what exactly is a retread tire?
If they meet the sound level limits set by law, there's nothing that can be done. What is loud to you may not be too loud for the law. Sound levels are measured with a decibel meter at a specified distance from the vehicle with a specific set of conditions established (engine speed, gear selected, etc.). Sound levels are a judgment call and sometimes can be difficult to prove unles it's obvious (like a missing muffler). Also, I don't believe police carry sound decibel measuring instruments in their car.
Some people like loud rides. If the noise is too loud, yes law enforcement officers can write citations to the driver. They are not being enforced probably because cops are undermanned and underfunded. Making a noise or dance violation pretty far down on the things to enforce list.
Ah, yes, the differences of location. Re-tread: A used tire (does not need to be worn to limits) is pared down to it's carcass. This is the base rubber and cords. The carcass is inspected, any bad ones junked. The carcass is then encased in fresh rubber and placed in a mold. It is then pressed and heated (same as the original). This process is used for many tires, but not motorcycle tires. They are not only used on trucks, I have run quite a few on passenger cars. What bikinkawboy describes are called re-grooved tires, where the tires have new grooves cut into the remaining rubber. This is done on large truck tires, you may notice the legend regroovable on the sidewall. This practice is not allowed on passenger car tires.
Sorry JMakk, you don't know shuh, let's not go there. But that's ok, you're too young to know what an old fart like myself has learned from experience. What everyone is describing is actually called a recap in the industry. In the old days (1930's-60s) the new tread was vulcanized (basically melted on) onto the prepared tire carcass while today glue is used almost universally. Bandag is one of the major players in the recap industry. A true retread describes semi tires where the tread is worn down and new, deeper sipes (grooves} are ground or burned onto the carcass following the old grooves. Normally this can only be done once and after that new tread is worn down, it must be recapped to be serviceable. When new, the tire has the extra rubber thickness on the tread but doesn't have the extra deep sipes because they would cause the tread to squirm under load and cornering. Excessive squirming and the reduction in traction is why tractor and truck pullers often shave down the lugs on brand new tires and let them set out in the hot sun or on a tin roof so the rubber will harden and become stiffer. If you've ever noticed the big pieces of truck tire tread laying along side the road, that's the reason motorcycle tires are never recapped. Too much liability.
basically take a tyre that has been used and worn down to the limit, the tyre is then taken by a company and the remains of the tread is then mechanically scrubbed off. Then the remaining carcas is then placed into a machine where liquid vulcanized rubber is injected around it and then set to recover the tyre carcas with more tread, hence the term RETREAD. They are legal in most countries but they are not made for motorcycles and should never be used on motorcycles or performance cars.
