ColoradoGT3

I had a tech tell me that Porsche has changed its recommendation for wheel torque from 98 ft./lbs. to 118 ft./lbs. for 996 and newer 911 based cars.
What say you all? Is this correct? Pros and Cons?

himself

I read about this a while back. IIRC, the new spec applies to the new wheel hubs and lugs. If you have the old stuff, you use the old specs.

-td

powdrhound

I track my car hard. Been using 118 for 5 years now. I use studs with OEM steel nuts. Not a single stud failure while using 118. I've broken hubs, gearbox output shafts, but not a single stud. 96 is a carryover from the old aircooled days when they were using aluminum lug nuts. Back when I ran 96 I would have to retorque which is an indication of an insufficient clamp load. With 118, retorque is not necessary but I still check it after each session. With 991 cars the spec changed to 118 with the same size 14x1.5 lug bolts. All my track buddies are using 118 also with zero stud failures. It works..

993GT

been running ~115-120 forever...maybe info from 6 Cup days?

Rob S

Deleted -- duplicate post

Rob S

Agree on using a higher wheel torque on a 996 or 997 GT3 -- especially if you're using studs and lug nuts and you're on the track with the car. If you're using the factory wheel bolts with the captured spherical "washers" it may be less critical, because more of the applied torque ends up preloading the bolt. But if you're using studs and nuts at 96 ft-lb, you're definitely running the risk of undertorque -- which allows the studs to bend and fatigue -- and has been the cause of the many failed wheel studs posted about for years on this forum. There is no downside risk to the higher torque - the later (2012 onward) cars -- 991s, Boxsters, and Caymans -- all use the higher 118 ft-lb torque, and they use the same wheel bolts as the earlier (996 and 997, Boxster, and Cayman) cars. Though Porsche has not publicized their reasons for changing to a higher torque on the later cars, logic would suggest that they discovered that 96 ft-lb was no longer adequate, and that 118 ft-lb provided a better margin of safety.

powdrhound

^^^^I was too lazy to type all this but that's spot on. I always shake my head when I read about all the guys with broken studs as their tale of woe invariable ends with "and I always torque to 96....". I've been advocating 118 for many years but guys don't wanna hear it.

ColoradoGT3

Thanks for the replies. My car is a 6 GT3 that still uses the factory bolts/washer set up and stock wheels. My track use is much more limited now than it once was. I've never had a problem with factory torque of 98 ft./lbs. I also check my torques religiously during track events. I was wondering if the 118 ft./lbs. recommendation was passed down by Porsche's attorneys regarding an extra margin of safety for the folks that never check a damn thing on their car?

T10Chris

I just switched to H&R studs with OEM nuts, but even using OEM wheel bolts I changed my torque spec from 96 to 118 after reading around here since I track the car. No ill effects. I was having to retorque a wheel bolt or 2 every so often running 96 ft lbs....

From what I've read, if you are running studs and have to retorque after a session, you should change that wheel stud since that stud could have been subjected to extra loading that bent/fatigued the material.

Rob S

T10Chris,

I would agree with your philosophy: if you find your torque level dropping (that is, if you need to tighten your lug nuts after running), then two things are likely true: 1) the target torque level that you were using is too low, and 2) you may have already damaged your wheel studs, and should consider replacing them. These studs fail from fatigue damage, which is cumulative. If they run in an undertorqued condition, a crack may have already formed and begun to grow. It's not good enough to check the torque level frequently (though that's certainly better than not doing so). If the target torque level is too low, you may break wheel studs -- and they may not give you much warning.

P-nache

COGT3 - you and Powdrhound were running on the track together on Saturday - you two should talk - you'd both enjoy it!

powdrhound

Hey Scott! Great seeing you this weekend. Love your new car! See you soon my friend.

ColoradoGT3

Love to meet my fellow GT3 drivers....
As you know, I don't get out much any more!

Gofishracing

118 ft lb for newer cars- in manual- I believe 2016 on. NNJR just changed Tech procedure for checking luug nuts.

177mph

What did NNJR change? I was at Tremblant with Ed and didnt hear this.