The Tubeless Tire Tango: Why Even Pros Check their Air Pressure at the Start Line

Partway through Ironman week now, and one thing that is always a frustration for the modern bike mechanic is setting up tubeless tires, specifically high-performance road tires. These tires are challenging to get a complete seal that doesn't slowly leak over time. Unsurprisingly, we have set up lots of bikes with these types of tires this week, and we have one or two people come back with tires that have lost air overnight.

The biggest challenge, and why some of these high-performance tires are so hard to get perfectly sealed, is that the sidewalls are so thin, and sometimes the air will just seep through the sidewall of the tire. The best way to fix this problem is to ride the bike a few times, and this allows for the sealant to be pushed around inside of the tire and seal all the small leaks in the carcass of the tire.

The challenging part of the situation is that, albeit simple, it is challenging to convince the customer to take their bike out for a ride when they are not confident in their tires holding air.

The customer’s hesitation is understandable, but for lots of tires, this is really the only solution. It is not unheard of for a customer to pick up their bike with fresh tires one day, only for them to be back the next day with tires that have gone soft. I'm never really sure what to do in this situation; I can unmount the tire, look at everything, and put them back together, but normally there is nothing wrong, and ultimately this probably won't fix the problem. Unfortunately, the only solution that I can recommend to a customer who wants a tire that doesn't leak air when the bike is sitting is putting tubes back in.

One thing that puts me at ease is that even at the highest level, they still deal with this issue. I just watched a video with a mechanic at the Tour de France, and he was saying that they inflate the tires in the morning when they are prepping the bikes for the day, then right on the start line, they top up the tires to bring them back up to the exact pressure. So, as a rule of thumb, the best solution is to set the customer's expectation ahead of time, so they are not caught off guard when they see some air loss, especially if the tire sits for a while.