Dave wrote on 05/10/23 at 03:28:49:


It did go through the threads, so the loss of pressure was very much sudden. Luckily it happened a block from where I work, so I pushed it to my shop and then loaded it to my van and brought it to my mechanic.

Regarding the tube within a tubeless tire, I think a lot of offroad guys do it, not sure for what purpose.

[quote author=78434E5948445F59424A47582B0 link=1448021014/135#137 date=1683739688]och wrote on 05/10/23 at 04:54:46:


My KTM 690 Supermoto uses spoked wheels with tubeless tires, and the spoke holes are inside the rim. Many people with these bikes switch them to tubeless hybrid/offroad tires, and add a tube. I guess this is to be able to run very low pressures, like you said.

I'm just wondering over the general logic of tubed vs tubeless tires.

I am thinking tubeless tires are clearly safer than tubed tires - they are more modern, durable, etc.

However, if a tubeless tire is used in combination with a tube, wouldn't that be an extra layer of protection? I can kind of see it going both ways.

I worked at a K-Mart automotive department in the 80s.  I remember them stocking various automobile tubes for those people who couldn't find it in themselves to trust tubeless tires or wanted to squeeze a few more miles out of some junk tire.  I highly doubt tube type car tires were still being sold at that time.  Maybe they were still sold for trailers.  Who knows?

och wrote on 05/10/23 at 04:54:46:

On my KTM I caught a piece of metal in my rear tire last week. My mechanic put a brand new tire and I picked the bike up last Friday. Come today, I caught a screw in the brand new tire much to my frustration. My mechanic says he doesn't patch tires for insurance reasons, but he can put a tube in there - which brings me back to the original dilemma.

I am thinking if he puts the tube and if I should catch a screw or anything else that may puncture both layers - shouldn't the tubeless tire still prevent sudden pressure loss?

Tubeless tires are built with a wider shoulder that can seal on the "tubeless rims".....which have a shoulder built into them.  With the valve stem sealed to the rim the air is retained.  Generally when there is a screw or nail or some other puncture where the object is small and stays in place - the air is released slowly and it may take days or weeks for the air loss to become apparent.  The tire bead stays on the rim by the aid of the raised lip where the tire bead is.  If the object that caused the puncture does in and then out.....as if you ran over a board with a nail in it, the air runs out faster but may still take minutes/hours/days to become apparent.

Tires with tubes are more likely to have a "blowout" where the air loss is sudden.  The inner tube is very much like a thick balloon, and when it is punctured it can "pop" just like a balloon does.  This sudden release of air can be very dangerous and cause you to lose control.....you can't steer or brake well with a flat tire.  Also the tubed rims don't have the safety bead to help hold the tire on the rim.

However - not every puncture on a tube tire results in a blowout, and most times you will get a slow air loss and notice the problem long before it causes you to crash!  Motorcycles have been using tubes for more than a hundred years, and a large number of new motorcycles still have tubes in the tires.  The one big advantage of a tubeless tire is that it can be patched with a "plug" while still on the wheel - and there are numerous kits that will allow you to do this while out riding.

I can understand dealers not wanting to "patch" a tubeless tire for liability reasons - however plugs and interior patches can work just fine.  I got a screw puncture in the rear tire on my R1200 when the tire only had 100 miles on it.....the hole was just about in the center of the tread.  I patched it with a rubber mushroom plug and rode the tire until is was worn out and it worked just fine.  The one "universal" believe is that you should never patch a hole in the sidewall.