Mopar Muscle Association UK

Need your expert knoledge please

The Duster ran well at the Nats but with motorway gears i cant get a good ET. I would love a Sure Grip but guess i am going to have to settle for change to different gears over the winter. I would like to run Quicker at the HRD's , would
i improve things if i went from 14" wheels with 215 /70/ 14 tyres to 15" wheels and wider rubber or would that just make it even slower.

Cheers Andy { novice racer }

Use DaveR's fantastic math spreadsheet. You need to know the height of your tyre. Put it this way. I have 4.10s and a SureGrip. I run 285/70x15 on the street. They are very tall, but I can cruise to the strip at 3500-4000rpm doing about 70-80mph. Then bolt on 28" tall 10.5"x15 slicks that let the car do 6,000rpm through the top end, which it likes. So! Smaller diameter tyres will make your acceleration better. Width will only slow you down if you are very underpowered. IE my car probably wouldn't like those steam roller wide slicks.

I agree, Dave's spreadsheet is very good for that.

Thanks