with my Stans rims, with a range of tyres.

I’m still hopeful its a seating issue but your 30 psi minimum worries me.

FWIW I’ve got much older mavic rims (effectively 819s) and used to run a 2.5 at about 10psi on the front, on my rigid xc bike- so far too wide for the tyre, and stupidly low pressure. Never burped. Did weigh too much though.

I’ve used both the charge and roam on crossmax enduros without issue, I’ve only used either on the rear but in theory they should run better on the wider front. I’ve had them both in the low 20’s (psi). 26er version, ran with a scoop and a half of stans. I’m about 13st kitted up. Possible dodgy bead on the tyres, bad batch? They are average tyres at best though so I wouldn’t be too fretful about swapping em out for something else. Not found a tyre that doesn’t play nice tubeless on them yet – various maxxis exo’s, schwalbe sg, wtb tcs, conti non tubeless BC barons.

oh well thats encouraging to hear. I quite like the tyres, burping aside.
Are they difficult to seat in your experience? I thought 70 psi would do it!

No I don’t remember them being a pain to seat, in fact I didn’t even have my compressor when I got the wheels so they will have gone on with the track pump. I’ve also had them on my flow ex’s on the other bike for a while too. You sound like you’re fitting them correctly by over inflating to ping them on then dropping to desired pressures and I don’t class low 20’s as silly pressures, if you’ve got to run them at 30psi to stop em burping something is wrong (unless you’re 20st plus)!!

I’m happy to hear that the rims aren’t fundamentally a bit shite. Ive ordered more tyres so if all else fails I’ll fit them. Cheers

The rear wheel is in fact fundamentally shite, too narrow and not enough spokes meaning I had about twelve months of broken spokes and spokes ejecting themselves from the hub on big compressions or heavy landings. I had a knackered old crossmax sx rear so I’ve just had my lbs build me a yellow front rim on to the sx hub giving me the wider rim and more spokes which is pretty much what every sponsored Ews rider is running! Ease of tubeless set up is a major plus point normally though.

hmmm thats really good info. I might (hopfully) get away with the rear as I’m only 10.5 stone but if I get similar trouble I’ll follow suit. Thanks

Riding a bigger bike with silly low pressure if you are riding it half decently must be horrible anyway.

Anything less than ~25psi in the back it’s easy to roll the tyre off the rim, let alone burp it on a decent bermed corner. You can feel the tyre wall collapse when loading it up even at moderate speeds.

There is a reason why people run 28-30psi in the back on a bigger AM bike they plan on using properly. I imagine one run down a rocky trail with 20 psi would leave a wrecked rim.

I changed the tyres and no longer have an issue. The beads audibly pinged into the rim at 50psi. I don’t think I ever got the mavic tyres seated properly, I didn’t bother trying again as they weren’t great anyway. Low pressures are fine now, no burping so far. (New tyres are conti trail king protection)
I rode at a hopton on Xmas day and using low pressures on the roots gives a massive increase in grip.