Lotus Elan

Oversteer on corners

PostPost by: JonB » Tue Feb 06, 2018 1:46 pm

All well and good, but what can I do if rear toe in is bad, other than fit adjustable wishbones? Can I compensate with front toe in adjustments, for example?

Actually, I am pretty sure it didn't do this before I overhauled the front end, so an alignment check is the thing to do. It's all been done by myself, probably badly.

One reason I have not had it done professionally is that I don't know what the required angles that modern rigs use are. I do not think they work on "fractions of inches of toe in" as quoted in the manual.
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PostPost by: gus » Tue Feb 06, 2018 2:15 pm

Yes they do, go to a decent alignment shop that is not afraid of your car.

While terminal oversteer is not unusual, it should not come into play at normal street speeds

The only flaw I have ever noticed is when the rear struts are dying is gets squirmy in the rear, so yeah, a high speed sweeper it will be loose in butt puckering fashion
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PostPost by: JonB » Tue Feb 06, 2018 2:42 pm

Right then. One of my local tyre dealers has a Hunter Hawkeye 4 wheel laser alignment system and he says he often does Lotuses, including the classics. He certainly didn't sound afraid of it!

However, his system works in degrees and minutes, so I would like to ask what the settings should be when converted from inches of toe in. Anyone know?

Of course, the Hunter system may already have values preloaded into its vehicle database, but I would like to be sure.

Will be visiting on Saturday!

Cheers
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PostPost by: Orsom Weels » Tue Feb 06, 2018 2:51 pm

Wheel alignment conversion chart.pdf
(106.5 KiB) Downloaded 183 times

Does this help ? Any wheel alignment centre worth their salt should have one ! :wink:

Regards, Tim
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PostPost by: john.p.clegg » Tue Feb 06, 2018 3:17 pm

JonB

lotus-suspension-f42/tracking-t19506.html

I did this ages ago but can't find it here anywhere but if you have your old Trig tables it should be easy to find the angle using the figures above SOHCAHTOA

John :wink:

P.S.
1/2" over 96"

P.P.S.
tan 1/192 .

P.P.P.S
0.29841282 degrees ?
0.00520829 radians ?
Last edited by john.p.clegg on Wed Feb 07, 2018 9:08 am, edited 1 time in total.
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PostPost by: stugilmour » Tue Feb 06, 2018 4:16 pm

Jon, coming to your thread late. All the best for Saturday. Let us know if they can solve the issue.

My Spyder framed Plus 2 had exactly the same behaviour immediately after I rebuilt it. Four wheel alignment solved the issue. I have Spyder adjustable wishbones so they were able to adjust rear toe.

HTH

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PostPost by: MarkDa » Tue Feb 06, 2018 4:38 pm

Jon
The Hunter system has elan angles in the database so should have Plus2 as well.
Only problem I had was that the rear toe in specified same angle as front rather than 'double' required because they are individual rather than combined.
Lots of threads on this and consensus is that the rear toe in is per wheel.
Certainly I found my Sprint was very 'nervous' until I got the extra toe in.
Of course until you get adjustable wishbone it will be just academic.
Technically the alignment should be done at a specific ride height which is normally lower than an empty car.
I don't know how critical this is though - others may pitch in.
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PostPost by: pauljones » Tue Feb 06, 2018 4:58 pm

Just wondering, does having poly bushes make things difficult to adjust or is it same as having standard bushes fitted.
Kick the tyres and light them fires...!!!!!!!
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PostPost by: MarkDa » Tue Feb 06, 2018 5:11 pm

Poly bushes shouldn't change the geometry as they are nominally the same.
The only thing that can be adjusted on a standard car is front toe-in.
The full laser alignment check will measure castor and camber as well so can help identify chassis distortion/damage.
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PostPost by: pauljones » Tue Feb 06, 2018 5:18 pm

Now thats what i was thinking, ie didnt old Chappers make it non adjustable. So how can a refurb throw out the alignment.?
I could only assume there was a difference in bushes.
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PostPost by: vincereynard » Tue Feb 06, 2018 5:32 pm

Maybe it now toes out on the side you straightened the wishbone.
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PostPost by: gus » Tue Feb 06, 2018 11:11 pm

You should not need adjustable wishbones on a street car

The factory chassis was not that well done, but if there is an error, fix the error, adjustments just add randomness
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PostPost by: MarkDa » Tue Feb 06, 2018 11:23 pm

I tend to agree with Chapman's view that if we have adjustability then we'll f**k it up.
However if you have a flakey chassis then the ability to readily fix a tracking error makes sense.
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PostPost by: gus » Wed Feb 07, 2018 12:51 am

I don't think he has a flaky chassis
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PostPost by: miked » Wed Feb 07, 2018 8:10 am

With A frame and chassis errors lots toe out one one side or the other to some degree. Nothing wrong with adjustable A frames to correct. Makes for a much nicer car. Had it on brand new chassis and A frames. Lots on left and an amount on right.
Mike

PS will bump thread on cheap as chips fix.
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