Why run a higher profile tire in the front?

[jonvo]

I bought a set of Boxster wheels a while ago and the rears came with 255/40/17 tires and the fronts with 205/50/17. According to Tirerack, this is the original size that they came with. Is there a reason for this? I need to get new tires soon and i plan to keep the same size in the rear. Should i keep the same size in the front? Or would it be ok to get a 205/45/17? or maybe even go wider with a 215/45/17? I believe these wheels are 17x7 in the front and 17x8 in the rear (not positive)

Are there any sizes you guys recommend? This is for a 944 by the way.

[jpk]

From the factory, my 968 had 255/40/17 and 225/45/17. Since the fronts are a bit narrower, the larger aspect ratio keeps diameter (and circumference) pretty much equal and you don't have any issues with ride height differences.

The staggered width helps to induce understeer in turns (a safer situation than oversteer).

205's are a bit narrow in my opinion.

[jonvo]

Originally Posted by jpk

From the factory, my 968 had 255/40/17 and 225/45/17. Since the fronts are a bit narrower, the larger aspect ratio keeps diameter (and circumference) pretty much equal and you don't have any issues with ride height differences.

The staggered width helps to induce understeer in turns (a safer situation than oversteer).

205's are a bit narrow in my opinion.

I was thinking the narrower tires in the front would cause more under steer on the 944 than actually wanted. From my understanding the 944 comes from the factory with some understeer with the same width wheels all around.

Just for future reference, would it be a good idea to find another set of rear Boxster wheels to put in the front so that they all match? For now i may just get some 215 or 225/45/17s for the front wheels

[krystar]

with a 17x7, 225/45 would be a pretty good choice.
with 17x8, 245/40 or 255/40 would be good too.

that'd be a lot of tire for a 944.....is it 8v or 16v or turbo?


as for handling, it takes suspension and air pressure to dial in what characterstics u want. but inherently having more rubber in the rear is goign to cause understeer.

i run 205/55/16 and 225/50/16 on my 8v with an upgraded rear sway bar. it's pretty neutral in turns.

[jonvo]

Its an 8v that I will be autoxing. I originally wanted to buy the 16" phone dials, but came across a great deal for these Boxster wheels.

Planning on either an s2 or ls1 swap in the future. Still doing my research and haven't decided yet.

[racer]

The boxster wheels should be 7" front and 8.5" rear

A tire size breakdown:

205/50-17 means:

205 = tire width in mm
50 = aspect ratio. ie, sidewall size as a percentage of width. 205 x .5 = 102.5
17 = rim size

if you do the 255/40 math, you get 102.. so the tires, as mentioned have a nearly identical overall diameter.

I would suggest a 225 width front to help combat some understeer.

I have a similar current set up (225/45-17 and 255/40-17) on my 8V N/A and am actually looking to go 225 all around to help balance the car a bit better. imho, the 255s are just too much for the car.

[Tervuren]

My 944 has the m474 option which gives it stiffer springs, shocks, and rollbars. I run 205/50/17 on the front, and 245/40/17 on the rear. I have 7.5" wide wheels front and 8.5" wide back. I narrowed my rears from the 255's that where on them when I bought them when it came time to replace them. My car has a very happy balance, and I can induce both understeer or oversteer depending on how I drive it through corners.

My biggest complain is the extra weight of the 17's, I can feel the difference in acceleration between the cookies and the 17" ROH cup wheels.