Thought this was interesting as it covers some of the questions that crop up on here from time to time.
View: https://youtu.be/hWijfooeSyU
Wheel Spacers & Adapters - Good Or Bad?
- Thread starter GazHyde
- Start date
Had mine on a few months now with no problems at all. Check the torque settings regularly and they've never moved.
Interesting Gary thanks. I wonder if using wheels with different to standard offset has the same effect?
It's definitely worth browsing his channel as he's done quite a few interesting vids. There is one somewhere where he talks about exhaust systems too.
Not all of what he says is applicable, but for a basic easy to understand tutorial they are pretty interesting.
Not all of what he says is applicable, but for a basic easy to understand tutorial they are pretty interesting.
Using this guy's thinking Brian, it must. All fairly common sense really. Educational info for those who need it.
Tony.
I with Tony on this, different offsets will do the same thing, it would be interesting to know the acceptable tolerance BMW built in. I use spacers on my car (no bigger than 12mm) but use a stud and nut kit, personally not a fan of the bolt on big spacers, don't know why but they just do not sit right in my head.
I use 20mm rear hubcentric ones i think in theory a hubcentic spacer because of its design is similar to a deep wheel hub.
The studs are longer but they bolt in the same distance as stock and as they are hubcentic no force is applied to the studs other than to hold it on.
Short of them being loose they react as stock.
Agree that in the video a spacer would be the same as a wheel with a different off set.
The studs are longer but they bolt in the same distance as stock and as they are hubcentic no force is applied to the studs other than to hold it on.
Short of them being loose they react as stock.
Agree that in the video a spacer would be the same as a wheel with a different off set.
Z
zedonist
Guest
Couple of points for me, the Z3 does not have double wishbone suspension, so the effect will not be present. Secondly the bearings will only come under increased loading if the tyre / wheel sits outside of the bearing, when fitting spacers for larger wheels the weight of the wheel is more or less where it was in the OEM position with the oem wheel.
The key thing with spacers is to ensure the joint is torqued correctly to negate loosening of the joint, 99% of joints fail because they are loose or become loose, that is why bolt on spacers are preferable to slip on spacers, as they maintain joint integrity, slip on spacers adds two extra joint faces and you will need extra torque to hold the joint firm. You also need the correct bolts to achieve the correct torque, both in mechanical properties and surface finish.
Lastly never over torque bolts as you will induce permanent set into them, and the joint will come loose as the bolt continues to stretch under load. Use recommended torque figures where ever possible.
The key thing with spacers is to ensure the joint is torqued correctly to negate loosening of the joint, 99% of joints fail because they are loose or become loose, that is why bolt on spacers are preferable to slip on spacers, as they maintain joint integrity, slip on spacers adds two extra joint faces and you will need extra torque to hold the joint firm. You also need the correct bolts to achieve the correct torque, both in mechanical properties and surface finish.
Lastly never over torque bolts as you will induce permanent set into them, and the joint will come loose as the bolt continues to stretch under load. Use recommended torque figures where ever possible.
Agree with those comments Rich, that's why when I fitted mine the Carweb system rated BMW Z3 wheels bolts @ 110 - 130 NM, so I used the upper limit as opposed to the lower one without spacers. Slip on spacers don't add an extra joint but they do then rely on one fastener holding two joints together, whereas the bolt on ones have two bolted joints.
Each to their own for peace of mind, I'm happy with my type and they remain torqued correctly.
Tony.
Each to their own for peace of mind, I'm happy with my type and they remain torqued correctly.
Tony.
We see that when over torqued equipment comes back from the rigs, we call it "belled box" on the female connection and "raised shoulder" on the male connection, the equipment can be scraped if a re-cut is not an option as you don't want stuff falling down a well, just as you would not like to see your wheel come off your car.
The least loading on bearings is with a zero offset so the tyre is centred over the bearing. Most wheels have a large offset which pushes the wheel nearer the diff so more of the tyre is inwards of the bearing. Spacers usually have the effect of bringing the offset closer to centre putting less leverage on the bearing than the original wheels
Also I use bolt on Spacers now as I feel they are stronger than the extended bolt version.
Hub centric may help with the weight of the car being carried on the spigot, but it does nothing to stop the rotational forces which are greater with longer bolts.
If you bolted your wheel onto a 1 metre wide spacer, 5 x 1 metre long bolts screwing 12mm into your hub threads,
loosen every bolt slightly then try and do a fast start and see how easy it is to rip out those threads out. that is what worries me about standard spacers with longer bolts.
Compare the rotational deflection in the long bolts versus doing the same with bolt on spacers and two sets of short bolts,
I bet by turning the wheel hard enough I could rip the threads out easier with the long bolts than I could do with the bolt on version.
I am not talking about shear forces on the csa of the bolt itself, I am talking levering the threads out.
I have just fitted these steel versions, I wouldn't fit bolt on aluminium as the holes can rip out around the bolts.
Also I use bolt on Spacers now as I feel they are stronger than the extended bolt version.
Hub centric may help with the weight of the car being carried on the spigot, but it does nothing to stop the rotational forces which are greater with longer bolts.
If you bolted your wheel onto a 1 metre wide spacer, 5 x 1 metre long bolts screwing 12mm into your hub threads,
loosen every bolt slightly then try and do a fast start and see how easy it is to rip out those threads out. that is what worries me about standard spacers with longer bolts.
Compare the rotational deflection in the long bolts versus doing the same with bolt on spacers and two sets of short bolts,
I bet by turning the wheel hard enough I could rip the threads out easier with the long bolts than I could do with the bolt on version.
I am not talking about shear forces on the csa of the bolt itself, I am talking levering the threads out.
I have just fitted these steel versions, I wouldn't fit bolt on aluminium as the holes can rip out around the bolts.
Fair comment, however how thin can you go with that type of spacer and still have enough thread to maintain a secure joint, ie thread depth?
Tony.
ps. I wouldn't fit bolt on alloy ones for that reason either. I don't think a properly torqued bolt with a correct taper for the seat in the wheel will allow any "spin" unless the bolts bend. I don't see that happening to be honest.
Tony.
ps. I wouldn't fit bolt on alloy ones for that reason either. I don't think a properly torqued bolt with a correct taper for the seat in the wheel will allow any "spin" unless the bolts bend. I don't see that happening to be honest.
Z
zedonist
Guest
You need 1 and half times the diameter of the bolt for correct thread engagement minimum, as they are M12 that is 18 mm, so minimum spacer depth is really 20mm allowing run out of threads. You could go thinner by using the stud type such as @Brian H, on these the stud is held captive from the rear via a cheese head and knurled spline arrangement.
The number of joint faces is really important, on the bolt on ones you mirror the same application as oem and you only have two joint faces which is the minimum and best case scenario, the number of bolts and the torque has been calculated to ensure enough clamp loads exists that the joint faces do not move once tightened. However on the slip on type, you have added another two joint faces. The clamping force to prevent this joint moving will be a lot more than the original joint, and hence the torque applied to each bolt will need to be increased, and this is the Unknown, as it has not been calculated. Using the original torque may cause the joint to become loose. Best to avoid the situation in my opinion.
The number of joint faces is really important, on the bolt on ones you mirror the same application as oem and you only have two joint faces which is the minimum and best case scenario, the number of bolts and the torque has been calculated to ensure enough clamp loads exists that the joint faces do not move once tightened. However on the slip on type, you have added another two joint faces. The clamping force to prevent this joint moving will be a lot more than the original joint, and hence the torque applied to each bolt will need to be increased, and this is the Unknown, as it has not been calculated. Using the original torque may cause the joint to become loose. Best to avoid the situation in my opinion.
Which, as I said, is why I use the higher torque figure. I still can't see where using slip on type spacers adds two "more" joint faces though Rich, surely it's only one more. I agree with your comment about avoiding it by not using any but that's just down to personal choice.
Just as a matter of interest, has anyone one here who uses spacers ever lost a wheel through bolts coming loose?
I don't hear many people saying that they have and spacers are a bad idea!
Tony.
Just as a matter of interest, has anyone one here who uses spacers ever lost a wheel through bolts coming loose?
I don't hear many people saying that they have and spacers are a bad idea!
Tony.
I very nearly lost both back wheels Tony, on a trip earlier this year i had a terrible noise coming from the rear of the car, I thought I had ripped the diff out, turned out that the previous nights spirited run had backed off the nuts. On inspection I lost 2 wheel studs and the remaining nuts were loose
.With all that said I do take 100% blame for this though, I am usually so meticulous when it comes to using the torque wrench, I guess I just missed it this time.
When I started track days I used to take off the spacers due to fears of failure etc. I now just leave them on, I see stacked spacers up and down the pit lane!
Z
zedonist
Guest
Each face counts as 1, so face of the hub and face of the wheel equals two, the clamp load stops these two faces from slipping against each other and vibrating the bolts loose, using a slip on spacer adds two more joint faces, so hub to spacer (2) and spacer to wheel (2). The later joint requires more clamp load to prevent it coming loose.
When I say loose, you would not be able to detect it by eye, or by shaking the wheel, it is at the micro level, see the link to a video below:
View: http://youtu.be/YRYYWQKh-bU
Under tightening is number 1 cause of joint failure when all parts are quality assured. You also need to ensure that all joint faces are dry and free of grease as this can lower the coefficient of friction of the surfaces and allow the joint faces to slip.
In the video, you see the nut coming loose, in real life on a wheel, the wheel does become loose once the bolt is loose and then you get bending moments, that lead to either fatigue failure of the bolt or the spacer being ripped apart. But the cause will have been under tightening,more in some cases over tightening passed the capability (elasticity) of the bolt.
When I say loose, you would not be able to detect it by eye, or by shaking the wheel, it is at the micro level, see the link to a video below:
Under tightening is number 1 cause of joint failure when all parts are quality assured. You also need to ensure that all joint faces are dry and free of grease as this can lower the coefficient of friction of the surfaces and allow the joint faces to slip.
In the video, you see the nut coming loose, in real life on a wheel, the wheel does become loose once the bolt is loose and then you get bending moments, that lead to either fatigue failure of the bolt or the spacer being ripped apart. But the cause will have been under tightening,more in some cases over tightening passed the capability (elasticity) of the bolt.
There's my point exactly Brian, you have to torque the wheel bolts correctly. So now you leave them on all the time, is that because you feel that they will be ok or that in a track environment it's not so critical if you loose a wheel? I assume that when you say you see stacked spacers up and down the pit lane, that means people still take them off because they don't trust them either, but then they're happy to trust them on normal roads.
Tony.
Tony.
The other thing not mentioned is that I am now using 10 bolts to hold a wheel and spacer rather than just 5 longer ones