well i've never seen any proof, but at the same time the largest rims i would put on a teg would be 17's for clearance issues, but as for the tranny it could cause a problem cuz my friend has a toyota tacoma and he put bigger tires and rims on his truck and the added weight put too much strain on the tranny so he had to replace it, when it destroyed the tranny! where as a truck tranny should be stronger than a car tranny so, the added weight of chrome 18's could easily attribute to tranny probs!