OK, I have been following this forum for awhile and have seen and read various threads on front and rear tire combos, etc. I recently went to 050A PP 225/255 and have noticed that the handling has not been adversely effected at all compared to stock. This despite the fact that the ratio of front tire width to rear tire width is considerably lower than stock. My idea was that this would make the car more prone to oversteer but I haven't seen it

Just for the heck of it I was browsing Boxster S pricing on Edmunds and there were two 19" wheel tire options, a 235F/265R and a 235F/305R. I would think the second would put much more understeer into the car.

All this makes me think that exact tire width is not as important to handling as I thought. At least for the street maybe the characteristics of a particular tire are more important.

 

In my experience, +/-20mm or so on tire width or "stagger" doesn't make a huge difference in the overall demeanor of the car. Changes in alignment and front/rear roll stiffness are generally more profound.


Boxster S actually has 305mm rear tires optional?!

 

[QUOTE=ZDan,Sep 12 2007, 06:21 AM]In my experience, +/-20mm or so on tire width or "stagger" doesn't make a huge difference in the overall demeanor of the car.

 

You can not compare the Boxster to the S2K. The suspension is differetn and they have a bigger stagger from Porsche. On the S2K if you reduce the stagger the car will likely oversteer more easily.

 

My two cents... (And a quick disclaimer: I've been driving high-power, high-torque RWD cars for most of my life. A person who has primarily driven FWD or AWD vehicles may not agree with my assessments, and may find my comments dangerous in practice - KNOW YOUR OWN SKILL AND DO NOT EXCEED IT!)

AP1 and AP2 will have VERY different handling characteristics for every setup. A stock AP2 will always be more tame than an AP1.

I've run three different stagger setups on my AP1, and two different setups on Jenny's AP2. Ignoring the section width and instead looking at the tread width, the staggers were 1", 1.5", and approximately 2" (OEM).

Almost all of us know how OEM stagger handles: plenty of understeer, fairly safe and tame - more so on an AP2. Driving to the edge of the tire's grip will still leave you with the nose pushing out of a corner. (did for me anyway)

Drop that down to 1" and an AP1 becomes slightly less than neutral, with a minor rear bias. Flicking the rear out requires very little effort and when cornering, lift oversteer is just a slight twitch of the foot away. This stagger is still very controllable, but you have to pay constant attention to the balance of the car. You are always using the throttle to control the car. Great fun for those who know how to maintain control of a RWD vehicle. **When using this stagger on an AP2, there is very little difference at all. The softer rear end on the AP2 keeps the back end planted, but the lesser stagger allows the front to turn in *much* quicker. I preferred this stagger over the OEM on her AP2, as it made the car very fun yet still very easy to keep under control - practically neutral.**

Now the middle ground - 1.5" - is a nice option for the AP1. Not so aggressive that you have to be paranoid. In fact, with this stagger I feel the car to be just slightly more than neutral (very minor front bias) - safe and sane for daily driving, but much better turn in than OEM. Using this stagger I've been able to put the car into a perfect four-wheel slide without the nose pushing or the tail swinging. Great for cornering, not so great for drifting, but still better than OEM stagger.

!!!!!!!!!WET CONDITIONS WARNING!!!!!!!!!

Running any less than 1.5" stagger will throw the car into "Mr. Toad's Wild Ride" mode once the streets get wet. Cornering at any speed, including simply turning from a stop will often become a "JDM Tyte" drift (y0!).


Final suggestions:

Most drivers should stick with OEM stagger. The average driver doesn't have the skill required to deal with an oversteer-prone car, as proven by the complaints and problems people faced with the stock AP1 (which actually ISN'T all that prone to oversteer for an RWD car).

1.5" stagger is a fun setup for people confident in their skills.

1" stagger is for the crazy, suicidal, or skilled. This stagger will turn an AP1 into a drift car, and an AP2 into an unpredictable mess when VSA is enabled (VSA disabled makes this a fun stagger for AP2).


All of these assessments were made on highways and surface streets, taking each set of tires to the end of their grip (yes, I've slid out RE050's on both cars). These comments do not reflect the experience on a proper, prepared track surface. Be aware that driving over road paint and lane markers negates all commentary and can result in unpredictable handling. I make no guarantees that your experiences will reflect mine, and reserve the right to refer back to the first paragraph which states KNOW YOUR OWN SKILL AND DO NOT EXCEED IT! No liability is held by me or S2ki for accident or injury resulting from using a stagger that is beyond your ability to control.

 

Synchro, Good info. Never owned an AP1 but it must be a much different animal than the AP2.

Stock AP2 tread width stagger is 2.3 inches. So when I replaced the OEMs, tread width stagger went to 1", but to no ill effect at all. Obviously different than the AP1 situation you describe. I think many people are surprised at how much stagger can removed from a stock AP2.

It would seem that an inherently understeer suspension allows much more flexibility with stagger than an inherently neutral suspension. Zdan mentioned rollbar and camber adjustments as being more profound than stagger and that seems to be the case.

 

Absolutely. On our AP2, moving from 2.3" to 1" (tire swap) actually improved the handling to the point that it handled almost exactly like an AP1 with 1.5" stagger. I've been tempted to try some zero-stagger tires on our MY07 just to see what happens.

They are very, VERY different in the handling department. I prefer my AP1.

Oh yeah, and I'm falling in love with 1.5" stagger. Had all four tires singing around a corner today and never once felt like the car was going to lose balance and push or spin.

 

[QUOTE=Synchro,Sep 12 2007, 03:38 PM]Oh yeah, and I'm falling in love with 1.5" stagger.