Last year I lowered my 2003 VRS having my friendly mechanic install a v-maxx coilover set. Since then the rear handling is best described as "squirelly" - I mentioned it to mechanic last year who initially pointed out my near illegal rear tyres......

 

Long story short, I think I compensated for this poor setup until this years MOT when the same mechanic made reference to the rear end handling being less than confidence inspiring. Basically on uneven road surfaces (manholes even in the dry) the back end skips and jumps left/right. Initially he suggested replacing rear axle bushes which we did to no avail. Having decided to try and figure this out, I'm suspecting that lowering the ride height has thrown out the camber. Using a rudimentary approach of a spirit level, both the front and rear have negative camber but the rear is way more negative than the front. I guess this means that nowhere near enough of my rear tyres are actually in decent contact with the road hence the poor grip?

 

Does this sound like I am on the right track?

 

What is the best approach to remedy? Would it make sense to get an assessment of the alignment now and get a reading for the rears and order shims to try and bring the camber back the correct way? I was thinking I need to know how many degrees they are out and by the correct size shim such as these. It seems the most correction you can get is 2 degrees:

 

https://www.ebay.co.uk/itm/153618705388?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338343596&toolid=10001&customid=eb%3Ag%3Avms%3Aeb%3Ap%3A153618705388%3BCjwKCAiAuOieBhAIEiwAgjCvcmH0K1AzMZS45x9fzlDVMjF-YYjRtsHeF8I6NqJdK1KvTob6O6ARIhoCYTMQAvD_BwE&gclid=CjwKCAiAuOieBhAIEiwAgjCvcmH0K1AzMZS45x9fzlDVMjF-YYjRtsHeF8I6NqJdK1KvTob6O6ARIhoCYTMQAvD_BwE

 

http://vi.vipr.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=280528999347&t=1505473742000&category=180399&seller=venommotorsport&excSoj=1&excTrk=1&lsite=3&ittenable=false&domain=ebay.co.uk&descgauge=1&cspheader=1&oneClk=2&secureDesc=0

 

What should the camber be on standard setup and is that what I should be aiming for on a lowered car?

 

Thanks!

 

2 hours ago, dan4280 said:

 

Does this sound like I am on the right track?

No. The rear axle is a torsion beam, so the wheels remain parallel throughout the suspension travel. Do you have an additional RARB fitted?

No I don't have an additional rear arb. I have booked an alignment check so I'm hoping that would identify if the camber is indeed out.

18 minutes ago, dan4280 said:

No I don't have an additional rear arb. I have booked an alignment check so I'm hoping that would identify if the camber is indeed out.

The only way I can see that happening is if you jacked the car on the rear beam and bent it.

So you are saying that due to the rear suspension design, even if I lowered the car it shouldn't impact camber?

 

The plot may thicken. I needed a new rear axle at the same time as replacing suspension. The supplier at time provided a non vrs rear axle. They claimed the only difference was thickness of built in arb - as I intended to add an aftermarket one anyway I took them on their word....

5 minutes ago, dan4280 said:

So you are saying that due to the rear suspension design, even if I lowered the car it shouldn't impact camber?

Pretty much yes (or no depending on you read me above); either way the trail arms pivot in the vertical plane if the beam they're mounted on is straight.

Quote

 I needed a new rear axle at the same time as replacing suspension. The supplier at time provided a non vrs rear axle. They claimed the only difference was thickness of built in arb

Also correct, if the used part was straight! Get a straight edge the length of the beam or thereby and measure its straightness properly.

Thanks for the advice, I will investigate further. Having only a vague understanding of how camber is measured, should the rear camber be zero degrees?

Not sure what the rear camber should be standard but it won't be a lot. Somewhere between 0 and 1 degree negative camber I'd expect.

 

What wheels and tyres are you running, and what do you set your tyre pressures to?

 

Were the coilovers just installed or were they also set up after? By set up I mean ride height, any damping adjustments and wheel alignment.

 

If the beam was bent from jacking then I would expect that to cause positive camber.

Edited 2 February, 20233 yr by petrolbloke

17 hours ago, petrolbloke said:

What wheels and tyres are you running, and what do you set your tyre pressures to?

 

Were the coilovers just installed or were they also set up after? By set up I mean ride height, any damping adjustments and wheel alignment.

Standard 17 inch spiders wheels and tyres. He set the ride height, which I felt was too low and I ended up adjusting the rear to the max height it would go which is still pretty low. There is no damping adjustment, it's set. I'm not sure he has any sophisticated alignment equipment.

 

I'm off to kwik fit today to get an alleged free alignment report...

So this is the reading I just got. It appears the toe is out on the rear and not the camber. Could that account for a skittish back end?

Nothing looks really concerning to me on that printout. The toe is a bit different on the rear from left to right but they are both toeing in. If I remember I'll dig out the sheet from when I last had my alignment checked and see how yours compares. Mine does have visibly more camber on the rear than the front.

 

What tyres do you have, what size and what pressures do you set them to? Standard is 205/50 but a lot of people run 225/45 (myself included). Can't remember what the book says but I normally use about 33/30psi front/rear.

 

It should be unlikely on newly fitted parts but I'm wondering if there could be a fault with one/both of the rear shocks or the springs are just too firm. Do you still have the original shocks/springs?

 

Edit: Had a quick look for an alignment sheet but couldn't find a legible one and there are a lot of receipts in my folder!

Edited 3 February, 20233 yr by petrolbloke

6 hours ago, dan4280 said:

He set the ride height, which I felt was too low and I ended up adjusting the rear to the max height it would go

AH!!! If you're running high rake like that, that will make the car "pointy" itself. Either drop the back end again or raise the front.

22 hours ago, petrolbloke said:

 

What tyres do you have, what size and what pressures do you set them to? Standard is 205/50 but a lot of people run 225/45 (myself included). Can't remember what the book says but I normally use about 33/30psi front/rear.

I have 205/50 Firestones on atm at 30 psi.

As Ken said, raising the rear ride height will induce a tendancy for oversteer, unless you make supporting adjustments to counter the effect.

 

However, that being said, something is not quite right with that readout on the geometry.

 

As this axle has come from another vehicle, has it had had stubaxle camber shims fitted incorrectly to throw the toe out?, if not can you see any odd creases in the plate on the rear axle that the stub axle bolts to indicating previous kerbing or impact damage?.

@dan4280 - I suspect that @kentphil1 is correct here, but we can't prove any of this except the high rake statement without access to the vehicle, which only you have.

Your problem sounds like the dampers are at fault. You may also possibly have springs that are too hard.

 

I experimented a lot with different dampers and spring rates on my old TVR. It is amazing how bad a car can feel with the wrong set up.

I tried a set of especially set up coil overs from Nitron, quite expensive and they were absolutely rubbish on the road with the car skipping about all over the place. I returned them and stuck with my will proven Gaz  Mono’s.

 

I would say your spring rate may be too hard, but the dampers are set to stiff, not allowing the car to absorb minor bumps and literally just bouncing off them.

 

I run my vRS for the track with a set of budget lowered coilovers which are firmer and perform really well on Road and track. Suspension set up with as much negative camber as I can induce on the Seat Cupra lower wishbones and tracking set at zero.

To clarify the axle was brand new. Based on @phazed response, skipping is the best description when on an uneven surface. I wonder if raising the front would improve anything or if it is just a case of poor dampers/springs.

 

5 minutes ago, dan4280 said:

To clarify the axle was brand new. Based on @phazed response, skipping is the best description when on an uneven surface. I wonder if raising the front would improve anything or if it is just a case of poor dampers/springs.

 

There are other questions too, like what sorts of tyre pressures you're running?

13 hours ago, dan4280 said:

To clarify the axle was brand new. Based on @phazed response, skipping is the best description when on an uneven surface. I wonder if raising the front would improve anything or if it is just a case of poor dampers/springs.

 

 

I suspect the latter but it might be worth a try.

 

13 hours ago, KenONeill said:

There are other questions too, like what sorts of tyre pressures you're running?

 

See here:

 

I think it is definitely down to the damper/spring combination. It could be just as simple as the dampers are not very good. Or at the very least not set up for this particular car.

 

Suspension upgrading is a black art. so easy to get wrong. As I might have mentioned, I had some expensive dampers supplied specifically by Nitron for my car, (TVR) sometime ago and they were awful. They went back for revalving three times and they still couldn’t get it right. In the end I went to a different make, (Gaz Mono’s) and the problem completely went away, and I had good suspension again.