Mount Chop Mod Necessary?

[Tanker75]

Tire rub on body mount

Throwing my experience out there with my 2019 4runner TRD OffRoad Premium. I have a 2.75 in Toytec lift riding on 275 70 R17s. My tires rub with the stock rims and with aftermarket rims on full turn. I would think if you put too much castor into your alignment that you're going to get some float on the road if the wind blows just right. I have the JBA UCA installed that will allow more castor but then you're having to shave the front fender plastic. Does anyone have their alignment specs that they could share because I am about to do the Body mount chop as well and would like to avoid doing this. Thanks

 

[SD2808TR4]

I'm in a similar situation.... Got about a 2.75/2 Lift on dobinson's, After market rims 17x9 on 285/70/17, 1.25" spidertrax spacers. Rub the BM pretty bad. Plan on lifting the front a tad more with a spacer, and getting an alignment before I start chopping away. I'd like to get away from the BMC, but if I can't then it's getting chopped. Lots of info throughout the forum. Hopefully my alignment guy can do some magic.

 

[jthoms1]

Get everything put on. Get alignment. And then see what is necessary. I wouldn't do a bmc unless it was needed.

☝This. I have 285’s, Total Chaos UCA’s on a about a 2.5-3” lift with 1.25” Spidertrax spacers and did not need a BCM. I was prepared to get one, but took it to an alignment shop and had them give me an alignment with as much caster(?) as possible...pulling the wheels forward as much as possible while retaining the right specs. I’m no alignment experts but read lots of threads that indicated this could fix rubbing issues. Could...not would. As I understand it the aftermarket UCA’s are what give me the added flexibility in the alignment. Worked for me. Not sure if you have aftermarket UCA’s, but if not you could try that and a good alignment first.

 

[4runnin4mylife]

I'm in a similar situation.... Got about a 2.75/2 Lift on dobinson's, After market rims 17x9 on 285/70/17, 1.25" spidertrax spacers. Rub the BM pretty bad. Plan on lifting the front a tad more with a spacer, and getting an alignment before I start chopping away. I'd like to get away from the BMC, but if I can't then it's getting chopped. Lots of info throughout the forum. Hopefully my alignment guy can do some magic.

If you want to try it without the spidertrax (you may like the stance to much to give that up), that may help with your solution without needing a BMC. I am not sure of your wheel specs as far as backspacing, etc. but if you get high caster UCA that will help dial more caster (wheel forward in wheel well) and get you away from the Body Mount!

 

[jmf_tracy]

285/75r17

It depends...
I'm running 285/75R17 on 8" wide rims and i have not yet experienced any rubbing and i do not have a BMC. I am running ICON suspension with 700lb springs in front and the overland springs in the rear.
YMMV

 

[tristero]

Throwing my experience out there with my 2019 4runner TRD OffRoad Premium. I have a 2.75 in Toytec lift riding on 275 70 R17s. My tires rub with the stock rims and with aftermarket rims on full turn. I would think if you put too much castor into your alignment that you're going to get some float on the road if the wind blows just right. I have the JBA UCA installed that will allow more castor but then you're having to shave the front fender plastic. Does anyone have their alignment specs that they could share because I am about to do the Body mount chop as well and would like to avoid doing this. Thanks

I'm running a +4.75 caster. It steers and tracks great. With 285/70 tires I have a ton of room to fit 285/75 or even a 315/70 with a BMC when I need to swap. No issues rubbing issues locked and stuffed.

FWIW I had zero issues with the 285/70 on stock rims with a +3.5 caster.

Not sure what you meant by float on the road with more caster, but in my experience the more positive caster, the better and less likely to wander all over the road like the truck is drunk.

 

[SD2808TR4]

If you want to try it without the spidertrax (you may like the stance to much to give that up), that may help with your solution without needing a BMC. I am not sure of your wheel specs as far as backspacing, etc. but if you get high caster UCA that will help dial more caster (wheel forward in wheel well) and get you away from the Body Mount!

Worked like a charm. I was stressing out about it too haha. No longer have the rub. Sad that I took out the spacers but I'll get over it. lol

I have JBA UCA, 17x9 Venomrex rims. Now only get the front fender rub which is easily fixable. Thanx for the info. Love this forum

 

[mrblah]

Worked like a charm. I was stressing out about it too haha. No longer have the rub. Sad that I took out the spacers but I'll get over it. lol

I have JBA UCA, 17x9 Venomrex rims. Now only get the front fender rub which is easily fixable. Thanx for the info. Love this forum

One day you will return to the dark side.............. you'll see

and we will accept you with open arms :vader:

 

[Khope]

Alignment after mods

Throwing my experience out there with my 2019 4runner TRD OffRoad Premium. I have a 2.75 in Toytec lift riding on 275 70 R17s. My tires rub with the stock rims and with aftermarket rims on full turn. I would think if you put too much castor into your alignment that you're going to get some float on the road if the wind blows just right. I have the JBA UCA installed that will allow more castor but then you're having to shave the front fender plastic. Does anyone have their alignment specs that they could share because I am about to do the Body mount chop as well and would like to avoid doing this. Thanks

I just happen to get an alignment today after the JBA Standard UCAs were installed. I have about a 2.0-2.5" lift due to installing FJ TRD Pro suspension and a 1" spacer. They did an alignment when this was installed and said I was at 2.0 Caster and that I should probably consider UCAs. The vehicle drove fine so I just left it alone. Then about three weeks ago I put on SCS Stealth 6 custom wheels ( 17"x8.5" with -10mm offset) and KO2's 285/70/17. I had inner liner rub and front bumper rub at full lock. Easy enough fix. However after the wheel and tire install the 4R felt strange like too easy to turn and not planted. So I decided to put UCA's on after reading and re-reading comments on this board.

The vehicle drives great EXCEPT it now rubs the body mount. Very frustrating and I have no desire to do the chop. I'm going to call JBA tomorrow to see if they have any suggestions. In the meantime, all forum members are welcome to provide input

 

[Josh_357]

I just happen to get an alignment today after the JBA Standard UCAs were installed. I have about a 2.0-2.5" lift due to installing FJ TRD Pro suspension and a 1" spacer. They did an alignment when this was installed and said I was at 2.0 Caster and that I should probably consider UCAs. The vehicle drove fine so I just left it alone. Then about three weeks ago I put on SCS Stealth 6 custom wheels ( 17"x8.5" with -10mm offset) and KO2's 285/70/17. I had inner liner rub and front bumper rub at full lock. Easy enough fix. However after the wheel and tire install the 4R felt strange like too easy to turn and not planted. So I decided to put UCA's on after reading and re-reading comments on this board.

The vehicle drives great EXCEPT it now rubs the body mount. Very frustrating and I have no desire to do the chop. I'm going to call JBA tomorrow to see if they have any suggestions. In the meantime, all forum members are welcome to provide input

I haven’t proven this but my understanding is adding positive caster by adjusting the lower control arm moves the tire away from the body mount, adding caster with the upper control arm moves the tires closer to the body mount.

 

[Dillusion]

Worked like a charm. I was stressing out about it too haha. No longer have the rub. Sad that I took out the spacers but I'll get over it. lol

I have JBA UCA, 17x9 Venomrex rims. Now only get the front fender rub which is easily fixable. Thanx for the info. Love this forum

Where did you go for alignment? Lex Brodies in Kalihi only could get 3.8 caster

 

[Khope]

Where did you go for alignment? Lex Brodies in Kalihi only could get 3.8 caster

I had my local Toyota dealer do the alignment (lifetime alignment $199) and the install of the UCA. Just to clarify the attached alignment printout in my previous post shows "Before Measurements" and "Current Measurement" The "Before" was based on the new JBA after install not the stock UCA.

 

[Dillusion]

I had my local Toyota dealer do the alignment (lifetime alignment $199) and the install of the UCA. Just to clarify the attached alignment printout in my previous post shows "Before Measurements" and "Current Measurement" The "Before" was based on the new JBA after install not the stock UCA.

I have Icon UCA's.

Lex Brodies did my alignment. Before I go bug the shit out of them I wanted to see what my other options were.

I'm getting minor rubbing on the mount and want to avoid chopping if all possible.

 

[Signal]

Worked like a charm. I was stressing out about it too haha. No longer have the rub. Sad that I took out the spacers but I'll get over it. lol

I have JBA UCA, 17x9 Venomrex rims. Now only get the front fender rub which is easily fixable. Thanx for the info. Love this forum

Is yours the one on the left?

 

[JohnWick]

Will report back my findings...

I have icon coilovers and dk uca’s going on with Scs ray10 And wildpeak 285’s. I will report back with my rubbing issues or hopefully lack thereof. Fingers crossed!

 

[SD2808TR4]

Is yours the one on the left?

Yup.

 

[SD2808TR4]

Where did you go for alignment? Lex Brodies in Kalihi only could get 3.8 caster

I didn't need that much caster...2.9 and 3.3

Scottie's by pearl ridge, go early so there's not a long line. Cost about $120-130 for me. Rub on the front fenders but only in reverse. Doesn't even bother me enough to trim yet. Took it to Ka’ena Point, no problems whatsoever. Rides like a dream. Dobinson's definitely legit.

 

[mashalatheballa]

I haven’t proven this but my understanding is adding positive caster by adjusting the lower control arm moves the tire away from the body mount, adding caster with the upper control arm moves the tires closer to the body mount.

does anyone with knowledge have input on this theory?

 

[Mutant138]

285-70-17 wildpeaks, 2.5-1.5 lift, trail wheels, 1.25 spacers (to clear uca's), jba uca's (caster maxed to 4).

BMC was necessary. Maybe if I had gone with a different UCA that didn't require spacers I may or may not have cleared the BM. But, I didn't realize it would be an issue and now it's chopped. Would have gone 34 if I had known I was going to rub.

DO NOT let anyone say 285's wont rub. Just because it worked out for them does not mean it will for you.

 

[BackOff]

does anyone with knowledge have input on this theory?

Here. Using a SPC UCA.

With the SPC arm set at the 'D' setting, that is +2* castor.

If you set it to 'G' that would move the UCA to the stock 0* and forward.
3rd gen guys with BIG tires seem like the 'G' to keep the tire out of the BM.

Orange is castor.
Green is the setting.

Front passenger side. 4th gen T4R.