paradocs98

I'll most likely be ordering MSI wheel studs this week for my 2014 991 Carrera S. I'm coming from BMW, so I have a few questions regarding Porsche- and 991-specific wheel studs. Any advice would be appreciated.

• I don't want to do press-in studs that require hub removal and/or modification, so I'm doing the "double ended," screw-in type wheel studs.
• I'm assuming that the standard 14x1.5mm Porsche fitment pertains to the new chassis 991 as well. Is this correct?
• Based on MSI's website, the options for 14x1.5mm double-ended Porsche wheel studs pertain to finish and overall stud lengths. I'll be using both OEM 20" Carrera S wheels and 19" Forgeline GZ3R wheels. No spacers with the Forgelines. If I ever use spacers with the OEM wheels, they will be relatively thin and not overly aggressive. Any advice on overall length? Based on my calculations, the options for total lengths are 78mm, 88mm, and 98mm. I want the studs to be long enough that the nut's threads are fully engaged on the stud, but I don't want a huge excess of stud sticking out beyond the wheel, either.
• Any advice on coated finish vs. "M-Phosphate" finish?
• For the nuts, is it correct that a 14mm radius or R14 ball-seat nut (with 19mm head) is to be used for the OEM Porsche wheels? And the Forgelines, as a standard aftermarket-style (BBS, HRE, etc.) wheel, would use a 60 degree conical nut in 19mm?

Thanks for any help!

Rob S

I'm sorry that I can't answer many of your questions, other than it's my understanding that the 991s use the same 14 x 1.5 mm threads that previous Porsches have used since the dawn of time.

In case you haven't seen the two threads that have been active on the topic of wheel studs that fail, it might be good for you to look at them here.

https://rennlist.com/forums/996-gt2-...ken-studs.html

https://rennlist.com/forums/racing-a...replacing.html

I'd be interested if you could confirm the factory wheel bolt torque spec for your car. I understand it's 118 ft-lb. If so, is that what you're going to use with your new studs/nuts?

Rob

paradocs98

Thanks. I had indeed just read those two threads on wheel stud failures. Based on that info, it would seem that MSI is one of the reputable/reliable stud suppliers, making their own high-quality products in North Carolina, USA.

My understanding is that recommended lug torque is 160Nm (118lb-ft) on the 991 chassis, but I will reconfirm in my owner's manual tomorrow. Interesting that the 14x1.5mm sizing for lug hardware is the same with the 991 as it always has been with Porsche, and yet the recommended fastening torque for the new cars is significantly higher than for previous chassis. Is this Porsche acknowledging a previous issue in their own quiet way?

FFaust

Interesting indeed about the torque delta. I wonder if we could/should use the higher torque with the older chassis?

Tarett also sells studs, and I think that they are the MSI units, so that is a good endorsement in my book. I might be ordering a set soon to replace my current batch. Search for "studs" on www.tarett.com They also have brake caliper studs BTW.

I have the Apex, which have been good, but I broke one last season (after ~70 track days), and found another one or two ready to break when I removed them over the winter.

Mvez

+1 for Apex....also have 70+ days on my "Race" studs, zero issues. Only using Toyo/Nitto tires certainly helps. Will probably time them out sometime this year though.

I always make sure to take some weight off the car when breaking them loose, and on final install torque. Also, people often use way too long of a stud...use only what is needed for your wheels. Mine are 65mm, and perfect for CCW's.

paradocs98

I'm able to answer some of my own questions.

I spoke to Curtis at MSI on the phone today--very nice gentleman and very helpful. I'll be going with the double-ended wheel studs (screw-in type), with coated finish. I'll be doing the medium length.

As for the nuts, Curtis saved me from a potential bad mistake. I knew that the OEM Porsche wheels use an R14 ball-seat nut, but I had assumed that my new 19" Forgelines used a standard aftermarket 60-degree conical nut, such as on a BMW fitment. Au contraire--Curtis told me that Forgeline typically drills wheels for Porsche fitment to use the ball-seat nut.

I called Forgeline, and sure enough, the wheels were made for the R14 ball-seat nut. So now I don't have to worry about remembering to switch nut types when I switch the wheels back and forth.

For installation, Curtis recommends 15-30 lb-ft of installation torque into the wheel hub, using red Loctite.

During the conversation Curtis mentioned that MSI supplies wheel studs and nuts to NASCAR teams as well as GrandAm teams such as Fall-Line and BGB. Good enough for me. Feeling confident in MSI and looking forward to getting their stuff.

FFaust

What are the prices from MSI?

al@cpt

+1 for Curtis and MSI.

paradocs98

Yep--wheel nut/bolt torque confirmed in the manual. See pic below.

I don't have the invoice yet, but I believe it's around $12 per stud and $3 or so per nut.

FFaust

Thanks for that, price is in the ballpark with other high-quality studs.

Rob S

Paradocs98,

Thank you for the scan of your manual. Very interesting. I know that there are two factory wheel bolt lengths available, but I didn't know they were discussed in the owner's manual.

Now for the million dollar question: what are you going to use for wheel torque with your new MSI studs and either your factory or your Forgeline wheels? I assume you'll be mounting both sets of wheels on your car from time to time. Obviously, Porsche recommends 118 ft-lb for the factory setup. What does MSI say? How about Forgeline?

The MSI website doesn't have data on this, but here's what the Tarrett Engineering website says about the studs they sell, which, according to Francois, are from MSI:

GUIDELINES FOR USE OF COMPETITION STUDS & NUTS
INSTALLATION
1. PROPERLY LIFT AND SUPPORT THE CAR.
2. REMOVE THE WHEELS.
3. CLEAN THE INTERNAL WHEEL HUB THREADS MAKING SURE THERE ARE NOT ANY CONTAMINANTS.
4. START EACH STUD BY HAND (PINK/YELLOW END, SHORT THREADED END GOES IN HUB). TURN STUD UNTIL IT BOTTOMS OUT IN THE WHEEL HUB.
5. USE THE TWO STANDARD HEX NUTS. THREAD THEM ON THE WHEEL SIDE THREADS OF THE STUD AND JAM THEM TOGETHER.
6. TORQUE THE STUD TO APPROXIMATELY 60-70 FOOT POUNDS MAKING SURE IT BOTTOMS OUT IN THE WHEEL HUB.
7. LOOSEN JAM NUTS AND REMOVE FROM STUD.
8. REPEAT STEPS 3 THRU 6 FOR EACH STUD BEING REPLACED.
9. ALLOW 10 MINUTES FOR THE THREAD LOCKER TO CURE.
MAINTANENCE
1. TORQUE LUG NUTS TO 85 TO 90 FT-LBS.
2. AVOID RETORQUEING NUTS WHEN HOT, ALWAYS WHEN COOL.
3. WHEEL STUDS USED FOR COMPETITION ARE CONSIDERED TO BE WEAR ITEMS AND SHOULD BE REPLACED AT THE REGULAR INTERVALS LISTED BELOW.
CLUB RACE/STREET USE – EVERY TWO YEARS
RACE CAR, 10+ EVENTS/YR – EVERY YEAR
PRO TEAM RACE CAR – TWICE A YEAR
4. STUDS AND NUTS SHOULD BE INSPECTED REGULARLY AND REPLACED IF THERE ARE ANY NOTICABLE ISSUES OR SIGNS OF DAMAGE.

Note that they recommend torqueing studs into the hubs at 60-70 ft-lb, and then torqueing the wheels at 85-90 ft-lb. That's a huge difference from the factory recommendation of either 96 ft-lb for pre-2012 cars or 118 ft-lb for the newest cars. This kind of stuff doesn't sit well with me!

Rob

FFaust

Well, either MSI or GLS Topstud, also made in USA and very similar.
http://glstopstud.com/Home_Page.php

I had an e-mail from Tarett, which I can't find at the moment, that gave the source.

FFaust

Tarett is incredibly responsive, so I am sure that they will respond quickly if you ask. The 118 ft-lb of the newer cars might simply not have been addressed yet.

I could e-mail them if you guys don't.

trackjunky

Call or e-mail John Tecce over at BGB Motorsports. He is a wealth of knowledge and I have purchased wheel studs from him both recently and in the past. Heck, if they are good enough for his Grand Am race cars then they are good enough for me.

Tarett Engineering

FYI, the Tarett stud installation instructions apply to the studs that Tarett carries, not the MSI design. Although they are of very high quality, the MSI studs are different and do not have a shoulder to bottom out on the hub, and should not be installed to the same torque specs.