Tracking

[80Sprint]

Any tips to set up tracking on a Sprint before I can get it to a specialist. I may have to drive it for a day before I can. I have seen something on you tube with string line from the back wheels.
It's a replacement quick rack so I don't have original turns on the rod ends to match the original set up so I am starting from scratch.

[xvivalve]

Jim King in Somerset has a set of tracking gauges for sale (probably formerly owned by Brian Kitley) as Jim has now sold his car. I can let you have his number if this is of interest; I understand he's looking for £120 for them.

He also has an engine crane available

[Bumpa]

Years ago I bought a Gunson's Trakrite gauge and I have never regretted it. Such a simple idea. Set it to zero and drive over it. If the tracking is out the tyre squirms and alters the gauge. If the tyre is parallel to the direction of travel the gauge doesn't alter. You don't need to know how many mm or degrees the toe-in or toe-out should be, you just adjust the track rods until the tyre travels straight forward and the gauge shows zero deflection. I have used it on many cars with 100% success. My MGB has independent rear suspension and wore its rear tyres out very quickly. The Trakrite showed me it had massive toe-out. Once rectified according to the gauge, tyre wear is now how it should be. Highly recommended, by me anyway.
http://www.gunson.co.uk/product/G4008

[Richard the old one]

I also have a Gunson trackrite and am very happy with its results.

[shaunroche]

It's very easy to do with a few canes and some fishing line.

Just make sure the distance is the same from the centre of each wheel front and back, perpendicular and parallel to the car and then at the front, just measure the distance from the front and back of the wheel rim and adjust the tracking until both dims are the same or whatever you want it to be.

Genuinely simple.



Depending how steady your hand is, you can easily be accurate to within .5mm...

[bazyerma]

ATS Euro Master checked my tracking and just put it to Parallel. They were very helpful and for £29.99 If though it was not to bad.

The Check was free, worth a punt?

Regards

Barry

[Bumpa]

Parallel should be all right, but generally rear drive cars need the front wheels to toe in slightly. This is because they are being pushed along by the driven wheels and so there is a tendency for the front wheels to splay out a small amount. The Haynes manual says the wheels should toe in by 0 - 1.588 mm. What you are trying to achieve is for the wheels to be parallel when the car is moving. Because you have to drive over the Trakrite gauge, it automatically compensates for any tendency for the wheels to splay out when moving.

Front drive cars are generally set parallel, although if I remember correctly the old Mini was set to toe out, because the front wheels are dragging the car along and can show a tendency to splay inwards.

[Carledo]

There USED to be a lot of variation in manufacturers tracking figures and, as Bumpa says, largely featured toe in for RWD and toe out for FWD.

But that was in the days of crossply tyres, which are vastly more critical of small errors in this area.

Modern radials are far better in this respect and as a result most professionals, including me, just set to a default parallel without worrying about what the factory said. Most modern cars are actually factory set parallel, plus or minus a gnats dick cos they never had a crossply option.

Most of "our" cars were built around the crossply/radial transition and, as a result, have a hangover, non parallel, figure quoted. (My own December '73 Toledo was factory fitted with the (cost option) radial tyres from new, according to the original invoice that I have, but even that late, cars were rolling out of Speke with crossplies fitted!)

I must have tracked thousands of cars in my nealy 50 years in the trade, it's a VERY long time since I set to anything BUT parallel and the last one (IIRC) was a crossply fitted Rover 110 (auntie Rovers HATE radial tyres, something in the steering geometry just rebels and makes them very wandery, especialy at any significant speed!)

Steve

[Galileo]

With 123 bhp and a top speed of a ton and Auntie sat on crossplies, I'll bring my brown trousers!

[Carledo]

With 123 bhp and a top speed of a ton and Auntie sat on crossplies, I'll bring my brown trousers!

You'd need them if she was on radials! Trust me!

I briefly owned a 105S in my youth, recently equipped with a spanking new set of G800s. (think they cost more than I paid for the car!) It needed all 3 lanes of the motorway and cojones of pure steel at 90mph! One reason why I didn't keep it long! I didn't find out about the allergy until years later!

The Sprint, at least, was thankfully only ever available with radial ply tyres early advertising made quite a thing of it! Though the tracking figure given in the manual was the same as that for a crossply equipped Toledo. A lot of Brit car companies were a bit late in getting the word! I think it's something to do with the increased sidewall stiffness on radials means the tread deflects less, so you don't have to allow for it in the tracking figure.

Steve

[Bumpa]

Modern radials are far better in this respect and as a result most professionals, including me, just set to a default parallel without worrying about what the factory said. Most modern cars are actually factory set parallel, plus or minus a gnats dick cos they never had a crossply option.

I didn't know that Steve. Just shows how out of date I am. I looked up the manual for my Z3 and it says the front tracking should be 0 degrees, 18 minutes, plus or minus 8 minutes. As you say its parallel plus or minus a gnat's dick!

Mike

[roadster]

My recently acquired Sprint felt a bit odd when turning in to a 90 degree corner and I also noticed that the steering wheel wasn't quite straight when it should be.

I set up some strings which I taped to the back of the front tyres and lined up to pass over the rims and through the wheel centre line taking it in front of the car by a couple of meters. Final alignment with the string taught was to get the string just touching the front of each rim. I then marked two measurement points on each string at equal distances from the wheel centres and finally measured the distances close to the wheels then as far out in front as practical. This immediately showed that, as I suspected, there was some tow out. To turn this into an angular figure I took the difference between width readings, which was 10mm, divided by the distance apart of the two readings, which was 1000 mm, and with the help of a very ancient set of tan tables came up with an approximate angle of 0.5 degrees ( arctan(5/1000) * 2). After a bit more guesswork and approximation I decided that one turn out on a track rod would be about right and because the car steered slightly to the right when the steering wheel was straight ahead I adjusted the offside track rod only.

This certainly improved matters and the steering wheel is now straight when it should be and corner entry doesn't give rise to any shopping trolley like effects. There are lots of caveats with this approach and it helps that the standard alloy wheels are likely to be true at the rim edge. I had also adjusted wheel bearings etc. Given that its a forty something year old car, and I'll be driving it accordingly, its close enough for me.

[cliftyhanger]

The "quick and dirty" way to do tracking is with a tape measure and an assistant (or maybe gaffa tape)

Simply measure from a chosen groove in the tread between the tyres, at the front and back of the tyre as high as you can without interference. Adjust until the 2 are the same.

A step up and gives very good accuracy, is to use some flat wood, maybe 4-6" wide and about 2' long. Lean against the tyres so just touching the sidewall front and back. Measure distance at the front an back as before. (I use a variation, a bit of steel bar sitting on a block to get it over the tyre bulge)

With my spitfire, being IRS, it was a whole lot more grief to get 4 wheel alignment, did it with string. Started setting fronts parallel, rears parallel, strings about a foot off each side. And lots of tweeking until I was happy the strings were parallel, the car was parallel to the strings, and the wheels were all parallel to the string. Took me a couple of hours, the centrelining being the tricky part. I do wonder if I should have measured a centre point at the front and rear of the chassis to make the centrelining part simple.

[Carledo]

With my spitfire, being IRS, it was a whole lot more grief to get 4 wheel alignment, did it with string. Started setting fronts parallel, rears parallel, strings about a foot off each side. And lots of tweeking until I was happy the strings were parallel, the car was parallel to the strings, and the wheels were all parallel to the string. Took me a couple of hours, the centrelining being the tricky part. I do wonder if I should have measured a centre point at the front and rear of the chassis to make the centrelining part simple.

I had similar grief with my GT6 convertible that I built back in the 80s. I had the advantage of tracking guages, a (borrowed) caster/camber/KPi set and a factory shop manual. Being a MkII GT6 chassis, it had the rotoflex rear end with adjustable tie bars and I started with a blank canvas, having had the chassis stripped and shotblasted and built it up from first principals.

So I set the front up first, matching it side for side and dialling/shimming in an extra degree of negative camber as I went then turned my attention to the rear and this is where the fun started! I found a wheelbase figure and a rear tracking setting (1/16" to 1/8" toe OUT) in the manual, but quickly discovered I could have one or the other correct - but not both! If I set the wheelbases correct and equal, the rear wheels toed IN horribly, about 1/4" and if I set the tracking correctly the wheelbase was around 1/2" too long. Knowing what rear toe in does to a GT6's handling (it's not nice) I settled for getting the tracking correct and the wheelbases equal but wrong. Even this took me the best part of a day to get set to my satisfaction as every adjustment affected the other settings. The hard work paid off in the end though as once i'd finished, it cornered as if on rails!

Steve

[trackerjack]

Years ago I bought a Gunson's Trakrite gauge and I have never regretted it. Such a simple idea. Set it to zero and drive over it. If the tracking is out the tyre squirms and alters the gauge. If the tyre is parallel to the direction of travel the gauge doesn't alter. You don't need to know how many mm or degrees the toe-in or toe-out should be, you just adjust the track rods until the tyre travels straight forward and the gauge shows zero deflection. I have used it on many cars with 100% success. My MGB has independent rear suspension and wore its rear tyres out very quickly. The Trakrite showed me it had massive toe-out. Once rectified according to the gauge, tyre wear is now how it should be. Highly recommended, by me anyway.
http://www.gunson.co.uk/product/G4008

MGB independent rear suspension!!! I had an MGB V8 and it, like my wife's MGB 1800 had a live rear axle cart sprung as befits the old nail.