tire size on 1988 328

The OEM sizes are 205-55s on the front and 225-50s on the rear (all on 16" wheels).

A popular upgrade, which preserves the outside diameter and the same front-to-rear relationship, is 225-50s on the front and 245-45s on the rear. I have seen both pros and cons about doing that.

 

225/50 F and 245/45 R are the best for performance (lateral), and are generally the best all around.

205/225 combo is faster in linear performance (ever so slightly), and the steering (in theory) would be slightly lighter, assuming the air pressures are the same between the two types of fronts.

 

I have extensive experience with both stock sizes and upsize on road and track. I would stick with stock sizes. Trying to outsmart the engineers who designed the car is not always a good thing.

Dave

 

I also have extensive experience with both stock sizes and upsize on road and track. I *definitely* prefer the upsized... handles MUCH better on curves. Keep in mind that tire technology has improved quite a bit in the last 20 years including better sidewalls on moderately low profile tires and there's nothing wrong with taking advantage of it.

 

Could any of the "upsize improvement" be due to the bigger tyres being a newer/better/stickier/etc design? Have the size comparisons been done with exactly the same make & model of tyre? Is there a shortage of "good" tyres for the std size but not for the upsize? Questions, questions, ...

 

My experience is with new Bridgestone S03's in both cases. The fatter ones felt grippier to me, but a stop watch at the track showed no real improvement. For road driving, the stock sizes are more pleasant. I'm sure that stiffer suspension combined with fatter rubber would result in a big improvement in handling at some expense to everyday comfort. However, doing so would put strain on other parts to designed to handle it if you track a car.

Dave

 

I did the switchover testing with Yokohama Intermediates at the time. I did the rears first, fronts later, tires still in very good condition. Additional contact patch and width made driving at my most driven track Talladega Grand Prix, definitely able to take the corners faster and at higher G's. Doing the rears made a difference, but when I then upsized the fronts, it was a an even bigger difference in the turns, able to push harder before the car would slide.

I don't find any comfort difference for regular long trip road driving -- and no real benefit there unless I take some of those back country roads and some aggressive turns! Then it's just like the benefit at the track.

 

Here's a link for tire size calculator:

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

 

225/50 front and 245/45 rear fit on the stock 328 wheels without excessive rolling, or rub inside the wheel wells?

Are hub wheel spacers required?