Toe-in

[Raahauge]

I hope it is acceptable to put a request on here, - does anyone have a spare track rod I can borrow whilst I compare/check/modify mine, or buy.
I need more toe-in and I have run out of adjustment .
The rod was bent when I bought the car, as if it had been towed with it, and I think in straightening it may have lengthened a little.
The published figure is 6 to 8mm and I have about 4.5
Thanks and regards
Mike

[Mikenoangelo]

I can measure mine which I think is original if that would help.

Mike

[Raahauge]

Thank you Mike, that would be most useful.

[Kari]

A very interesting subject!

To my surprise, I didn't find any information about toe-in in the original owner's manual issue Aprile 1935 Xll. However, I did find data in the Belna Handbook which states a toe-in of 5 - 6 mm. That would be about 0° 40' to 0° 50'

About 10 years ago, I wanted to know the length of the Augusta track rods. During a Sliding Pillar Rally and on other occasions I did measure several track rods. I have found several different lengths but not by much difference. I've found lengths between 1110 mm and 1116 mm from centre of bore to centre of bore. The toe-in can be varied by turning the eccentric bolts 31-4430. I wonder if the adjusted toe-in can be checked on a drive-on test stand.
I look forward to the length of track rod Mike has on his car.

Early cars had a very thin track rod which was replaced by a more substantial one later on. Diameter of tube approx. 25 mm.

regards

Karl

[Raahauge]

Good evening and thank you. My dimensions are from La Lancia by Weernink.
I have been playing with tyre pressures but have concluded that I really do need more toe-in.
By my rough measurements and calculations the 2mm available adjustment at each side would produce a maximum variation at the wheel rim of 5.3mm
My trackrod measures 1113mm between centres and is 24 diameter (flat rad car)
I have spherical plastic bearings at each end so there is no give whereas there would be a small amount with standard rubber bushes.
I recall some discussion about the originality or not of rubber bushes with eccentric centres, (might have been about Aprilia) I wonder if these were available as a fix for such a situation?
Mike

[Mikenoangelo]

On my car the trackrod bolt centres are 1115mm apart. The trackrod itself between the insides of the "u" shaped yokes is 1051mm and the trackrod is 27mm diameter - this being a late car made in 1936. So it seems we have the same length although different diameters.

When I worked on the front axle I reassembled the trackrod with the same adjustment as received, having no means of measuring the toe in and no reason to think it might be wrong. However when my son, who is very well attuned to such things as he works for JLR, said he felt there might be too much toe in I kept an eye on the wear of the front tyres and sure enough are now showing more wear on the outer side of the tread. So I need to check the toe in which my local garage are able to do with some laser kit.

Without taking the trackrod ends apart, which I did not have time to do today, I can't say at which extreme they are adjusted but all 6 holes on the top bolt head are symetrically aligned to the rear of the car with the locating pin in the extreme inner hole as in the photo below which perhaps suggests that the toe in is currently set to the maximum? The UK translated version of the instructions advises 6-8 mm or a quarter inch of toe in.

This converation is for me very timely!

Mike Clark

[Raahauge]

Mike, thank you for the measurement.
I agree you have it set at maximum toe-in.
I measured mine by placing straight edges (planks of wood) elevated on tins against the tyres and measuring the distance between them at the front and rear of the tyre.
You then have to take into account the distance for and aft between the measurements, in my case 22inches and calculate back.
There a number of components involved and therefore lots of scope for variation apart from any bumps it may have had.
My front wheels are rebuilt and the tyres run true as otherwise it would not of course work.

[Running Board]

the original silent block bushes are eccentric , many argue otherwise as theirs have been replaced by concentric bushes and the parts book drawing doesn't illustrate them as eccentric , i have a very original belna ,every steering bush is eccentric , this gives more toe in any direction depending on how its fitted into the steering arm .
There have been many debates on this topic with arguments on wrong track rods fitted etc   , early cars have a much lighter track rod, there were less made so impossible for every late car to have an early track rod fitted "by chance"
we made new eccentric bushes out of polyurethane type bushes off the shelf in demon tweeks , they machined in the lathe have been fitted since 2006 with no issues and correct track 

[Mikenoangelo]

James are you saying that the eccentric bushes gives additional adjustment over that given by the through bolt with the locating pin? If so do you have any dimensions for the PU bush that you made?

I'll have to dismantle my trackrod ends to look at the bushes. They are a tight fit in the steering arm ends and are nipped by the bolt  so that any turn of the steering winds up the bushes and has a self centering effect. Is that how you PU bushes work or do they rotate on the bolt?

Mike Clark

[Running Board]

James are you saying that the eccentric bushes gives additional adjustment over that given by the through bolt with the locating pin? If so do you have any dimensions for the PU bush that you made?

I'll have to dismantle my trackrod ends to look at the bushes. They are a tight fit in the steering arm ends and are nipped by the bolt  so that any turn of the steering winds up the bushes and has a self centering effect. Is that how you PU bushes work or do they rotate on the bolt?

Mike Clark

yes as it moves the pivot point of the trackrod end , we had terrible problems getting the toe in correct, with concentric bushes and standard track rod (we measured 3 all the same)it had too much toe in , fitted eccentric bushes and  could get correct toe , my dads car had 1 eccentric bush when we restored it , the belna cabriolet had none but my belna saloon had a full set , it has been argued that the rubber " moved " rubber simply cannot shift from one side of the bush too another and remain unform in thickness , i will have a look on my dads pc to see if he has any pics of the bushes he made or drawings ,from memory the sleeve in the pu bush is only pressed in so can rotate in the bush so the bush doesn't twist 

[Running Board]

this is a factory bush

[Raahauge]

All the rubber bushes were unusable when I came to it on my rebuild.
From recollection the typical maximum advised torsional rotation in degrees on these type of bushes which are commercially available is in the low 20's with the highest I found to be about 30.
The one on the drop arm has to rotate over 40. The originals must have had a rubber composition that allowed for this high degree of torsional flexing.
I couldn't see a way forward with rubber so changed all mine to Igus plastic rod-end bearings which are an exact replacement save for the axial length, - spacers are needed. The one on the drop arm is bigger and needed a sleeve.
From all the comments it looks as if the eccentric rubber bushes allowed a general adjustment and the fine tuning could then be done with the eccentric pins at the ends.
I will investigate PU rather than alter my track rod.
Mike R.

[Running Board]

My dad did a lot of research into eccentric bushes , he learnt a good amount from ruberry owen trailers who used them on steering trailer axles , the main reason was that they can articulate through a steeper angle than a concentric bush , i suppose this would make sense with them being such a small diameter i would imagine there would be a hell of a strain on them if one suspension was fully up and other fully down , from what my dad found out there was less load on the bush in these extreme circumstances DO NOT ASK ME TO EXPLAIN HOW OR WHY!! 

[Raahauge]

I was just thinking about Pu bushes and the amount of eccentricity needed when I realised that my statement that the 4mm of adjustment available at the rod ends provides 5.3 at the wheel is correct but misleading, the affect on toe-in is double that. 
I think that means that the movement of the pin by one hole on one side changes the toe-in by just under 1mm.
There is a surprising amount of adjustment available with the addition of eccentric bushes.

[Kari]

As I have predicted, the subject is gaining momentum!

May I pass my personal opinion. The “eccentric” silent blocs (bushes)

With all respects what the late Morris has passed to us Augusta boys by publishing the Augusta Newsletter and collecting valuable information for us to use, there was one little thing Morris and I agreed that we don’t agree: the eccentric bushes in the Augusta steering. I do agree that there are other applications which are using eccentric bushes as Morris has stated.

Now, why would Lancia go to the expense and install adjustable eccentric bolts in the steering when the toe-in could be adjusted by eccentric bushes? And how would that be done during assembly of the car in the factory? As experience shows, the range of adjustment by the standard bolts is enough in most of all track rod lengths.
If a eccentric bushes are found on a car, they are very old and the car has been standing a long time in a position causing permanent load on the bushes, thereby getting deformed (plastic flow).

Another point that might rise an eye brow or two: to clamp or not to clamp the silent blocs.
I think the bolt in question is not designed the inner bush of the silent bloc to be clamped to the track rod. The surface area is just to small.  If clamping would be needed, there would be a serrated bush like the silent bloc at the front of the rear springs. The nut is very light, the few treads can be stripped easily. I don’t think the rubber in the  silent bloc is soft enough to allow a turning of 60° + as it does at the drop arm at full lock. Therefore, I believe that the bolt should be tightened just snug to allow the inner bush of the silent bloc turning around the eccentric bolt. There is only little movement while driving, even on a curved road, there is almost no wear.
There is an argument that the twisting of the rubber would aid the self-centering effect of the steering. It might help, but I think the self-centering is done by the built-in castor.

On my car, in the last 60 years, I have changed many silent blocs but there are still the original bolts present. Every couple of years, I remove them and put a light coat of grease to the bolt and bush. For about 2 years or about 6’000 miles I use PU silent blocs which Peter Renou has given me to test. No problem.

I look forward to the comments.

Regards

Karl