I've just got back from a ride on the shiny new mmmBop, bike was great, shame about the wheels. They are Mavic EX819s on Pro2s (not that I can fault the hubs).
I've been running these wheels for about 6 weeks now with a couple of different tyres and I'm always getting flats, mainly burps on very rooty/rocky stuff which lead to complete failure very quickly (has happened on my Five in Whistler, then just now on the mmmBop on some rocky stuff around Tal-y-bont and Dol-y-gaer despite pressures at 40psi). Both a 2.2" UST Mountain King (useless tread but it ought to hold air!) and a 2.35" High Roller do this on practically every ride despite using industrial quantities of Stans solution. Having forked out for the Tubeless upgrade 6 weeks ago I'm pretty miffed about these supposed 'All-Mountain' wheels.
Does anyone have any similar experiences with these wheels, I've checked valves and am about to resort back to running inner tubes filled with stans to stop the thorns. If you have, how did you get around it? My options seem to be dual-ply/bigger volume/higher pressures! None of which I'm overly keen on for everyday riding.
Nope, burp occasionally but only when Ive been daft. HTH 😀
never had these issues. 819 are some of the best tubeless rims you can get for reliability, also have some some ztr crests.
i think its probably to do with the way you mounted them, or the tyres you have are faulty or your psi readings are not right or yo are simply too rad for the wheels?
mine fine pro 2's with xm819's
Conti rubber queens 2.2 ust with a little milk and 22psi
Been running pro2 with XM819 for ages on HT and full sus with no problems, I'm not a slow/light rider either, 15st and raced DH at a high standard for 10 years. I've dented the rim and lost pressure a couple of times, straightened out with an adjustable and the tyre holds air again no worries
If I had to guess I'd say your pressure readings are out, possibly you are running a lot lower than you think
are you pumping them up good and hard to amke sure the bead is seated ?
5 years of faultless trouble free use here *touches wood*
Thanks for the ideas, I've been using a range of different pumps/compressors recently as I've been away. I'm pretty confident that the pressure is accurate.
1nten5e - did exactly the same thing last week with the front rim as the tyre rolled completely off the rim on a very steep rocky section in Whistler, lucky to ride out!
Perhaps I need to bang them right up to the maximum pressure before letting air out to get to something reasonable (I'd hoped to be running them at 35 - 22psi is a little optimistic with the rocks in these parts I think!)
Better get out to the shed again...
Thanks, Neil
yeah, you have to pump them up rock hard to seat the bead onto the rim properly, then let air out to your required pressure
usually pump mine to the max rated and wait for the beads to "ping" then let air out as required.
Another very happy UST user here. No real problems to report bar a little burping on very rare occasions. Sealing bead has never been an issue, with a track pump to start things off.
Aye it sounds like you're not seating the bead. I love UST rims and tyres, all except for the price!
Been using XM819 rims for a few weeks now and XT UST wheels on my other bike since March.
I can recall two burps in that time and thats it. Been running 2.2 Rubber Queens at 30 psi (on the 819's) with no problems whatsoever except one slight dent (but no lose of air) achieved during a clumsy moment at Coed-y-Brenin.
I see you.
I suffered the exact same issue (nearly slung them) until I discovered the joy of KY jelly!
As others have said, it’s ALL about ‘seating that bead’ (walk away from the metaphor).
I’m currently running the same tyre combo and I’m not shy with the Peaks rock gardens either...no problems at all since adopting following method..
1. Ensure the rims bead is clean from crap/stans etc
2. Run a little KY with finger tips round tyres bead
3. Add a couple of caps worth of Stans for taste
4. Lift wheel from floor, blast up to 50psi with track pump
5. Spin, angle, spin
6. Leave for ‘a while’?? (I usually go for overnight)
7. Deflate to working psi
Like I said, exact same happened to me...I actually dinked my front rim a little ....bit of a pisser but they’re tops now and yep, ZERO pinch flats or thorns hereon in....a new day, a new dawn brother 🙂
One thing I’ve noticed is that tubeless tyres indeed deform differently than tube types. Insomuch as they don’t share the same psi to deformity ratio...clear as mud that 🙂 That is to say if your rear ‘tubed’ set is running at 20, then (for my set up anyway, can’t speak for other tyres) I’m put 30 in the tubeless set due to their apparently lower ‘squish’ co-efficient...I’ll leave it there before I receive a kicking.
Stick with it, if your in the Sheffield area then I’ll help if you wish?
I've wacked in 60 psi and am leaving them there, it's always good to hear that someone else has struggled, never had any issues with getting air in them and would class myself as mechanically competent but this was really hacking me off! Time will tell if it's right this time.
Cheers,
Neil
dunno about the ky jelly thing, but a bit of plain water or some washing up liquid should also do the trick, tbh i usually just wack em up to 60 psi and make sure the bead is even
Not had issue with them flatting but getting the bastads to inflate with anything but CO2 is just a waste of time. Not like my XT's....piece of piss.
When they're seated properly you can let all the air out and the tyres still stay firmly planted on the rim. It takes quite a bit of force to 'pop' the bead of the rim with your fingers.
Had 819's for ages, not a problem with any tyre nor pressure...
But I use a compressor and when installing bang them up high so they seat properly - then let them down to whatever pressure feels right for the particular tyres/ground (somewhere between 20 and 40 psi).
When you say 'industrial quantities' of Stans liquid - exactly how much? I vary between 50ml and 100ml, depending on tyre size.
that isn't a good idea!despite using industrial quantities of Stans solution
823's with HR LUSTs and never once had a problem, fitted with a track pump. as others have said, are they going "PING" when you're pumping them up?
Not had any problem with mine, like the rest of the posters I pump them up to 60ish to make sure the bead is fully seated (the crack you hear as it seats always makes me jump!), then lower it to working pressure.
No issues with mine on the exact same setup on my Blue Pig, I always pump them up to the max rating on the tyre initially. I don't always run sealant either (serial tyre changer).
Running 2.2 mountain kings on an mmmbop seems wrong, the 2.4MK UST's I have are too small as it is...
Get a nice dry cotton cloth and clean the rim spotless and also rub off all the excess crap from the contact points of the tyre bead from new.I wipe down the valve too so that its not got any of the white powdery stuff in there.It all helps with a good seal. choose whatever fluid to rub inside the hook of the rim/tyre bead and put the tyre on. *dont go over the max pressure in hope of having a better chance of seating the bead. i went a bit over the max once when i was having trouble with one. not long after, the bead blew off and i thought i lost my fingers. It also deformed the tyre and i had to bin it.hand was sore for hours and ear drums were thrashed!