mbe

I have a Checkpoint SL5 that I recently purchased a few weeks ago. Before I took delivery from my LBS, I had them convert the stock Bontrager GR1 tires to tubeless.

I have only put on a few hundred kms and so far have had two punctures, both occurring while riding on the road. The first puncture was literally within 5 minutes on my first ride from picking the bike up, when I was unable to avoid riding over some broken glass on the shoulder due to traffic. Today I encountered a second puncture when nearly home from a ride. On my most recently puncture today, the tire was only showing about 10 PSI when I got home and inspected the tire. I currently run about 40-45 PSI when riding on mixed road and gravel paths.

I find the Bontrager sealant to takes quite some time to seal. By the time it does seal, most of the air has already escaped from the tire. When inspecting the tire, I found the leak by spraying some soapy water on the tread as there was no visible sealant showing anywhere. It was still leaking quite considerably. I couldn't see any physical debris still stuck in the tread so I went ahead and spun the tire around a few times to get more sealant in the spot of the puncture. When I went to inflate it back up it started leaking again, but this time it also released sealant into the tread. This was about 30 minutes after first discovering the puncture.

Perhaps I am expecting too much and these stock GR1 tires are just really mediocre and prone to punctures beyond what any tubeless sealant can seal. I should note that the punctures were approaching 1/4 inch in size, which is the upper end of Bontrager's maximum claimed puncture size for its tubeless sealant. I am relatively new to tubeless so I am not sure if this is normal or if there is a better sealant out there that will seal a bit better.

dwmckee

A 1/4 in pincture is beyond what most sealants can realistically seal unless you are really lucky. Sometimes you can get a bit of luck and get a low-pressure seal after a lot of air loss that will get yoy back home, but a full-pressure seal of a 1/4 in puncture would be beyond the realistic limits of what current sealants can normally handle...

DrIsotope

Yeah, any sealant is gonna spit 'n spray with a hole that big. In the future, you'll either want to use a plug (like a Dynaplug or Stan's Dart) for punctures that large in the field, or with a traditional patch on the inside of the tire at home.

mbe

That is what I sort of figured. Just bad luck to have had two punctures so soon.

Is it okay to use CO2 with tubeless to refill the tire once either the tire had sealed itself or been plugged?

DrIsotope

That's all I use.

richdirector

I had GR1 on my lynskey and just ripped sidewall that was beyond repair... They seemed to wear a bit quicker than earlier WTB nano and resolute. GR1 are for well suited to loose, dry conditions and not bad in the wet. Not meant for mud or wet grass as they spin out.

I've just gone on to Michelin gravel King SK but too early to say (apart from fitted really easily)

chas58

Yeah - although it may temporarily freeze the sealant (and anything near the valve). Generally no issues. I tend to take a tiny lezyne hand pump with me if my sealant doesn't get it quick enough. Saved my butt with some pinch flats which take a while to seal.

wheelsmcgee

To me, 1/4” is a decently sized puncture, and I am more surprised that sealed at all and you arrived home with 10psi left. Most every time I have gotten a tubeless puncture (most much smaller than 1/4”) I have stopped riding, made an effort to find the puncture quickly and put a finger over it to help stop the flow of sealant and encourage drying, and even then it’s not uncommon to lose enough air that I have to add a few pumps or some CO2...sometimes I even end up topping it off again a few minutes later. I use orange seal, FWIW.