g2bme

iTrader: (6)

Went from the stock 18s to 19s. My new wheel sizes are 19x9.5 in the front with 235/35/19 tires and 19x10 in the rear with 265/30/19. This is about the same wheel diameter. I've see a lot of people run this setup, not so aggressive but just the right amount. I'm dropped on f sport springs.

I've noticed ever since I put on the 19s that the VSC is going off more frequently doing hard turns. An example would be freeway transition turns doing about 25 to about 45. My offsets would be +35 in the front and +40 on the rear. I noticed that the front fender liner has some signs of rubbing and I can hear it too during quick u turns or sharp quick turns.

I'm a little concerned about how the light is now going off more frequent when it didn't use to do that on 18s. I would be able to take freeway transition round about a at 30 to 40 with ease.

Is this common? Is there something I missed? Or is this because the tires are new?

I have some Pirelli pzeros in the front and some lionharts on the rear. Any input would be of great help!!

g2bme

iTrader: (6)

Reading a couple of other forums it looks like it maybe an alignment issue? I've read the "will it fit" thread and saw so many others with the same size tires and wheel specs but no VSC complaints when cornering. Going to do an alignment in a couple of days and see if that helps.

laobo979

iTrader: (5)

I'm pretty sure it those cheap tires your running in the rear with no grip. Alignment doesn't affect vsc as most member run negative camber with no issue including me.

sm1ke

iTrader: (5)

AWD or RWD? I think it may have to do with the different front and rear tires (different tread pattern=different handling characteristics), and also differing tread life between front and rear tires.

I'm going to bet its because of the two different tread patterns.

g2bme

iTrader: (6)

It's RWD. I've ran different tread pattern before, both are directional tires. Just noticed a lot more of the VSC going off. On my OEMS I ran Achilles directional in the front and Toyo proxy 4's in the rear with no problem before.

I guess I'll try swapping out the rear to the same and see if it helps. Thanks for the input!

laobo979

iTrader: (5)

Alot of people run different tires on rwd it doesn't matter much. I ran different tire brand on my E46 M3 no issue in the 4yrs of owning it with VSC. Trust me i take corner in the M3 like nothing.What matter is it the tires are good to stick to the pavement or bald. I had Achilles too there cheap but handles well but noise. Probly way better than lionharts which I never heard of.

g2bme

iTrader: (6)

Yeah I had Achille's ATR sport on my previous setup on 18s. Nice tires but very loud. I'm more concerned about damaging the car's differential? if the VSC continues to keep going off on corners. There's some relief to know that there are some people that run two different brands front and rear on here.

laobo979

iTrader: (5)

Don't worry if you want just turn the traction/vsc off for the mean time. I do it during the winter time with no issues.

g2bme

iTrader: (6)

Now the question is if I should do 265/35 or stick with the 265/30. I did a comparison on tire rack from oem to now and the 265/30 would be best? I saw a mix of people in the "will it fit" thread running 19x10 265/30/19 in the rear with no worries but I'm presuming their speedo is off?!

redspencer

iTrader: (1)

You can use this calculator to see how much your speedometer might be off with your aftermarket setting:

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

g2bme

iTrader: (6)

I've used the one on Tire Rack. Doing the 265/30/19 setup has the speedo off by about 3/4 mph doing 65. Doing the 265/35/19 is a 1mph off.

Unsure if this is contributing to the current issue, or it's just the fact the rear tires have no grip.

sm1ke

iTrader: (5)

Not contributing at all, its just the tire grip.

NYKnick101

I would think that your rotational distance around both front and back tires are a little off. I know with AWD cars, it has to be exactly the samebut I had a friend with another RWD car that he had to always turn his traction control off because sensors on his front tires said he was doing say 63 mph and his rears said he was doing 61mph so traction control would kick in to correct that all wheels were doing the same speed. It was on a 5 series BMW.

Tire sizes may be common among people who used this size but does one set have a deeper tread than the other. That could be your problem.

sm1ke

iTrader: (5)

Doesn't have to be exactly the same. The car's electronics can compensate to a certain degree. The front and rear rotational difference is very small in this case, .85% to be exact. Cars have run setups that have a difference of 2.5% and more, and they haven't reported any issues with the VSC.

Its definitely the different tires. Different tread means different traction; the VSC kicks in to compensate.