Tire to front tower rub during articulation

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GASnBRASS

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So I'm doing the oft recommended "Pull the springs and jack the axle" test to see what fits, what hits before anything is modified. This is a completely stock steering, shocks, control arms, track bar, bump stops, everything. Tires are 33x12.5 on a 15x8 rim with 4" BS.

When it's jacked up til bump stop, wheel straight, no issues, plenty of clearance.

flex 1.jpg



When I attempt to turn to full lock with the tire stuffed, the tire rubs the corner of the spring tower and the stock sway bar at about the same time. But there is still a considerable gap between the steering stop and the stop bolt. Is this just the nature of wider tires and I should expect to lose some turning radius to keep things from hitting? Do you extend the steering stops, or just be mindful to not crank the steering when stuffed?

flex turn 2.jpg

steer stop.jpg
 
Part of me wants to say it'll hit the fender that isn't there before it would run into that? In which case you would have added bump stop to prevent that from happening.
 
Vasq said:
Part of me wants to say it'll hit the fender that isn't there before it would run into that? In which case you would have added bump stop to prevent that from happening.
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Let's ignore any potential fender issues at the moment and assume it'll get highlines.
 
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GASnBRASS said:
The other side is dropped, hanging by the shock. Full stuff on this side, full droop on the other side.
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The other end of the sway bar must be disconnected then.
What's the back spacing on the wheels? It appears that adding to the steering stops would solve the issue, I'm just racking my brain because my tire does not contact the spring bracket like that. I was wondering if the track bar is pulling it in that direction more that it should?
 
GASnBRASS said:
Wheels are 15x8 with 4" of BS.

Looking through your build you are running 33x10.5 tires, I have 33x12.5
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I think it might just be the nature of the beast unfortunately.
I have 3.75" BS which I wouldn't imagine making much of a difference by itself but I remembered I also have 10.5" wide tires and that probably makes it work for me.

Unless anyone else has more insight than I do.
 
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Stock springs? I'm running 35, 12.5-17s with 4" back spacing. Around an inch and a half of bumpstop. My tires clear the towers, but they do rub on my control arms
 
Full bump with the wheels straight is a big deal, those are hard hits at speed. Full bump at full lock is generally no big deal, just let off a bit so you don't kill your turning radius for nothing. It's just going to rub, as long as it isn't your brake lines it is absolutely nothing to worry about.
 
pagrey said:
Full bump with the wheels straight is a big deal, those are hard hits at speed. Full bump at full lock is generally no big deal, just let off a bit so you don't kill your turning radius for nothing. It's just going to rub, as long as it isn't your brake lines it is absolutely nothing to worry about.
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The spring tower is right at the middle of the sidewall, so it was a bit disconcerting that I still had quite a bit of steering left after contact. But like you said, it'll typically be at slow speeds. Perhaps I'll weld a slightly curved "rub skid" to the spring tower corner, something the size of a credit card, so it won't gouge and cut the sidewall during incidental contact.

I need to extend the steer stops a bit anyway, just noticed the ears of the chromoly shafts don't have as much clearance as the stock shafts at full lock.
 
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Bind on those ears sounds like job one but don't most people just grind a bit off? My tires have marks from where they hit just about everything and it hasn't been too bad but I'm not fixing the tear in your sidewall so there's that.
 
GASnBRASS said:
The spring tower is right at the middle of the sidewall, so it was a bit disconcerting that I still had quite a bit of steering left after contact. But like you said, it'll typically be at slow speeds. Perhaps I'll weld a slightly curved "rub skid" to the spring tower corner, something the size of a credit card, so it won't gouge and cut the sidewall during incidental contact.

I need to extend the steer stops a bit anyway, just noticed the ears of the chromoly shafts don't have as much clearance as the stock shafts at full lock.
Click to expand...
FWIW, my 35x12.5’s on 15x8 with 3.625” BS rub the towers. They’ve done so for years starting back when I had 33’s. Never been a problem.
 
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What you are doing is a very good exercise.

FWiW, this is what you get with 35x12.5, 3.75" backspace, no steering stop extension, and 12" of shock travel.
20210307_204748.jpg


Light rubbing at the far end of the movement is fine.
 
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GASnBRASS said:
I'd rather just trim the steer stops than risk farking up the ears of the shafts.
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Shafts very often are not made to exact specs. It is also common to just ease over the sharp corner of the ear where it will make contact with the concave part of the opposing shaft. If you really want to fuck up a shaft, let that ear make contact when the tires are turned which has astoundingly high leverage trying to break the cross on the u-joint.
 
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jjvw said:
What you are doing is a very good exercise.

FWiW, this is what you get with 35x12.5, 3.75" backspace, no steering stop extension, and 12" of shock travel.
View attachment 284008

Light rubbing at the far end of the movement is fine.
Click to expand...
I know you always advocate people to do this test, seems few actually do. It's surprising how much stuff will shift from where you'd expect and how close things get to hitting each other. Sounds like rubbing at full flex with steering cranked is just par for the course.
 
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mrblaine said:
Shafts very often are not made to exact specs. It is also common to just ease over the sharp corner of the ear where it will make contact with the concave part of the opposing shaft. If you really want to fuck up a shaft, let that ear make contact when the tires are turned which has astoundingly high leverage trying to break the cross on the u-joint.
Click to expand...
I'm sure the leverage from the steering on those ears would be very high. Only reason I discovered it was rotating the tire at full lock and felt something bind up. Never would have thought a direct replacement chromoly shaft would have less operating angle but I was proven wrong.
 
GASnBRASS said:
I know you always advocate people to do this test, seems few actually do. It's surprising how much stuff will shift from where you'd expect and how close things get to hitting each other. Sounds like rubbing at full flex with steering cranked is just par for the course.
Click to expand...
There's almost always something. It's a matter of finding the stuff that will cause actual damage and figuring out how to mitigate it.
 
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