12 replies to this topic

[YankWithAMini]

1988 Mayfair

Mini Spares Adjustable heavy duty tie rods

Mini Spares Adjustable lower arms

 

I think I know what is going on, but I want to make sure I’m not missing something.

 

My last alignment job (at a shop) resulted in the inside of the front tires wearing down after only a few hundred miles. I bought a set of toe/camber/caster plates and discovered the total toe was out of spec. I just fit new track rod ends (genuine, original length). The old TRE had 10 turns each, and using the thread pitch and toe measurements, I calculated I need 7 turns on each side. That seems low for safety, and I have seen people on the forums quote a minimum of 10 turns are needed. Even if 7 isn’t exactly correct, I need less toe, so it will be less than the 10 turns it had before.

 

The camber measurement is more negative than the book value, but it looks to me like the adjustable arms are at their shortest limit (so I can’t add more pos camber). I bought the adjustable components not for performance, but just for durability and the ability to dial things in. I haven’t seen a quote for the range of camber the adjustable arms are supposed to allow, but I would have thought the standard book value would be within their range. I know negative camber can affect toe, and people talk about needed the longer TRE to accommodate more neg camber.

 

So…. Am I correct that the limit of the adjustable lower arms won’t get me to book value (what is the most pos/non-negative they will allow camber to be)? If so, is the extra neg camber most likely the cause of low thread engagement of the TRE, and I need the longer TRE? Is there anything else I am missing that could be relevant?

 

Suspension measurements:

Total Toe: 7/16 out (book value 2/16)

Camber: 1.1 deg neg, both wheels (book value 2 +- 1 pos)

Caster: 1.1 and 2.4 (book value 3 +-1)

 

I am a bit suspicious of the caster measurement. I have had issues with the repeatability of the measurement, and even after large adjustments, the measurement didn’t change much. I will figure that out after this.

 

 

 

[Spider]

BMC stated the minimum thread engagement is 1/2", which equates to 10 turns.

 

 

My last alignment job (at a shop) resulted in the inside of the front tires wearing down after only a few hundred miles.

 

,,,,,,,,,,,,,,,

 

The camber measurement is more negative than the book value, but it looks to me like the adjustable arms are at their shortest limit (so I can’t add more pos camber).

 

 

This here raises some flags for me.

 

Even with adjustable arms, you say you can't achieve standard camber angles.

Is the car sitting low ?  As the ride height is lowered, the camber on the front wheels becomes more negative.

If it's at standard height or not far off that, then something on the front end is skewif,
 

 

 

[nicklouse]

How much camber has it got? 
You can also change the lock nut to a half nut. 
 

but it does sound like your are running very low.

[YankWithAMini]

Unfortunately, the front end is up on stands at the moment, so I can't measure the ride height. I haven't done anything to lower the ride height, but the cones are of an undetermined age and could very well be tired out. We bought the car in 2013 and have not put a lot of miles on it, but I highly doubt the cones were new then (based on the look of the metal bands).

 

I will put it together as-is, take new measurements (including the ride height) and check back in.

 

Thanks!

[YankWithAMini]

Update:

 

I got it all back together and worked on the alignment. The camber is at 1.5 deg negative, but there is no adjustment left on the bottom arm. Castor is within spec at about 2.4 deg on both sides. With total toe, I got to where I was chasing my tail, and the changes I was making didn't match up with what the measurements showed, and repeatability was bad, so I might be at the limit of my equipment. I have it at 5/16 toe out right now. Having said all that.....

 

After spending too long getting it aligned, I remembered the question about my ride height. Sure enough, the driver's side upper arm is only 1/8" from the upper bump stop, and the passenger's side is maybe 1/2" from the upper bump stop. That can't be right. I will check the knuckles next session, but the cones are at least 10 years old, so I'm thinking I will just order new ones anyway.

 

#1 lesson learned: my calculations on how many turns I needed to bring the toe into spec were way off, and my theory is that I failed to realize the adjustment made at the TRE is amplified by the geometry of the system (the relative lengths of the steering arm and wheel). So if you make a 1/8" change at the TRE, the toe will change more than 1/8". So instead of the predicted 7 turns of thread engagement at the TRE (not good), right now I'm sitting at 11.5 turns, with about 9/16" exposed thread inboard of the TRE.

 

#2 lesson learned: Doing the alignment took way longer than I expected. The process of setting up the plates, measure, make a change, roll the car to settle, set up plates, measure, takes time, and it adds up fast. Two people would help. Castor measurement requires turning the wheel, check the angle, turn the wheel, etc, which adds time with one person. If you have to put it up on stands for any reason, it's even worse. I'm not sure how often I would attempt this myself in the future, except finding a shop with the knowledge and equipment to do an old car with such a small track width has proved elusive so far. I will keep looking. I plan on getting it as good as I can, take it to a shop if I find one, and that will tell me how accurate I am, which will help with the future DIY/pro decision.

 

I guess this has now become a suspension cone thread (unless there is something else the community thinks I should look at)! I will update if that fixes it.

[Spider]

Whoa !   You've had a big learning curve here !!

 

 

#1 lesson learned: my calculations on how many turns I needed to bring the toe into spec were way off, and my theory is that I failed to realize the adjustment made at the TRE is amplified by the geometry of the system (the relative lengths of the steering arm and wheel). So if you make a 1/8" change at the TRE, the toe will change more than 1/8". So instead of the predicted 7 turns of thread engagement at the TRE (not good), right now I'm sitting at 11.5 turns, with about 9/16" exposed thread inboard of the TRE.

 

#2 lesson learned: Doing the alignment took way longer than I expected. The process of setting up the plates, measure, make a change, roll the car to settle, set up plates, measure, takes time, and it adds up fast. Two people would help. Castor measurement requires turning the wheel, check the angle, turn the wheel, etc, which adds time with one person. If you have to put it up on stands for any reason, it's even worse. I'm not sure how often I would attempt this myself in the future, except finding a shop with the knowledge and equipment to do an old car with such a small track width has proved elusive so far. I will keep looking. I plan on getting it as good as I can, take it to a shop if I find one, and that will tell me how accurate I am, which will help with the future DIY/pro decision.

 

 

Roughly,,,,,, 1/4 of a turn on the Steering Rod will change the Toe by approx 1/32" on that one wheel. I stress, this is only approximate !!

Yes, doing wheel alignment takes quite a while, especially with adjustable Arms and Rods as adjusting one, throws out the others. Keeping at it, you eventually work in to a spiral, hopefully working down to the numbers you are after !
 

[mbolt998]

1988 Mayfair

Mini Spares Adjustable heavy duty tie rods

Mini Spares Adjustable lower arms

 

I think I know what is going on, but I want to make sure I’m not missing something.

 

My last alignment job (at a shop) resulted in the inside of the front tires wearing down after only a few hundred miles. I bought a set of toe/camber/caster plates and discovered the total toe was out of spec. I just fit new track rod ends (genuine, original length). The old TRE had 10 turns each, and using the thread pitch and toe measurements, I calculated I need 7 turns on each side. That seems low for safety, and I have seen people on the forums quote a minimum of 10 turns are needed. Even if 7 isn’t exactly correct, I need less toe, so it will be less than the 10 turns it had before.

 

The camber measurement is more negative than the book value, but it looks to me like the adjustable arms are at their shortest limit (so I can’t add more pos camber). I bought the adjustable components not for performance, but just for durability and the ability to dial things in. I haven’t seen a quote for the range of camber the adjustable arms are supposed to allow, but I would have thought the standard book value would be within their range. I know negative camber can affect toe, and people talk about needed the longer TRE to accommodate more neg camber.

 

So…. Am I correct that the limit of the adjustable lower arms won’t get me to book value (what is the most pos/non-negative they will allow camber to be)? If so, is the extra neg camber most likely the cause of low thread engagement of the TRE, and I need the longer TRE? Is there anything else I am missing that could be relevant?

 

Suspension measurements:

Total Toe: 7/16 out (book value 2/16)

Camber: 1.1 deg neg, both wheels (book value 2 +- 1 pos)

Caster: 1.1 and 2.4 (book value 3 +-1)

 

I am a bit suspicious of the caster measurement. I have had issues with the repeatability of the measurement, and even after large adjustments, the measurement didn’t change much. I will figure that out after this.

 

Hang on, is the total toe supposed to be 2/16"? I thought the book value of 1/16" was the total? I'm just setting mine up now...

[imack]

Total toe should be 1/16" (1/32" per side)

[Gaz66]

Im dreading getting to this point! 😣
Does it make it any easier if everything is rose jointed?

[imack]

Rose joints only make the adjustments easier if they're the 'on car' adjustable type.
My KAD rose jointed tie bars are a doddle to adjust and are infinitely adjustable. But my old Aldon automotive rose jointed lower arms need removing at the subframe to make a 1/2 turn adjustment of the rose joint for the camber (minimum amount of adjustment) or the lower ball joint and tie bar detached to make a minimum of 1 full turn of adjustment.
I also have old Ripspeed hilos that adjust via a 2 foot long Allen key via the rear valance or bulkhead that makes corner weight settling very easy too.

[YankWithAMini]

Total toe should be 1/16" (1/32" per side)

Edited by YankWithAMini, 18 May 2023 - 01:11 AM.

[68+86auto]

Remember that the factory specifies a certain diameter for the measurement to be taken at which is not the rim or outer diameter.

I think when you say plates you are talking about plates used to measure the toe and not turn plates?

If you can get some turn plates or "make" them (there are many simple solutions online using grease etc) then you don't need to roll the car to settle the suspension so much.

Edited by 68+86auto, 18 May 2023 - 12:33 PM.

[YankWithAMini]

Sorry for the delay; been working on the car!

 

Yes, Mini Mad, I only have toe plates, no turn plates. I might try to fashion up some DIY turn plates to speed it all up next time. I'm getting closer... My alignment job turned into cones, upper arms rebuilt, radius arms rebuilt, brake hoses, some brake pipes, fixing some rust, subframe refresh, rear wheel bearings, and exhaust. Phew!