Discount Tire ******!!!...Over

[cnynrat]

Well you are correct, I was referring to the first picture.

And I apologize for not reading the thread correctly, but still, in the second picture, if you are spacing out your wheels THAT FAR that you need to bolt the spacer onto the old lugs and then need new lugs for the wheel to bolt to; then that also seems really unsafe to me!!

Again, no proof, or examples of it, but that just doesn't seem like the RIGHT way to gain the look you want, or the clearance for wider tires!

It's not necessarily the thickness of the spacer that drives this design solution, it's how close the two bolt patterns align with each other. If they overlap, or are close to overlapping you need to go to this type of two piece solution. That does increase the minimum thickness - I think to 1" or so, but that may vary from one manufacturer to another.

 

[Pskhaat]

One thing to employ spacer/adapter for a wider stance/look/whatever. Another to employ spacer/adapter to correct for the OEM wheel/tire offset and/or KPI. Doing the napkin statics/dynamics I can't necessarily see where a lug-centric wheel adapter putting a wheel/tire into the proper OEM KPI &| offset would be of concern. Can anyone comment?

Seif1, PM me if you want a reference to top-notch tire service guy in the Phoenix valley.

 

[getlost4x4]

i had 1.5" spacers on my Commander for 2 years. I wheeled it hard and put 50K miles on the spacers and tires.

NEVER ONE PROBLEM.


the people who have problems are the ones who do not read the directions and install these parts incorrectly. they have to be installed correctly or they will fail. i've never seen one set fail, i've never seen one set fail that was installed correctly.

go take a look at new mercedes cars. they all have factory spacers built into the brake rotors.

 

[modelbuilder]

Thank you for being a voice of reason....spacers are safe all the way.

 

[DrMoab]

The place I bought my spacers from build them for drag cars that push in excess of 1000HP. If they can handle it running them on a Jeep shouldn't be an issue.

Another thing. We really should get the terms right. A spacer and an adapter are two separate things. We are having a conversation about adapters.

 

[inked33]

Did yours come from the factory with spacers? Apparently there are some late model Dodge pickups with OEM spacers that Discount will service...

no mine are aftermarket i didnt know dodge put wheel spacers on some of their trucks.....maybe the techs think mine came that way from the factory if thats the case

 

[modelbuilder]

The place I bought my spacers from build them for drag cars that push in excess of 1000HP. If they can handle it running them on a Jeep shouldn't be an issue.

Another thing. We really should get the terms right. A spacer and an adapter are two separate things. We are having a conversation about adapters.

Very true...

 

[BigAl]

:safari-rig: Still safe even if they don't look it. The ones in the second picture are similar to what I have...spidertrax...proven safe and never met anyone that had a problem.

You keep demanding proof and only offer anecdotal evidence yourself. Generally for any regulated product, it's up to the manufacturer to prove that it is safe for use. Is not up to the public to prove that tylenol is unsafe. If the manufacturers of these spacers say they are safe for the street, the tire shop should not have a problem.

However if you just want your tires rotated and you know you are in a grey area legally, just do it yourself????

 

[Martyn]

You keep demanding proof and only offer anecdotal evidence yourself. Generally for any regulated product, it's up to the manufacturer to prove that it is safe for use. Is not up to the public to prove that tylenol is unsafe. If the manufacturers of these spacers say they are safe for the street, the tire shop should not have a problem.

However if you just want your tires rotated and you know you are in a grey area legally, just do it yourself????

I think within what you have said lies the truth. The company who manufactures adapters makes them with the intention they are used on the road.

However if a wheel comes flying off when the vehicle is driving down the road the legal blame is cast across the vehicle manufacture, the spacer manufacturer, and the company who fitted the tires. The fact that the adapter came off the hub because the owner may have not tightened the adapter nuts to the specified torque is irrelevant.

What we are witnessing here is Discount Tire protecting themselves from what they see a frivolous law suites brought against them by drivers who use adapters.

The most common cause of adapter failure is incorrect installation, where the nuts holding the adapters in place back off and eventually the adapter falls off. This is followed by mechanical failure of the adapter itself. Mechanical failure does happen, but it is much less common than incorrect installation.

 

[BIGdaddy]

I just ran to work holding a pair of scissors.

just fyi.

 

[MotoDave]

As a mechanical engineer that works in the aerospace field, including performing stress and fatigue analysis, I think the use of wheel adapters definitely requires diligence and some careful thought. My gut feeling says I wouldn't run a set on my daily driver, but they have their application.

ANYTHING that is made from Aluminum and is subjected to cyclic stresses will fail from fatigue eventually. That is a hard fact, there is no disputing it. A correctly engineered part will have this failure point well beyond the life span of the part. An example from my current job would be a pump housing desired life span being in the range of 100,000 cycles, I would design the part so that the failure point comes at 300k+ cycles, possibly more depending on the part and how well known the actual stresses in the system are. Fatigue life is also drastically reduced with increased temperatures, especially with 6061 material.

Now I've never seen a 'useful life limit' called out for a set of wheel adapters. My gut feeling, looking at the design, is that the nature on the part leads to some areas of high stress concentration, which are the killer when it comes to fatigue. If I were ever to run a set I'd probably impose some life limits on myself, such as treating them as a serviced component and replacing them every 30-50k miles. If they were used on a primarily off road vehicle, or something that is rarely driven, I'd be more inclined to use them, as you're not putting nearly the number of cycles into the part as high speed daily driving.

Anyways, as with anything on the internet you can feel free to discard my opinions and form your own, but that's my two cents for the day.

 

[DrMoab]

Do you feel the same way about aluminum wheels?

 

[MotoDave]

I don't think wheels have nearly the same stress concentration points that a wheel adapter does, but yes, I do think any Al wheel will have a fatigue limit.

Edit: I guess this thread has gotten off topic somewhat. Think about what you would do if you ran an independent shop and someone came in to you with ANY modification that you were unsure about. If you do the work they want, and the part fails later, there's a damn good chance in today's society you'll be sued, have to close up shop, and lose what you worked hard for. If I were a business owner I know for damn sure I would play it on the safe side, even if that meant turning away potential business.

 

[Photog]

This should be fun. I will throw my engineering education at this one also.

It is true, that aluminum has a finite fatigue life. If aluminum has cyclic forces flowing through it, it will eventually break. Aluminum can not be designed strong enough to escape this issue. But these forces have to be cyclic in direction.

The key point here is the forces must cycle in multiple (at least two) directions, through the material. Forces flowing stronger and weaker, in the same direction is not going to cause the same fatigue problems.

At first glance, these adapters may seem to have cycling forces running through them. This may not actually be true. Here is why. There is a tremendous compressive force being placed on the aluminum adapter, when the lug nuts are tightened down to 80 ft-lbs. For the forces to cycle, the loads on the adapter must overcome this compressive force, and create a force in another direction. Again, aluminum will not crack from fatigue, if the forces are stronger/weaker, but always in the same direction.

The two faces of the adapters have compressive forces placed on them, with the torquing of the lug nuts. One set is clamping the adapter to the hub, and the other set is clamping the wheel to the adapter. There is at least a 1/4" thick section of the adapter that is trapped between the lug-nut-seat and the stud seat. This 1/4" this piece of material is also being compressed by the lug torque forces.

Unless these compressive forces can be unloaded some how, it will be very difficult to change the direction of force through the adapters. The compressive forces may increase and decrease; but they should always be compressive, and therefore not cyclic.

Serious problems would arrise, if any of the lug nuts is not maintaining proper clamping force. Say 50 ft-lbs instead of 80 ft-lbs of torque. The clamping force and therefore the lug torque must be maintained.

These torque and force ideas are the same principles applied to aluminum heads, connecting rods, etc. This is nothing new, and well understood in the automotive industry.

Just another aspect to think about.

 

[MotoDave]

Sorry but that isn't accurate. I agree that the forces in a correctly installed wheel adapter isn't going to cycle from compression to tension and back (alternating stress). The wheel adapter is subjected to fluctuating stress, meaning a stress fluctuating around a mean value. Think about how a valve spring works, it is always under a preload, but sees fluctuating loads around this mean value. Fluctuating stress can definitely cause fatigue failure, the difference between max and min stresses is more important than whether the stress is alternating or fluctuating.