penningtron wrote: Wed Aug 20, 2025 7:13 am
It's kind of warped my brain a little. I was taught many years ago that max-filled tires was the way to avoid flats, which has worked pretty well but then I just accepted the stiff ride was part of the experience. It's no longer necessary on wide tubeless tires, and the cushiness feels almost indulgent!
There's a two part reply to theing from me.
About 10 years ago, the cycling industry really started to look at cycling efficiency with a more holistic view. I think the advent of relatively cheap, personal power meters helped kick this off. It used to be that they would put a tire on a smooth drum and run a rolling resistance test. Of course, high pressures win for rolling resistance on a perfectly smooth surface. The real world is bumpy, and the harder the tire, the more it bounces around on the road. High tire pressures cause the tire to briefly lift and reconnect with the road surface, and that adds rolling resistance. Reducing the pressure causes the tires to deform over the little bumps, and the bike can cross rough terrain more smoothly.
Yes, there's is an increased rolling resistance from lower tire pressure, but it turns out it about the same as the increased rolling resistance from the micro-vibrations of the higher tire pressure. Over the years, people associated the micro-vibrations and road chatter with "the feeling of going fast". So, tires with lower pressure don't feel as fast to a lot of people, but tests with power meters show similar effort. As a side benefit, the micro-vibrations are tiring for the rider. Elimination the vibrations can make the rider perform better. So, in many endurance cases, lower pressure is the same effort to move the bike, and less tiring in the long run from pneumatic suspension.
Point 2: flats. Hard tires would prevent pinch flats with inner tubes. That's not a thing with tubeless. However, harder tires are more likely to get a flat with road debris. If you run over a piece of glass wit ha hard tire, the glass will often cut into the tire. You can think of the high pressure as "fighting back" against the ground. With wider tires and softer pressure, the tire conforms to the ground and the debris. If you run over a piece of glass, the tire will give and the pneumatic suspension will absorb some of the force of the glass pushing into the tire. Lower pressure tires receive less damage from sharp or semi-sharp debris. Nothing is impenetrable, but I've had WAY fewer flats on the road since lowering my tire pressure; tube or tubeless.
penningtron wrote: Wed Aug 20, 2025 7:13 amDo you tubeless guys top off your own tires? Supposedly they dry up faster than I realized (every 3-6 months?) but with removable valve stems, it seems DIY-able. I have a stand and a track pump.
I try to check every 6 months. I remove the pressure, pull the core, and use something as a dip stick; zip tie, log and thin allen wrench, etc. In a perfect world, the tire beads don't come off the lip of the rim, and re-inflation is just like if you had a tube inside. If the tires and rim are compatible, you should be able to seat them with a floor pump.
I had SO MUCH problem with tubeless, but it was a comedy of errors for me. First, I had rims that weren't REALLY tubeless compatible. Then, my favorite tire brand (Panaracer and companied who use Panaracer for OEM) was the brand that is notoriously hard to set up tubeless. I got some Teravail tires for my gravel bike about 18 months ago. I put them on, pumped them by hand, and "POP!", they set right on. They even held air overnight with no sealant. I added sealant the next day, of course. I was just curious. Some brands just works better. Schwalbe and Teravail have always hopped right on. Specialized Mondo was super easy as well. Vittoria and Panaracer, amazing tires, but a struggle for tubeless in my non-professional garage.
BIKES!
