924Board.org

Stu2j · Posted: Fri Nov 22, 2002 2:36 am Post subject: Rear wheel spacers

[I did do a search on this and it turned up way too many hits and none seemed to address this specific issue]

On my 924NA, I think the rear wheels sit too far inside the wheel well. I would like to add spacers to the rear wheels if possible. I assume the spacers are simply slipped on behind the wheel.

The car has the standard 4 bolt alloy wheels and 185/70 R14 tires.

1) Can spacers be used on just the rear wheels?

2) What size is best?

3) If the lug bolts must be replaced, what size is needed to match the spacers?

4) Are there any problems with using the spacers?

I know Performance Products sells the spacers and lug bolts but I need to know sizes. Also, is there anyone cheaper?

Thanks for any assistance.
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-Stu
924 owner since 1988
924S owner since 2002
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Lizard · Posted: Fri Nov 22, 2002 2:53 am Post subject:

yes you can add spacers to the rear wheels

I don't think that you will need to get longer bolts

I have 1/4" on my back and they are just a hair too small
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3 928s,

Alex Roy · Posted: Fri Nov 22, 2002 3:05 am Post subject:

I have 1.25 inch spacers in the rear and it looks MUCH better. For that you have to get longer wheel bolts (it works perfectly with the long wheel bolts from the spider web wheels). The only problem is finding the wheel spacers, the 4 bolt 924's have a really rare bolt pattern. It took me months to find some on ebay that would work.......so you can either keep an eye out there, or have some custom made.

Stu2j · Posted: Fri Nov 22, 2002 3:35 am Post subject:

Ok... to sum up so far...

It is ok to use spacers on just the rear wheels without any problems and I am correct that these just slip on behind the wheels.

Also, if I use the 5/16th sold on Performanace Products ($22.98 each

) then I do not need to change the wheel bolts. (Another site agreed with Lizard that 1/4 inch could use the same bolts and I assume 5/16ths is the same).

Otherwise, keep searching for larger spacers that can be used knowing that I will need longer wheel bolts to go with them.

Is all this correct? Anybody got some spacers lying around

_________________
-Stu
924 owner since 1988
924S owner since 2002
Click here to view them:

Lizard · Posted: Fri Nov 22, 2002 3:49 am Post subject:

ok yes 5/16th is less than 1/4 so same bolts should be fine,

the other thing the both me and alex forgot to mention the size of the spacers you want depends on what the offset of the rim

to measue the offset of the rim is very hard to explain and I will let someone else do that task, or if you have a haynes manual it describes it in there
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3 928s,

Lizard · Posted: Fri Nov 22, 2002 4:07 am Post subject:

http://www.mrtrally.com.au/performance/howwheels.htm

they try to describe wheel offset in here but I don't think they did it well
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3 928s,

Stu2j · Posted: Fri Nov 22, 2002 4:13 am Post subject:

""ok yes 5/16th is less than 1/4 so same bolts should be fine,""

Uh, not in the US it isn't

""the other thing the both me and alex forgot to mention the size of the spacers you want depends on what the offset of the rim ""

Isn't this irrellevant if I get them from Performance Products for my car?

Also, these are standard 14" alloy wheels. Isn't the offset well known or published?
_________________
-Stu
924 owner since 1988
924S owner since 2002
Click here to view them:

Lizard · Posted: Fri Nov 22, 2002 4:14 am Post subject:

here is a better explaination

What is wheel offset?

A wheels off set is the distance between the flat surface which comes into contact with the hub and the centre if the wheel's width. If the flat surface were in line with the centre, the offset would be 0mm (also expressed as et0). et0 is not a usual offset, most are effectively pulled in further than this. If a wheel were et30, it would mean the wheel is positioned 30mm inwards from the centre.
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3 928s,

dwak · Joined: 03 Nov 2002 Posts: 839 Location: Eastern Ontario

Be careful which rim and tire combination you use. Find a tire company that lets you try a few sizes until you have it right.
I just fitted 4 x 205/60/15's to my 7 inch ATS cookie cutters and they look really purposeful on my 931. The rims definitely were offset for a 944 though and what worked with spider-webs were too big for the cookie cutters. Looks like a muscle car now.

macho dwak

Lizard · Posted: Fri Nov 22, 2002 7:30 am Post subject:

you are getting abit too complicated now
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3 928s,

Stu2j · Posted: Fri Nov 22, 2002 7:56 am Post subject:

john h · Posted: Tue Dec 03, 2002 9:37 am Post subject:

Just remember that if you use spacers that you also space out the centre rim on the hub. what you find on the 924 is teh wheel sits on this lip and some of the load on the wheel is transferred through from the wheel.

If you don't have the lip for the wheel to sit on all the load is through the wheel bolts. On the Porsche these are 14mm dia so are pretty strong. Over here we had a few guys shear their bolts/studs while racing as the centre bore of the wheel doesn't fit snuggly against the lip.
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Stu2j · Posted: Wed Dec 04, 2002 1:17 am Post subject:

Lizard · Posted: Wed Dec 04, 2002 1:20 am Post subject:

I would also have to mention that it isn't going to be alot of stress on the wheel bolts w/ just a 1/4" spacer.
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3 928s,

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

The lip on the factory wheel hub or drum, or rotor (depending on whether you are talking about the front or rear of the car and whether you are talking about a car with four wheel discs or discs/drums), is not mainly to support or take part of the wheel load.

It is there to mostly to help center the wheel when you are installing it, so you don't go wop, wop, wop, from off-centered wheels.

High quality fully-machined spacers (like the Porsche factory spacers)have the center hole precision machined to fit the centering part on the rotor, wheel hub, drum (the rotating part that the wheel is normally bolted directly to), and an identical part machined on the front face that will then become the contact mounting surface for the wheel.

Cheaper, slotted/universal spacers and generic spacers in many cases do not have the centering part on the wheel contact mounting surface, and as a result, the wheel may not be mounted concentric, and may wobble (like an unbalanced wheel/tire).

Good spacers are not cheap, or easily found for the four bolt disc/drum setup. This is another reason to convert to four wheels disc brakes. Spacers are more easily found, in more sizes at a lower cost, because they don't have to be custom made, and there are lots of used one available out there.