Went out for a ride yesterday, before doing so took my 2 well worn High Roller II’s off and stuck on 2 Conti Mountain King II’s (with protection sidewalls) – these tyres were essentially free after Canyon gave me a gift voucher for a minor problem I had with my new bike back in March.

Had a decent run at Scolty in Aberdeenshire and packed the bike in the car (left it there as I was going out this today too) – no issues with the tyres being flat at that point.

Unpacked it at the carpark this morning, saw both tyres were flat as pancakes – pumped them back up but wouldn’t hold air, tried taking them off to put new tubes on but getting them off the rim was an almighty pain and the time wasted doing that used up enough time I wouldn’t have gotten a full run in so just packed up and went home 🙁

I’ve had one puncture in 5 years before this, so not especially hard on tyres (the one before was landing hard and fast back wheel heavy on a big rock on a hardtail so all my fault) so just wondering if I’ve picked a duff set of tyres and should look for something else?
Had a few issues with front wheel grip on the new tyres too, but figured that was just getting used to different tyres.

I had been after some Minions, but struggling to see them in stock anywhere. Any advice on what other tyres I could try? Thinking about trying some Specialized tyres, or just bunging on the old worn HR2’s instead of using the MK tyres again.

Sometimes the mould release agent on Conti tyres stops sealant from working. It’s a pain but if you clean them with IPA it should sort it. They can also take a while to seal up. A shame because their rubber is excellent!

Was running them with tubes – so rare that I get a puncture that I never really bothered, but very tempted to go tubeless after this.

I would say it’s just back luck but if you pumped them up until they felt right rather than to a certain psi, you could have been running at too low a pressure hence getting a couple of snakebites. The Protection carcass is stiffer than anything Maxxis bar dual ply, so the thumb test is not very reliable!

Might have just been coincidence, but gone ahead and ordered another Highroller and a minion tyre as well as a tubeless kit. Was feeling squirmy on the tyres anyway so wasn’t sure about it up front. Think i had them at 32/35 front/rear so a little more pumped up than usual (of 28/32).

32/35 is too much for Conti MKs IMO. Should be under 30, like 26/28. At 30 or over they aren’t squirmy, but ‘pingy’. They deflect of off every pebble, skittish.

If both tyres were flat overnight, maybe dodgy tubes? I wouldn’t have bothered buying new tyres at this stage.

If getting them off was hard, presumably so was getting them on ?

I wonder if you nipped the tubes with a lever or trapped them under the tyre beads

I run ProTection MKII’s exclusively. Most of my riding is in and around managed woodland where there are so may thorns and sharp flint stones I used to get at least 1 puncture every week. Changed to MKII’s and I have only had one puncture in the last year. In terms of protection, I think they are unrivalled for my locale. I’d be more inclined to think it was poor tubes/valves/fitting than the tyres themselves.

Just my opinion, mind.

I had MKII’s non protection for a while, with tubes. I had a puncture EVERY time I rode them up the woods. I mean every time, it just got silly.
I bought some protection ones which did prove to be much better. I rode them for about a year.
I popped some old Minions on a spare bike for a ride and the revelation was amazing. It felt like coming home. I immediately ordered HR2’s for my main bike again. So much better IMO.
I gave all my MKII’s away.

I’ve had one puncture in 5 years before this

😯 that’s quite a run of luck, good going!

If they were inflated when you put them in the car and deflated when you got them out then that must have been a slow penetration puncture of some kind (rather than delayed-deflation snake bite) I would have though, did you actually find the cause of the puncture?

The tyres had been on the bike for a day with no issues/deflation before I took them out first time. They went on fairly easily – guessing the nightmare getting them off was either down to it being a much colder day or the time pressure of needing it sorted pretty quickly.
Not a fan of low pressures, generally run at 30psi with no issues, tyres planted and just right. Back MK2 felt fine riding but the front kept giving me the feeling of skidding away (the feeling you get when you catch wet rock or root at speed, slip a little then the grip comes back a fraction after), but wasn’t confidence inspiring. Just weird to get 2 flats after no flats in about 2 years (never had issues fitting a tyre before either, so doubt it was that). May stick them on the wife’s bike as they’re at least gripper than the cheap tyres on that 😀

I’ve had one puncture in 5 years before this
that’s quite a run of luck, good going!

If they were inflated when you put them in the car and deflated when you got them out then that must have been a slow penetration puncture of some kind (rather than delayed-deflation snake bite) I would have though, did you actually find the cause of the puncture?[/quote]

Mostly luck I guess – pretty much no thorns to be found up here – lots of rocky trails but learned to be smooth even when flying on them. Mostly as I’m conscious that I’m a big guy and crashing into rocks would kill wheels (and my wallet)! The one I got was a belter as I misjudged a jump and landed on the flat edge of a huge rock and could immediately hear hissing as I tried to get to the end of the trail before it went flat 🙂

Guessing so. The front held air but the back whooshed air out. Been lazy and left the bike outside (it’s rainy now!) in the motor so not seen the exact cause but guessing snakebites.