So keeping a budget Im looking at the Falken RT-615 since I hear alot of good things about it and they're cheaper. Not good with tire science as you can tell with my probably stupid question. Are 235-40's no problem to use? Should I consider another size? I'm on Swifts with stock 17' BBS if that helps.

 

255/40/17 is where it's at

 

will 255/40/17 rub on swifts?

 

you should be fine, tons of people run this size (self included with BC racing spec) and I've never heard of any rubbing.

 

255 on stock rims wont rub but i would run 245 some people dont know that it buldges on the inside witch gives you worse handling

 

255

 

I know what you're trying to say... but no, it's pretty much a proven science that the 255s work great on the evos. Would it be better to put them on 9" rims? sure, but he'll be just fine on the stock ones until he's running a competition tire.

 

The diameter is an inch off but they do make load.

 

Ownt Goose.

 

After running a tire that is too wide for the rim, I would rather give up a little width and gain better overall performance by going with the smaller tire.

Yes, 255s work on stock rims, they are however sub optimal. Why spend more money on a heavier tire that won't work as well? Thats silly.

Please note, some tires such as RA1s however are often a little less money as 255/40s than as 235/45s which makes the choice harder. If I were putting another set of them on stock rims however guess which way I would go next time.

 

255/40s are not optimal on 8" rims, but they are still better than 235/40, which are smaller than stock.

 

yup thats the size i have, how much are the tires each?

 

why is the 245-45-17 not recommended? Can I run those ?

 

For the reasons just mentioned above... the overall diameter is different than stock. This is not necessarily bad, just either desirable or not. this affects your final drive ratio, speedo, mileage, etc. If you are going to do it you should be aware of it.

 

just so you're aware - the second number "45" is a percentage.

so you would say for this size "the sidewall's height is 45% of 245"

that's why you can't just get different width tires with "45" for the sidewall and explains why 255/40/17 would be correct.