These are the Response Racing 3.8 Tires by Traxxas.
FEATURES: Soft compound narrow profile short knobby design
Traxxas, Revo, Response, 5.75x2.76-3.8 printed on tire
INCLUDES: Two tires with foam inserts
REQUIRES: Wheels, TRAC5372, TRAC5373
SPECS: Width: 3.2?!? (82mm)
Diameter: inner diameter 2.8?!? (72mm), outer 5.3?!? (135mm)