solid tires meets the standards TRA in USA,ETRTO in Europe,and JATMA in japan. Solid tire 4.00-8 ,15*1/4-8,5.00-8,16 ... *6-8,18*7-8,21*8-9,23 ... *9-10,27*10-12,6.00-9,6.50 ... -on solid tire10*5*61/4,10*5*61/2,101/2*6*5,131/2*51/2*8,14*5*10,14*41/2*8,15*5*111/4,15*6*111/4,15*7*111/4 ...