Tire Sizes

[PeeBus]

Hi Guys,<P>I've got a tire question. My '95 MX-3 V-6 came with Bridgestone 205/55-R15 as original equipment. I've now worn out two sets and I haven't even hit 100k yet! The reason, I'm told is that these are "sticky" performance tires. I've decided to go with a tire with more tread life and less performance like the Michelin T series (140k tread wear guar.) Trouble is I can only get them in 205/65-15. Can these be safely used on my original mags? What differences will I experience apart from a speedometer which under-reads by 6.8%?<P>Thanks for any help.<P>Paul

[92MX3GS]

Generally, it's a good idea to keep your overall wheel and tire diameter combination as close to factory as possible. With 205/55 R15's, factory tire diameter is 23.9". With 205/65 R15's, the tire diameter would be 25.5". Your sidewall height would be close to an inch more, and your revolutions per mile would be less. Basically, you'd lose a little bit of power (probably not noticeable), your gas mileage would change (better if you live in a flat area, worse if you're in the middle of the appalacians like me) and your odometer would read incorrectly. Also your speedometer would read approx 3.7 mph less than you're actually going. i.e. at 55 mph you'd actually be moving 58.7 mph. <P>I'd shop around a little if I were you and try to find a different brand. Michelin isn't the only company that makes tires with more tread life. (Personally, I sort of like Cooper Cobra's or BF Goodrich Radial T/A's. They're not quite as soft as say BF Comp T/A's)

[DiGiTaL]

Maybe you should try using 195/50-15 size tires. They would fit fine on your wheels and there are a lot of companies that make that size tire.

[PeeBus]

Thanks for the input. I appreciate the help from both of you. I wasn't aware that a 195 size would fit on a rim designed for 205's. How is this so? How much of a range can I look at?<P>Paul

[mazdamaniac]

195's would be almost an inch <I>thinner</I> than the stock tires and I can't recomend that either.<P>On a 15" stock rim, you are stuck with 205/55 or, possibly 215/50 (with only a 1.7% error on the small side that way).<P>------------------<BR><B>Jeff Abrams</B><BR> jeff@mazdamaniac.com <P><B>SUPERCHARGED</B> 2.5 liter 1993 Mazda MX-3 GS <BR> <A HREF="http://www.mazdamaniac.com" TARGET=_blank>http://www.mazdamaniac.com</A> <BR>Normally aspirated 1997 Mazda MX-5 Miata