Tracking

PostPost by: carrierdave » Fri Jan 27, 2006 6:53 pm

Just a quick question for you all.

I decided to check the tracking on the car the other day. I measured the location of the vacuum takeoff on the front chassis cross member and found it to be central to the car, therefore I used this with a piece of rope to check out the distance/tracking of the wheel.

After adjusting one side I then measured across between the center of the tire treads. This came up at around 52 1/4 inches.

Looking at the workshop manual it should have been 54 inches!!

I then measured (as best I could) across the rear of the tyre?s and found them to be just over 52 1/2 inches.

Is this OK - Do I need to loosen off the front suspension and then load the weight on until I get to the magic 54 inches? My concern with this would be that the car would be sitting on the ground, as it is I have trouble getting the trolley jack under the car.

Any advise would be appreciated.

Dave
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PostPost by: rgh0 » Fri Jan 27, 2006 11:51 pm

Dave

I dont think you need worry about the 1/4 inch extra you measured. Where did you measure the track width at the bottom or sides of the tyres ? Track width varies with where you measure it and with the ride height setting. If the ride height is OK and there are no worn bushes or bent suspension or chassis components then the track you have is the right track and a small variation from the Lotus nominal 54 inches is to be expected given all the tolerances in both the components and the measurement.

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PostPost by: carrierdave » Sat Jan 28, 2006 12:30 pm

Hi Rohan,
I measured across the front of the tyres, say at 3:00 and then at the back at 9:00.

The ride height appears to be OK and there is no movement in the bushes so hopefully all should be well.

It was just a little concerning to see that I was at least 2" out on the width and I could see no way of increasing the tracking, that all.

Thanks for the reassurance

Dave
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PostPost by: rgh0 » Sun Jan 29, 2006 5:48 am

Dave

I miss read your first post sorry. I read your 52 1/4 inch as 54 1/4 inch. 2 inches difference is a lot larger than I would expect just from assembly tolerances.

I just quickly measured my Plus 2 and its near enough to 54 inches both front and rear.

Do you have the original wheels ? Different offsets are about the only thing that could make the 2 inches difference and the car still be driveable.
The 4 1/2 Elan wheels may give the track difference you are measuring

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PostPost by: M100 » Sun Jan 29, 2006 6:27 pm

carrierdave wrote:I measured across the front of the tyres, say at 3:00 and then at the back at 9:00.


Try it again at midnight under a full moon :twisted: :evil: :twisted:
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PostPost by: carrierdave » Sun Jan 29, 2006 10:45 pm

Very good idea Martin, I think I should just clear the front timing case with the tape measure.

Rohan
Yes I have the original wheels. All I can do is to loosen off the front suspension and reload the front end and then check it again.

Dave
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PostPost by: rgh0 » Mon Jan 30, 2006 8:06 am

Dave

If you have the original wheels then I dont know what can be causing the 2 inch tracking difference without something else being obviously wrong in a major way. Resetting the suspension is not going to change the track signficantly if the ride height is about right.

When I measured mine I measured at about 4:30 and 7:30 on the wheels where I could pass the tape under the car and measure between 2 chalk lines I made on the centre of the tyres. You may want to check measure directly between the 2 wheels rather than using the vacuum tapping as a central referance point as you initially described to confirm your orginal measurements.

Rohan


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PostPost by: M100 » Mon Jan 30, 2006 11:45 am

Maybe you have +0 hubs fitted?
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PostPost by: triumphelan » Mon Jan 30, 2006 4:38 pm

What are +0 hubs ?
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PostPost by: M100 » Mon Jan 30, 2006 8:49 pm

Not +2 ones :D

+2 on the left +0 on the right, these are rear ones but you should get the general idea :wink:

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PostPost by: triumphelan » Tue Jan 31, 2006 7:50 am

Can you get different length hubs ,is it to allow wider tyres to be fitted
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PostPost by: carrierdave » Tue Jan 31, 2006 6:51 pm

Hi All,
Certainly the rear hubs are are per the left hand picture - the right hand hub looks as though its off of the front.
I think I will first check the rear track width and compare it against the manual.

Can anyone tell me the front cross member to road clearence dimension.

Thanks

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PostPost by: rgh0 » Wed Feb 01, 2006 9:34 am

Lotus specifies ground clearance as 6 1/2 inches at the bottom of the chassis closing plate with the specified seat loadings. The bottom of the front cross member is at the same level.

As this measurement depends on the tyre rolling radius and specified loadings in each seat you need to also check this and correct for any differences. The drawings in the manual of the front and rear suspenion give the needed dimensions. You can see from the drawings that the lower suspensions arms are horizontal at the right ride height and this is actually the easiest way to check the setting I find

Most plus 2 unless they have had a recent rebuild are low at the front as the standard front springs are over stressed and sag over time.


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PostPost by: tdafforn » Wed Feb 01, 2006 12:15 pm

A number of people have commented that I have too high a ride height at the front by about an inch..
Is the only way this can happen through the fitting of incorrect springs?
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PostPost by: M100 » Wed Feb 01, 2006 12:25 pm

carrierdave wrote:Hi All,
Certainly the rear hubs are are per the left hand picture - the right hand hub looks as though its off of the front.


Althought at first glance it might look like that It's not supposed to be (pic was from Robinshaw and Ross 2nd edition)

Having 2 seat (ie +0) elan hubs looks to me like the only way the track can be anything but factory spec (unless you have dodgy wishbones as well!)
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