[USStrongman]

Things can be lost in translation online, but if I had a shop, and you bugged the **** out of me like it sounds you did with him, I'd charge extra too.

 

[rgreen65]

Even with the stock LT255/75R17 tires, I found the Jeep handles and rode better at 33 than the specified 37. I would have gone down to 31 (as I had done on my '15 Sahara) but the TPMS nanny objected. I have since used the Jscan to reset the alarm threshold on my '17 to 25. I run 30PSI and it rides and handles well on my LT285/75R17 tires.

 

[zipman35]

Even with the stock LT255/75R17 tires, I found the Jeep handles and rode better at 33 than the specified 37. I would have gone down to 31 (as I had done on my '15 Sahara) but the TPMS nanny objected. I have since used the Jscan to reset the alarm threshold on my '17 to 25. I run 30PSI and it rides and handles well on my LT285/75R17 tires.

That’s basically a 34” tire. You run at 30. I need to drop mine down a bit more. I ran 28 in a 33x12.5x15 on my TJ

My JK currently run about 32 but it’s still too high IMO on a 33.2 (285/70/18)


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[Bob Sanders]

In general Firestone will not get to involved with nonstock setups other than adjusting toe. And setting up caster on most adjustable control arms is time consuming as it involves disconnecting control arms to make the adjustment hence the increased cost to have it done.

But setting up caster at home is fairly easy. The first thing you are going to need is an angle finder. I find the digital ones to be easy to use and very accurate. Set zero to whatever surface you are working on.

Good instructions.... and yes, alignment is Sooo easy on a jeep compared to other vehicles, you can do it at home pretty easily, and it doesn't take that long either. Save yourself a boatload in shop charges.

I use fastrax though. It's a bit more expensive than an angle finder, but you can shoot a measurement in less than a minute without even climbing under. It's fast, simple, and clean. You can also get the optional toe measure kit with it if you wish. They suggest a turnplate in the video if you have one, but it's not absolutely necessary.

 

[rgreen65]

That’s basically a 34” tire. You run at 30. I need to drop mine down a bit more. I ran 28 in a 33x12.5x15 on my TJ

My JK currently run about 32 but it’s still too high IMO on a 33.2 (285/70/18)


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My error - the correct spec for the tires on my Chief are 285/70R17 which are 32.8" tall (basically a 33" class tire).

 

[zipman35]

My error - the correct spec for the tires on my Chief are 285/70R17 which are 32.8" tall (basically a 33" class tire).

Even better. Is that a 2d or 4d?


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[rgreen65]

Four - JK Unlimited

 

[zipman35]

Four - JK Unlimited

Ok cool. Sorry for the derail. I just have not found that perfect pressure for my 2d. I need to look up the weight difference in an 05 TJ bs my JK. My TJ rode like a Cadillac of Jeep’s lol


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[rgreen65]

zipman35 - I run about 28 in my '03 Rubicon with LT245/75R16 tires. Of course I don't have to worry about a TPMS nanny in it. Your 285/70R18s are most likely Load Range E which have a stiffer side wall. The tires on both of my Jeeps are LR C. If your avatar is with the 35s you have a lift on your JK. Have you installed adjustable LCAs in front to adjust the caster back close to stock spec? It may not help the ride, but will help the handling.

 

[zipman35]

zipman35 - I run about 28 in my '03 Rubicon with LT245/75R16 tires. Of course I don't have to worry about a TPMS nanny in it. Your 285/70R18s are most likely Load Range E which have a stiffer side wall. The tires on both of my Jeeps are LR C. If your avatar is with the 35s you have a lift on your JK. Have you installed adjustable LCAs in front to adjust the caster back close to stock spec? It may not help the ride, but will help the handling.

Unfortunately not yet. It’s all stock and I think the shocks are stretched too with the 2” BB that’s under her. And that was a typo. It’s 33.2


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[Qomomoko]

Installing a lift will change the numbers, but not what the numbers should be. Can't change the camber easily and a lift won't. Toe in can be changed and the correct specification should not change. That leaves castor. Lifting a Jeep will change the castor and the purpose of the alignment is to bring the castor back into spec (or at least closer) - which has not changed. The way this is done is by changing the length of the control arms, most often the lower. This is the purpose of the adjustable control arms.

Makes sense, the numbers are the numbers. Calling an alignment "just toe" alignment when there is caster to wiggle is not a true alignment, but I had given up, gonna try and do it my self again.

In general Firestone will not get to involved with nonstock setups other than adjusting toe. And setting up caster on most adjustable control arms is time consuming as it involves disconnecting control arms to make the adjustment hence the increased cost to have it done.

But setting up caster at home is fairly easy. The first thing you are going to need is an angle finder. I find the digital ones to be easy to use and very accurate. Set zero to whatever surface you are working on.

Angle Finder

Next here is a picture of the front differential. As you can see pinion angle and caster have a fixed relationship. With 0 pinion you have 6 degrees of caster. As you rotate the pinion up you lose caster. Most of us shoot for 5 degrees of caster meaning that you pinion angle is going to be 1 degree up. But as long as you are 4 degrees or better you are good.

View attachment 4484096

I find measuring off the pinion flange to be a pain so instead I measure of the front of the diff as shown in the picture below. With the angle find zero'd to the floor and set for 180 measurements your angle on the diff should be 95 degrees.

View attachment 4484097

Last but not least a couple of words of caution.

First only adjust one arm at a time. Write down how many turns you adjusted it and after you have reattached that arm do the other.

Second look at your rod ends, they are probably offset meaning you have to make full 360 turns of the end. With the lift I own caster is adjusted via the upper control arms allowing for half turns which don't have an offset.

This is not hard but it is time consuming. Taken the initial measurement, then jacking up the vehicle, removing tires, making the adjustment, putting tires back on lowering vehicle, taking measurement then repeating if it is not correct. If you can find a shop that works mostly 4x4 or Jeeps that does alignments you can pay to have it done but it will be a few hundred dollars.

I used my iphone "bubble app" for an approximate caster angle and with the floor not being level (appx 0.7 deg, and measuring from the differential ( I used several locations) I got from 2.0 deg to 1.4 deg. In other words my caster is way below 4.0 degrees. I used bolts on each side as well as the flag flanges you circled in your pick. There was a video where a guy took of his tyes and set the truck on his brake disks and then a tool like the FASTTRACK to do an alignment lol

Being so uninformed, me changing the caster, extended the lower CA 2-3 turns ( I'll do 2 turn at a time max lol), I should not run into " ohh my brakes lines are now to tight or my steering is too extended " right?

I wrote down and measure mostly threads for ::
Driver and Passenger Side
Tie Rod ends
Drag Link
Track Bar
Control Arm Lower (my uppers ARE NOT adjustable)
Sway bar disconnect.

I bought the jeep used but liked that when I bought it there were grease pen markings on my bolts and such, I my self do so when instructions tell me to or when I saw that previous job did so.

For 35" tires I think you will find better results at around 28 - 30 psi. Larger tires do not need as much air pressure in them to support the same load. The stock air pressure spec was for the stock tires and means nothing when you are running 35" tires.

LOL yeah, I will try the lower PSI as per your recommendation. I remember that when I first got the JKU I started at 40# but felt comfortable doing 33-35# after playing with the CHALK test when I had Cooper Discoverer AT3 (me previous tyre). Still have not played much with the Destination MT's as they are pretty much brand new.

Things can be lost in translation online, but if I had a shop, and you bugged the **** out of me like it sounds you did with him, I'd charge extra too.

yeah absolutely, lost in translation can happen. JAJAJA maybe I did bug him over the phone when asking about doing the alignment under the 1 year warranty. There is another well known alignment shop that I might try out.

Good instructions.... and yes, alignment is Sooo easy on a jeep compared to other vehicles, you can do it at home pretty easily, and it doesn't take that long either. Save yourself a boatload in shop charges.

I use fastrax though. It's a bit more expensive than an angle finder, but you can shoot a measurement in less than a minute without even climbing under. It's fast, simple, and clean. You can also get the optional toe measure kit with it if you wish. They suggest a turnplate in the video if you have one, but it's not absolutely necessary.

View attachment 4484107

Looks awesome that Fasttrax level. Back in Winter 2020 I looked around for tools to do my own alignment but I was in a rush and tried using string and good old tape measure. My accuracy felt so poor that I felt that 1/8 of an inch adjustment was impossible when my measurement seemed to be +- 1/4 of an inch. I had seen some others use stretched plastic container from milk or O.J. for turn plates lol; I use them for installing my moto tyres onto the rims and some lube.

My previous post about me having that Rock Krawler 2.5 Max travel kit is not total true. I have a RK 2.5 max travel kit but it is older than that one as my upper CA are not adjustable and my Lower CA do not have grease fittings. I measured both lower CA and both are 23.25" and greased marked with about 3 threads left from shortest length. Will contact RK and see if they can tell me specs for my kit.

In all honesty , I am almost complete NOOB when it comes to real alignment comprehension but know it is not rocket science either.

thanks again for help and feedback.

Ohh.. at least I did install my new rock sliders..

EDIT::: my shaft is a DANA Spicer part # 5010867-1 ( the paper is still on it believe or not lol)

 

[Qomomoko]

EDIT ( when I was measuring I was not paying attention if the angle was up or down and assumed it was down, I failed to realize the fixed relation between the pinion top and the C of 6 fixed 6 degrees).

Well
I measured Caster twice Using my iphone again but this time subtracting the angle at the pinion from that read at the top of the C ( the flat top part of where the top ball joint enters)

Front axle ( I put it on stands to wiggle the tyres and see if anything was obviously worn /loose and it looked great, tie rod boots are slightly tearing)
attempt A
axle Pinion:: 2.5 deg
Top of C :: 9.0 deg
Caster :: 6.5 deg
Attempt B
axle Pinion:: 2.7 deg
Top of C :: 8.3 deg
Caster :: 5.6 deg

Of stands, on ground
Attempt C
axle Pinion:: 2.0 deg
Top of C :: 7.0 deg
Caster :: 5.0 deg

So my caster in this method is between 5.0 degrees and 6.5 degrees.
How I hold the phone on the C or the Pinion can make the angel vary so I attempted to hold the phone as true as possible from the front to the back of the jeep.
Extending the Lower control arm would increase my Caster correct? Do not think this is needed.

I think my first measurement from the Diff are misunderstood by me.

 

[TerryC6]

If your pinion angle up (refer to the picture I provided) you have between 3.3 - 4 degrees of caster. If your pinion angle is down you have between 8 and 8.7 degrees of caster.

 

[Qomomoko]

If your pinion angle up (refer to the picture I provided) you have between 3.3 - 4 degrees of caster. If your pinion angle is down you have between 8 and 8.7 degrees of caster.

Besides me being an idiot, I get it now lol

Pinion measures down 1.7 degrees (floor is 0.4 degrees sloping down too) so the pinion really measures 1.7 MINUS 0.4 so it is 1.3 degrees.

Because of the built in offset of 6 degree from pinion to the C (6 degrees down), my caster is 6 deg down Plus 1.3 deg down so 7.3 degrees!! is this correct?



FYI, the shop wanted me to extend my lower control arms to "push the front axle forward", estimation was no more than 1/4 inch of the lower control arms. Very likely as misunderstood as that would add caster and IF my last measurements are correct I do no need to add more caster.

 

[Wlfman]

My tire pressures (Fire Stone MT Destination MT) were 37# all around untill I went to 35#

I ran these same tires for a lil over 3 years. You have way too much air in them even at 35#. Drop down to 26-28# range and you'll find that they ride and grip better.

 

[TerryC6]

Besides me being an idiot, I get it now lol

Pinion measures down 1.7 degrees (floor is 0.4 degrees sloping down too) so the pinion really measures 1.7 MINUS 0.4 so it is 1.3 degrees.

Because of the built in offset of 6 degree from pinion to the C (6 degrees down), my caster is 6 deg down Plus 1.3 deg down so 7.3 degrees!! is this correct?



FYI, the shop wanted me to extend my lower control arms to "push the front axle forward", estimation was no more than 1/4 inch of the lower control arms. Very likely as misunderstood as that would add caster and IF my last measurements are correct I do no need to add more caster.

If your measurements are correct no you don't need more caster. If fact I wonder if you are running to much. With a stock driveshaft you pinion angle should be the same as the output shaft of the transmission (see picture below. One degree either way probably does not make much difference but the further away you get from it can cause unwanted vibrations and lead to pinion bearing failure.

 

[Qomomoko]

98" tall, the top of my roof top tent.

He was not able to do the alignment this time. They added some cables on the top and would touch the top of my RTT.

In conclusion he said he would charge me $65 for the control arm adjustment and he would "eye ball it" by using the alignment papers from where ever I can get it done.
He gave me my money back $90.

I like the guys and owner, they are personable, think they are very busy and possibly "misspeak" when given quotes / prices or I mis-hear lol.

I'll try them again, just need to communicate precise with them.
Looks like they "outsource" the alignment.

Thank for all the help and knowledge shared.

 

[Qomomoko]

Ohh and the brakes are NOT dragging, did my rear pads replacement Sunday.

Found a Guy who seems to know and does the alignment at his shop

$100 Toe and wheel center, and $20 he gives me read out on adjusting Lower Control Arms.

He was patient and spoke slow enough for me to follow. He said when he adjust the toe and centers wheel, it wont be affected after any control arm adjustment.

 

[Qomomoko]

Teo aligned, here are the pre numbers from Fire Stone, they could not do it as they said the tie rod could not be loosed.
Another shop did adjust. here are the numbers...

Time to drive and enjoy it till next project..

Still pulls a little to right. He says it might be because my camber on PS is .4 and DS is 1. He suggested maybe off set ball joints, or extending the PS control arm 1/4 to 1/2 inch.


Below is the before and after from the alignment.

Below is Pre adjustment #'s from FireStone