Changing tyres

[K20A2]

The scissor jack is fine, but this jacking position isn't recommended as it can upset the geometry. The jack should be as near to the chassis as possible.

I agree, this is not the jacking position as in the handbook.
However I cannot imagine any reason, why this would upset the geometry.(?)

[Fastlane]

The scissor jack is fine, but this jacking position isn't recommended as it can upset the geometry. The jack should be as near to the chassis as possible.

I agree, this is not the jacking position as in the handbook.
However I cannot imagine any reason, why this would upset the geometry.(?)

I would imagine (you can always check with the factory) because the car is designed to spread its weight on each front corner via 2 wishbones, 3 rod ends and 4 bolts/metalistic bushes. Putting the jack near the wheel puts localised and unnecessary stress on the lower wishbone, its metalistic bushes and the lower rod end. Atoms are very sensitive to even very small changes in any of these and so not jacking them up as suggested risks (at best) the geometry gradually being out and at worse long term stress damage and potentially catastrophic failure.

Ultimately it's your car and your risk, but it's hardly a challenge doing it as suggested...

[K20A2]

No worries, I understand your opinion and point of view and basically I follow the factorys recommendations.

With a hydraulic jack you cannot reach the jacking point I use on the image above because it is too close to the wheel.
So "not recommended" in this particular example could also mean "not taken into account".

From a mechanical point of view looking at force transmissions I would expect my jacking point to be even better than the handbook one, because it is quite precisely below the point, where the spring force from the shock absorbers is transmitted through the pushrod.
So you kind of neutralise the forces at this point (jack up, shock springs push rod down) and there is no other force to the suspension than gravity to/from the wheel (being held in the air) and the force from the spring like when standing still.

At the handbook jacking point you (theoretically) bend that tube, because you have one force up roughly in the middle (the jack) and two forces down (fixing at chassis and fixing of shock spring pushrod) at the ends of that tube.

I hope, my typing is reproducible. I am certainly missing some english words here


Perhaps [mention]Henry JS [/mention] wants to share his thoughts. Just forgot, how the "call" button works...


BTW:
Just found the scissor jack in the following link.

https://www.amazon.co.uk/Silverline-Too ... 257&sr=8-2

Mine is from a Honda Civic and I do not know the one in the link, but it would be suitible for the job I guess and only 90mm high. So if the price is no argument against it , it might be worth a try.
A piece of soft wood will prevent damage to the coating for the jacking point I use or a piece of anti-slip-mat or rubber for the handbook jacking point.