NewB Question: Spacers, Torque and Lugs

[gustav]

I just got some new wheels that I was told would work on my SC with the spacers provided. Actually, I got them a long time ago, but I'm just now getting to trying the fit on them.

Questions are:
1) Is there anything wrong or dangerous when using spacers?
2) My understanding is I want to torque my lugs to 90ft/lbs. Is this correct, and is it correct for the spacers to the car as well as spacers to the wheel?
3) What size of socket do I use? I know this is probbably a dumb question... I really don't know though. 3/4 seems to fit, but is just a little bit loose. I assume I want to use a metric socket?
4) Should I use a 'special' socket or do normal sockets work just fine?

Thanks in advance.

Gus

[Britwrench]

No, the correct wheel nut torque is 130Nm, which is 93ft/lbs. If you are using wheel centers make sure they are Porsche specified and hub-centric. You need a deep 19mm six-sided socket, make sure the nut will go fully into the socket. Sears sell a suitable socket. If you are installing 17" or 18" rims note that the wheel nuts must be torqued with the car off the ground.

[jtcmuga]

Gus,

Spacers or adapters? My understanding is that spacers are like washers, you lose thread depth of the wheel bolt stems to offset rims outward - spec torque (93 ft-lbs) would apply. Adapters bolt to the wheel hub and have their own bolt stems to mount the wheel.

115ft-lbs adapter to car hub
93ft-lbs wheel to adapter

My thoughts are 99% confident. Can I get an "AMEN" from someone?


Jojo

[Rufblackbird]

H&R instructions for adapters says to torque adapter to hub the same as normal lug torque.

[fireant911]

Yes, this is being anal but when it comes to something as serious as keeping my wheels on my car it is important... I have always used 96 ft/lbs when torquing the aluminum lug nuts (according to both Bentley and Haynes). The 130 nm value is indeed correct but the actual conversion to ft/lbs is 95.88 ft/lbs ~ 96 ft/lbs. I have nothing to add about torque specs and the use of spacers though it is important, I think, to ask gustav what alloy are his lug nuts manufactured from because that could make a difference.

[Rot 911]

I always torque to 96 ft. pounds for the reasons stated by Daryl although I don't think the wheels are going to come flying off if you only torque them to 93 ft. pounds.

[gustav]

Originally posted by jtcmuga

Spacers or adapters? My understanding is that spacers are like washers, you lose thread depth of the wheel bolt stems to offset rims outward - spec torque (93 ft-lbs) would apply. Adapters bolt to the wheel hub and have their own bolt stems to mount the wheel.

Good catch, I guess I mean adapters. I can't upload a pic, but one is available at: http://bourg.net/~gus/DSCF0309.JPG

Thanks all for your responses, much appreciated.

Gus

[Gunter]

Gustav: What size/type are your new wheels? If they are mags like Fuchs, use a little lub between the steel lug nuts and the mags for a wet 96ft/lbs torque. To transfer the power from a future 3.6 to the ground I would recommend an 8 or 9-size Fuchs with a 245 in the rear.

[gustav]

Originally posted by Gunter
Gustav: What size/type are your new wheels? If they are mags like Fuchs, use a little lub between the steel lug nuts and the mags for a wet 96ft/lbs torque. To transfer the power from a future 3.6 to the ground I would recommend an 8 or 9-size Fuchs with a 245 in the rear.

Hey Gunter. These are cup wheels (7s and 9s). A gratuitous pic of which can be found here: http://bourg.net/~gus/cupwheel.JPG

[Gunter]

Good stuff! X-mas came early. I wonder if it will fit the rear wells. If you mount 245's on the 9's for the rear, even with a little lowering, you'll touch the fender lip. A 16X9 Fuchs has a 15mm off-set, what is the off-set on the cup 9's? Even without adapter, a 9-size Fuchs with 245's is a tight squeeze on an SC. The adapter looks like a 1 inch (25mm) size which brings you out even more. Mount them and see. Keep us posted. Cheers.

[jtcmuga]

I bought the cup 17x7 and 9 (55mm offset) for my 84 coupe. I haven't put rubber on them yet, but most people are reccommending 1" adapters in the front and 1.5" in the rear... I am not sure what tire size I'll be going with to avoid fender interference... An SC fit may be a different story...

Jojo

[gustav]

Welp, the 9's fit on the rear. Off to get the fronts on.

pic: http://bourg.net/~gus/DSCF0310.JPG

[Gunter]

Gus: That looks good. Are they 17 inch? From your pic, it is hard to tell but it looks like your rear was not lowered. When lowered, the measurement from the floor to the fender lip at 24.5" rear, and 25" front is popular. What camber do you want? For mildly agressive street driving, ~3/4 deg. rear, and ~1 deg. front would probably do it. A side-shot would tell us how far the wheels stick out from the fender lip. For final alignment, corner-balance and lowering, you may want to wait until your conversion is finished because changes in weight and suspension components make a difference on the final settings. On the other hand, if the wear pattern on your old tires indicates a problem, a new alignment is in order. Are you keeping your Fuchs wheels? Cheers.

[jtcmuga]

Looks good! I second that request for a side shot... :-)

Jojo

[gustav]

Here's a sideshot: http://bourg.net/~gus/DSCF0313.JPG

Gunter: I have no idea how to set my suspension up... I'm pretty clueless with all this stuff, so for the moment I'll just be looking at what people like yourself say would be reasonable. :]

Thanks,
Gus

[dad911]

Originally posted by Britwrench
....... If you are installing 17" or 18" rims note that the wheel nuts must be torqued with the car off the ground.

? Why ? I never heard that before.

[gustav]

Originally posted by dad911
? Why ? I never heard that before.

I was wondering the same thing, actually. I did end up torquing the lugs with the car off the ground to be safe, but it was a real pain I ended up applying pressure to my brakes for this using my old center console and other stuff I found laying around the garage... At least the center console finally became useful.

[jtcmuga]

I would like an explanation on tightening the 17's or 18's off the ground...

Jojo

[Gunter]

Re: Torqueing 17inch wheels off the ground has to do with not enough side-wall deflection if you use the standard procedure. To get around that, with the car raised, apply emergency brake, mount your wheel, snug the lugnuts semi-tight, lower the car, em. brake off, now roll the car a little to make the wheels find the correct undeflected setting, then tighten with the correct 96ft/lbs torque. Use some lub on threads and the round mating surface of the lug-nuts.
Nice shot of a nice 911, Gus, but, we need to see the wheels from the front or rear in an upright position to determine visually what kind of camber you have. Take aim from the sides showing the wheels in comparison to the ground. If they are straight up, you have 0 camber. If they lean in, you have negative camber. Straighten the front wheels and take a pic along the side of the car so that the rear wheel is barely showing, Then, do the same from the rear. Cheers.

[jtcmuga]

Gunter,

I'm still not convinced. In your explanation, wheel diameter is not the factor, it is the sidewall stiffness. So if I have 15" rims with a low profile tire or a run-flat tire (stiff sidewalls), I would have to perform your suggested procedure.

I think that if you place the wheel on the hub and hand tighten all five lugs before you lower the vehicle, you will avoid any instance of improperly setting the wheel to the hub. Once lowering the tire to the ground, if there is any compliance between the hand tightened wheel and the hub, it will be overcome by your torque (and the domed mating surface of the lugnuts to wheel, designed for aiding alignment). Roughly calculating the tighening force of 96ft-lbs to the lugs at hand (a high pitch estimate of 45degrees) gives about 3500lbs of inward tightening force for one lug to secure the wheel to the hub. Multiplying by five lugs, this force is huge in comparison to the sidewall stiffness and tire grip/friction to the ground.

The only outlier is camber. If you have alot of camber, and barely hand tighten the lugs, there's a chance of the wheel not seating properly... You would probably notice the problem, too. That's when it wouldn't hurt to check the torques after a drive around the block...

Well, the bottom line is that either method is fine. I just think it would be an unnecessary pain to torque the lugs in the air.

if i'm incorrect, i got you're next beer, Gunter.

Cheers,

Jojo