how do you stop them from jumping all over the road

[redcorvette]

hi my corvette c5 is struggling to cope with the rubbish english roads every time it hits a small bump or hole in the road it jumps sideways on the front or back end. Shame because it scares the hell out of you when you are only doing 40mph any one out there know how to stop it or what could be wrong with the car

[Dee Gee]

Do you have the F45 or F55 shocks?

If you have the latter are you sure the stuffers were removed? jack up the rear and see if the little yellow tabs have been removed. there are lots of stories of dealers not doing the proper prep.

If that's not the problem, the stock tyres are well known for "tramlining". I replaced mine with Michelin Pilot Sport AS ZPs and it improved the handling no end.

Edited by Dee Gee on Wednesday 7th March 06:43

[te51cle]

Get rid of the runflat tyres ! Anything other than the OE Goodyear EMTs will help enormously and will give you a better ride too.

Also, check the tracking to make sure there is no toe-out either.

Edited by te51cle on Tuesday 6th March 07:42

[anonymous-user]

Well hello Redcorvette and welcome to the forum. Are you sure your speedo isn't broken? Are you sure you're actually driving a C5 Corvette? In my experience no modern Corvette ever jumped anywhere at 40 mph and I've never heard of the front jumping anywhere at any speed. You may have a more "press on" driving style than me although at 40 mph it doesn't sound like it.

Runflat tyres have very stiff sidewalls and this can cause the rear of the car to hop slightly on transverse ridges at higher speeds. Changing to conventional tyres gives a very noticeable improvement in both ride and handling. If you look on the BMW forum you will find they have exactly the same experience of runflat tyres and many owners switch away from them.

We look forward to seeing some pictures of your Corvette and hearing more of those first hand driving experiences.

[vetteheadracer]

I would also check tyre pressures. Mine was handling really badly and I discovered I had a slow puncture in one of my already nearly bald rear tyres. One was at 32 psi the other at 25 psi. Since changing the tyres the handling has improve dramatically.

IF none of the above works then I would recommend a set of coilover shocks and a set of upgraded swaybars as this will give you go-kart style handling!

[seefive]

It's true what VHR says about low tyre pressures. Mine has Z51 suspension and Z06 wheels without runflats. If I let the pressures drop a bit, the differential between the width of the rear track compared to front tends to pull it around a bit in ruts even on a straight roll. Also, I have heard that some US cars are set for a right hand side of the road camber - so they run odd on the left side over here.

One idea - when having new tyres fitted, I had the geometries set up on the laser system at Micheldever Tyres, and that made it roll dead straight and no real issues apart from the 3 inch ruts in the inside lane of the M3....

Final settings (L/R = Left and Right, F/R = Front and Rear) on mine were:
Front:
Camber L 7.17 R 6.82
Caster L -0.44 R -0.37
Toe L 0.02 R 0.04 Total 0.06

Rear:
Camber L -0.62 R -0.22
Toe L -0.02 R 0.03 Total 0.01

Thrust angle: -0.02

SAI: L 9.38 R 8.99
Included Angle L 8.84 R 8.62
Setback: F 2mm R -7mm
Track Width Diff: -33mm
WheelBase Diff: 9mm

It ran straight and had no bad habits on this set-up.

Good luck - I am sure you will crack it.

Kev.

[vetteheadracer]

Seefive reminded me that when I took the suspension apart on my Yellow Z06 I shifted the shimming from left to right on the car as he is right the cars are shimmed for left side of the road not right side.

[redcorvette]

te51cle said:

Get rid of the runflat tyres ! Anything other than the OE Goodyear EMTs will help enormously and will give you a better ride too.

Also, check the tracking to make sure there is no toe-out either.

Edited by te51cle on Tuesday 6th March 07:42

Thanks for your advice yes it is running on oe goodyear emts.
But more strangely it just failed its mot on a worn rear trackrod end. Since having a new one fitted the problem is much worse so ill look into that
thanks

[redcorvette]

5 USA said:

Well hello Redcorvette and welcome to the forum. Are you sure your speedo isn't broken? Are you sure you're actually driving a C5 Corvette? In my experience no modern Corvette ever jumped anywhere at 40 mph and I've never heard of the front jumping anywhere at any speed. You may have a more "press on" driving style than me although at 40 mph it doesn't sound like it.

Runflat tyres have very stiff sidewalls and this can cause the rear of the car to hop slightly on transverse ridges at higher speeds. Changing to conventional tyres gives a very noticeable improvement in both ride and handling. If you look on the BMW forum you will find they have exactly the same experience of runflat tyres and many owners switch away from them.

We look forward to seeing some pictures of your Corvette and hearing more of those first hand driving experiences.

Thanks for your reply everyone is saying dump the run on flats so thats a good place to start. But i was serious when i said the front and back end jumps at 40 mph . What i properly should of said is it jumps at speeds as low as 40 mph . Its like driving a car with solid tyres and no suspension the problem has got worse sinse having a new rear trackrod end fitted because it failed its mot but only on that.

thanks redcorvette

[franv8]

Sounds like time for four wheel alignment...

There are many adjustments available on most Corvettes, but obviously if they're not all pretty much correct, then handling misbehaviour is one likely symptom...

Something possible on C3's and C4's (not sure on C5's on) though is problems with the UJ's - since the driveshaft is also one of the suspension links, if you've got one that's badly on it's way out it can also cause intermittent 'hopping' of the back wheels.

[monkfish1]

Agree with Franv8, a full alignment is the first step to sorting out your problem. Do this before changing tyres etc. Choose your alignment specialist with care! Check out www.wheels-inmotion.co.uk