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Knocking on full lock? - Ride/Handling/Suspension/Brakes/Wheels/Tyres - The Lotus Forums Jump to content
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Justin182

Knocking on full lock?

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Is this normal? Only noticed it a few times but I seem to be getting a loud knocking sound at low speeds when on full lock ?

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Esprits do that due to the anti-Ackerman steering as the wheels skip but I don't recall hearing it on any Evora I've driven...

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I've noticed it to... Will check again when we get back behind the wheel!

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I notice it on mine when I reverse on full lock, mines more of a rubbing than a knocking though

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I notice it on mine when I reverse on full lock, mines more of a rubbing than a knocking though

That sound familiar, I get it also backing out of my garage. I normally loosen up a twitch and the noise is gone. Sounds like the tire hitting the wheel inner liner.

Semms like Lotus went to the limit to maximize turn angle, i. e. minimize turn radius.

Edited by TBD

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Just to clarify, the actual reason for this is 100% due to the anti-ackerman steering on full lock. There is no chance of a wheel rubbing on the arch liner at all, I've just spoken to vehicle attributes at the factory to clarify. :)

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Not at all, it's meant to do it and many sports cars are configured the same.

 

Google 'anti-ackerman', it basically means you can have good high speed or low speed cornering but not both. Unsuspectingly the Evora and Esprit have the benefits focussed on high speed cornering. 

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The Bibs. I never stop learning on this forum.

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It's the same on my 1992 Excel SE... and many people ask the same question. Same answer: It's anti-Ackerman steering geometry.

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That sound familiar, I get it also backing out of my garage. I normally loosen up a twitch and the noise is gone. Sounds like the tire hitting the wheel inner liner.

Yeah that's exactly what I do, problem solved! :)

 

Just to clarify, the actual reason for this is 100% due to the anti-ackerman steering on full lock. There is no chance of a wheel rubbing on the arch liner at all, I've just spoken to vehicle attributes at the factory to clarify. :)

Thanks Bibs, I've googled this and found lots of technical stuff, but in simple terms, on the Evora what's making the rubbing sound when reversing on full lock then?  ta

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Since the wheels are at slightly different angles, a tyre is dragging or skipping on the road surface.

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Mine too - slow and full lock only.

 

I'd been told it was "due to the geometry", but your Google suggestion brings up more than the geometry basics. A key point striking me was that as the load/slip angle characteristics of the tyre is central to the design of the geometry, that's presumably a significant reason to stick with the specified type of tyre. 

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Interesting thanks Bibs, yeah tyre skipping is probably how i'd describe it.

 

So if the Evora is set up for fast cornering, what car is the slow cornering?  city cars?

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Exactly that mate, they use Ackerman steering :) 

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Excel does it, Evora does it...can't remember that Elise and Esprit did it... :huh:

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From what I was reading Lotus seems to be one of the few cars using anti-Ackermann steering.

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Very interesting.

I like the fact that Lotus puts time and effort into these things rather than on dual-zone digital climate control.

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I assumed mine was normal, but I also occasionally noticed the knocking when going forwards. Normally when manoeuvring out of a car park. My dealer replace a spacer on the steering, and I haven't noticed the knocking at all since.

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