On Saturday, January 26, 2019 at 3:59:53 PM UTC-8, wrote:
I was doing a hilly ride today. I came down out of the hills at 35 mph and stopped at a stop sign in the downtown Oakland Broadway. I came to a stop light and waited. A couple of other guys caught up with me. As I pull off on the green I accelerated up to perhaps 12 mph and that damned tubeless tire blew completely off the rim. It had about 90 psi at the beginning of the ride so it wasn't too high nor too low pressure.

I hit pretty hard but with so many clothes on because of the cold, I got relatively light injuries though it's a damn good thing that I had out-accelerated the cars and they saw it happen and had time to swerve out of the way as I landed almost in the middle of the street. The other two cyclist helped me up. After a couple of minutes I installed a tube and inflated it and rode home.

So I am now off of tubeless tires with actual proof that they aren't safe..

BTW, I fell on my side and slapped the helmet on the ground and it is broken.

After a nights sleep and waking early and really heavy thinking on this subject I was bothered by something:

When I put the tube in the tire yesterday I pushed the tire back on by hand and without using the levers. A tubeless tire should NEVER mount like that..

Originally when I was buying tires the Michelin add said that the Pro4 Endurance was a "bi" tire meaning clincher or tubeless. Now looking all over the place the ads only say "clincher".

Though we had arguments here about the way tube and tubeless exert pressure on the rims let's not go through that now except to say that the same tire that blew off of the rim without a tube didn't give any problems with a tube in it.

The tubeless tires offer so many advantages that I have a very hard time wanting to retreat from them. In the really cold days we've had around here the Pro4's picked up a couple of what would have been a sure flat but no pressure was lost. Also the narrow roads I ride on offer no place to pull over to fix a flat and so it is very nice not to get one.

So at this point I am up in the air. The only way to solve this is to get some tires that definitely claim to be tubeless. I just bought a set of Maxxi's that are definitely defined as Tubeless And I'll go from there.

Other things: The sealant I am using was Orange Sealant. It was all over the inside of the tire surface. While you can wash this out there wasn't any water out on the road so I has to rub this stuff out as good as possible by hands and wash my hands with my water bottle.

They recommend that you replace the sealant every couple of months but it has been several months and there was very little sign of drying. Looking around again the advice has changed from "a couple of months" to "six months is a good figure". The last bike shop I was in that I trusted told me that Stans actually works better than Orange and it doesn't need changing for the life of the tire. OK, I'll also try this this time around.

When this tire went off it sounded like a gunshot blowout. It was so loud that I wouldn't tell which wheel it was for a couple of seconds so I couldn't brake. When I was dumped over I have only slowed to about 8 mph. If I had known that it was the front tire I could have put the rear brake on hard and probably stopped it with little damage to self. surprisingly the only damage to the bike was the levers being pushed out of alignment from my death grip.

My Pearl Izumi Winter Jacket doesn't even show a mark. I had some thermal tights on over some normal shorts so I only got minor abrasions on my elbow and hip. But my knee got a pretty good and large abrasion that will take a month to heal properly.

Now I can think of me going 35 mph just seconds before that blow-off. But with a clincher I've been in almost identical positions with a rear tire exploding from a large glass cut. I was going about 25 mph at that time and was lucky to be in a turn that was properly banked so when the back slid out I could steer up the banking and stop safely. So can we say that using any clincher, tubeless or tubular tire is safe?