Sponsored by The Tire Rack

[jasonic]

Hey guys,

My first day on the MPSS, and off the stock RE050's good lord what a difference. So much better ride across the boards. They have that pre-break in "slippery and greasy" feel, and sound a little loud, but I'm sure this will subside in the next couple hundred miles.

For me, right away the loss of unsprung weight was apparent. It feels like running in ultra light racing shoes by comparison, and far more alive through the steering wheel. Acceleration and general responsiveness has also improved according to the butt dyno The car now feels lighter, happier, and far more "tossable" somehow.

Thanks to all for taking the time to post your thoughts on this subject. I was able to make an informed decision based on real world experiences because of you, and it really made the decision easier for me.

For the record, I went with 225/255's and am running stock tire pressure on the stock rims for now.

Hmmm...I have the day off, maybe I'll pull a 4am blast up to Santa Barbara to break in the shoes

-j

[Pyrat 2]

Bridgestone runflats are 24 and 26 pounds. Mpss are 22 and 25 in your selected sizes. You probably aren't feeling an unsprung weight difference after you add in the weight of the wheel which I assume you didn't replace with a lighter wheel at the same time - you've reduced usw by 2 to 4 percent. Most people mistakenly assume that the runflats are very heavy and will penalize you several pounds per corner in unsprung weight. In most cases it's less than a couple pounds. Nothing to ignore to be sure but the major performance gain is from the tire itself.

[jasonic]

Ok, 190+ mile Santa Barbara morning cruise complete.

At around 130 miles the dynamics began to change, and by 175 things felt even better. I'll check back into this thread after 500 with my thoughts. The steering definitely feels "looser" going from the RFT's, but the car feels much more dynamic, and far less sluggish. The car has this "happy and light" feel, begging me to jump on it and toss it around. I can see how folks would choose to stiffen up suspension components coming from the RFT's. Overall it feels far more agile. This is all kinda tuff to explain of course, but as you can tell, I've got no complaints here.

Heya Heeltoe, you are correct, it seems I miss-read the specs initially. After re-checking the specs it seems its really only -2 lbs per corner. It really does feel alot lighter and responsive to input at steering wheel and throttle however.

For those on the fence, I'd say take the plunge, and choose to upgrade suspension components when you get around to it if it all feels a little too "loose" for you...I'm going to try to give it some time before making any major changes.

-j

[ASAP]

The only real issue that I had with the car after taking the runflats off and putting the PSS on was an extreme amount of bounciness and side to side chassis flex. The car was bought with only 16K miles and driven by an older lady to work and back (so you know everything suspension wise was not worn out)... replacing the dampers and rear subframe bushings fixed all of that but IMHO, the car feels a bit unsafe with all of that loosiness until that is done... that's the nature of a short chassis car.

[Pyrat 2]

Put on some light weight wheels and it might feel even lighter on its toes.

[aloksatoor]

I did not notice any floaty issues, I did use the 215 and 245 size on the mpss though to keep it close to the spec. Do run a bit more tire pressure and its great. Still getting the solid subframes done though.

[bmw1racer]

I just switched over from NCT5 RFTs to non-RFT RE760s and though the ride is much better, there's a significant softness/squishiness when cornering... Bumping up the pressure to 36F/36R has helped some, but hasn't solved it completely.

[jasonic]

Hmmm... they filled me up to my door stickers 39 frnt, 41 rear. The tech filled it "in the air" saying its the best way to do it accurately. Maybe I should add a few lbs and see if the loose feeling improved a bit.

Will a few lbs make that much of a difference?..maybe I need to get used to it...lol.

-j

[aloksatoor]

Hmm my hardtop is 36 39 on the door jamb (the vert is a bit higher due to weight I suppose), I did 40/40 and it was good. Now we got some rain so I am back to the factory settings.

[jasonic]

...rain in California???

you jest.

[bmw1racer]

Originally Posted by jasonic

...rain in California???

you jest.

LOL.

If there's drizzle, we call it rain.

[aloksatoor]

Hah yeah we do!!

[jasonic]

Quick follow up...

Put over 600 miles on the new MPSS to date, and have had the chance to drive it hard, sporty and otherwise. We've been having alot of rain here the last few days, and they still stick like glue. Also, I seem to have become used to the lighter feel thru the wheel, and the car feels great to me. I'm detecting no real bounciness or chasis flex that others have experienced. I might upgrade suspension components in the future, but I'd really have to drive a car with the mods to know I was missing anything. In short to me it feels great as is.

I'd say if your thinking about making the move just do it, and give yourself some time to adjust to the new feel..its a vast improvement in ride quality and overall agility as compared to the stock run-flats.

-j