bud-weis

......

On the new cossie i have a bit of a problem which i'd like to solve......

basically when driving on any uneven road (which is about 90% of UK roads!) the car tramlines really badly and pulls you into the grooves/bumps in the road....it's very noticeable on the motorway in the left lane where lorries have left a groove.

Now i've tried different tyres and it's not that,my next port of call will be checking the wheel alignment/geometry i think,and possibly replace the lower arms,maybe with adjustable jobbies from Zoo,

what i want to know is what is the usual cause of this? i'd like to fix it asap,because frankly it's verging on dangerous if going at any speed....and i'm not sure if the quaiffe diff exaggerates it a bit too

LOVE cossies

Rhys

I hate it when they tramline, i always thought its was down to low profile tyres but its not that as the BM doesnt do it.

Be interesting to see why, as my saff used to tramline but i wouldnt say its was Dangerous bad.


Hows it feel mate to be back in a cossie?

simonc

Mine is exactly the same, seems worse since i fitted coilovers, trying to go point to point quickly on B roads can be hairy if the roads are poor /uneven but it now handles better than it ever did on trackdays but ruined for the road !

Whats the answer ? Apart from the obvious (change the car) My M3 was worlds apart in the B road handling & was sure footed whatever the road surface.

Simon.

Andreas

If I remember it correctly a toe-in setup at the front will make it wander around more.

bud-weis

It feels great,every time i start it up i know i'm in something much more special than the TT

thanks for the replies people.....i have a feeling it may be towing in too,it turns in very well and handles very very well too,but it's just tramlining like a bitch!!

Andreas

Yes, toe-out will make it turn in better but it will also become a bit more nervous in a straight line.

Mike1

Is it Jim's old car? Didn't he have 3-dr hubs on it and adj TCAs already?

One of the downsides of the 3-dr hubs is that they will make the car feel more nervous isn't it? The upside is that this nervousness translates into quicker turn-in and desire to change direction quickly?

Also, what tyres are you running - some directional tyres exacerbate tramlining.
Not saying it's not worth checking your geo as a first port of call but additional points to bear in mind

Rhys

Nice one Martin, Cossies are cool!

Iw ill have another one day

Jim Green

Hi Martin.....

This became exagerated when I had the 3 door hubs and arms fitted, but as I intended to do track days, I was looking towards the better turn in and it being very sensative to the steering.

I do still have the original hubs and bottom arms and if you want them, then just let me know. I was just about to put them on E-Bay, but I'll wait till you've spoken to Mike & Zoo. The wheels are ET40, which is the correct off-set, so it's not due to the wheels.

Give Mike a call though, and see what he says....he & zoo, are the experts on this, but if you want the original arms, they're here and yours if you want them.

Regards Jim

CabbyRS

Hey i was allowed a drive on Saturday nite!! (even on me own!!!), superb motor , bet ur gonna miss it Jim ?

bud-weis

Thanks for the offer Jim i'll let you know asap

The turn in is definitely sharper with the set up how it is,but IMO the trade off for a smooth ride isn't worth it,so i'll try to get both at the same time rather than one or the other

i guess on a track it would be fine

Mike1

Yes, I thought Jim had gone for the 3-door hubs to give quicker/sharper turn-in


This is supposedly the changes from 3-door to Sapphire 2wd made by Ford.
Obviously the 4-dr shell was stiffer which has to be taken into account.
Spring rates went up from 106 to 118lb/in at the front and 263 to 286 lb/in at the back.
Damper rates were made softer in bump and stiffer in rebound.
ARB was increased to 16mm on back
Castor increased by over one degree
Camber made fractionally more negative
Kingpin inclination made slightly greater.
Front knuckles re-designed to lower the front roll centre from 144mm to 70mm

Work was also done to rid the tendency of the 3-door to "pitch" front to rear.

Much of the work above was done to create a less "nervous" car and for it to have better straight line stability

Hope that's interesting



Also I remember when they first brought the 3-door out it was supposed to be even sharper on the press release - some press journalists complained about the razor sharp turn in and nervous handling - Ford took the criticism on board and changed from rigid plastic joints in the front suspension to rubber and re-valved the power steering to make it slightly less responsive before it was put on general release apparently

Mike Rainbird

iTrader: (3)

I would guess that the geometry has been set to Ford recommendations, which means that it is statically parrallel. Unfortunately on a shonky Ford, this is completely pointless, because as soon as the car is rolling, the bush deflection means that the car immediately toes out, giving the nervous state described. This is why I always recommend some static toe-IN, that way, with bush deflection the car runs almost parrallel in forward motion. It greatly improves stability. However, only a geometry check will reveal all. Obviously the problem is trying to convince any non-performance orientated laser alignment place NOT to use the factory settings .

CossieRich

iTrader: (1)

Interesting stuff this Mike. How much toe-in do you suggest?

Mike1

It's not necessarily low profile tyres but some directional tyres can make it worse

Mike Rainbird

iTrader: (3)

1-2mm on the front and 2-3mm on the rear.

Mike1

How much front camber did you run in conjunction with that out of interest Mike?

Mike Rainbird

iTrader: (3)

Depends on what sort of use the car gets, 1.5-2.0° negative for a road car.

My Escort is set up as per Grp A cars, so runs 3° front* and 2° 45' rear.

*Please note this amount of camber on a 4x4 car requires longer front drive shafts .

bud-weis

Thanks for the reply Mike

i have it booked in for an alignment check,hopefully we can sort it

the guy who works there,Andy Fisher used to work on the RS500 touring cars for brooklyn and he knows his shit about everything cosworth so hopefully he'll have a good idea how to set it up

Jim Green

Martin : I'm sure I gave you the Laser Alignment sheet that I got when I had all the geometry check done....... They stated that it was perfect ....... However, remember they would be checking it agains fords specifications....so it will be correct, but wrong for what you want and what mike suggests.....If you know what I mean.

Jim

bud-weis

Yep that makes perfect sense

just spoke to Karl too and he gave me a few things to check out

oh and i forgot to grab the tool to remove the centre caps from you

Vic

mike, my 3 door is going for a wheel alignment tomorrow and would like to know what sort of specs i should ask for?

my car at the moment has 17 inch wheels, polybushed and lowered 1 inch. I'm getting a fair bit of tramlining as well!

wildheart

iTrader: (4)

Can you change the toe on the rear beam? (3dr)

Mike1

I think Mike sells a shim kit to do this if you have a std beam.

Mike Rainbird

iTrader: (3)

Don't run the car with static parrallel then .

foreigneRS

you can make the hole in the beam larger and put big and thick washers on the bolt either side and then when you have the geometery that you want just tighten the bolt to fix the position. you might also like to weld the washers in place, but it isn't totally necessary and makes adjustment next time difficult without getting the grinder out.

Mike Rainbird

iTrader: (3)

This is exactly how they adjusted the geometry on the Grp N cars .

foreigneRS

not rocket science is it?

you can also do the same on the front x-member to move the inner TCA pivot point for adjusting the camber

don't know why more people don't do it - suppose it's not as 'bling' as adjustable tca's etc

Mike Rainbird

iTrader: (3)

You can't always get the full range of adjustment you require, that's all .

Tony Ryan

Between Mike & Nick You are describing a "package " of adjustments or parts that are required to assist , its the same on the adjustable beam thread above this one , for most of you who have road cars and do the occasional trackday all these expensive Motorsport parts aren't needed , and even if you did use them you'd skimp on the dampers and still wonder why it understeers or tramlines or whatvever . The 2 single best mods i ever made on my GpN Sapphire are already described in this thread .

foreigneRS

there's loads of things that people do to their cars tony that "aren't needed" - that doesn't stop people wanting to do them for whatever reason

Mike1

Slammed it in the weeds and stuck 19s on?

Seriously though Tony, just looked through this and the adj beam thread - what, in summary, were the 2 best mods you did on your Group N?

Mike1

Was it the shims on the back and front then Tony? What settings did you go for or are there limits on Group N?

Tony Ryan

Got it in one , i shimmed the back by machining Exactly the right angled plates , and sorted the front geometry - although i go back to what i said , if you dont spend the right money on dampers & tyres all this is worthless.

Mike1

What dampers and tyres did you use on yours Tony?

Tony Ryan

Koni & BF Goodrich but later change to Dunlop slicks

Fiecos Dan

As mentioned above.


i used Mike R's shim kit to set both the toe and camber on the rear of mine.


But dont wide tyres on the front also cause Tramlineing?

Mike1

Were they a track-day orientated BF Goodrich? What size were they? As it was GpN was it standard springs?

bud-weis

can this be done to a 2wd rear beam though? i was under the impression that the camber can't be adjusted properly without a proper adjustable beam like the Zoo one?

even slotting the mounting holes won't do it properly will it? (thinking in my head about the shape of the beam and the mounting points of the trailing arms )

Mike Rainbird

iTrader: (3)

Martin,
You are correct. You NEED a 6° rear beam, otherwise the camber will be randomly adjustable (bump steer) with suspension travel.

The shims just doe the toe, and are just a cheap small improvement. The beam is the cure, the shims are a "plaster" .