924Board.org

[Mavfan]

i was just wondering what a good length for the rear wheels on my 1988 924s would be, because those wheels always look set in too far, the front ones are fine, but the back need a wider stance i feel. the rims are the stock phonedial wheels, no mods on them or anything. so how big of a spacer should i get or maybe its a very bad idea? ha thx
_________________
Black 1988 924S SE
Red 1985.5 944

http://mavfan72.tripod.com/
http://www.cardomain.com/id/mavfan

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[chris24]

I was waiting for a reply to this; mavfan posted it in 924s and general discussions. I have been wondering the same thing. I note in the Tech Section that Jim Pasha wrote:
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Subject: 924 4-Wheel Disc brake option

The 1979 Sebring M471 option was for four-wheel disc brakes. The wheels
were 6" X 15" with 205/60 H15 tires, usually Pirelli P6s. The option
added $1400 to the price of a 924. The option was offered MY1979 to
MY1982 in the US. My 1981 924 has this option.

The same 5-bolt wheels were made standard for the MY 1981-82 US 924
Turbo, all ROW markets had these wheels as standard. 16" X 6" forged
wheels were optional in all markets with the M471 option, front and rear
swaybars and mandantory four-wheel disc brakes. The standard 924 M471
wheels were the cast spider-web type ATS cast wheels, 5-bolt versions of
the 4-bolt normally offered.

The rear wheels also used a 19mm spacer to improve handling, this
induced understeer. The 4-bolt application did not use a spacer, though
the factory offered one and recommended it to improve handling.

Jim Pasha
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And the last paragraph seems particularly pertinent. Can I put 19mm spacers on the wheels to stick them out a little? Do people think it improves handling? If it was factory offered then it must be pretty good right?

ALSO, what do people think to four lug-five lug converters (yeah, I'd spend a few days and £200 converting to M471 if I had the cash and time at the moment!!) But I do have four nice 6" porsche S2 (??) five studs at my dads. I ahve heard ideas about them being a bit weak, but no excess engine power, and they're not much wider, so there can't be much extra force going thru them can there??

Cheers
Chris
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1983 - 924 (185K miles) - not mint
1985 - 924 (148K miles) - mint
1990 - 944S2 cab (52K miles)

[gohim]

The spacers are not cheap.

Anytime you try to add that much width, you must either replace the wheel studs (or the wheel bolts in the case of a disc/drum 924), or buy the spacers that bolt onto the car with the original wheelnuts or wheel bolts, that have wheel studs (or threaded holes to bolt on new wheel bolts).

A decent quality set of this type of spacers is going to cost you $100s of dollars.

Just replacing the wheel studs (if you had studs) is shockingly expensive. The long wheel studs used by the five bolt 924/931/944 are close to $20 each ($20 X 20 = $400), plus the shop time to remove the old ones and press in the new ones.

But of course, you still have the 4-bolt wheels, so let's say for the sake of arguement, you could find a set of 4-bolt spacers, and longer 4-bolt wheel bolts. You still have to seal with the hassle of trying to install the wheels on the car, while juggling the wheel lug bolts, wheel, and the spacers. Not worth the hassle IMHO.

I say live with it, save your money, and buy the parts for conversion gradually, as your finances allow. You will get sick of readjusting the rear brakes soon enough, and be glad that you didn't waste your money on the spacers because you can get the parts for the brake conversion sooner.

[-nick]

Shorter answer:

You can add 10mm on an "S" without changing studs. These are relatively cheap, but you want "hubcentric" spacers to keep the strength up. Or, you could just upgrade your wheels to 8x16's in the rear (and 6 or 7 x16's in the front). The '87+ 951 phone dials and 911 Deign 90's fill the space up perfectly with 225/50/16 tires on the rear.

I think Performance Prods sells 4-lug spacers. If you pick these up then find a set of used wheel bolts from a car with the stock 15" BBS/Basketweave wheels. Those bolts are longer and will accomodate spacers. A set of 8, used, shouldn't run you any more than $25 (at most).

nick

[chris24]

Sound advice. Cheers.
_________________
1983 - 924 (185K miles) - not mint
1985 - 924 (148K miles) - mint
1990 - 944S2 cab (52K miles)

[gohim]

Hubcentric spacers are not necessarily stronger, they are keyed to the wheel hub in an attempt to make them rotate rounder.

Your reference to finding a set of ( is puzzling... Are you talking about finding ( spacers, or ( longer wheel bolts? If you are talking about wheel bolts, are you talking about only adding the spacers to the rear of the car, because doing the whole car would require (16) wheel bolts (4 X 4).

I don't thing I would try running spacers with the wheel bolts that are designed to be used with the ATS basketweave wheels, and the basketweave wheels themselves, in my opinion, there would not be enougn thread left if you were adding spacers for safe thread engagement (you need a minimum of 7 complete turns).

Of course if you were talking using the longer wheel bolts with the original 14" wheels that the early 924s came with, 19mm spacers would/should not be a problem.

Attempting to run spacers with any wheel combination needed to be test fit to determine whether there is enough thread left for save engagment. Preferably before going to the expensive of mounting new tires, just incase the wheels are not going to work out with the bolts and spacers. This would also give you an idea if there was going to be a clearance problem with the tires.

[ideola]

I wouldn't mind widening the stance in the rear only on my NA. I have the stock 15" 4-lug spider webs with the matching 72mm lug bolts (I think ... they're 70-something mm). Could I safely add, say, 10-15mm of spacer without having to worry about new lug bolts?
_________________
erstwhile owner of just about every 924 variant ever made

[gohim]

ideola,

It takes a minimum or 7 complete turns of the lug bolts to get safe engagement with this diameter of fastener (one diameter of the fastener in depth).

To see if you can add any spacers (and if so, how much), take off one wheel, stick a lug bolt through a hole, and measure how much protrudes above the contact mounting surface of the wheel.

Figure one diameter in depth minimum for safe engagment of the threads, and whatever is left could be used for a spacer. From what I remember from having the 4-bolt 15 X 6 ATS basketweave wheels, you are not going to have enough left of even a 10mm spacer.

Be careful when you take the lug bolts from the wheel you are going to remove. If you have not had a wheel off yet, you will be shocked by the weight of the wheel/tire combination. The wheel weighs around 19lbs, wheel and tire combination will weight something close to 50lbs (depending on the tire size). The 15 X 6 phone dials wheels are somewhere around 15lbs (just under) so the weight difference is easily discernable.

[ideola]

Thx Gohim, very helpful rule-of-thumb approach. That's what I was afraid of...so most likely, I am going to need something like 90mm lug bolts. Ouch!!!

Oh, and yes, I've had the wheels off before...I replaced the stock 14" rims with the spider webs and put new tires on right after I got the car last summer.
_________________
erstwhile owner of just about every 924 variant ever made

[Mavfan]

so a good size on an 88 924s is 19mm? for the back wheels, thats all i want. will i have to get longer posts with these?

At http://www.9xauto.com/944.html click under "Porsche Deluxe Wheel Spacers" and which one would help my back wheels. i do NOT have a GT body kit, its all stock, so which one would push the wheels out enough without rubbing against the body?
_________________
Black 1988 924S SE
Red 1985.5 944

http://mavfan72.tripod.com/
http://www.cardomain.com/id/mavfan

Video:
http://video.google.com/videoplay?docid=-5193982457901018136

[gohim]

No, you can't add 19mm spacers to your 924S. Not without buying the more expensive spacers with the integral lug bolts, or having the existing lug bolts on the wheel hubs replaced.

First of all, the 924S is already wider in the rear, than four bolt 924 models (no factory spacers) because the 924S has the alloy rear trailing arms which have a wider track width than the five bolt 924, 931, and steel trailing arm 944 cars (which have factory spacers). This is why the factory installed rear wheel spacers that were used on those cars were been eliminated on on the 924S and other alloy trailing arm 85/2 944 cars.

Before you go out to modify your car, you really should take the time to learn about what you already have.

Did you take the time to look under your fenders and measure the clearance before you sat down to type your latest message? If you did, you would have seen that you can't go 19mm, without rubbing. Of course it is your car, you could bend the fender lips to create more clearance for the tires. Or you could cut away the fenders and graft on flares, but if you were going to do that, you might as well just buy wider tires and wheels, right?

The cheapest, trouble free way to add some tire/track width to the rear of the car is to buy a pair of factory 15 X 7 phone dial wheels. This is the solution that Porsche used. BUT, Porsche also cautions that with the 7" wheels in the rear, there isn't any room to install tire chains (clearance must be at minimum with 7" wheels installed).

From what I understand, some people have found some 8" wheels that can be stuffed under the rear fenders. I don't see that as offering any sort of performance gain. The wider tires and wheels are heavier (lowering accelleration & increasing unsprung weight), the track width can't be any wider without modifying the fenders and/or rubbing, and the engine does not need any more width to try to increase traction on take-offs, because the engine does not have the hp to break the tires loose to begin with. If you are doing burnouts with your current rubber, it is shot, and your clutch with soon be joining it, as the 924S/944 clutch does not take to abuse. Better start saving the $1500-$2000 that it will cost to replace it.

Porsche does not recommend 7" wheels in the front for good reason. While some people do mount them in the front, they will either rub on the fenders when the suspension works, or if the additional width is to the inside, they will interfere with the suspension (rub on swaybar) and/or steering at full steering lock or suspension travel. This problem is worse if you lower the car.