Would you swap these lug bolts for lug studs?

"Urambo Tauro" (urambotauro) 02/26/2018 at 12:15 • Filed to: saab 900, project, wrenching

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Life got in the way of getting anything done on the Saab this week, but let’s take a moment to talk about a potential modification that I’m finding very tempting.

This car is one of those weirdos that uses lug bolts instead of lug nuts. This means that every time you go to install the wheels, you have to line up the holes first.

This isn’t a total nightmare, because the brake rotors are locked into place by set-screws, and there are also locater pins to help hang the wheel while threading the first bolt in.

But we must be missing some hardware, because these pins and set-screws aren’t present at all four corners. The hubs are threaded to accept them, though. There’s nothing wrong with skipping this hardware, except that it makes lining up the rotor and wheel a massive PITA. Not only do the holes need to align, but you have to hold all that weight up against the hub on that shallow ring in the center. With one hand, that is, since your other hand needs to be free to thread the bolt in. Otherwise, this becomes a two-person job.

Why not just convert to lug studs? If the rotors and wheels can be hung on studs while threading the nuts on, who needs pins and set-screws? Any downsides to this I’m overlooking?

We could save a few bucks by keeping the lug bolts, and skipping the missing hardware. But if this were my car, that’d piss me off to no end. I don’t think it’ll take long for my brother to discover how much of a hassle this can be.

It’d be much easier to threadlock some studs into the hubs and be done with it, using normal lug nuts ever after.

I haven’t looked into pricing on new set-screws and pins, but I did poke around looking for conversion studs. !!!error: Indecipherable SUB-paragraph formatting!!! of M14x1.5 studs for a little over 30 bucks. It’s a set of 20, which is more than we’d need, but I can’t seem to find a set of 16, at least not for what I reckon to be a reasonable price. Granted, we’d still have to add a set of lug nuts on top of that...

So here’s my challenge to you, Oppo. What’s the cheapest way to convert from lug bolts to lug nuts, using sufficient quality hardware? The current lug bolts are M14x1.50, 27mm thread length, 60° seat angle.

crowmolly > Urambo Tauro 02/26/2018 at 12:37

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It’d be much easier to threadlock some studs into the hubs and be done with it, using normal lug nuts ever after.

Just my opinion, but I don’t like that solution. I’d drill the holes larger and get appropriate splined wheel studs that have pull-through protection.

Akio Ohtori - RIP Oppo > Urambo Tauro 02/26/2018 at 12:37

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Could try RockAuto or Advanced (with coupons) first. Doesn’t seem like it would be hard to find, but I’ve never looked either.

Schaef_Camaero Z/28 > Urambo Tauro 02/26/2018 at 12:45

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This doesn’t answer your question... But, I’d just keep the bolts.

My old Festiva had lug bolts, and I believe many BMW’s also have lug bolts. I never recall it being a huge burden putting a wheel back on. It helps if you can sit next to it and use your legs to help hold the wheel in place while starting the first couple bolts.

Urambo Tauro > Akio Ohtori - RIP Oppo 02/26/2018 at 12:50

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RockAuto only offers OE-style bolts for this application, and it doesn’t look like Advance carries conversion studs, either. That’s too bad; they’re always sending me coupons...

Urambo Tauro > crowmolly 02/26/2018 at 12:50

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I’d have to check and see if there’s enough room to slide studs through the back of the hubs. How critical is the “pull-though protection” offered by the head of those studs? I’ve never heard of threads pulling through (unless they were already damaged via cross-threading or something like that).

Textured Soy Protein > Urambo Tauro 02/26/2018 at 12:51

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My BMW has lug bolts. A benefit to bolts instead of studs is you can add spacers much more easily. I have this little wheel hanger pin that I use when changing wheels that speeds up the process greatly.

Urambo Tauro > Schaef_Camaero Z/28 02/26/2018 at 12:52

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I’d like to hear more about your technique. Do you sit looking at the wheel straight-on, or are you coming at it sideways?

Urambo Tauro > Textured Soy Protein 02/26/2018 at 12:56

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Neat. Looks like they do have the right size available, too.

PartyPooper2012 > Urambo Tauro 02/26/2018 at 12:56

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I hate lug bolts. I have a mini cooper and it uses lug bolts. What a pain in the ass. Especially if you have a bad back.

If you can, use lug nuts

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 12:58

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!!! UNKNOWN CONTENT TYPE !!!

I wouldn’t trust that.

LimitedTimeOnly @ opposite-lock.com > Urambo Tauro 02/26/2018 at 12:58

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Many German contemporary cars are lug bolts, like my 2016 VW GTI. I’m not the one who spoke about sitting next to it - I bought a wheel hanger to screw in one spot (no fancy locator pin for the GTI), then put the wheel in place using the hanger, hold at the top with one hand, stabilize the bottom of the wheel with my foot, and use the other hand to put in a bolt.

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 13:00

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Why not? The thread would be the same at the hub and at the nut. All the threadlocker would do is keep the entire stud from unscrewing when you loosen the nuts.

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 13:01

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Saab guy here, I swap wheels/tires couple times a year. Lining them up is easy but I’m sitting looking dead on at them. They hang on that little lip pretty well. Bolts are close by so they only rest a few seconds.

Schaef_Camaero Z/28 > Urambo Tauro 02/26/2018 at 13:04

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Straight on, facing the hub sitting indian style, wheel next to you. Then take the wheel and hold it roughly in place on the hub. Scoot forward just a bit and position your legs so they can support the wheel while you start a couple of the lug bolts. Or you could set the wheel on your lap first, then scoot forward and hold it in place.

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 13:05

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What keeps the new lug stud from backing out? Beyond the thread locker, it seems like they would back out. I don’t know how you would sufficiently torque the studs linked, they don’t seem to have any place to put a socket on them.

diplodicus > Urambo Tauro 02/26/2018 at 13:06

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I do the same thing, you’re facing the wheel straight on. Feet behind you with your knees down then you just prop the tire up on your knees and line it up and thread the bolts in. Textured soy proteins solution is definitely easier. It’s just never been enough of a pain in the ass for me to bother with ordering one.

I actually prefer the bolts myself. Don’t have to worry about the chrome plating swelling or coming loose like a lot of lug nuts. Never had one seize into the hub. Plus when you change rotors it’s way easier to clean off the hubs since they don’t have any studs in the way.

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 13:07

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I’m probably just spoiled by always having cars with studs that you can easily hang the wheel on. Anything else feels like a hassle. Ultimately, this car won’t be my problem, but I’m curious as to how affordable it could be to make it even easier.

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 13:12

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Those studs have a recessed hex in the end for tightening.

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 13:15

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I’ve snapped multiple hex keys when attempting to get to 100 ft-lbs of torque required for a given application. That is pretty close what wheels are torqued to.

That’s my worry, if you can’t torque them because you keep snapping hex keys, you are kinda screwed.

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 13:17

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Whatever time you spend making it easier will exceed the extra minute it takes to sit and slap them on. Think about all the time spent researching, buying, installing, tweaking......

Ssfancyfresh > Textured Soy Protein 02/26/2018 at 13:22

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That’s the right answer.

Keep the bolts. Use an alignment pin to assist in the rare occasion that the wheels come off

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 13:26

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Because racecar, bro! Who wants to deal with lug bolts during a pit stop? :)

Die-Trying > Urambo Tauro 02/26/2018 at 13:34

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large tapered punch to hold the wheel in place?.........

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 13:42

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Good point. These hexes look to be about 7 or 8mm. Not sure how much torque those keys can take, but this car calls for about 80 lb-ft at the lug bolts.

Future next gen S2000 owner > Urambo Tauro 02/26/2018 at 13:43

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That’s fair.

BigBlock440 > Future next gen S2000 owner 02/26/2018 at 13:53

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Do you snap these? Or is it just the L-shaped allen wrenches?

BigBlock440 > Urambo Tauro 02/26/2018 at 13:55

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I can’t understand what the advantage could be to lug bolts, studs are much easier.

Echo51 > Urambo Tauro 02/26/2018 at 14:00

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There’s aftermarket options for some cars, http://www.motoiq.com/MagazineArticles/ID/3283/Project-E36-M3-Part-2—Wheel-Studs-Motorsport-Bracing-and-Cup-Holders.aspx

Urambo Tauro > Echo51 02/26/2018 at 14:07

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Nice article, that’s pretty much what I was expecting the job to look like.

Urambo Tauro > BigBlock440 02/26/2018 at 14:08

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Well, price is one advantage. So far, it looks like a full conversion to studs and nuts at all four wheels would run close to $50. I don’t know if my brother can justify spending that much just to save himself some hassle.

Future next gen S2000 owner > BigBlock440 02/26/2018 at 14:08

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Something similar to that. I don’t have a big set of L shaped that I get use for accurate torque.

BigBlock440 > Future next gen S2000 owner 02/26/2018 at 14:17

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I would have thought they’d have been a bit better. You could also double nut the studs to turn them in though.

BigBlock440 > Urambo Tauro 02/26/2018 at 14:19

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No, I mean for a manufacturers’ perspective, why do they use them? I can understand not wanting to do the conversion (though I’d want to, or find an easier way), but I can’t understand what the advantage is to design the car with them from the start.

Urambo Tauro > Future next gen S2000 owner 02/26/2018 at 14:19

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Huh, so I guess they don’t need to be torqued down quite so much after all. The set used in this article calls for 30-35 lb-ft, and the listing for this set says 15Nm. I guess that threadlocker is even more critical than I thought. 

Echo51 > Urambo Tauro 02/26/2018 at 14:20

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Don’t listen to the naysayers. My car runs studs from the factory but i still want to murder whatever engineer skimped on that if i fix other people’s cars with bolts.

Twingo Tamer - About to descend into project car hell. > Urambo Tauro 02/26/2018 at 14:26

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Only one of my 5 cars have had studs, all the rest are bolts. You get used to hanging them on the hub and lining up the holes.

crowmolly > Urambo Tauro 02/26/2018 at 14:29

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I guess they are probably OK for most applications. I’ve just seen enough issues with regular studs to just be a bit skeptical and some stud conversion kits seem to be cheap hardware.

duurtlang > Twingo Tamer - About to descend into project car hell. 02/26/2018 at 16:02

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Exactly. All my cars have bolts. No issue whatsoever. The Mitsubishi I had had struts. The oddball. I hadn’t seen that before.

Twingo Tamer - About to descend into project car hell. > duurtlang 02/26/2018 at 16:23

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Only my Daihatsu has had studs, which ironically would be the easiest to mount wheels on, since they’re so tiny.

gmporschenut also a fan of hondas > Urambo Tauro 02/26/2018 at 20:34

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I had one of these. Wheel alignment tool. screw it into a thread, put wheel on. put 4 lugs in, remove tool, place 5 lug.

MM54 > Urambo Tauro 02/26/2018 at 20:48

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The RX7 has bolts, it’s not really an issue for me, sit facing the wheel, lift it into place, hold it with your foot while you start a bolt or two.

MM54 > crowmolly 02/26/2018 at 20:49

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If the studs are threaded into the hub and the lug nuts installed and torqued, the clamping force on the threads of the hub is the same as if the bolt was installed and torqued...

Rusty Vandura - www.tinyurl.com/keepoppo > Urambo Tauro 03/05/2018 at 12:49

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Personally? I wouldn’t bother. Never would’ve occurred to me to do so.