Owner's manual says the original front tire measures 225/45R19 and rear measures 245/40R19...

... ran it in the tire size calculator (http://www.miata.net/garage/tirecalc.html) and turns out it reads 0.9% too fast (no big deal).

So... let's say I want to change from the stock Bridgestone Potenzas to say a Toyo T1R or a Vredestein Tire - the problem I find is that both the Toyo and Vred. don't come in 225/45/19 for the fronts - they do have the rears (245/40/19).

So... my question is what do normal people do in this scenario? Do they get a front 225/40/19 with a rear 245/35/19 and live with the 1.3% too fast rating (as per the calculator)? Or other? Or does this make the aspect too small for stock and would it look silly?

 

bump up to 245 in front and 275 in rear.

 

for summer tires, most people upgrade to 245/40/19 and 275/35/19. it gives you about 1" extra tire front and rear while being almost identical to stock height.

and i doubt changing from a 45 to 40 will be that obvious but why go smaller when you can go wider?

 

Thanks for the info. --- calculator says that size 245/40/19 and 275/35/19 (is actually better than stock is it's only 0.5% difference.

My next question - is (can you tell I'm new) will this new wider tire size fit on the stock rim without any problems such as rubbing etc... I guess the fronts are more suseptible to rubbing since they turn or make them noticeably more difficult to turn the wheel... and the second question is --- having a tire that much wider in the front 20 mm and 30 mm in the rear going to give me nightmares in the rain...

 

um WHAT? how is something better than stock?

no issues with rubbing at stock height. and why do you think they're worse in the rain? these tires are designed to be driven in the rain so they channel water, just not for use in snow.

 

Maybe he means difference between front and back diameters??

 

Yes - difference between front and rear diameters in that size is better than stock. Stock has a 0.9% difference (27.0" vs. 26.7") whereas the size you gave me has a 0.5% difference (26.7" vs. 26.6").

It was my understanding that wider tires were more likely to hydroplane in the rain. But again, I'm asking for someone with experience driving on them in the rain as I don't know if the extra 1" or so in increased width will make any appreciable difference? Or is wet traction more dependant on rubber compound and tread pattern?

 

Did a quick search on tirerack and the optional 19 fitment they recommend is:
Front: 225/45/19 (Sidewall 4.0" / Diameter 27")
Rear: 285/35/19 (Sidewal 3.9" / Diameter 26.9")
Only 0.4% diff.
Anybody running this setup?

 

i'd think 275 would be the max i'd run on a 9.5" rim. 285 would be pushing it.

245F and 275R. do it.

 

Stock wheels are 9 inch, which is perfectly fine for a 275.