[94SilverCab]

Dear Parptarf,



Lesson 1...never begin a post about wheels with "Quick Answer" in the title...that is all.



Jay

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[parptarf]

What about a 7mm spacer and new lugs?

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[flash]

again, a test fit is likely the only real way to tell, but if you are determined to do this, i think you should really go with somewhere between a 7 and 10mm spacer, depending on the tire and suspension setup, and install long studs and new lugs. no way to escape longer studs and steel nuts though, no matter what size spacer.



balance may get tricky. i would weld or otherwise attach the spacers to the wheels, so that they can be balanced with the wheel.

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[parptarf]

I'll have to check, but I have to get them shipped to me from across the country. We know the wheel will fit with 7-15mm spacing, but the problem seems to be the tires.

If I get Spacers that are attached to the hub balance shouldn't be a problem(like 15mm spacers).



Theoretically, running a car with about 1.5" lowering and Koni dampers, I could get a 265tire fit with 15mm spacing. That's judging by a local 958 owner running a similar setup.

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[flash]

we don't know that the wheels actually fit, as they are what determine the placement. what we need to know is the geometrical details of the suspension, so you can draw out where the tire will land. ideally you should be targeting an offset of about 57mm



of course balance can be a problem with a spacer on the hub, and not on the wheel. that is a lot of mass, which has not been balanced. it is no different than the wheel itself, in as much as the metal is not even in balance. granted, it is at the hub, which is less of an issue than at the outside of the rim, but it could still be an issue. also keep in mind that there is some slop in the centering (otherwise it would be a press fit). that will also move mass around. attach the spacer to the wheel, and balance with the wheel.



depending on where you started, 1.5" lowering is probably too far, assuming you have not moved the steering rack down, and altered the ball joint locations. you will be below ground on your front roll center, which will cost you speed in the corners. absolute minimum ride height is 630mm at the top of the wheel arch, and really should be no lower than 635mm. most people don't know that there is such a things as "too low", so you will see people running it like that a lot. however, they will be slower than they could be.

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[parptarf]

It only has lowering springs on it so then it's probably closer to 1" converting mm to inches is a bit rusty. <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />



I have had 10x18" ET65 with 5mm spacer on the car, they had 265/35 tires and they fit like a glove with at least 3-5mm clearance on the outside.

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[flash]

ok - 24.8" absolute minimum, and really should not be below 25"



re: tires - exactly. you ended up with a 60, and a narrow tire, yet still had only 3-5mm clearance at the outside (you probably had very little camber with that measurement, and would have more with the spec i listed). the rubber bushings will compress at least 2mm under any sort of fast turn. that sucks up some of your clearance.

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[parptarf]

So 635mm from the top of the arch and to the ground?

Doesn't look like a 295 tire will fit my rears.

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[kzem1]

This is probably a bit off subject, god help me, but should the top of the arch to the ground measurement of the front be the same as the back(25" min Flash mentioned)? or is there a "normal" front to back, arch height relationship? I hope that made sense to someone.



Thanks,

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[flash]

ok - this one has a couple of answers.



yes - and maybe no



being a hand built car, using body points is only going to get you there assuming the body was put together symmetrically front to rear left to right. you are supposed to use frame points underneath the car. they are hard to deal with though, so most of us just use the arches, and then corner balance from there.



that being said, yes, it works out to be the same at all 4 corners. you can verify this with a level on the door sill.



again though, corner balancing is the real determinate method.

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[parptarf]

I have 650mm at the back so it's not that low. Maybe a 10" rim at ET50 will fit after all. (ET65+15mm spacer)

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[flash]

it's going to depend on the camber angle and the spring rate. remember that things move as the suspension goes up and down

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[parptarf]

If I only knew the rear spring rate or camber angle. There's not a lot at the back.

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[parptarf]

I can try and measure how much clearance I have now. I'm not using ideal wheels but they work as the ones who fit are broken with bad tires.



Now I have a 8x17" ET70 + 15MM spacer at the back, so effectively an ET55. (235/50R17 tires)

The difference in with between that and the 10x18 ET65+15mm spacing with the 295/30R18 tire is 30.4mm on the outside and 20.4mm on the inside.

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[kzem1]

Thanks Flash

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[parptarf]

Now I feel really dumb. I've used my 5mm FVD spacer the entirely wrong way. No wonder I had balance issues.

Guess I can run the Alleggeritas at ET60 with a different set of tires after all.



Those small screws, or at least one of them, should be screwed into the brake rotor locking screw, right?

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[flash]

a 5mm spacer isn't going to be too bad. the variance in material will be minimal, and more importantly, if located correctly, with countersunk locating screws, it will self center.



more than that though, and i'd rather see the wheel tapped for the screws, and the spacer screwed onto it.

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[parptarf]

That would be my choice too, but you can't have it all <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />

As of now I want to test this out with the 295 tire, and if it doesn't fit sell the R-tires and get a set of normal tires with 265 rears. I know that will fit.

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[Cloud9...68]

Another thing to consider is the overall diameter of the tire. A 265/35-18 comes closest to that of the 17" rear tires that were optional on this car. If you go with a 285 or 295, you will effectively raise (numerically lower) your final drive ratio, which will hurt your acceleration, but will improve your gas mileage, as your engine will be turning fewer rpms for the same road speed. But you will also throw off the accuracy of both your speedometer and odometer. And of course you will add a fair bit of rotational mass at the outer periphery of your wheel/tire combination, which is also bad for pretty much everything. None of this will make a huge difference in the way your car drives - you may not even notice - but the fact that a larger, heavier tire makes just about everything worse is something to consider. I have 285/35-18's on my 10" wide Enkei NT03's, and I'm planning to go with a 265/35-18 next time.

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[flash]

cloud - why not a 285/30? that's the same OD as the 17

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