Wheels as Wear Items
“Wheels are metal,” Weiss continues. “They’re not magic.”
No matter the construction technique, a wheel in use continuously encounters stresses. Every acceleration, every braking, every turn and every bump adds up to a nonstop barrage of forces.
Then add in the forces encountered every time tires are mounted and dismounted, plus each time the wheels are bolted and unbolted from the hub.
“Those little impacts continuously work that metal,” Weiss continues. “Then a Big Bang will send it over the edge.”
And that Big Bang can cause a major wheel failure–and often leave a bewildered driver. Did one impact just knock a wheel out of contention? Likely, Weiss explains, it might have been a death from a thousand cuts.
What Stresses Wheels?
Then add in the additional stresses found in motorsports.
Sticky tires? Additional stress.
High g-load turns? Additional stress.
Fast pitstops involving impact tools? Additional stress.
Banging over curbs in order to tighten a turn? Additional stress.
Lower profile tires that minimize the cushion from road hazards? Additional stress.
“When tracking the car, be conscious that you’re working your wheels really hard,” Weiss says, adding that the load ratings assigned to each wheel are based on a static car. They don’t take into account hanging two wheels in the air. Or curb checking. Or contact with another car.
For a perfect storm, Weiss says, picture the leverage exerted by a tall, sticky slick fitted to a smaller wheel on a powerful drag tire. When the light turns green, the wheels are placed under enormous stress.
How to Inspect Wheels?
“What are you doing to inspect this wheel?” Weiss asks, adding a big take-home message: Be aware that wheels are a wear item–especially when subjected to severe use–and develop some kind of inspection schedule.
That schedule can be rather simple, he continues. For a street car, periodically look over the wheels–say whenever you’re stopping for gas.
Any curb rash? Do the lips look misshapen? Regularly look for obvious signs that hints towards a big impact.
Do you have a second set of wheels and tires for autocross or track events? Take a few minutes to clean and inspect the wheels–front and back–when swapping over.
Photography Credit: Christina Lam
Make that inspection part of the routine. Give the wheels a good wash and take a few minutes for a full visual look-over.
Methodically inspect the entire wheel: lips, barrel, spokes and center section. Are any little cracks manifesting? Do the lug seats still look fresh?
Are you road racing, running stage rallies or tracking a car with a lot of aero? Those situations can put even more stress on the wheel, so maybe perform even deeper inspections on a tighter timeline–again, Weiss stresses, make it part of a routine. The goal, as before, is to spot small issues before they become big ones.
Did you have a big off lately, perhaps one that dragged the wheels sideways across the infield? Rub wheels against those from another car while going side to side? Encounter a rougher than usual rally stage? Again, inspect the wheels–and this time, ideally, do it as soon as possible.
Two relatively easy ways to make a deeper inspection: DIY crack testing can be done at home with a dye penetrant kit, while a bare wheel can always be checked on a balancer. The unmounted wheels likely won’t spec out to zero, Weiss notes, but if it’s calling for a lot of weight, you might have a problem that warrants further inspection.
“Don’t treat them as a set-it-and-forget-it-type of part,” Weiss says of wheels. Be conscious of their use and keep a regular eye on them.
