UCA clearance question

[Labraptor]

Should be Camburg not Rpg


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Roger that, I asked someone else too lol.

 

[RPG]

There should not be any additional bulge at the TOP of the tire when aired down, only at the bottom of the tire / contact patch.

this is what we thought as well but with his 37" toyos at havoc in the hils he was rubbing and we couldn't figure out why so after airing the tires back up at the end of the weekend the rubbing went away. he was aired down to about 18psi and with so little air the weight alone from the steel belts could of been enough to make it bulge at the top.

 

[KaiserM715]

Probably more tire deflection due to reduced sidewall stiffness at the lower pressure.

---------- Post added at 07:57 PM ---------- Previous post was at 07:55 PM ----------

There is a video of an Ultra 4 in slow mo that shows the tire oscillating from side to side.

 

[wiz1500]

My Alpha 1 UCA rub like a bitch with my Toyo 37's at 40PSI... Yeah not impressed at all..

 

[ntm]

this is what we thought as well but with his 37" toyos at havoc in the hils he was rubbing and we couldn't figure out why so after airing the tires back up at the end of the weekend the rubbing went away. he was aired down to about 18psi and with so little air the weight alone from the steel belts could of been enough to make it bulge at the top.

With less pressure in the tire, the sidewall will deflect more readily. The whole wheel is shifting laterally in relation to the tread surface = rubbing at the top.
If I drop my truck off the jack from full droop on pavement, I can see it happen due to the track width change.

 

[pat'sRAPTOR]

Yea it seems like in order to run a 37" tire you need to either go with a 1" UCA bearing or go with a wheel that has a negative offset if you're running toyos or most 13.5" wide tires now there are 12.5" wide tires in a 37" but with a 35" toyo and 12.5" you will be right but shouldn't have an issue really

---------- Post added at 10:24 PM ---------- Previous post was at 10:22 PM ----------

I know when I hady 37" toyos they would rub when I went full turn but it didn't run enough to do any damage to the tire or the UCA just rubbed the paint off lol

 

[Labraptor]

What offset are you running? My RPG UCA's which are 1.5" do not scrub but are pretty tight and I'm on +18 offset and 9" wide wheels

American Eagle are +8, the Raptor specific ones they make.

 

[05Raptor]

When you hit big bumps at speed, your tire shakes a little bit as you can see in video. It may touch, but it won't be bad or cause real damage


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[MTUH3]

@Labraptor

I have a tight fit with my SVC UCAs also. The Goodyear Dtracs have beefier or knobbier sidewalls over stock BFG also, and at full lock I have seen some evidence that the tire rubs the boxed part of the UCA. I expect new wheels to help with that. I have noticed some tires build wider or taller than others, but I do not see any concerns

 

[mudblood]

When I discussed with SVC on their UCA's they asked me to measure from the point of the ball joint(edge of UCA) to the nearest part of the sidewall on my current set up. That is Fuel 18x 9 wheels and 35 Toyo's. The wheels are 5 inch backspacing and +1 offset. I had 2.25 inches from the point of the ball joint ( edge of UCA)to the nearest part of the tire. I was told that would be fine. Anything an inch or less would be a no go. Looks like you give up something in the neighborhood of 3/4 of an inch in space with their 1.5 inch UCA's and I would assume most all the rest of 1 1/2 inch ball joint UCA's.