Installed BDS control arms. Need some support please

[ThumperF150]

I’m running 35x11.50 tires on stock +44 mm offset wheels with JBA UCAs. My tires rub the front portion of the UCAs at full lock and only at full lock. I have added 3/8” spacers which is the absolute max I am comfortable with using my stock lug bolts.

The spacers helped but my tires still kiss the UCAs at FULL lock but no other time.

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[HammaMan]

I've shared this vid a couple times but it's important to understand what's going on especially with 'thicker' tires (more distance between ID (rim) and OD). It's not so much that it's touching because of lock, but touching because the deflection of the tire under cornering forces. However there is a component of camber gain at play as well and that varies between differing suspension geometry. You can see this when you turn the wheel to full lock and the tire's angle noticeably changes to assist in cornering due to the above mentioned slip angle. Tires with excessive lugs can cause them to rub as well due to being wider than other tire designs. I'm not a fan of spacers due to the additional load it places on bearings as they begin to move the load forces away from the center of the tire. It leads to premature bearing failure but if you want aggressive wide tires, you've got to choose your battle.

 

[ThumperF150]

I've shared this vid a couple times but it's important to understand what's going on especially with 'thicker' tires (more distance between ID (rim) and OD). It's not so much that it's touching because of lock, but touching because the deflection of the tire under cornering forces. However there is a component of camber gain at play as well and that varies between differing suspension geometry. You can see this when you turn the wheel to full lock and the tire's angle noticeably changes to assist in cornering due to the above mentioned slip angle. Tires with excessive lugs can cause them to rub as well due to being wider than other tire designs. I'm not a fan of spacers due to the additional load it places on bearings as they begin to move the load forces away from the center of the tire. It leads to premature bearing failure but if you want aggressive wide tires, you've got to choose your battle.

Everything you say is 100% technically true but…..

Tens of thousands of people run spacers on factory rims or wheels with a different offset from factory with zero issues.

 

[HammaMan]

Everything you say is 100% technically true but…..

Tens of thousands of people run spacers on factory rims or wheels with a different offset from factory with zero issues.

All wheel bearings eventually fail. Moving the wheel further out from the factory design increases the failure frequency. There's not enough data to say exactly how much of a shorter lifespan it impacts, but the further out the wheel goes, the higher increase in force on the bearing.

 

[ThumperF150]

All wheel bearings eventually fail. Moving the wheel further out from the factory design increases the failure frequency. There's not enough data to say exactly how much of a shorter lifespan it impacts, but the further out the wheel goes, the higher increase in force on the bearing.

Yes. 100% true and accurate.

Wheel spacers and wheels with less backspacing create more stress on wheel bearings and probably all suspension components.

But that added stress and wear appears to be negligible within reason as there are not mass reports of failures at unreasonably short mileage.

I’m only one data point but I’ve used 1/4” to 1-1/2” wheel spacers or wheels with less back spacing on two jeeps, one 4Runner and two Porsches over tens of thousands of miles with some hard core off road rock crawling and multiple racing /completion events with zero issues or indications of excessive wear.

I accept the possibility that at the very least, my wheel bearings will need to be replaced sooner than they would have, had I kept everything bone stock.

 

[HammaMan]

I've seen 2" spacers kill an F150 front wheel bearing in 8k miles with a catastrophic failure. Moderation should be used. Trucks like F250s with well-spaced tapered bearings are far more forgiving. Bearings in F150s are much weaker and much less tolerant than the latter's design.

 

[ThumperF150]

I've seen 2" spacers kill an F150 front wheel bearing in 8k miles with a catastrophic failure. Moderation should be used. Trucks like F250s with well-spaced tapered bearings are far more forgiving. Bearings in F150s are much weaker and much less tolerant than the latter's design.

I don’t think I’d be comfortable gong over 1-1/2” wide spacers or 1-1/2” less back spacing on a wheel.

My other concern beyond wheel bearing life is scrub radius and the added leverage of potential bump steer.

But choices must be made for custom vehicles.

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