Storing on lift over winter: bad or good on suspension?

[chriscmore]

For a couple winters I've lifted her up on a QuickJack for the winter. This solves the tire flat spot issue, but is it beneficial, detrimental, (or neutral?) on having the wheels hanging down? I'm saving compression, but stressing bushings like the upper control arms that are torqued at sitting height.

Cheers.

[Dewi 2]

I am not an engineer, but would have thought leaving the suspension in its designed compression state might be best.
I too store my car during each winter and during 10 years of ownership, have never had flat spotted tyres.
Park on thick carpet mats, inflate tyres to about 45 psi, and push the car a foot or so every 6 weeks, thereby placing the weight on different contact patches.

[8Tech]

Ideally, you can raise the car and then lower it onto 4 axle stands under the suspension arms to support the weight of the car on the suspension legs but with the tyres clear of the ground. This keeps the suspension in its loaded position whilst keeping the tyres unloaded.

The official way to rectify storage induced flat spots on the tyres is to get them up to full operating temperature and then inflate to 60psi for 48 hours.

If you dont mind spending a bit, then do a search for EAN: 5056297519607 (3200WW) and buy 4 of them. This is IMO the ultimate solution with 4 of these mounted on axle stands. I use these when loading the suspension up to pre-load bushes I install professionally.

[john ryan]

Isn't it a very bad idea to support a VH aston under the suspension arms?

[8Tech]

john ryan said:

Isn't it a very bad idea to support a VH aston under the suspension arms?

Why? The wheels act on the uprights that are directly connected to the suspension arms through the upper and lower balljoints so supporting the car through the lower arms at the outer end is exactly the same loads they see as sitting on the wheels.

[john ryan]

The hub supports you reference are fine ; they replicate the wheel. I don't disagree about supporting under the lower ball joint, if you can get to it. But the lower suspension arms of a VH Aston are not designed for jacking or supporting as far as I know. I certainly don't let my MOT tester or tyre fitter go there.

[LTP]

8Tech said:

Why? The wheels act on the uprights that are directly connected to the suspension arms through the upper and lower balljoints so supporting the car through the lower arms at the outer end is exactly the same loads they see as sitting on the wheels.

This is technically not quite correct. If you were to model the suspension arms in a free-body diagram the ball-joints and inner bushes would be modelled as pin joints, free to rotate about their axes. This means in normal operation the wheel hub or the body mounts cannot put the suspension arms into bending, but they operate in pure compression or tension with the forces acting only directly along the suspension arms. If you jack on the arm then there is a very good chance you could introduce bending forces that the arm was not designed to withstand.

Agreed this is a very technical answer and all suspension arms can cope with some degree of bending forces due to the offset load inputs from the coil-overs and the roll-bar, as well as the bushes will have some rotational friction and elastic torque from the rubber of the bushes. If you jacked the car directly under the ball joint without touching the arm itself, as 8Tech implies, you'd probably be OK, but I think you'll find both the lower ball-joint and the attachment point for the coil-overs are actually inside the wheel barrel so you'd end up jacking on or around the roll-bar attachment, which I don't think would be a good idea. The warning in the handbook it to stop the likes of the local tyre fitters putting their trolley jacks under the middle of the suspension arm and bending them as they jack the car up.

[cayman-black]

Dewi 2 said:

I am not an engineer, but would have thought leaving the suspension in its designed compression state might be best.
I too store my car during each winter and during 10 years of ownership, have never had flat spotted tyres.
Park on thick carpet mats, inflate tyres to about 45 psi, and push the car a foot or so every 6 weeks, thereby placing the weight on different contact patches.

I agree with Dewi. overthinking imo.

[2 sMoKiN bArReLs]

Not an Aston...but logic must be similar.

I've parked my TVR up for maybe ten winters. I've never had an issue with tyres?

[Dewi 2]

2 sMoKiN bArReLs said:

Not an Aston...but logic must be similar.

I've parked my TVR up for maybe ten winters. I've never had an issue with tyres?

Do you increase your tyre pressures and push the car occasionally?

As I have already mentioned, I too have never had flat spots during the winter, after taking basic precautions.
However, I did once experience flat spots during the summer, after leaving the car unused for a longer period than was anticipated.
Initially a very vibrating ride on a straight dual carriageway, but then I took to the side roads for some 'Italian cornering' and that must have scrubbed away the flat spots.
I don't remember how many weeks the car was left in one position, but it was a reminder about how easily this problem can occur.

[2 sMoKiN bArReLs]

Dewi 2 said:

Do you increase your tyre pressures and push the car occasionally?

Nope, roll it in December, roll it out March. One turn of the key & away we go.

[2 sMoKiN bArReLs]

...but then I guess as the TVR is lighter each tyre is supporting less weight

[chriscmore]

And higher profile, and not $350 each.

The question is if the suspension parts are happier or less happy hanging down for the season.

[2 sMoKiN bArReLs]

chriscmore said:

And higher profile, and not $350 each.

The question is if the suspension parts are happier or less happy hanging down for the season.

Then my money is on let the suspension sit in its designed situation.

Perhaps have tyre supports if flattening is a concern?

https://www.blacks.co.uk/15900268/streetwize-tyre-...

[MichaelV8V]

Last year I bought some Quickjacks and left the car raised up on them over winter. When I lowered the car and took it for its MoT, they found two broken front springs.

The MoT tester hates cars that aren't used over winter, and suggested that the springs broke because the car hadn't been driven enough. Which has to be a stupid idea, it would mean that driving a car over crap, potholed roads is good for springs, and I can't believe that, nor can any of my neighbours that have broken springs on local roads.

Which leaves two possibilities, I think the most likely is that the springs broke some time over the last few years, but the crack wasn't visible because it was right at the bottom. Pulling the weight off the car opened up the cracks and made them visible.

Option two is that the springs were unloaded and that broke them. I can't work out the physics of that, so I'm going with Option 1 - the springs were already broken. What do you think?

[8Tech]

MichaelV8V said:

Last year I bought some Quickjacks and left the car raised up on them over winter. When I lowered the car and took it for its MoT, they found two broken front springs.

The MoT tester hates cars that aren't used over winter, and suggested that the springs broke because the car hadn't been driven enough. Which has to be a stupid idea, it would mean that driving a car over crap, potholed roads is good for springs, and I can't believe that, nor can any of my neighbours that have broken springs on local roads.

Which leaves two possibilities, I think the most likely is that the springs broke some time over the last few years, but the crack wasn't visible because it was right at the bottom. Pulling the weight off the car opened up the cracks and made them visible.

Option two is that the springs were unloaded and that broke them. I can't work out the physics of that, so I'm going with Option 1 - the springs were already broken. What do you think?

I think the springs were already broken but went unseen. Since the introduction of speed humps and potholes, I now see at least 20 times more broken coil springs than I did back in the day prior to these. Mind you, they are probably not made "like they used to be" on these modern, disposable vehicles.