Tyre/rpm relation question.

[Justin182]

... also not clio related.

Say you have an old crappy car that is going to be driven a long distance and only has 13" wheels and a 4 speed. Is it possible/legal to stick on some 14s at the front to hopefully reduce the rpm at say 70mph ?

So basically, is it legal and will it make a significant different to engine speed ?

Thanks

 

[BrianR]

You can calculate the difference, check the rolling radius of the two different set ups, then there is a formula which I cant remember atm, but I'm sure someone will know.

I don't think you are going to notice the difference TBH and your speedo will be out as well.

 

[Lagerlout]

Definitely will make a difference but I doubt very much whether or not you'd actually notice it.

 

[cuddles]

have a look at carbibles.com (in the tyre bibles section there is a rolling radius converter). tells you speed and percentage difference when comparing different tyre sizes

 

[Pep]

http://www.miata.net/garage/tirecalc.html

hope this helps mate

 

[C.slicker]

Isn't your car lowered?

I doubt there would be enough room under the arch to increase the tyre diameter enough for it make a real difference to economy/ride quailty.

Sam

 

[Justin182]

Cheers for the replies guys. Will have a look at those sites to see if its worth it.

Sam: I was not talking about my 182 mate.

 

[Djw John]

Yeah the thing is your speedo would still read 70! Would make so little difference probably not worth it

 

[Justin182]

Yeah, just been looking on these sites and it will increase it 3.5 mph at 70mph lol

As you guys have said, really isnt worth it.