I know you shouldn't believe everything you read but I was convinced by an explanation that tracking/toe-in should be done when the car is fully loaded. So I'm heaped up with buckets of sand on the seats and in the boot to find this changes the previously perfect toe-in so that it needs serious re-adjustment.
The problem is that when the weight is removed the toe-in may turn into toe-out.
Any opinions or knowledge from experts or otherwise.

most manufacturers give a precise weight to be put into the car when carrying out camber and caster wheel alignment. In the (pucca, Fiat factory) workshop manual it states:- place the car under 'static load' (corresponding to an orderly load of 4 passengers). I assume that this must also be the case for toe-in (0-2mm). Fiat also give height measurements that the car must sit at when the correct weight is in the car. if you would like to contact me direct (with your home address), I will copy out the appropriate pages out of the work-shop manual for you.

the hobbler said:

most manufacturers give a precise weight to be put into the car when carrying out camber and caster wheel alignment. In the (pucca, Fiat factory) workshop manual it states:- place the car under 'static load' (corresponding to an orderly load of 4 passengers). I assume that this must also be the case for toe-in (0-2mm). Fiat also give height measurements that the car must sit at when the correct weight is in the car. if you would like to contact me direct (with your home address), I will copy out the appropriate pages out of the work-shop manual for you.

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Thanks for that explànation Hobbler but as I two-time this forum (as do others) I obtained the technical details elsewhere. I suppose the real solution is to take the car to a specialist and if I observe strange handling or tyre wear characteristics after this, I have such a place in mind.
For now I am very pleased with the results achieved by attampting to follow Fiat recommendations.

You could try one of those Gunson? TrackRite devices for checking toe-in, the sort you drive over and shows if tracking is correct.

One of the reasons for setting toe-in (or toe-out) is to ensure the wheels are close to parallel when moving forward i.e. when all play/give is taken up in the linkages/bushes and car pushes the wheels forwards and so minimise tread wear.

You should be fine if you just keep an occasional check for abnormal tread wear. If you run your palm in and out across the tread and it feels the same in both directions you're good, if you feel sort of wedging/chamfering effect in one direction (like little sawteeth) but not the other, probably need some adjustment to tracking.

Al.

I recently spotted that Murf's front tyres, already getting very close to wearing out, were both getting scuffed on the outside edge. Looking closely it was obvious that he had a severe case of toe-out. I'm guessing this has developed since I recently renewed the bolts and nuts of the upper pivots on the stub-axles and that there have been slight changes in orientation? I had noticed that his unerring stability on bends was coming slightly adrift.....as nearly was I at one point.

For a long time I have been planning to adjust the steering-wheel which does not point straight ahead, so I used this opportunity to see if simply adjusting one of the track-rods and leaving the other alone might solve both issues. I don't have a flat, concrete, garage floor as previously so it isn't possible to achieve my normal precision. But with a relatively few turns of the rod I appear to have sorted things out. But something tells me that there are reasons why both track-rods need to be of the same length, for instance in order to avoid problems at full lock. I haven't measured them and they can't be way different, but I'd welcome opinions on this.

In Athens where i live if you take your ''old'' car to the shop for wheel aliment, nobody wants to mess around with it and almost everyone will send you to a specific shop in Athens that he is there from 1959. Their excuse is that he has the ''old machine'' so he can only adjust it. Anyway i been there twice, with my Renault 8 and now with the 500. He has an ancient machine but he is using a modern and very expensive one for all the cars, truth is that he is expert and knows what he is doing (one of the last). He adjust my steering with me sitting in and he asked me if i am driving alone or with load. When i am alone car is perfect, when family is inside, everything goes to hell (toe-out), steering wheel position moves from neutral to slightly right in order to drive straight.

That's exactly what it's like Thomas. [emoji3]

I think that one has to decide in what condition the car is most driven in---1 person in the car or 2/3 people in the car, and then set it up for that condition. My car has been set up for basically just 1 person, as that is how it is driven most of the time. When I have Ann with me (I have no back seat--I have to put the spare tyre there as I run 13in wheels) the steering wheel has a bias to the left (RHD car)----with just me in the car, the steering wheel is practically central and the car drives beautifully---I spent some time getting the toe-in correct (zero) and the track rods the same length. I use old fashioned Dunlop gauges.

I overthought it for a long time. I had considered taking it to a local garage but I then I thought they don't normally deal with older cars, then I thought about taking it to a classic fiat specialist. High cost and reasonable distance to get there put me off.
In the end I used a long piece of string and 4 axle stands to allow me to measure from. I have a concrete driveway, but I would have used a supermarket car park if needed. vast improvement. I done it with no weigh in the car. I normally drive on my own, although I agree that loading my weight in the car would give better results suited to me. Maybe that's an excuse for me to sit in the car while someone else does it!

fiat500 said:

But something tells me that there are reasons why both track-rods need to be of the same length, for instance in order to avoid problems at full lock. I haven't measured them and they can't be way different, but I'd welcome opinions on this.

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Mr Ackerman and his angles, and I don't mean the guitarist in Focus.

D

Although the toe-in seems OK after I replaced the front spring I think it's wise to check it again.

Previously I have done this with the car pre-weighted as per the Haynes instruction for the 500 and latterly I see that I have stumbled upon the method described in the Haynes for the 126; by using concrete blocks as ballast.

The specifications I have are;

0-2mm for a standard 500]measured with equivalent load to 4 occupants
0-3mm for an early 126 ]as above
7-11mm for a 126 from 1977 to 1979] measured with no occupants in the car
2-6mm for a 126 from 1979 onwards ] as above

It wouldn't be right to directly apply the 126 specifications for the 126 to the 500, as they differ in quite a few ways that might affect the toe-in requirements. But I am interested to see that it was latterly recognised that measuring toe-in whilst fully laden isn't exactly easy.

But if you set toe-in to the original 0-2mm spec. whilst unladen, the implication is that this might reduce to an effective measurement anywhere between 11mm toe-out and 0mm if the car was ever fully laden.

It's pretty obvious that many of us drive our cars solo for most of the time with an occasional passenger. So I make the assumption that it's probably appropriate to adjust the toe-in to target the measurement applicable to a vehicle laden to 25% of full capacity. So I could try measuring with about a quarter of the weight that I usually fill the car with and still aim for between 0mm and 2mm toe-in. Alternatively it's possible that an unladen car should have between 1mm and 4mm of toe-in if it will usually be driven with no passengers. I'll check the current state unladen and if it's between these parameters I will leave it alone.

Has anyone used professional garage services to get the toe-in adjusted correctly? If so, what was their approach and did it work?

I worked as a Mechanic in a Fiat/Lancia Main Dealership workshop in the '70's i.e. when 500's and 126's were often in for servicing etc.

We never loaded the car when checking/adjusting toe-in/out on any of the cars (fwd cars were set to toe-out). What we did was iirc set the tracking to roughly 1/2 the Fiat figures, so e.g. if Fiat stipulated 0-2 mm, we set to 1mm.
Seemed to work fine. With lots of regular customers we could track the tyre wear, never had any problems with excessive tyre wear (other than if e.g a balljoint/kingpin was worn).

Adjusting the 2 track rods so that they are the same length is very important - if they don't match, they need to be equalised first, then the tracking checked/set. Otherwise the 'Toe-Out-on-Turns' will be wrong leading to excessive tyre wear and weird handling/cornering issues. Toe out on turns means that the inner wheel when turning e.g. the left wheel when turning left) turns through a greater angle.

If your steering wheel is misaligned when travelling straight, 1st equalise the length of the track rods, then set the tracking, then remove and re-position the steering wheel so that the angle of the 2 wheel spokes are equal relative to horizontal.

To remove the steering wheel on older Fiats, you don't need a puller or to use a big hammer, simply loosen the central nut a few turns, then grip the wheel on each side (left and right), push down on one side while pulling up on the other, then do the opposite, as if you were trying to rock the wheel on the steering column - it'll pop loose. When refitting the wheel, be careful to align any pin on the wheel with the indicator switches (self-cancelling feature) and mind you don't bend any horn contact strips.

If after setting the front tracking you continue to experience steering problems (e.g. pulling/wandering to one side) or excessive tyre wear, it might be worth checking the rear tracking (idk the settings) and also to check that the front and rear wheels on each side are still in correct alignment (not so easy due to the different camber angles etc), maybe use a straight edge/plank/length of string or find a puddle in an otherwise dry car park and drive through it slowly while someone watches the tyre prints left behind on each side.

Professional garages with modern 4 wheel alignment systems should be able to get all the settings spot-on providing the operator knows what they're doing and cares

Hth,

Al.

F123C said:

We never loaded the car when checking/adjusting toe-in/out on any of the cars (fwd cars were set to toe-out). What we did was iirc set the tracking to roughly 1/2 the Fiat figures, so e.g. if Fiat stipulated 0-2 mm, we set to 1mm.

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That's the same principle (but in reverse) that I plan to use. But my manuals give the impression that the toe-in dimension reduces as weight is added to the vehicle given that the 1977 to 1979 126 (unladen) tolerances are 7 to 11mm.

fiat500 said:

That's the same principle (but in reverse) that I plan to use. But my manuals give the impression that the toe-in dimension reduces as weight is added to the vehicle given that the 1977 to 1979 126 (unladen) tolerances are 7 to 11mm.

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I don't have any manuals for either the 500 or 126 to consult so have to rely on my memory from 40 years ago - so if I sometimes get it wrong, hopefully you'll forgive me...

11mm toe-in sounds crazy. Maybe try setting (if you have gauges/trammel bar) the toe-in laden as per Fiat specifications and then check what it changes to when the car is unladen. This would confirm/refute your impression?

As others have said, the wheel alignment especially camber/toe-in can change significantly on the 500 depending on number of people carried. My approach would to set things up to best suit how the car is normally driven - for many, this would be solo i.e. driver only.

In a previous post, I suggested using one those Gunson's TrackRite? devices, which indicates side-slip - you need minimum side-slip for maximum tyre life and performance.

Did the later 126's have rack and pinion steering? This might also result in different toe-in figures being quoted. Might also have different caster/camber angles? Anytime one thing is changed in a suspension/steering system, it might result in several other settings being changed. Iirc, some? 126's were fitted with wider? Dunlop Denovo Run-Flat tyres, these might result in different suspension/steering settings being specified.

Al.

Thanks Al. I agree...the later toe-in figures wouldn't be applicable as various differences exist in the setup.
I intend to do as you suggest and see how the dimensions change under load.
PS. There's now't wrong with your memory.......but but quite frequently there are problems with my wacky theories.[emoji3]

Al, you are correct in thinking that the 652cc (Mk 2) 126 cars had rack-and-pinion steering. According to "Haynes" the toe-in measurement changed at the end of August/beginning of September 1979. The early cars had a toe-in of between 7 and 11mm, whilst on the later cars this was reduced to between 2 and 6mm. In both cases,according to Haynes, the measurement was made with the vehicle at kerb weight and WITH NO OCCUPANTS.
According to the Factory "book of words" the toe-in adjustment for the 500 should be made with, and I quote "car is in a static load condition or with an orderly load of 4 persons"---i.e, no drunks or rowdy people.
As my car is driven mostly with only me in it, I have set the toe-in at ZERO, and with no load in the car (with 5-1/2 x 13in wheels). So far, I have suffered no undue tyre wear, and the handling has been very favourably commented on by the person who drove it around Brands Hatch at the big Abarth gathering in August---and being that his job is re-building/restoring classic Abarth cars I think that he might just know what he is talking about!

the hobbler said:

Al, you are correct in thinking that the 652cc (Mk 2) 126 cars had rack-and-pinion steering. According to "Haynes" the toe-in measurement changed at the end of August/beginning of September 1979. The early cars had a toe-in of between 7 and 11mm, whilst on the later cars this was reduced to between 2 and 6mm. In both cases,according to Haynes, the measurement was made with the vehicle at kerb weight and WITH NO OCCUPANTS.
According to the Factory "book of words" the toe-in adjustment for the 500 should be made with, and I quote "car is in a static load condition or with an orderly load of 4 persons"-

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The objective of my deliberations is to find out if it's possible to find an accurate way to measure Fiat 500 toe-in without loading the car with concrete blocks or "with an orderly load of four persons" and whether or not that has been done successfully by others; so with that in mind I'm grateful for previous answers to both questions.

Whilst I have noted that there are many differences between the 500 and the 126, there are also many similarities; so much is that so that, as we know, some (many?) people have transferred significant chunks of components from one model to the other. Fitting a 650 engine and gearbox will add a few kilos and slightly change the stance of the car; whilst some people have actually fitted a steering-rack and made modifications to suspension arrangements which I think would entail a complete re-think of toe-in setup which would not be applicable to a standard car.

The only way to be sure is to do what I have done previously and load the car before measuring toe-in. But that is a bit of a ballache, so as I have already said, I'm going to measure it in the unladen and then in the laden condition and compare any changes in order to see if there is any formula I can apply in future.

From my own anecdotal observations, both of this car and my modern car, whilst the handling can change quite significantly with incorrect toe, excessive tyre wear only seems to become an issue when the steering is way out of spec. or the reverse of spec. ie. toed-out when it should be toed-in.

I've completed my "scientific" test and it correlates the suggestion of the hobbler. It also supports what F123C said about setting to about a half of the manufacturer's figure if checking unladen.

I measured the relative dimensions at the rear and the front of the inner rims whilst the car was on flat ground under differing loading with concrete blocks.
Measurement was relatively crude, using a threaded rod inside a tube against which a nut could be wound to lengthen or shorten its effective distance.
The car wasn't driven or moved forwards between loadings. All of this could accrue errors but as all the measurements were achieved the same way there may be some validity in the readings.

The empty car with its new front spring had a slight toe-out of 1mm.
Evenly loaded with 36 and then 72kg the car had a toe-in of 3mm.

So for my car, if I'm aiming for neutral or very slight toe-in as the only occupant, the car is probably set-up as well as it could be. Adjusting an empty car to zero toe or even a very slight toe-out unladen will get me within the manufacturer's original specification once I'm in the car.

It leaves me completely perplexed about what's happening with the 126 toe-in, but that's not my problem.