Autocross tire size

OK firend of mine is going to autocross this summer and we are sticking with Kuhmo Ectsa Supra 712 and rim is 15in 6 in depth. Want to know the widest tire we can go with and not offset the speedo to bad.

195/50HR15
Blackwall Serv. Desc: 82H Price Each: $50
Estimated Availability: Low Stock



Road Hazard Program: $24.00 total with four tire purchase
195/50VR15
Blackwall Serv. Desc: 82V Price Each: $50
Estimated Availability: In Stock


Road Hazard Program: $24.00 total with four tire purchase
195/55VR15
Blackwall Serv. Desc: 85V Price Each: $61
Estimated Availability: In Stock



Road Hazard Program: $29.28 total with four tire purchase
205/50VR15
Blackwall Serv. Desc: 86V Price Each: $58
Estimated Availability: In Stock




Road Hazard Program: $27.84 total with four tire purchase
205/50WR15
Blackwall Serv. Desc: 86W Price Each: $59
Estimated Availability: In Stock



Road Hazard Program: $28.32 total with four tire purchase
205/55VR15
Blackwall Serv. Desc: 88V Price Each: $60
Estimated Availability: In Stock

We do plan on upgrading rim later this year but this it what we goto work with for now.

This is what I see alot of people use. As far as width on a tire size it won't make the difference that height will

http://www.discounttiredirect.com/direct/findTireProductCategoryDetailBrnd.do?tpc=FALHZA&tp=Passenger%2FPerformance