Original equipment : 17x7" S Lite 8 spoke white wheels with 205/45r17 Pirelli Euphori@ run-flats tires:


Upgraded equipment: 16x7.5" Kosei K1 Racing 6 spoke white wheels with 205/50r16 Yokohama AVEs 100 tires:


Here's a top view comparison of the two treads:



Initial reactions:

Smoother overall ride, but squirely going thru corners (the back end feels "mushy&quot giving the car a little more character in the corners. I'm not a seasoned race car driver so I can't say if this is just because of more grip of because of the taller and more flexible side walls.

I'm not sure if they grip better or not over the stock run-flats. In some cases I thought they "felt" better and in other cases I thought they "felt" worse in the cornering department.

I wonder if I should have got them plus sized more than the 205/50r16 size, to better suit the 7.5 wide rims. I wonder what the 205/50s would look like on 6.5 or 7.0 wide rims. I also wonder if some of the "less grip" thing I'm "feeling" is pyschological since it appears the width of rubber meeting the road appears (see photo above) to be slightly less.

As a side note, I should have got the wheel caps to go with the rims. I was unaware (not obsertvant enough when on-line shopping) that the centers showed thru to the car's axel.



After a few more days of driving I'm putting my stock wheels/tires back on for another comparison.


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did you happen to notice any difference in weight between the stock wheels and your new Kosei wheels? also, did the new wheels help or hurt straight line performance?

 

Seat of the pants tells me no noticable
straight line performance.

By the end of the week, I should be
able to tell you if it helped or hurt
fuel mileage.

They are definately lighter. I'll put them
on the scale as soon as I do the swap back
to the factory later this week after a tank of fuel.
The rims are 10 lbs lighter than the stock ones,
so there's going to be a big difference overall.

 

How many miles on the new tires? You'll probably find that it will take a few hundred miles to scrub the tires in before they start to stick to their maximum potential.

I'd probably wait until I had 400-500 miles on the new tires before doing the comparison testing.

They look good, though!

 

10 miles on Friday night
550 miles on Saturday
10 miles on Sunday
30 miles today

 

>>How many miles on the new tires? You'll probably find that it will take a few hundred miles to scrub the tires in before they start to stick to their maximum potential.
>>
>>I'd probably wait until I had 400-500 miles on the new tires before doing the comparison testing.
>>
>>They look good, though!

2Mini's on the $$ as usual! What your experinceing is called tread block flex, very tall tread blocks, easier to bend sideways than your last set.

2 things correct this Heat cycles( just using the tires) and wearing down a bit of these super tall tread blocks.

Think of a pencil eracer, its flexes easy when its new and tall, and when its in its last 1/4 it will barley flex.

You may wish to add a few PSI in the rear, for more neutral handling.

 

I'm running 36 PSI all the way around currently. Does 39-40 psi sound about right to run in the rears?

 

Alex, do you think plus-sizing is in my future? You're a ninja, you've gotta know this one.

 

>>Alex, do you think plus-sizing is in my future? You're a ninja, you've gotta know this one.

1st try 34 front 39 rear cold.
I would not get any wider, I think we aught to 1st break in the tires you have, and see if you need more grip. 2nd check out S-03 I will be impressed if you would overdrive it.

Alex

 

OK, I'll get them pumped up tonight.

I think I might take you up on that wheel cap offer. I'll email you.

 

wait untill morning, unless you haven't been motoring today!

Alex

 

>>wait untill morning, unless you haven't been motoring today!
>>
>>Alex

They've been sitting here below my office window all day long. It's been a scortcher here. 118 F in parts of the valley! So I figure there's plenty of heat in them right now. I'll take you advice and do it in the AM.

 

Just make sure you havent driven the tire recently, the deflection from rolling adds heat and pressure.

Alex

 

alex should i put 34 front/39 rear on my 17X8 yoko es100s 215/45/17s when i get them on later this week?

 

>>alex should i put 34 front/39 rear on my 17X8 yoko es100s 215/45/17s when i get them on later this week?

Those are nice sporty "handeling focus" pressures. This might pose less than ideal tire wear for street use.

Alex

 

so what would u recommend for me?

about 100 miles a week, about 40 of those in the twisties, rest freeway

about 2/3 people in the car on weekends
rest of the time just me

no driving in rain

thanks :smile:

and am too lazy to change pressure all the time

 

those pressures will work (smiles, not miles),
Just rotate every 3k, and adjust pressures at the same time.

Alex

 

>>>>Alex, do you think plus-sizing is in my future? You're a ninja, you've gotta know this one.
>>I would not get any wider, I think we aught to 1st break in the tires you have, and see if you need more grip. 2nd check out S-03 I will be impressed if you would overdrive it.

Alex, can you elaborate why going with a wider tire than 205/50 on that 16x7.5" wide rim would not be the way to go?

 

I know seval owners using 215/45/16. They have no issues, it juts happens to be wider than Tirerack's guaranteed fitments allow me to promise will fit.

Alex

 

Excellent! I forsee plus sizing in my future!