TicketMagnet05

My 2005 car has always exhibited lots of understeer unless i really got hard on the gas and tried to make the back end come out. That all changed a few days ago when i put new rims on my car and i am at a loss to explain why the car now wants to oversteer a lot more. I hope you guys can help me figure out whats going on.

Before the car completely stock. Stock wheels with 225 F and 255 R Dunlop star specs.

Now: new rims are OZ alleggerita 8.5" +59 on all 4 corners. I am going to do 255 all around in the future but right now i reused the same tires as before. I had the tire shop switch the tires to the opposite sides. The fronts are pretty stretched.

I also got an alignment that day.
____________Before:_________________________After
Front
Caster______ L 5.9 R 5.9 ____________________ L 5.8 R 5.7
Camber ____ L -.7 R -1.0 ____________________ L -.5 R -.6
Toe ________ L-.05 R +.20 Total .15 ___________ L 0 R 0 Total 0

Rear:
Camber ____ L -1.3 R -2.3 ___________________ L -1.3 R -1.2
Toe ________ L .35 R .15 ____________________ L .15 R .10 Total .25

Thrust angle 0.1 ___________________________ 0.0

Tire pressure 32 psi cold all corners before and after.

Driving impressions:

The first thing i noticed was that the steering felt much more sharp and accurate. Probably because of the stretched front tire and lighter rim.

The next thing i noticed that it was a lot easier to break the back end loose. The car feels more willing to rotate around corners and much less gas can bring the back end out in a controlled predictable slide.

I have to admit that the car is a lot more fun to drive like this but i feel that the car is ultimately slower because I have less grip to work with in the back. I just need some help figuring out what is going on. I have no idea what would cause this.

Thanks.

danx

Wheel width does have an influence on the contact patch of a tire. Your new wheels are slightly wider than stock in the front, leading to a larger front tire contact patch. Therefore, you should have more grip in the front and, hence, more oversteer tendency.

TicketMagnet05

Edit: i misread your post. hmmmr that could be.

I get the feeling from driving it that i have lost grip in the rear rather than gained grip in the front.

JLUDE

Is it possible that your tire air pressure is much higher than it was on the old rims? Shops that mount them often over-inflate when seating the beads on the rim.

PS: You selling your AP2 rims?

TicketMagnet05

I'm sure that the tire pressure is the same as before. My OEM rear rim had a pinhole leak in it so I had to refill the tire every day. But the feeling is similar to an over inflated rear.

I would be willing to sell the rims, but i doubt you would want them. Besides the pinhole (repairable) they also have some dings and scratches on the face. If you want em make me an offer.

patinum

danx is right, also small changes in alignment will effect how the car feels. You haven't lost grip, you've just changed the balance.

zeroptzero

unless I'm reading things wrong, on your alignment you went from negative camber to positive camber on the rears, while retaining negative camber on the fronts. This will give you oversteer as you have lost grip on the rears. I just had my alignment done at my local Honda dealer and they left me with some negative camber on the rear. You'll get a bit more tire wear on the outer edges but at least it will give you some grip. IMO, positive camber is not good. If I'm not reading it properly then my apologies but it looks to be that way unless you wrote things down wrong. The final settings on the rear may be within spec (I'd have to check to be sure) but they aren't good IMO. Lastly, on my alignment I got total toe on the rears to be zero, same on the fronts, I think I'd like total toe to be zero all around but I'm not sure if that affects the oversteer issue. I think the main culprit is positive camber on the rears.

wadzii

i hope you just forgot the - sign for the rear camber..

if not, thats why your car wants to slide.

you should NEVER have positive camber.. ever.

take it back and tell them to fix it. you want the camber to be about as negative as spec will allow.

mister x

Also running a 225 tire on an 8.5" rim will improve steering response, again changing the overall balance. Personally I run more negative camber on the Star Specs (-1.5 F, -2.5 R), that may help keep you from being the drift king.

zeroptzero

correction on my rear toe, I ended up with a 1/4 inch toe on the rear and that is within spec, front toe was zero. My Honda dealer gave me the specs for all four corners, they gave me the readings before the alignment and readings after the alignment so you can see if all corners were within the specs. You should have gotten the same if it was a reputable alignment shop.