I've tried HR's exception series, but the final descent of the Penhydd trail made short work of the side-walls – Stan's everywhere and no more tubeless.

Looking for reassurance a 2.25 Crossmark/Ardent combo will have tougher sidewalls and thus be OK tubeless. Thanks.

No, they're not tough enough for rocky trails/clumsy riding.

Exceptions are superlight race sidewalls. Have you considered LUST's, intended for tubeless setups, they sit somewhere between single-ply and duel-ply as far as sidewall support goes.

I tried it with some ADvantage Exceptions and learned my lesson the hard way! I now use LUST tyres and they feel so much better.

I ran Ardent/Crossmark tubeless at the Dyfi and have not had a problem with cut sidewalls yet…so rocky trails=yes…clumsy riding(does rigid count?)=yes.
But then I've never sliced a sidewall tubless or not.

i use standard advantage tubeless no problems

Monorail on the front, Crossmark on the back, both exception and never had a problem tubeless. They have been on for over a year and im certain the sealant has all dried up yet they hold pressure perfectly month after month. If your clumsy then yes you will cut the side, but mine look pretty tatty and havnt failed yet.

I'm running 2.35 singleply minions up front as tubeless and they're perfect. I wrecked a set of 2.35 HR LUST's in under a week for comparison.

I've got standard 2.25 Advantage on the back but don't think they're up to being tubeless out here.

Put Ignitor (F)/ Crossmark (B) Exceptions on mine. The Ignitor is losing air – imperceptible though it just needs a little bit of pumping every 3-4 weeks if that. I managed to kill the sidewall of the Crossmark on its second ride. Crossmark Exception sidewalls are way too thin for tubeless in my opinion. Saw it after it was sliced and I wouldn't ride anywhere rocky with it tubeless. Absolutely brilliant tyre otherwise.

Replaced it with a LUST version of it on the back and the sidewalls are extremely sturdy but I can feel the extra weight/rolling resistance though that was partly my fault cause I ordered a 2.25 by mistake (the exception was a 2.1). Have a couple of 2.1 LUSTs coming which will hopefully be better. They are quite big though as the 2.25 Crossmark is bigger than the 2.35 ignitor, the 2.1 was about the same size.

EDIT: LOL 05-five Sorry didn't even see that was your thread – you know all about my Crossmark split :p

I seem to search out any flints (there's a lot around here) or slate over in Wales 🙁

If the 2.1 LUST Crossmarks are a good size then I could be tempted away from my Nevegals with SWS. The Sidewall Shield seems to have protected them well and it seals the tyre for tubeless. Nevegal SWS 2.1 is 640g, so the 2.1 LUST Crossmark is only a little more, might try it on the back.

I found Crossmarks too fragile for rocky stuff and also had problems setting them up tubeless, they were very pressure sensitve and had to be run very hard or they squirmed around a lot and burped a fair bit

What size was your HRs? The 2.1 Crossmarks are about the same size as 2.35 HRs.

The HR's were a very skinny 2.1

Ok they will be bigger than your HRs then.

After ripping three tyres (Mud X, Bonty Jones and then a NN) earlier this year, I went for a 2.35 Larsen on the rear of my HT. Run tubeless on a XM819 rim with latex.

Seem strong plus the way the tread is they are less likely to 'catch' flints etc – also bugger all grip on wet grass…

I've run Minion DHF and Crossmark 2.1 eXCeption/2.25 tubeless. The 2.1 Crossmark was fine for local stuff but i slashed it open on the Skyline trail so went up to the 2.25 and that was alot tougher.

Now running a UST wheelset with Igintor 2.35 LUST/Crossmark 2.25 LUST. Did have a 2.1 Crossmark on the rear intially but that recieved a tear through the casing under a side knob and just wouldn't seal so thats now on the hardtail (tubed).

2.25 Crossmark LUST is just over 900g so not lightweight but it's on the full-sus which i ride in rockier/rougher places so feels great for that kind of thing. It's still a bloddy fast rolling tyre for it's weight and width though.

BTW I reckon the 2.35 Ignitor/2.25 Crossmark combo are pretty evenly matched width-wise.

I've been running standard wall 2.35 HR upfront and 2.1 Advantage out back on tubeless rims no problem. Previously tried 2.1 Ignitor Exceptions ghetto which kept rolling off the rim. I've also slashed 2.1 Advantage exception sidewalls so I'd Exception walled tyres a miss for tubeless but standard wall Maxxis tyres are fine.