I have 17 x 10 rears and I am currently running 275 / 40's. I have seen some other members with 265's on the same rims. I need to buy some new tires.

Why would I choose one over the other (265 vs. 275)? I just drive the car for fun - no racing.

Any input is appreciated. Thanks

 

It comes down to gearing and your speedo. Ideally you want to retain the stock tire diameter of a 225/50/16. The 255/40 or 265/40/17 stay closer to that whereas the 275/40/17 is definitely taller. For your purposes whatever looks better to you. Going to wide in the rear may also adversely affect the naturally neutral balance of the FD.

Rishie

 

Rishie's correct. By comparision a 225-45 17 is 25" and a 275-40 17 is 25.6" tall. All tyres are not the same, but you get the idea

 

Get the 275/40/17. The whole "gearing" issue is massively overblown.

I don't know what size your front wheel/tire is, and if its really narrow, 225/235, you MIGHT want to get a 265/40/17 rear instead based on personal preference, but i've run virtually ever 17 and 18" combo there is, and honestly, unless you're running on the track AND that track has the sort of corners that beg for an extra-large front tire, a "staggered" set up is just fine. There's no point in running some massive 275 or 285 section tire up front on the street just because you rear tire is that size.

If you've got a 9" front wheel (or even 8.5" in a stretch, i'd try a 255/40/17 with your 275/40/17 rear, or try a 245/40/17 front with a 265/40/17 rear... or some slight variation thereof

 

The corners don't always beg for large front tires, but the braking zones at the ends of the straightaways sure can...

 

Of course.

The point I always try to make though, is that there's no need to limit the rear tire size in order to match the front in the name of "ballance"... So just because you only have a 9" rim 255 front tire doesn't mean you have to run a 255 rear on your 10" rim or your car will be an ill-handling pig. For the street, a little-less-than-275 mm tire up front is a little nicer and less likely to rub, so if that's your only set...

... and no need to limit yourself to a 255 tire on 17" wheels so that your gearing won't be "off" (of what?).

 

when "your gearing is off" your speedo is inaccurate. if you have taller tires your speedo says you are going faster if you have shorter ones it says you are going slower. get 275/35's in the rear and 245/40s(or 45s) up front. those are the correct ratios to be the same as stock height although the rear 275/35 is the important one to keep your speedo accurate.

 

Dude, it's a couple MPH at most... and within the range of error in many factory speedos.

Nobody MAKES a 275/35/17 anymore, and there's no need in sacrificing performance with skinny 17" tires to satisfy an obsession (that's all it is) over a minute difference in gearing or speedo accuracy... Hundreds of FD owners have run 275/40/17's, and I personally have run 225/50/16, 245/45/16, 245/40/17, 255/40/17, 275/40/17, 275/35/18, and 285/30/18 on the rear of my cars alone. You're talking about a range of maybe 5 mph tops from the tallest to the shortest, and no discernable difference in gearinng.

 

youre right about the 275/35-17...i was thinking about the 18s my bad..

 

I run a 275/40 on my fronts and a 285/40 on the rears, both 17x10. there is barely half inch difference in contact patch although unmoiunted bare tires look much different between the two sizes. when either are compared to a 265, the difference is minimal and I would think a 265 is the low limit for the rim width, you still may see some nice performance out of a 265 "stretched" over a 10" wide wheel.
it really depends on what specific tire brand and model you want to drive on. I love the kumho MX and it has been great for a daily driver and autox tire... but there are plenty more nice tires out there to run on an rx7.

 

Actually that's backwards. The speedometer only knows how fast the axles are turning and a shorter tire covers less ground with each axle revolution. Therefore the speedometer will read faster than actual speed with a too short tire.

 

One reason is that some tires are only available in one of those sizes. That's why I had 265/40 S-03s. I would have purchased 275/40 if they were available in that size.

If you are worried about putting the power down or drag-style launches, the larger diameters have two advantages: larger dia gives longer contact patch, and taller sidewalls generally help straight-line traction.

-Max