Tire pressure: ignore the sidewall.

I just saw a post on a forum asking about proper tire pressure for a modern Vespa. Several people said “it’s on the tire, duh!” That seems like an obvious answer, but tires are usually designed for many applications, and that number is the MAXIMUM pressure the tire can handle, not the pressure for your vehicle. Filling to that pressure (on any vehicle, but especially on a scooter or motorcycle) can affect handling, traction, suspension, safety, and fuel efficiency. Modern vehicles always have a tire inflation sticker somewhere. On cars it’s almost always in the driver’s side door jamb. On motorcycles, it’s usually a sticker or metal plate on the swingarm or fork. On scooters, it’s usually a sticker in the glovebox or helmet bay. If you can’t find the sticker, consult the manual for proper pressures (If the sticker and manual contradict each other, go with the sticker, it’s more likely to be accurate for your specific bike/country). If you’re in a pinch and don’t have the data, it’s usually best to inflate it to several PSI below the “maximum” listed on the sidewall, then adjust to the proper PSI as soon as you can.

3 thoughts on “Tire pressure: ignore the sidewall.”

  1. I’ve had to tell a number of people about that too. It’s good advice to trot out periodically.

  2. It took me forever to find out the suggested PSI for the Continental Zippy 1 tires that I put on my ET4. They were a different tire so the suggested pressures were different than stock – however, trying to find the recommended PSI was tough, and the PSI on the sides of the tires were super high.

    Of course, I also got some “duh” answers. There’s always people waiting to pounce with those kinds of answers.

    One person person suggested that I fill my tires with “what feels right” and increase and decrease pressure until I found the right combination that “felt right” to me. I’m still confused about how someone could really use this method.

    Finally someone pointed me to a page on the Continental web site that had suggested pressures for their tires on particular scooters. For the life of me I can’t find that page now, but it turned out to be higher than stock but not nearly as much as the sidewalls suggested.

    Thanks for bringing this topic up!

  3. See, you learn something new every day, It never even occurred to me that changing from stock tires would affect tire pressure, unless they were narrower or lower-profile or something. I’ve always used the stock recommended pressures for the various tires I’ve used on vintage bikes. I can’t imagine it’d be radically different than the spec for most tires, but it’s good to know.

    I *have* noticed some bikes recommend different pressures depending on whether you’re riding 1-up or 2-up. Since I weigh as much as two post-war Italian teenagers, I usually fudge it towards the 2-up spec.). That coud be stupid, I dunno.

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