Everytime I first start up my car and reverse off the drive or out of a parking space and put the lock on full the front wheels sort of jump or judder across the road
Its as if the 2 front wheels are not going in the same direction!
The only thing I can think of similar is like watching a HGV when its doing a tight turn and the trailor wheels skip across the road because they are not turning!
Its got worse over the last week or so and only happens when reversing
I looked over everything a month back when I fitted some pads but everything seemed fine!?!
worn ball-joints or loose suspension mounts ? check them with a torque wrench
if that’s all okay then geo like Uldis suggests. ??
I don’t think it can be a complicated problem and a little checking should get you the result. Remember tho’ that you won’t be able to stress the balljoints with your hands anything like they will get stressed whilst driving but if they are worn you should be able to detect some ‘play’ in the wheel if you jack it up.
I remember something my mate told me a while back who works at Paul Mattys.
It was that to check the suspension properly you need to check it all at normal height (ie not jacked up) because if its jacked up then the suspension is at full stretch and can disguise the play and any knocks.
That might be why I didnt notice anything last time.
Strange thing is, it appears to go away when warm!
I was reversing in and out of car park spaces this morning when I got to work and it had gone
I think a good tug and pull is in order the weekend
Andy, If your sure you dont mind Saturday would be great.
Let me know what time your free… It will get me away from sorting my mortgage out anyway
Mine has had this ‘feature’ since I bought it. Never been able to bottom it out - everything when checked has always been nicely tight. Be interested if you find anything wrong…
Is straight ahead in the middle of the rack? I know when they fitted my removable steering wheel B&C messed up the tracking/centre point of the wheel, so at extreme steering angles (nothing you’d do at speed) the wheels can skip a bit like you’re describing.
I’m sure this is completely normal. I don’t know if yours is worse than most, but they will all do this to some extent.
On full lock, the tyres will follow slightly different lines. The tyres get pulled sideways relative to the rims, and then the tread blocks suddenly give up their grip, and jump back in line with the wheel.
Uldis, the ackerman angle was what I was going to mention
But it must have some just because of castor OYSWIM… But looking at all the settings most Exiges seem to have Elise castor (2.8 or something) while the Exige should have a mighty 3.8 deg which may cause this to be worse with some peoples cars…
But if it goes away when warm then… er… scratches bumsuck in air through teeth Next thursday mate, parts have gotta come from Japan you know, the inverted angle dongle do dad can only be setup by ninja…
Hmmm, why would having big Castor angles would mean having Ackerman as well?
I can visualise a perfectly symmetrical situation with Castor and zero Ackermann.
Shouldnt’ Ackerman angle depend on the steering hub/arm geometry?
(have to reforesh concepts)
Simon E, Glad to hear Im not the only one with the ‘Lotus engineered’ feature
IDG, Im interested in what you said, Im going to have a look to see if the rack is central…ish, I would have thought the amount of visible thread at each track rod end would give a clue if its near central!
Brendan, Thanks for the link…Phew…Quite a few others who seem to have the symptons!
I thought it might have been the rack before, hopefully not now! I changed one on my Elise and it was a PITA!
If it is the steering angles and tyre blocks causing the skipping. Anybody got any clues why it goes away when warm
Uldis, the ackerman angle was what I was going to mention
The answer TADTS is entirely valid here because they all do. It will happen going forwards if you ‘give it a bit’ … Tyre tread patterns, pressures etc may make it a bit different between cars and most people don’t use full lock in every day use.
Lotus has a long tradition of ignoring Ackermann (ask anyone with a 70/80s Elite/Eclat variant, early Esprit or even Elan). It is very difficult to get the Ackermann principle to work at the extremeities of lock, regardless of castor and camber angles. Most mainstream car chassis designs go to a lot of trouble to make Ackermann work at the extremities, often at the expense of ultimate handling but as we know most mainstream cars are a compromise. Lotus do not compromise on handling and the fact that Ackermann washout appears at full lock is acceptable on a true sports car… They designed it to be good when its going quickly not when its being parked…
Hmmm, why would having big Castor angles would mean having Ackerman as well?
I can visualise a perfectly symmetrical situation with Castor and zero Ackermann.
Shouldnt’ Ackerman angle depend on the steering hub/arm geometry?
(have to reforesh concepts)
Actually I think you’re right there… Had a brain seizure! LOL!
Lotus do not compromise on handling and the fact that Ackermann washout appears at full lock is acceptable on a true sports car… They designed it to be good when its going quickly not when its being parked…
Regards
Considering the above it seems strange that the Elise/Exige has c.rap bump steer characteristics, generally crap dampers/brakes etc. and the Exige has Gjob wheels that mess up the suspension geometry.
and the Exige has Gjob wheels that mess up the suspension geometry.
It does?
With the Exige you have a relatively low ride height combined with taller wheels and the combination significantly changes the angles the wishbones sit at. Thats why Exiges tend to move about alot at the rear unlike an Elise. I have a cure in mind which I will try to put in place some time next year. Will be sure to let you know as, if and when I do something about it.