rfn026

Here's a really new SAE paper on wheels. If you're serious you need to learn about this stuff. Yes, wheels do wear out.

Every wheels bends. Every wheel is really a spring. When Bilstein builds you a set of shocks they need to know what wheels you're using since that's part of the spring rate.

The really bad part is that there is not precise fatigue limit for aluminum.

Enjoy the article.

Richard Newton
Historic Racing Images

froggy47

Well I scanned it just to figure out whether I would understand it or not, I won't.

Who wants to do an executive summary for us?

drivinhard

I got to spend some time at Finspeed for a couple of days back in the summer, and learned more about wheels in 2 days than the previous 20 yrs.

Bill Dearborn

Well the first thing that needs to be done is to have a tech writer go over it to correct the English. The second is to take a couple of courses in mechanical design and strength of materials along with a course in FEA. Then you are ready to read the paper.

This sounds like it will eventually result in a new chapter in an updated version of:
To Engineer Is Human: The Role of Failure in Successful Design


Bill

parsonsj

Exec summary: using advanced engineering techniques, a wheel was reduced 50% in mass without any significant loss of strength or increase in stress.

As Bill indicated, the paper was pretty rough, English-wise. Lots of good information, but much of the dot-connection between the tech information was left to the reader.

It needs a glossary, some organization, and more effort in smoothly describing the experiments and the data.

Matt_27

Yeah they reduced the weight from a solid wheel by making it spoked. Wow! I didn't see anything about race wheel tech in there. Camber and toe compliance under cornering loads is important to know and they could easily have shown that in that paper but they don't care since they were designing it for an SUV.

froggy47

Would it not be true, that almost any part on a vehicle, or on anything, could be lightened without sacrifice to strength or function, given the engineering & manufacturing & money to do it.

From the **** on a radio, to a pedal, to the glass, etc.



But still, I like these techy papers even if just to make the brain work a little harder.

0Anthony @ LGMotorsports

I have not looked through the paper, but I can tell you that those of us in the racing world do look at our wheels, and most of them will be checked for cracks at the end of the season, unless we have data that says they need to be done before hand.


With wheels getting lighter, and thinner....of course they are going to take more of a hit the more G's a car can pull, the stronger the tire, the more aero....it puts a lot of load out there and most of us don't think to much about it.

If you want to go to the extreme's.....if I remember correctly the F1 teams are changing wheels every other tire mounting...or they might be doing it every tire mounting because the stress of putting the tires on and off the wheels combined with what the car puts them through is to much for them and they have to cycle the wheels out that quickly. Again...I'm going off memory here so correct me if I'm wrong on this.

Most of us don't have to think about it, because the wheels we use day in and day out are over engineered with enough factor of safety for most not to worry about (notice I say 'most').

If you get right down to it, on a race car, everything has a life....even the frame of the car. Wheels are no different.

fatbillybob

Good point! I wonder why we racers don't factor in the spring rate of the tire and its effect on overall wheel rate. Compared to the tire the wheel is like an unbending iron tablet.

froggy47

The Continental (Hoosier) slicks come with spring rate @ pressure marked on the mfg label.