Subaru field engineer says OEM wheel studs only good for 75 to 80 wheel changes

[Norville Rogers]

Originally Posted by Pat

I was talking with a BRZ friend of mine recently that is a knowledgeable, experienced driver. He pays close attention to vehicle maintenance including wheel lug torque specs. He recently had a couple OEM wheels come loose on the track. Fortunately he was able to get the car slowed down in time to keep them from coming off. His wheels were damaged, so he spoke with his dealership about it. After giving him a hard time, he was finally able to speak with the field engineer about this issue. The engineer said the OEM studs and lug nuts are only designed to withstand 75 to 80 changes over the life of the vehicle. My friend actually had the failed studs tested and said the metallurgy is terrible. Here is an email I got from him about it:

re : the Subie engineer and my wheel studs and lug nuts, he was a pretty cagey dude. he would put nothing in writing for me despite several requests. Clearly, the design life of parts is not something they want to discuss openly. I felt pretty lucky that they replaced both ruined wheels as a "courtesy" rather than under warranty. He made it very clear however that our cars "arent designed for track use ". and "this car isnt a Porsche". of course I said they "why isnt all that in the owners manual ?" .
bottom line is the "design life" of the lug nuts and studs is 75-80 wheel changes, on average, in the lifetime of the car. "Kmart" parts used in quite a few places on a $25K car, I suspect.
In order for you to avoid my issues, I strongly recommend you go to ARP studs, kit # 100-7727 for FRS or BRZ. their tensile strength exceeds grade 10.9 steel so they are the best you can get.
For your information, I researched the stock studs and lug nuts. they are made from < grade 8.8 carbon steel. in short that means they are el-cheapo Kmart parts.
grade 10.9 alloy steel is generally the best steel other than "aircraft quality" . ARP has a tensile strength rating system and their's are better than grade 10.9.

Be careful out there, kids!

I love these type of posts. . Hilarious.

[Alan]

I lost count of the number of studs I replaced before swapping to ARP. Haven't had an issue since. Nuts were always taken off with air/electric tools but put back on by hand/torque wrench.

[Tokay444]

Originally Posted by nikitopo

And ironically do you know who builds Boeing's wings? Subaru!

You guys, don't know what you buy. Do you know about their special ring-shaped structure? Firefighters are doing special training on the Subaru's because they could not cut their b-pillars. You can read more details here: http://www.firehouse.com/article/105...orcement-frame

If something really matters, then be sure that Subaru will do the best and use the best materials.

Maybe for one plane, but one of our customers builds wings for many Boeing aircraft, and they're not Subaru. Another one of our customers is Boeing.

[joe strummer]

Originally Posted by renfield90

Mine didn't even last that long before cross threading.

Nuts don't cross thread studs.

People cross thread studs.

[nikitopo]

Originally Posted by Tokay444

Maybe for one plane, but one of our customers builds wings for many Boeing aircraft, and they're not Subaru. Another one of our customers is Boeing.

They build wing boxes for the Boeing 767, 777 & 787 and will build the same in future for the Boeing 777X:

http://www.subaru.com.au/news/fhi-ce...entre-wing-box
http://www.fhi.co.jp/english/news/pr...12_07_11e.html

http://www.fhi.co.jp/english/news/pr...0e_111090.html

And this know-how is transferred also to their cars! Anyway, I just mentioned it because there was a question about the quality of Subaru and some side comparisons with Porsche.

[joe strummer]

Originally Posted by nikitopo

They [Subaru] build wing boxes for the Boeing 767, 777 & 787 and will build the same in future for the Boeing 777X:

I sure hope the airlines' mechanics remember to change the wing box studs and nuts after the 74th removal/reinstallation.

[Tokay444]

Originally Posted by nikitopo

They build wing boxes for the Boeing 767, 777 & 787 and will build the same in future for the Boeing 777X:

http://www.subaru.com.au/news/fhi-ce...entre-wing-box
http://www.fhi.co.jp/english/news/pr...12_07_11e.html

http://www.fhi.co.jp/english/news/pr...0e_111090.html

And this know-how is transferred also to their cars! Anyway, I just mentioned it because there was a question about the quality of Subaru and some side comparisons with Porsche.

Aerospace and automotive are at the polar opposite ends of the manufacturing spectrum.

[renfield90]

Originally Posted by joe strummer

Nuts don't cross thread studs.

People cross thread studs.

Horseshit. On my Celica I easily swapped tires a couple hundred times over 8 years on the stock studs and never once had an issue - and neither did the other ~100 owners on the forums who tracked/autocrossed their cars and also changed wheels regularly. It was simply not an issue.

The number of people I know personally, in real life, who have had this issue with their twin but not their previous car is more than I can count on one hand. The number of twins owners I know in real life can be counted on two hands.

The studs suck and they cross thread on their own.

[joe strummer]

Originally Posted by renfield90

Horseshit. On my Celica I easily swapped tires a couple hundred times over 8 years on the stock studs and never once had an issue - and neither did the other ~100 owners on the forums who tracked/autocrossed their cars and also changed wheels regularly. It was simply not an issue.

The number of people I know personally, in real life, who have had this issue with their twin but not their previous car is more than I can count on one hand. The number of twins owners I know in real life can be counted on two hands.

The studs suck and they cross thread on their own.

There's a difference between cross threading and galling. No stud gets cross-threaded on its own.

[renfield90]

Originally Posted by joe strummer

There's a difference between cross threading and galling. No stud gets cross-threaded on its own.

I'm not a mechanical engineer so I'll leave that distinction to those in the know. Point is the stud gets ruined and becomes unusable, and it's happened to too many people who knew what they were doing and were being painfully careful when changing wheels due to the reputation of the twins' studs.

[renfield90]

Originally Posted by DarkSunrise

This is what I've always heard as well. Is there a recommendation as to how frequently to replace studs/lugs?

Depends on frequency of usage and how much lateral acceleration the car can generate. Cars with slicks and aero will need to replace them more often than cars on street tires and stock suspension.

Someone quoted 2-3 years to me once. That probably sounds right for the faster cars out there. As you can see in this thread some people get away with longer, but at some point you run the risk of a wheel coming off. Most every car I know that has lost a wheel had R comps and aero, but I also know a street-tired EF Civic that nearly lost a wheel (3/4 lugs were spotted loose).

[xwd]

I've done 100+ on the BRZ with stock studs and have never had an issue. Never had an issue on my other Subarus either. I loosen them by hand and always thread them by hand first, and don't use shitty lugnuts.

[Sleepless]

A friend had issues with aftermarket lug nuts coming loose and the wheel fell off. turned out the nuts an incorrect shape so didn't properly seat against the wheel. Wonder if this may be causing some of the issues since loosening nuts will damage the studs.

I've been using the nuts from TireRack exclusively and they have performed well.

[xwd]

I doubt it. You'd seriously have to go out of your way to buy the wrong lug nuts since almost all aftermarket lug nuts are the 60 degree conical seat all aftermarket and the stock wheels use.

Someone putting the wrong nuts on there and not noticing it when they did is baffling.