mgordon18

You should definitely do this. Very easy, doesn't take long, and is a great way to save $100 over what a dealer would charge you.

An added benefit is that it's a great starter project. I was a complete mechanical newbie until I started changing my wheels for the winter. Now I'm doing brake pads, rotors, flushing brake fluid, and changing cabin and engine air filters. Every time I try something new I get to buy all the tools and gadgets to make it happen - still cheaper than going to a mechanic. And this way you know it's done right - no one is going to leave a bolt out or forget to torque something down. I once found the crust of a turkey sandwich in the engine compartment of my Audi. Eff that.

It's all just nuts and bolts in there. You can do it!

JW911

The beauty of this task on a 911 is jack up from the rear and both front and rear tires lift off the ground. There's no need to jack up the front corner. Just change wheels one side then the other.

koala

Don't I feel dumb. Never realized the wheels were 118 ft lbs. Time to re-torque!

Southbranch

More tips:

For mounting wheels on the hubs, I made two hangers (guide studs) from 90mm x 14mm, 1.5 fine thread hardware store carriage bolts by cutting off the heads with a hacksaw and rounding off the shaft ends on a bench grinder.

Be sure the car is on a level surface before you jack up one side of the car, and block the wheels on the opposite side so it can't roll off the jack. Then, with the car in neutral and the parking brake off, you can safely rotate the hubs by hand for visual inspection.

When tightening the lug bolts, be sure to do it in a star pattern as mentioned above, and torque all 5 of them in 3 stages of 40, 40 and 38 ft-lbs to minimize potential rotor warping.

Nin Din Din

FWIW guide stud/rods/hangers (Wheel Mounting Guide Bolt) are available from Suncoast for about $10.

worf928

And they are identical to cheap ones on the ASC site except 130% of the price. And, they suck. They are very soft and bend easily. The Swabian-brand wheel hanger I linked to is a much sturdier piece and the shaft end is knurled so that you can grip it unlike the “Porsche” version that’s smooth and offers no purchase for fingers.

mgordon18

Wow. This is something I've never heard before and sounds completely overkill. I hit them with my impact air wrench and they instantly get to probably around 90-100ft/lbs and then I lower the car and use my torque wrench to fine tune it to 118. Never warped a rotor in dozens of wheel swaps. I can't imagine going around each wheel 3 times to get to 118.

bkrantz

This is just good mechanics/mechanical engineering practice. It might not matter as much for wheels, but try ignoring this when installing cylinder heads and you might do some expensive damage. At least tighten in cross-cross patterns.

IMO, impact wrenches are also risky for alloy wheels. And if you don't have the wheel on square, tightening on one side (not criss-cross) maybe result in the lugs getting tight while the wheel is not actually mating to the rotor.

mgordon18

Criss cross yes. 100%.

Southbranch

Some makes and models of cars may be more prone to warped rotors than others. I learned about doing it in stages after repeated warped rotor problems with my 1991 Nissan 300 ZX Twin Turbo, probably due to the dealership using air tools to save a little time. Never had an issue since. I only change wheels twice a year on the 911, so its no big deal.

worf928

This is overkill.

--^

Two or three stages is fine, but it is just as effective to progressively, in a star pattern tighten the lug bolts/nuts 'by feel' until you get close to the required torque and then break out the torque wrench (or attempt, in earnest, to achieve the spec torque.)

Right. There are a least two reasons to progressively tighten the wheel lugs:

1) This ensures that the wheel is flat on the wheel hub. If the interface (flanges on modern Porsches, rings on others, etc.) between the wheel and the hub is 'tight' it's possible to have the wheel 'cocked' on the hub. If you 'choose unwisely' and torque-to-spec one lug, torquing the other lugs to spec may not cause the rest of the wheel to seat flat against the hub. Or, IOWs, you just torqued the wheel so that it can't seat flat on the hub.

2) If you just go from finger-tight to full-torque-spec in one go, the first lug you torqued will be over-torqued when you're done.

Right.

Impact wrenches are just plain risky for tightening any fastener unless you have invested in high-dollar calibrated equipment like automotive assembly factories do or you've done some closed-loop calibration of your air wrench and your compressed air system.

Impact wrenches are for loosening fasteners. And then only sparingly.

Air impact wrenches - power tools in general - remove any 'feel' from the process of fastening or unfastening. It's a good way to not notice that threads are damaged when you remove a fastener and a better way to damage threads or over-torque a fastener on the way back in.

Tightening a steel fastener in an aluminum hole with a power tool is a big no-no. The torque spec is usually a 'any more than a little tighter than this and you strip the aluminum threads' spec.

I always torque wheels to spec with the suspension unloaded. I use a wheel chock to keep a wheel from turning. This further ensures that the wheel stays flatly seated on the hub.

Your lug bolts are likely way-over 90-100 ft/lbs after you apply your air wrench unless you a) have a week-a$$ed wrench or weak air or b) you've figured out which setting to use on your air wrench that has torque adjustments and have a torque wrench that reads torque when loosening a fastener to make sure.

When you use a torque wrench, if you don't see the fastener turn at all *before* the wrench clicks/beeps/vibrates that's an indication that you may have exceeded the torque spec.

For steel-on-steel exceeding the torque spec even by a large margin isn't usually a serious problem. For steel-on-aluminum exceeding the spec by a not-large margin often results in thread damage. This will usually only become apparent the 'next time' when the hole won't take the torque.

Hopefully, wheel hubs on modern Porsches are still steel and not aluminum. It's well known that the hub carrier is aluminum and why frequent brake pad changes result in stripped carriers.

good2go

Getting Started. Hardest part was getting the wheels out of the basements

Starting with drivers side rear.

Simple puck. Only 1 lug guide

One side done

All the wheels are swapped. Did not take long. HRE where moved to basement.

Summer wheels look awesome.

Love the new look.

good2go

One more thing to note. I was driving after changing the wheels and wanted to check tire pressure. It was not registering. After about 5 minutes, the car alerted, "Did you change wheels?" Do you want to update settings? I jumped into settings and changed to Summer 20" and saved. 5 minutes later the TPMS updated with the tire pressure.

How did the car know I changed tires?

I think 45psi is too high.Can I lower? Do I need to tell the car its lower? What do others prefer?

Bob Z.

There are countless threads on tire pressure...search for them and read what others have to say. There are many opinions so it is best to experiment but 45 is too high unless you are making high speed runs on roads such as the Autobahn. You can also consult your owner's manual.

991carreradriver

Someone mentioned torquing the wheels after a 100 miles, can't hurt. The point I wish to make is that when one torques, it should never be performed on a tightened fastener. Always loosen and re-torque. I use a torque multiplier, and I have become far more knowledgeable about torquing than I care to be.