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I haven't heard of it happening, but this isn't the first time that a Lotus rep has brought this to our attention. There is a past thread concerning this as well.
Possibly there is something to this......why else would they make a big deal out of the BMW wheelbolts?
 

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Discussion Starter #82
pianomaniac said:
I haven't heard of it happening, but this isn't the first time that a Lotus rep has brought this to our attention. There is a past thread concerning this as well. Possibly there is something to this......why else would they make a big deal out of the BMW wheelbolts?
All car companies do the same; stay stock is the mantra. They also don't like many other common mods.
 

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Stan said:
All car companies do the same; stay stock is the mantra. They also don't like many other common mods.
that's kinda what i thought also - but dave and the service guys at SVAG seemed like they wanted to swap the lugs out right there.
 

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vortrex said:
why would wheel bolts used on another performance car, that weighs 1500 lbs more than the elise, break?
good question, i'd like to know the answer also! today, my elise is in for 7500 mile service at SVAG. I just got a call, they are refusing to complete the service because I have the BMW bolts on! I talked with the service advisor for a bit, and they are going to discuss it further and call me back. this is ridiculous.
 

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Discussion Starter #88 (Edited)
Surferjer said:
What a load of BS. Yet another reason to do your own servicing...
Lots of shops are all PC and lawsuit-phobic. Around here several tire chains will not service a car without the exact tire sizes that come stock. Gone larger? Go elsewhere. An Elise with 245s out back? Bye bye. Same thing if you have spacers. Hmm..well some Porsches come with them STOCK. And many aftermarket ones such as H&R are TUV approved for Autobahn use. No, sorry.
 

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bmw bolts

I purchased the black bmw bolts from bavarian auto what ever, the quality seem excellant, but I feel that they tend to loosen up more than the factory bolts. (explaination) I ran the car on the track with my ssr and 048 with the lotus factory bolts, and locks, set to 77-78 ft lbs, never had any issues, I switch to the bmw bolts for easy of service, no stripping only one tools etc, I notice after cooling down the lugs had to be tightened more often than the old lugs, I would after each track session let the wheels cool, and re torque before the next session, and yes one or two lugs on each wheel would be less than fully torqued. Now this might be due to the heat then cooling of track conditions, but as a precaution , I now check everytime I go out for a session, I do not know if it is the ssrs or the lugs. probably a good habit anyway.
 

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Around here several tire chains will not service a car without the exact tire sizes that come stock. Gone larger? Go elsewhere. And Elise with 245s out back? Bye bye.
I never take the car in. I just haul in wheels and tires. "Mount and balance these, please!" The local shop guys LOVE mounting race rubber for some reason. But they always want me to bring the car around later. :)
 

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MitchT said:
I purchased the black bmw bolts ...but I feel that they tend to loosen up more than the factory bolts. (explaination) I ran the car on the track with my ssr and 048 with the lotus factory bolts, and locks, set to 77-78 ft lbs, never had any issues, I switch to the bmw bolts for easy of service, no stripping only one tools etc, I notice after cooling down the lugs had to be tightened more often than the old lugs, I would after each track session let the wheels cool, and re torque before the next session, and yes one or two lugs on each wheel would be less than fully torqued. Now this might be due to the heat then cooling of track conditions, but as a precaution , I now check everytime I go out for a session, I do not know if it is the ssrs or the lugs. probably a good habit anyway.
That is very very worrying:eek:
 

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Discussion Starter #92 (Edited)
MitchT said:
I purchased the black bmw bolts from bavarian auto what ever, the quality seem excellant, but I feel that they tend to loosen up more than the factory bolts. (explaination) I ran the car on the track with my ssr and 048 with the lotus factory bolts, and locks, set to 77-78 ft lbs, never had any issues, I switch to the bmw bolts for easy of service, no stripping only one tools etc, I notice after cooling down the lugs had to be tightened more often than the old lugs, I would after each track session let the wheels cool, and re torque before the next session, and yes one or two lugs on each wheel would be less than fully torqued. Now this might be due to the heat then cooling of track conditions, but as a precaution , I now check everytime I go out for a session, I do not know if it is the ssrs or the lugs. probably a good habit anyway.
Mitch, you should ALWAYS retorque before each session. Check oil. Check tire pressures. Exaimine tire treads, especially the outer edges. Glance at the pad thickness. Make sure coolant level is normal. Etc.

This has nothing to do with the bolts. If you don't retorque after sessions the alloy wheels compression yield. Aluminum gets softer with heat. That is, the bolt did not unwind itself. Rather, that which it was fastening moved/squished. All alloy wheels do this. If you have your car serviced and only drive on the street you should still retorque a time or two until the readings stabilize. After a day or two and about 100-200 miles they will stay steady. Normal.
 

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Stan said:
Mitch, you should ALWAYS retorque before each session. Check oil. Check tire pressures. Exaimine tire treads, especially the outer edges. Glance at the pad thickness. Make sure coolant level is normal. Etc.

This has nothing to do with the bolts. If you don't retorque after sessions the alloy wheels compression yield. Aluminum gets softer with heat. That is, the bolt did not unwind itself. Rather, that which it was fastening moved/squished. All alloy wheels do this. If you have your car serviced and only drive on the street you should still retorque a time or two until the readings stabilize. After a day or two and about 100-200 miles they will stay steady. Normal.
He is stating that he has noticed a difference between the Lotus supplied bolts and the BMW ones.
 

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Stan,

I do check every time I do a session, the point is , and I understand that alloy expands and contracts, the factory lotus bolts stayed tourqued to spec and I do not know why. Fastliz and I run our cars together alot, I check my wheels after each session, one or two loose lugs, (ssr/bmw bolts) Fastliz car, lls wheels factory bolts his do not get loose. I do not know why. I origanally thought I was not making them tight enough, but I checked with two other wrenches.
 

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Apparently the part number for silver bolts is really bronze. Does anyone know the correct part number for the BMW bolts in silver? There is one in pelican that says gold cadmium plated which does not sound like a match for LSS wheels.
 

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update - SVAG called Lotus for advice on the BMW bolts on my elise. They will complete the service, but I will be getting a "safety warning letter" from Lotus / SVAG now. I guess this is just to cover them from a legal point of view.

They also clarified, there has not been any cases of the BMW bolts "sheering off". (Not what I was told before...) Apparently, they just loosen over time easier than the stock bolts do. (like previously mentioned in this thread.)
 

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The service guys at SVAG haven't hassled me about my BMW bolts. Maybe they can't see them because they are black like my wheels :)
 

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Discussion Starter #98
MitchT said:
Stan, I do check every time I do a session, the point is , and I understand that alloy expands and contracts, the factory lotus bolts stayed tourqued to spec and I do not know why. Fastliz and I run our cars together alot, I check my wheels after each session, one or two loose lugs, (ssr/bmw bolts) Fastliz car, lls wheels factory bolts his do not get loose. I do not know why. I origanally thought I was not making them tight enough, but I checked with two other wrenches.
Wheel bolts holding alloy wheels on don't actually back out or unwind or whatever. That which they are compressing, yields. So if a bolt needs to be retorqued, it is not that the bolt unwound itself. I retorque bolts all the time on wheels that have been changed. By all means use what you prefer. If you want the strongest, most reliable approach, convert to studs of adequate length and thread engagement for the use. Which are also not Lotus approved.
 

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Discussion Starter #99 (Edited)
MitchT said:
Stan, I do check every time I do a session, the point is , and I understand that alloy expands and contracts, the factory lotus bolts stayed tourqued to spec and I do not know why. Fastliz and I run our cars together alot, I check my wheels after each session, one or two loose lugs, (ssr/bmw bolts) Fastliz car, lls wheels factory bolts his do not get loose. I do not know why. I origanally thought I was not making them tight enough, but I checked with two other wrenches.
Wheel bolts holding alloy wheels on don't actually back out or unwind or whatever. That which they are compressing, yields. Squishes out. Like if you shook someones hand only it was made of jello. Therefore the tension on that bolt, the stretch, is lost. You regain it back by retorquing. So if a bolt needs to be retorqued, it is not that the bolt unwound itself. If a bolt is not properly tensioned / torqued then things are not safe/stable and the bolt will experience premature fatigue failure at some point. I retorque bolts all the time on wheels that have been changed. Change a wheel back to your street stuff after an event? Well then retorque once or twice when you get home or the next day and you'll often find some that need it. By all means use what you prefer.

Suppose you retorque before a run on the track. You are out there for 20 minutes and the brakes and others things get hot. The wheel gets hot, mostly in the hub area. The alloy wheel expands a bit. But the wheel bolt holds steady. The tension on the bolt remains fine. That tension is the thing you want...the torque is just an indirect way of measuring it. Now when you pull in after a cool down lap and park, the whole deal cools off. It's common to lose some tension at the wheel fasteners due to the wheel itself compressive yielding (squishing). When the wheels cool off they get smaller. Get the situation? If you check right after you come in, most likely all will be fine. Check an hour later before your next run and they may not be. So you run around the bolt circle with your handy torque wrench..click-set to the desired figure. The whole car is done in maybe 2 minutes.

If you want the strongest, most reliable approach, convert to studs of adequate length and thread engagement for the use. Which are also not Lotus approved.

Also note that you might be seeing a difference between the wheels themselves. SSRs are not really forged they are semisolid forged. Sorta in between most cast and most forged in strength/toughness. The LSS wheels are true, real forged wheels and are stronger than they'd be were they semi solid forged. Forgings also tend to keep more of their strength when they are hot compared to lesser wheels. Soo what you may have seen is that the forged wheels are stronger, at least in the hub area. Forged wheels are formed by more or less squishing the aluminum into particular shapes under immense pressure from the forge. The forged material is denser than cast alloy. And it conducts heat through itself better too. It's more squish resistant, more likely to hold the torque.

EDIT: I looked for some strength comparisons for different wheels but found little useful information. I did find some mfr claims that the material in forged wheels is often about twice as strong as that in cast wheels.
 

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hello guys,
i work for a bmw dealership .. an in all these yrs i have worked for them i have never seen any seared off bmw bolts if TQ right... so that is bs!
henri
 
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