how are they derived? How big is the safety margin built in? I’m having a hard time finding 12” tires (DOT’s) for the Grom 250 with speed rating that are higher than my theoretical top speed. All I’m seeing are high mileage type tires. The good sticky stuff seems to max out around 75mph.
It shouldn't be problem. My Vespa 250 does 75 without tire been issue. How fast you think that grom will go
Should be fine. Your grom will be much lighter I would think. Vespa is pretty heavy (my is) and is fine doing 75 with 2 people on it. It may go faster but that thing scares me going that fast on those small wheels.
Some info in this thread, looks like there should be speed rating letter on tire. https://modernvespa.com/forum/topic95117
Thats a good link with the Conti info. Most everyone is running the Kenda Kwicks on Groms. But they’re 62mph for the front and 75 for the rear. Bridge and Michelin have S rated (109) but they are more Vespa oriented than sporty.
My is fine so far, 12k miles on it. Just need to figure front end wobble when you let off the handlebars one day.
What do you need to know? Once any DOT tire is built the standard tire engineering procedure is to test some by taking x amount out of the pre-production run and spin them on a drum at x pressure for x time to make sure they meet or exceed the speed rating and load rating. Then anytime a production run is done they test them again to make sure the standards are met. With these two sizes I see that the Diablo Rosso tubeless tires (P speed rating) are available. And fyi a P speed rating is around 92 mph or 150 km.
