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MG MGF Technical - MGF drifting on motorway

I've just bought a MGF Trophy and all is good except for a slightly unnerving effect i've been experiencing whilst motorway driving. Occasionally it seems to drift in one direction and then in the other. Could this simply be down to tramlining or sensitivity to the wind, or might there be some other issue with the car?

Driving around country lanes seems fine (and very enjoyable!), just speeds above 60mph occasionally cause concern. I'm wondering whether to take the hassle of returning it to the dealer to get it checked out.

Any help / suggestions anyone?

Thanks,
Steve
steven mancey

Hi Steve,

mine did the same - it was down to rear bushes and ball joints worn, not to expensive though.

Regards,
Mike Gibson
Mike Gibson

>>Could this simply be down to tramlining or sensitivity to the wind, or might there be some other issue with the car?<<

Good question Steve - and one that is difficult to answer having not experienced it for ourselves.

It *could* be tramlining. Does your car do this on every motorway or on particular bits of road?

Tramlining and aerodynamic problems tend not to effect the Trophy much - assuming that the suspension is correctly set up.

And it is suspension geometry that may be the problem here (assuming that there is one).

Check the suspension height - it should be about 348mm +/- 10mm. Too high could result in some undesireable handling traits.

Check the condition of the tyres (including pressures). Make sure that the tyres are worn equally across the width of the tyre.

Then get the tracking checked: should cost only 40 quid from a reputable specialist (i.e. not Quik Fit! ;o)

Mike mentions suspension bush wear. You don't say how many miles your car has covered, or how old it is, but I suspect that suspension bush play is the cause of your cars problems, but upgrading the bushes can be very desirable if you are someone who likes to take his car to track days.

Hope this helps!
Rob Bell

Rob / Mike,

Thanks for the quick response.

Rob, it does seem to only get badly affected on particular streches of road so hopefully it might just be tramlining??

The car is about 2 years old and has about 22k on the clock. I will check out the suspension height and tyre pressures to see if they are ok. Would any of the other work be covered by the manufacturers warranty? I bought the car two weeks ago from Priests in Chesham.

Thanks for the help,
Steve
steven mancey

Hi Rob (long time no see!!),

I've just been out in Steve's trophy (he works a few desks away from me).

I didn't spot any obvious problems with the way the car drove down the motorway (there was no constant drifting). The problem only occurs on specific bits of road.

Just to throw another idea into the pot - do you think it could be plain old bump steer? That may seem like the car is drifting across the road...

Daniel.
Daniel Ginger

Hi Daniel - indeed it's been a while!

It does sound from what you're both saying that this is a case of tramlining. Both tracking and tyre pressures could be contributing to this.

I don't think that Bumpsteer is going to be contributory, mainly because it is neigh on impossible to alter the bump-steer characteristics of an MGF (to do this, you'd have to alter the position of the steering rack).

Steve, I didn't ask - what tyres are fitted to your Trophy? I'm assuming Goodyear F1 195/45 front, 215/45 rear?

Daniel, does your car tend to tramline over the same section of road?

Steve, if the problem is more than simple tyre pressures/ ride height, then certainly any further adjustments ought to be covered by your warranty.

Hopefully you can get out and enjoy the good weather!
Rob Bell

Cheers Rob,

Yep, tyres are the Goodyear F1's.

Unfortunately I haven't yet found a piece of road around here to simulate the problem properly. Worst case was on the M20, and happened again on the M40 the other day. Seems to be a bit unpredictable when it will occur.

Apart from this problem, car has been great, especially with all the good weather recently. Think will take a while to bore of the driving experience (used to have a VW Polo...)
steven mancey

I found that a trusty front splitter resolved the problem.
Praveen

Trophy has a splitter though
Leigh Reid

>simulate the problem properly.

If it's the problem I assume you need no special road to simulate. Just a flat motorway .. with low traffic of course.

A. Go in high gear(5th) app 60mph and increase/decrease speed frequently very careful. The cars front must not move up and down while you increase/decrease speed.

B. The same speed in low gear (3rd) but kick and quick raise the foot to/from the accelerator. *use no brakes*. The cars front should strong lift and dive.

Notice what the steering does in both cases.

A. the rear suspension has almost any problem if it goes anywhere but not straight ahead. This cause the engine force and wheel torque 'moves' the rear axle out of the cars centre line direction.

B. The front suspension has any problem if the car *moves/steers* to any other direction than straight ahead. (Rear suspension troubles have influence of course)

I'd recommend this test as well for the Splitter Enthusiasts cause IMO some of you 'beginners' just hide suspension problems with the splitter.
I had one at my old MGF and was very pleased with it until I found my cars tracking values (Toe angles) not fitting to my wanted driving style. (most rides in top speed on DE Motorways).

HTH
Dieter
Dieter K.

I get the problem too with my Trophy sometimes which I am sure is due to tramlining in lane 1 on motorways where trucks have have worn the road surface. Changing lanes cures the problem!
Blue Pocket Rocket

I had the problem at first, which only appeared on motorways at speed. I've subsequently changed the wheels and tyres from the original 15" versions with standard rubber to 16" Trophy wheels with Goodyear F1 rubber, and have not experienced the problem since.
Bob
Robert Tulloch

This thread was discussed between 23/04/2003 and 24/04/2003

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