How do you measure a rim?
In order to find the rim size, you'll either measure straight across the middle of the rim, from outside edge to outside edge, or you can measure straight across the middle of the opening of the corresponding tire. Alternatively, we'd be happy to see if we can find out what size rim your scooter or power chair has - we'd need to reference your model and possibly the serial number to do that, and you can provide your scooter/power chair's model or serial number by calling us at 1-800-798-0325 or by emailing us at contact@monsterscooterparts.com