I bougt a set of M/T 14x32x15 stiff side walls last year from Summit is Sparks, NV on the way to the MATS race in Las Vegas this year in April. My car had a set of Goodyear 16x33x15 that had been on the car for over 6 years before I bought it and I could see the cords on the sidewalls breaking on the sides at the max section width, they where ran tubeless on the 15 inch wide rims with a bunch of rim screws and had a bunch of rubber left on them according to the wear dots I ran them at the big Spring Fling 4 day bracket race the weekend before the MATS race. I had the local Goodyear race tire warehouse mount my new M/T after that race, I tried to buy tubes from them and they told me that they hadn't sold or had race inner tubes or inner liners in over 5 yrs My M/T where no slower or faster than them old Goodyears No tubes in them yet, no soap either yet Probally take them off the rims this winter and soap them rascals up and try again IHTHs My car weighs 2750 with me in it, best 60 ft. so far has been 1.27 off the trans brake