Xantia toe in setting ?

[Mandrake]

Thanks Old-Guy,

I thought I better follow up with a post to say that the problem has finally been fixed, although it took them more than one attempt!

The date codes for the two tyres are 2412 for the right tyre - the one that still looks a little bit warped, and 1312 for the left tyre. I presume they are week numbers followed by 2 digit year ? If so one tyre was made in March this year and the other June this year, so not very old at all.

I took it back in again today, twice, they had a go at rebalancing it, I took it away for a test drive and if anything it was worse. Whole car shaking at 70mph and noticeable as low as 50mph. The second time the boss had a look at it himself, and commented that the amount of weight that had been added last time was very high, and that he was suspicious that the adaptor between the balancer and the rim wasn't aligning properly.

It looks like I got bitten by the infamous problem where many tyre fitters don't have quite the right adaptors for Xantia alloys to fit and centre the rim on their balancing machine, thus giving grossly wrong readings... When he fixed the problem with the adaptor the readings came back to normal.

Apparently they had previously been putting on about 145 grams (!!!) on the rims in an attempt to balance it and now they only have about 25 grams. I had noticed the large number of weights and been suspicious of that...

What compounded the problem further is that while I only got 2 new tyres fitted on the front I had asked them to balance the rear wheels as well, because there WAS a vibration at 75mph before I first took it into them, although nothing like as bad as what it was AFTER they fitted the new tyres...

So I had 4 wheels that were all about 120 grams out of balance. No wonder the whole car was shaking. Despite my skepticism that balancing alone would entirely fix what seemed like a warped tyre, I've driven it up to 80mph today and there is not the slightest hint of vibration. It's always had at least some vibration at speed since I've had the car so this is welcome news.

So we got there in the end. It does still pull a little bit to the right on acceleration in some circumstances but I'm beginning to think that's probably the worn lower arm bushes... new tyres with better tread and grip do tend to expose any problems in suspension geometry like worn bushes.

As far as the tyres themselves go, MASSIVELY better ride quality than the old ones, much much better in the rain, (old ones would spin from a standstill if you poked the accelerator a bit too much) and just generally feel quiet, smooth and tight.

Of course the tread was worn out on the old tyres as well, but I'm sure a good part of the difference is the difference in quality.

[Xantidote]

A good outcome in the end. 25 gms: that's a bit more like it! At least the boss had his wits about him

A useful reminder to us all about having the right adaptor on the wheel balancer machine

[Citroenmad]

Ive had a very similar situation with tyre on a C5, again fitted with new Michelins. It turned out to be a tyre fitter not being able to balance wheels correctly. I took the car back 4 times and still the same, I went somewhere else and the tyres were perfect from new to worn out.

Ive had quite a few tyres distort and make the car vibrate or pull to one side. The latest being on our eldest C5 which had Goodyears, it was pulling dramatically to the left, the steering wheel was well out of centre. There was also a strange sensation through the wheel when turning the steering wheel at low speeds. I fitted a new pair of Michelin Energy Savers to it and everything was cured, the vibration, the pulling, the steering was central and the steering sensation had gone. Its still perfect 10K miles on. Ill never be buying any more Goodyears, hopeless tyres.

[Mandrake]

I've had a week now to assess the tyres, and while I'm happy with the performance of the tyres themselves in terms of ride, handling, wet weather grip etc, I'm not happy with how the steering is feeling.

Before getting the new tyres on the steering was feeling very sharp - light and sensitive, very little dead band at the centre, especially after replacing a worn track rod end, and a good positive self centring action that pulled nicely to the centre. In short, the steering felt spot on, and very precise at high speed.

Now the steering feels a bit heavy and ponderous, like there is a lot of drag from flat tyres, despite me having 35psi in them. It doesn't centre very well, if I turn it to the left a bit and let go it keeps drifting off to the left, same for the right, there is no real self centring action in a +/- 10 degree arc around straight ahead. Furthermore, acceleration is often causing the car to pull or drift to the right, which it was not doing before.

When the wheels were fitted they "adjusted" the wheel alignment as described earlier in the thread, by drastically reducing the toe out (about 3 turns) and only adjusting the right track rod end - leaving a large offset in the straight ahead position on the steering wheel. (Before I took it in the steering wheel was perfectly centred) From that point on the steering has been vague and wandering near straight ahead.

I adjusted the track rod ends to balance the lengths and get the steering wheel back to centre, but apart from centring the wheel, it didn't really make any difference in the self centring nor the tendency to pull to the right.

I've increased the toe out by a small amount (half a turn on each track rod) in an attempt to increase self centring but its really not having the effect I expected - if anything it feels even more vague now. Should increasing the toe out cause a stronger self centring or will it make it worse ?

Anyone have any ideas whats going on ? Can wheel alignment cause the car to drift/pull to the right or can that only be an imbalance in the tyres ? Should I swap front left and right front tyres to see if it then pulls to the left (thus blaming the tyres) or stays to the right ? (blaming the suspension/steering geometry) Perhaps a handbrake is binding ?

Is it possible they've reduced the toe out so much (3 turns is a lot!) that I now actually have some toe in ?? Would toe in cause a vague feeling with little self centring and a tendency to pull to the sides ?

Whatever is going on, I'm not happy with the way its feeling, it drifts/pulls a dangerous amount to the right sometimes (yet not others, which puzzles me) and I'm worried that they might have got the tracking so far out that the tyres will wear quickly.

I'm reluctant to take it back to them though as they clearly don't know what they're doing, nor did they provide any sort of before/after print out of the toe out values. I'm also reluctant to take it somewhere else which will just "adjust" it without telling me what its set to before and after.

When I had my last Xantia wheel alignment checked it was done by a wheel alignment specialist who provided a computer printout of before and after figures, AND took it for a drive to check that the steering was centered and tracked properly...

Perhaps I need to make a tool to measure it myself ? If so I need to do it in the next few weeks so I don't wear the tyres if the tracking is a long way out. Between the tyre garages attempt to adjust it and my tweaking I now have no real idea what the degree of toe out (or in!) is.

[thorter]

Simon,

Assuming the track was not too far out before, 3 turns will make it wildly wrong. The thread is 1.5mm pitch, and there is a “gear up” to the rim. So one turn (on one side only) shifts each side of the rim by 2mm, giving 4mm change in track.

In my experience, you need to get the track in the centre of the range for best steering feel, so 1.0mm to 2.0mm toe out is the target for a Xantia. I suspect that what happens when it is wrong varies. With new tyres, the tread may flex equally, and it can feel OK for a while. Alternatively, each tyre takes it in turn to control, and the car wanders. Or one tyre is always dominant, the other scrubs, but the behaviour is erratic on corners, or in the wet.

I have set the track using my own method for many years, and it is easy to get great precision. Unfortunately I cannot manage to post to Photobucket at present, so here it is in words.

You need two cheap building laser pointers, and two target boards each consisting of a plank with small boards at each side reaching up to axle height. Mark pencil graduations every 10mm, so that the graduations line up exactly between the two boards on both sides (so targets as identical as possible).

Fix the lasers rigidly to each front wheel, pointing forward. Put one target board at 5 times the rim diameter so that the laser spots land on the scales. Push the car forwards (laser spot rotates downwards), and position the second target board under the car again 5 rim diameters from axle. Since 5 diameters = 10 radiuses, the “magnification” is 10:1, so the graduations represent 1mm of track. Use your initiative to work out the total difference between front and back!

You don’t strictly need two targets, but it makes things much simpler, since you just roll the car backwards and forwards repeatedly to take each reading. Note that this method eliminates errors due to run out on the rims.

All this would be much more obvious with a picture or two, and I will post up when I can.

Fred

[thorter]

Here are images of track measurement












Fred

[Mandrake]

Simon,

Assuming the track was not too far out before, 3 turns will make it wildly wrong. The thread is 1.5mm pitch, and there is a “gear up” to the rim. So one turn (on one side only) shifts each side of the rim by 2mm, giving 4mm change in track.

Yikes. I didn't realise so few turns had such an effect, I hadn't tried to calculate it. There are two different thread sizes for the track rod end for different model Xantia's by the way - the V6 has the larger size, are they also 1.5mm thread pitch or will they be a different thread pitch ?

Yes 3 turns was a lot, I know for a fact they only adjusted the right hand side too, because I had been very careful to re-set the track rod ends to the same tracking as it was before I replaced them, and I counted the number of visible threads on each side after I was done and before I got the tyres replaced, and they were equal.

As I mentioned earlier in the thread I was very careful to replace the track rod ends one at a time and adjust them (down to 1/8th of a turn or less) so that the steering tracked and centered perfectly, basically I replaced one joint, set it approximately, took it for a drive, checked the centring of the steering wheel while driving, then corrected the adjustment and retested a few times until it was exactly centered again and pulling straight ahead, then replaced the second joint and repeated the process, only adjusting the side I'd just replaced.

Although I don't know what the original wheel alignment was, I'm pretty sure I had it back to exactly what it had been, and as I say the steering felt sharp and precise with the right amount of centring action.

If you're right the change they made could be so great that it now has toe in, which might explain the odd behaviour. Apart from adjusting the centring I've only tried increasing the toe in by a 1/4 of a turn on each side, but if its not even in the ball park to begin with that might explain the ambiguous changes I noticed from doing that.

After the screw up they made with the wheel balancing, I'm quite prepared to believe they've set it to 1.5mm toe in instead of toe out!

In my experience, you need to get the track in the centre of the range for best steering feel, so 1.0mm to 2.0mm toe out is the target for a Xantia. I suspect that what happens when it is wrong varies. With new tyres, the tread may flex equally, and it can feel OK for a while. Alternatively, each tyre takes it in turn to control, and the car wanders. Or one tyre is always dominant, the other scrubs, but the behaviour is erratic on corners, or in the wet.

What you say makes sense, and it does seem to describe how the car is behaving. One of the two tyres may be slightly more dominant, hence the pulling to the right sometimes, but it is very inconsistent, sometimes it pulls to the right sometimes it doesn't, sometimes it will drift to the left, especially if the road leans left. If I make a turn I have to steer it back to straight ahead, if I let it self centre it will stop well short of straight ahead and keep drifting towards whichever side it was turning towards.

From what I remember the alignment specialist who did my last Xantia set it to 1.5mm toe out and the steering felt excellent on that, that also had Michelins, although XM1.

I have set the track using my own method for many years, and it is easy to get great precision. Unfortunately I cannot manage to post to Photobucket at present, so here it is in words.

You need two cheap building laser pointers, and two target boards each consisting of a plank with small boards at each side reaching up to axle height. Mark pencil graduations every 10mm, so that the graduations line up exactly between the two boards on both sides (so targets as identical as possible).

Fix the lasers rigidly to each front wheel, pointing forward. Put one target board at 5 times the rim diameter so that the laser spots land on the scales. Push the car forwards (laser spot rotates downwards), and position the second target board under the car again 5 rim diameters from axle. Since 5 diameters = 10 radiuses, the “magnification” is 10:1, so the graduations represent 1mm of track. Use your initiative to work out the total difference between front and back!

You don’t strictly need two targets, but it makes things much simpler, since you just roll the car backwards and forwards repeatedly to take each reading. Note that this method eliminates errors due to run out on the rims.

All this would be much more obvious with a picture or two, and I will post up when I can.

Fred

Your system looks ingenious, but I'm not sure I fully understand it - how are you aligning the targets left and right so that you know where parallel tracking is, for a reference ? Are you just moving it right up as close as possible to the laser targets, adjusting the target spacing until it hits zero then pulling it back the correct distance ?

[thorter]

The beauty of the method is that the laser beams do not need to be precisely aligned with the wheel rims. The beams are equivalent to long lever arms, and the offsets and slight angular differences will result in a negligible error. Once positioned, the target boards stay in their fixed positions on the ground so that the times 10 magnification is preserved. Due to rotating the wheels downwards, the distance between front and rear targets is less than 10 times rim diameter. In fact, the car only moves half a wheel rotation.

It is only the difference between the measurement across the front beams, and the measurement across the back beams, that matters. Consider first the case that the tracking is parallel. The front and back measurements will be identical.

Now if a wheel is toed out, the front beam will move out by 10 times the figure at the rim, and the back similarly move in. Exactly the same applies for toe out of the other wheel. The easiest way to do the measurement is probably to move the target boards slightly sideways, so that, at say the left side, the beams fall on a reference line. You then take the difference of the scale readings at the right side.

Fred

[Mandrake]

Genius

For some reason when I first read your post I didn't click that you were showing two separate scale boards side by side, one for in front of the car and one behind...or that you were rolling the car half a wheel rotation to point from one to the other...I now understand perfectly how it works, and I can see how nearly all sources or error are eliminated from this technique, including any imperfection in the alignment between the laser sight and the wheel rim. Pure genius.

The only slight snag I can think of - is 10 wheel radiuses far enough for the scale board to clear the rear wheels of the car ?

I'm not sure if I'm going to get the time and good weather in the next few weeks to attempt to build and use this system, I might just have to reluctantly take it somewhere to be adjusted, but I'd rather do it myself if I can.

I can envisage making a couple of scale boards with a hinge in the middle to fold them in half for storage. (Otherwise nowhere to store it in a small apartment! )

Any hints on where you bought your laser spirit levels ? I'm also wondering how well they'll be able to attach to my alloy rims which have nothing to attach to at the middle and a large slightly curved surface...

[thorter]

For the Xantia, 15” rim diameter is near enough 400mm, so the board positions are 2 metres from the relevant axle position. So the rearward board is indeed under the car, and the design needs to clear the underside. This is no problem in practice. You can, of course, make the “magnification” anything you want, but X10 is convenient.

Note that as the wheel rotation is half a turn or about 1metre, so the distance on the ground between the targets is about 3 metres. This reduces the length of flat ground you need.

Turning to the lasers, the ones I have are perhaps 15 years old. As far as I can remember, they were of the order of £12 each, but laser levels seem to be much more expensive now. Mine are fine for the present purpose, less so for the intended use as building levels since if you put them side-by-side on a flat surface, the beams are not particularly parallel. Note that with the set up in the photo, the beams only just clear the tyres, but are adequately clear of the bodywork.

However, all you really need is two laser diodes with their power sources, so cheap laser pointers should be a good solution. Look at Amazon or Ebay or specialist suppliers. You would need to arrange proper on/off switches rather than momentary push buttons.

The advantage of laser pointers is that they can be very small. I have thought about a better design, but it isn’t a priority. However, a possible scheme is to make a plate that attaches to the wheel bolt heads by magnets. You would probably need spacers to get clear of the wheel. Good rare earth magnets give an incredibly force, see http://www.first4magnets.com. At the centre of the plate would be a post sticking out on axle axis. The laser pointer would attach by a clamp that allowed rotation so as to align the two sides with each other very easily.

For stowage of the target, I would be inclined to use square steel tubes, and totally removable boards. The tube could be about 40 x 40 x 1.5 (not sure exact sizes available). You might find that a 6 metre length from a stockholder works out cheapest, even if you throw half of it away.

I hope this helps. This method is not quite as quick as the gauges used by the trade, but is certainly more accurate and less likely to get totally wrong.

Fred

[Mandrake]

For the Xantia, 15” rim diameter is near enough 400mm, so the board positions are 2 metres from the relevant axle position. So the rearward board is indeed under the car, and the design needs to clear the underside. This is no problem in practice. You can, of course, make the “magnification” anything you want, but X10 is convenient.

Ah ok so the back one is in front of the back wheels, gotcha.

Note that as the wheel rotation is half a turn or about 1metre, so the distance on the ground between the targets is about 3 metres. This reduces the length of flat ground you need.

Space is one thing I'm not short of around the car - we have a large shared car park that is fairly empty during the day so I could easily double the distances to x20 and get double the accuracy ?

Turning to the lasers, the ones I have are perhaps 15 years old. As far as I can remember, they were of the order of £12 each, but laser levels seem to be much more expensive now. Mine are fine for the present purpose, less so for the intended use as building levels since if you put them side-by-side on a flat surface, the beams are not particularly parallel. Note that with the set up in the photo, the beams only just clear the tyres, but are adequately clear of the bodywork.

I had a quick look on amazon and found these:

http://www.amazon.co.uk/Silverline-5984 ... 9DS176T196" onclick="window.open(this.href);return false;

Very cheap and probably not that good for their intended use, but given that run out of the rims (and therefore lack of perfect parallel between the level's edge and the beam) is compensated for in your method, they should be fine ? Only 210mm long so to hook onto the rim edges properly I might need to attach them to a metal strip cut to the right length. (Theres not much to attach to near the middle of the alloys - the gaps that I could attach rubber bands to are near the edge) As long as I can find a secure way to attach them they should do the trick.

Justs remembered I also have an LED torch with a laser mode with quite a good laser. Unfortunately I only have one!

Edit: Found this also, apart from the postage cost it looks like it could be a better unit, and length is 355mm which is ideal for mounting to a wheel:

http://www.ebay.co.uk/itm/355mm-laser-l ... 1228wt_888" onclick="window.open(this.href);return false;

Can't really seem to find anything else under £20...

[thorter]

No harm in increasing the accuracy, though I think you will find there is plenty already with the X10 geometry. Just ensure you do not need to put the target where the rear wheels are!

These laser levels look similar to mine, and should be very satisfactory. A better unit may have a smaller spot size, not really any benefit for this application. As you note, small errors in mounting do not matter. However, still consider pen size pointer units or pointer torches, and a mounting that allows rotation.

Remember that you need to adjust the beams to be the same height on the targets, so consider the mounting method to ensure this will be easy. It is a pain to need to jack up a wheel to do this, particularly as it takes a few passes rolling back and forth to settle everything before the measurement. A bit of good news with the Xantia – you can get enough access to adjust the track without the need to increase height or change steering position (I am sure you appreciate that the tracking must be adjusted at normal height).

Fred

[KennyW]

Hi All,

What about extending the wheel bolts ie finding 4 bolts with the correct thread and length using the wheel hub. I don't how difficult this would be but its just a thought

Kenny

[thorter]

Kenny,

I have though about this possibility, but to use all four bolts, you need to jack up the car to fit the laser pointer. In practice, probably two or even one bolt could be changed over to a special that provided the mounting. Another way would be to drill and tap the heads of the wheel nut M5 or M6, and fix to these.

However, I think the magnet route is better, since you could very quickly check the track at any time without even needing a spanner (unless you have to adjust), and it would work for both steel and alloys. I am still thinking how the whole thing can be further refined.

Fred

[jacksun1987]

my xantia shakes at 70 to 80. as well but i need to get it the tracking adjusted as well. But its ok below 70 75 starts shaking a tiny bit then 80 your hands are falling off. If got used to it lol