The new AMA Pro Racing rules for the 2020 American Flat Track season have been released and, as we predicted in back in October, the Dunlop DT4 is the new spec tyre, ending an era of the Goodyear Eagle/Dunlop DT3 that has existed since the early 1970s.
The most interesting element of the new rules I noticed was this passage.
'In 2020, use of wheel inner tubes is optional, however, it is strongly recommended the new DT4 tires (front and rear) be run tubeless. Testing has shown use of even a standard tube increases the tire’s carcass and tread temperature, degrading performance and endurance. When used, only a single inner tube per tire is allowed. No other devices aside from standard style inner tubes may be run. For 2021, use of an inner tube will only be permitted at TT events. At all other track configurations, nothing will be permitted inside the tire.'
Why is this interesting, because spoked wheels, favoured by many of the Singles and some of the Production Twins riders, cannot be run tubeless meaning cast wheels, from companies like RSD and PM, especially the RSD Hammer rear wheel (below, $799 for the wheel, $400 for the hub) will become the go-to wheel and that adds an extra cost for the teams who already have serviceable wheels. Still, no one started motorcycle racing to save money, did they?