what size wheels should i use ?

hi would like some of your opinons on what size wheels are best to use. im building a chair( its a rt24) and i have a 17 inch rear wheel and a 19 inch front. ive been told that alot of people use a bigger front and rear wheel. would i be better using bigger wheels ? And can you still buy 17 inch tyres ive heard they are abit rare ?

18,,, 21 choice of champions, 17 inch tires are as rare as a loving kev win!!!!

Much as it pains me to admit it, Anorexic Adam is correct
A 19" front will only be an advantage it some wet conditions and that's about it - tyre choice is also a problem. It has to be 21"
At the rear it's got to be 18" if only because you'll get a choice of tyres for it OK.
Adam himself found that gaining 3 inches overall vastly improved his performance . Who else can boast down the pub about having almost 2 feet out front whilst taking a foot and a half in the back end ? He could have done without adding to his rolling radius though.

looks like thats the way to go thanks for the help you dont no anyone who has a sidecar wheel forsale to fit rt 24 ?

19' front tyres are non existent. Use a 100/90-19 HARDPACK rear (small nobbles for a rear you see...), and shave the side nobbles off.
17" rear tyres are almost as bad, Bridgestone do 100/100-17 but it's a bit small, Mitas do 130/70 but they are pretty rare.
Hence my post about Morad rims before, Ethel's going 18" over the winter.