Offest questions??

wun911 · Postby **wun911** » Fri Jul 04, 2008 4:01 pm

So Im interested in +25 offset wheels....

If OEM is +40 that means the wheel stick out of the car by 15 mm...??

What does it do for the turning circle? Say if OEM turning circile is 9.8 meters, what will +25 offset do to this turning circle figure?

Does this agressive offset wear suspension bushes out faster? If so which ones?

Im guessing this setup is popular for track because it improves stability at speed?

Does it screw up alignment like lowering the car screws up alignment? If so what does it screw up tow, caster or camber and to what extent for each more positive or more netagive more in or more out??

Seeming its just the hubface that determines offset. Has anyone shaved the 15 mm off the hubface thus saving weight and converting the wheel back to OEM +40 offset?

Shoud I shave an additional 6.35 mm considering the new wheels are x 7 in width and oem is x 6.5 in width? Thus saving even more weight?

I have an angle grinder at home...

kula · Postby **kula** » Fri Jul 04, 2008 4:36 pm

thats not a massive change, you wont have any issues with tyres rubbing.

I'm running the equivalent of -10 on the front, and it rubs, otherwise its all good.

the only thing ive heard of it wearing out faster are the bearings.

green_comet · Postby **green_comet** » Fri Jul 04, 2008 5:04 pm

15x7 +25 is fine to run on your car, it is what most spec miata cars run. You will find the car will handle a little differently than stock (turn in etc) but thats about it, you just need to get used to it. +25 is not an aggressive offset, it will not affect your alignment! but if you are changing your wheel offset/width you should go get it re-aligned anyway... Bushes will be fine, and your wheel bearing should be able to handle the lower offset. If you were going to 15x8 0et then it would be a different story..

I would stop worrying about offsets soo much, and start worrying more about whatever it is your thinking of doing with your angle grinder..

Sheck · Postby **Sheck** » Sat Jul 05, 2008 10:15 am

I would stop worrying about offsets soo much,.........

Very strongly agree with this comment, all i hear on this forum is how bad non standard offset is, wrong. Every MX5 i've been in with stock offset has yet to out perform the feel of one with a 'good' offset (+25 or less), bearings will be fine. My car has been running anywhere from +35 to -15 for the past two years and its (was, until the stripping) still running. Most of that 2 yrs was spent running in about a +10.

Dave

Alfadog · Postby **Alfadog** » Sat Jul 05, 2008 2:35 pm

PUT THE ANGLE GRINDER AWAY MATE! :shock:

d-mag · Postby **d-mag** » Sat Jul 05, 2008 2:44 pm

But if you have to use an angle grinder, make sure it's a 9\"....fingers and limbs are overrated IMO.

manga_blue · Postby **manga_blue** » Mon Jul 07, 2008 1:35 pm

I've tried a +42, +32 and +22 offsets now on 15x6.5 rims. There were slight differences in feel, but you couldn't really say any one was better than the others.

At +22 the very outside edge of the the tread is just scuffing the metal inside the top of the wheel arch. The car is a lowered NA with a fair bit of neg camber. It's happening both front and back but, strangely, driver's side only. The wheels are fitting inside the guards on the passenegr side. It looks like rolling the guards out only 5 mm will give me clearance.

I'd regard extra the load on the bearings would be trivial compared to what I do to the poor car most of the time.