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I'm planning on installing 560SL factory 15" alloys on my '76 450SL

The original lug bolts will leave the head well below the surface of the wheel, and I'd like to avoid that look.

I'm aware that most of the cars that came with the later alloys had the 'extended' lug bolts that have the 'ball' halfway down the length, and the bolt extends (unthreaded) above the, raising the head so it is flush. But, I realize those bolts are prone to snapping off above the 'ball', making it impossible to remove the wheel.

I am searching for an alternative that still gives the 'flush' look, but doesn't have that problem.

I've seen a couple of Ebay listings with these bolts (apparently from a 380sl). Does anyone know if these had any issues (they don't look like they'd break), and whether they were OEM MB?

2605027


Another alternative I'm considering is aftermarket - I see a number of vendors selling chromed extended lug bolts that look very similar to the MB OEM, except (I think) they are slightly thicker in the part between the head and the ball (example here on ebay). Has anyone any experience of any brand that they would trust (or any they would recommend staying away from). I was considering LAWheel, but the link to their extended bolts seems to be pointing at the wrong page at the moment.

Thanks,
Steve
 

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I am going to go out on a limb and say the bolt in the picture was not OE on any Mercedes. Or any vehicle for that matter.
 

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Measure the shank below the ball on your 450. I think you fill find it is shorter than the 560 which is 40MM. I couldn't find my extra lug bolts for the early wheels.
 

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Discussion Starter #5
Measure the shank below the ball on your 450. I think you fill find it is shorter than the 560 which is 40MM. I couldn't find my extra lug bolts for the early wheels.
I've just measured. The original 450SL lug bolts, that held the bundts on, have 30mm below the ball (that includes both the threaded and unthreaded portion)

I believe the 'standard' 560SL extended bolts (for the 'man hole cover' wheels have 39mm below the ball (I found the diagram below elsewhere on the formum a while back).

I am assuming that the 560SL wheels will fit the 450SL without any issue, but with (based on ricks comment above) a slightly (10mm?) greater offset. Is this correct? I had bought a set of 560SL wheels very early on - but haven't tried them on the car yet (I just assumed they'd fit...)

I had also assumed that I should use OEM 560SL lug bolts with them, but reading about them breaking off has made cautious about using those, hence the search for an alternative lug bolt (and the original question about the '380SL' bolts I've seen listed. I've been looking for a new supplier of those.

If the 560SL wheels don't fit, I think I'm going to be digging out the credit card and looking for a set of 15" bundts, though some of the BBS 'basket' wheels look nice....

2605232
 

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The 560SL wheels will fit without a problem. Offset is 23 or 25MM compared with 30MM on your 450.. I could look tomorrow if you need it. They are also 1/2" wider so the offset is correct.
 

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Fixer
560 Manhole cover wheels can be installed on a 450 with no problems. See photo below of them fitted to my 76 450SLC, using the correct MB bolts. As mentioned they do have a different offset, but fit fine nevertheless.
Hope that helps.

2605238


2605239
 

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Discussion Starter #9
Fixer
.... And here are the wheel bolts that were used ...

Thanks for confirming the 560SL wheels will fit, and yes - I have a set of those lug bolts...but I became concerned over the last few days reading that they 'often' break off just above the ball, apparently due to the 'side loads' when tightening them and/or the over use of an air wrench. I'm trying to see if there's an alternative, that still gives the 'flush' look to the heads.

I've seen bolts listed (used) on ebay that have the hex head the full length above the ball (obviously stronger) - I'd like to find a set of those new, or at least in good condition, and LA Wheel appear to sell lug bolts that are a very similar to the MB bolts, but a little (not much) thicker than the threaded area.

-Steve

View attachment 2605241

View attachment 2605240
 

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Those extended lug bolts with mushroom 1/2 way down are known to break. And when they do, it's hard to get them out. Requires drilling. Those of with W210s know about this because of the failures that have been posted on W210 forums. Consensus is to change them. I seem to recall that Mercedes no longer offer them as a part.

I would not use these (my set are in my junk pile somewhere)


I bought these - they came off a C-class, I believe. There are aftermarket lugs that are a bit longer.

 

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I preemptively replaced the set I had on my W210 with ones that were recessed. The look isn't that terrible, and not having to destroy the wheel to get it off is a major advantage.
 

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The manufacturers torque specs are based on dry threads. No oil, no anti-seize. I clean bolts with a rag dampened with solvent. Threads in hub too if it looks like dirt may have entered from brake work etc. If you lube, you don't get the required torque. Not good.

The bolts do break. Why? Overzealous mechanics with powerful tools? Inherent design - long necked down bolt that requires to be at 80ft.lbs (or whatever) Regardless of the why, once they do, you have a big problem! I don't believe MB use/sell them anymore.
 

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I gotta be honest... in my over 50 years of working on cars, I have never once put a torque wrench on a lug bolt or nut and I have never broken a lug bolt or nut and never had a wheel loosen or fall off due to improper torquing. I'm sure there are good reasons for torquing the lug nuts or bolts to their prescribed values but my experience appears to indicate that close enough is good enough.
 

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I never dealt with a torque value for lug nuts before I got a Mercedes. Germans seem to think every fastener needs a torque specification. Still, it probably doesn't hurt to follow it.
 

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I agree... it probably doesn't hurt to torque lug bolts, but is it an absolute requirement? I tend to think not, although I do have a friend who insists on borrowing my dial indicator every time he does brakes on his disk brake equipped cars. He orients the rotor on the studs to produce the least amount of run-out. We're talking thousandths of an inch here. o_O

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I agree... it probably doesn't hurt to torque lug bolts, but is it an absolute requirement? I tend to think not, although I do have a friend who insists on borrowing my dial indicator every time he does brakes on his disk brake equipped cars. He orients the rotor on the studs to produce the least amount of run-out. We're talking thousandths of an inch here. o_O
I would imagine most of us older guys grew up without a torque wrench in our tool boxes. We usually didn't have access to manufacturer's shop manuals and maybe they too didn't specify bolt torques. Our cars probably didn't have disk brakes either. We probably had lug nuts instead of bolts? I am sure I recall broken studs!

When it comes to bolting, if you lubricate the threads, you need much less torque to achieve the design axial tension in the bolt. It is the axial tension that keeps the bolts tight. If you lube a lug bolt and then tighten it to 85 ft.lb., then you may be applying a much higher axial tension than required. It could be as much as 40% too high and result in damage to the threads or even a broken bolt if even higher torques are applied, as so often happens at tire-change shops. Unless oil was applied in exactly same way on all bolts, tension could vary. That is likely one reason why manufacturers specify dry torque. Too much possible variability in ways a bolt could be lubed.

I always use a torque wrench and clean and dry bolts. And make sure bolts are tightened evenly, especially on the type of disk brakes/hubs that later cars have.
 

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I would imagine most of us older guys grew up without a torque wrench in our tool boxes. We usually didn't have access to manufacturer's shop manuals and maybe they too didn't specify bolt torques. Our cars probably didn't have disk brakes either. We probably had lug nuts instead of bolts? I am sure I recall broken studs!

When it comes to bolting, if you lubricate the threads, you need much less torque to achieve the design axial tension in the bolt. It is the axial tension that keeps the bolts tight. If you lube a lug bolt and then tighten it to 85 ft.lb., then you may be applying a much higher axial tension than required. It could be as much as 40% too high and result in damage to the threads or even a broken bolt if even higher torques are applied, as so often happens at tire-change shops. Unless oil was applied in exactly same way on all bolts, tension could vary. That is likely one reason why manufacturers specify dry torque. Too much possible variability in ways a bolt could be lubed.

I always use a torque wrench and clean and dry bolts. And make sure bolts are tightened evenly, especially on the type of disk brakes/hubs that later cars have.
Everything you said is true... but we are left with the fact that virtually no one I know actually bothers to torque lug bolts (or nuts). Does it matter? Probably. But does it matter enough to be a problem? Probably not. :)
 

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Actually, Jyuma, these days places like Discount Tire are very careful to use torque wrenches and set the proper torque. It's lawyerbane.
 

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Actually, Jyuma, these days places like Discount Tire are very careful to use torque wrenches and set the proper torque. It's lawyerbane.
Here in Canada same is true. Even stores like Canadian Tire (affectionately known as Crappy Tire) check torque after installing wheels. I often had them install/uninstall our snow tires and could watch them through an observation window. They appeared to have a book that they referred to for proper torque. No matter, I didn't trust them, so would double check when I got home.
 
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