Effects of changing offsets?

[Pressure]

This is an often talked about subject, but I'm not asking because I'm worried about clearance, or the bling of my rim lip. Just want to make sure I fully understand the concept.

A higher (lower positive) offset increases track by the amount of milimeters that it is higher - are there any other effects on handling?
Specifically, I get aftermarket rims that are at a +15 offset, compared to +45 for stock. The effect is the same as getting a tire 30 milimeters wider than stock, but without the traction advantage, and no more. Sound right? Am I missing anything?

[scandalcat1]

the change is going to be negligible. On the back of the car, the tire
doesn't have anywhere to go. Too much offset and you hit the fender, not
enough and you hit the bump stop bulge. No matter what you do, the rear
wheel location is going to be about the same. If you go with a
nissan offset wheel, you are talking about a 1/2'-1" positive
offset on the front of the car. This is nothing. Wheel bearing loading is
going to be a tiny bit higher, but overall the type of tire you run is going
to make much of a difference.

[LanceS13]

As was said, the track width gain is negligable. You want to run the highest offset that will fit to reduce the scrub radius. A large scrub radius has negative effects on both steering input and feedback and can actually hurt handling if severe enough. Bearing loads increase as offset decreases as well.

[DuffMan]

Also will increase bump steer. Though our cars arent as sensitive to it as say, a BMW.

[reccakun08]

i still dont get offsets. COuld some explain in newb terms thx.

[Dousan_PG]

reccakun08: read here www.tirerack.com

[mrdaniel]

pressure, with cars, everything has its own soul purpose.


think about it.

+15 wheel with a small tire stretched over it (sidewall flex? wahts that )

or a +45 wheel that has a 30mm increased tire over it...they're two totally separate thing.

its possible to have a goal and attain it, but there is a smart way..and a not so smart way to do it. i used to run a 205/55/16 tire over an 8" wide wheel, why? well...no sidewall flex, and along with the negative camber i had dialed in, it provided ultimate response in both turn in and in turn exits because my tire wouldnt be squishing here and or scrubbing left and right.

its just like raising compression on old Z cars - there's a bunch of ways you can do it for example, mill the head and raise the cam towers, but if youd o that the rocker arms wont get a proper wipe pattern on the cam and eventually fill your oil pan with camshaft. or you can weld the combustion chamber, but its hard to find someone who will do it proficiently at a good cost. or you can be smart deshroud the head and get pistons to match your combustion chamber.


the above lesson in oldschool Z hot rodding serves this purpose, there's a situation you can go about in 3 ways, each one serves the same purpose but achieves it in a different manner.


imagine putting a wide tire on the stock wheel...it jsut wouldnt work out it'd scrub to bad on the suspension etc., but if you have a wide wheel with proper offset you can put a small tire with high sidewall over it...or you can get your low sidewall big section tire - both safely.


sorrty that was so long winded its just it seems as if you're trying to find "work arounds" to things that will 1. endanger yours and other peoples safety or 2. with regards to turbine, hurt your performance really bad.

[Pressure]

Originally posted by mrdaniel
sorrty that was so long winded its just it seems as if you're trying to find "work arounds" to things that will 1. endanger yours and other peoples safety or 2. with regards to turbine, hurt your performance really bad.

No, I appreciate the info, it's all useful. I wasn't trying to get around anything, just honestly trying to fill in holes in my auto knowledge. I had no idea about the whole 'tire stretching' technique, I had noticed it on JDM drift cars but not thought a whole lot about it.
As far as that goes, let me see if I understand the idea. The higher sidewall compensates for the narrower tread width, and thus gives you a rounded or stretched profile. No sidewall flex, and very smooth transition from grip to slip, I'm assuming also?
Now is there a hard fast rule for how much tire width to give up vs. more sidewall, or is it just one of those things that you have to **** up a few times before getting right?

Oh yeah, DuffMan, you were saying that 'it' increased bumpsteer. That was increased offset you were talking about, right?

[mrdaniel]

i wouldnt want to mess up a few times before finding out man, stretching a tire is serious business, there's no set rule but certain things are just common sense.

i've seen ae86 guys stretch a 195 tire over an 8 inch wheel though...oh wait. i did that


basically the high sidewall when its stretched out flattens the whole deal out and yes, gives you increased response. not really helping with the transition, thats driver input, but it does indeed give more feedback