Front end grip

[p.mole1]

I seem to have a problem with grip at the front, having returned from Croft the front tyres are in a right state. The front seems really vague around high speed corners. The Jim clark s bend I think they are at the top of Croft circuit. 

I have 13 wheels 205/60 13 and 185/55 13 tyres Toyo 888 inflated to 15 psi cold the car is a narrow track with a rear anti roll bar set to the mid position. A 15 mm rake with the tracking set to parallel 1.25 degrees negative camber and the castor is set to standard road setting. I have also corrected the bump steer. I am using quite soft springs but have adjustable damping as it is primarily a road car  

I have tons of rear end grip and the rear tyres seem to have even wear and do not look like they have melted.

I never mess with tyre pressures, should I ? Is it worth trying to get hold of a wide track suspension.  

Because I use the car on the road I do not want to go to extremes and spoil the cars stability.

 

[p.mole1]

Front tyre

[Amos91]

Not sure what we are looking at as that tyre looks absolutely fine.  That is all rubber pick up from the track which will go with road miles or you can remove it from a heatgun & scraper.

What were your hot pressures?  Could try a little more front camber if you're struggling for grip.

 

[p.mole1]

Hi thanks,

To be honest I just set my pressure cold and just leave it alone. I have never checked them hot.

I have never really had much confidence in the handling of the car, I can get around a circuit at a reasonable speed but reach a limit were I do want to push further as I can't really feel what the car is doing and it doesn't inspire confidence.

That said I have never driven any other Caterhams so I don't know if mine is good or bad. I was thinking of adding more castor to increase the camber whilst turning,increase the static camber a bit more and add a very small amount off toe out.

From experience with front wheel drive cars if there is any toe in it makes the steering terrible, but I have checked mine multiple times and it is almost parallel, just a few seconds of toe out. 

I don't want to ruin the cars stability, when I bought it, it had lethal amounts of bump steer so driving it on the road was a white knuckle experience. It took me some time to correct this, I am assuming that I haven't done some wrong by dialing this out.  

[TomB]

Sounds to me like you need to invest a couple of hundred quid in a setup/ flat floor session.  If your based in the north, I can recommend Dave Gemzoe near Wakefield.  

[Richard Price]

P.mole1,

What springs and dampers all round?

What ARB's front and rear?

The front seems really vague

What do you mean by that? 

As a rough guide, I's say that -1.25° camber is way too little for track use.

If its steering weight you'd like to increase, that increasing castor may help (more washers behind the lower wishbones). 

 

 

[Golf Juliet Tango]

I have never really had much confidence in the handling of the car, 

Get a professional to set it up to your liking.

[Geoff Brown]

15 psi cold is a little low for a Seven?

The recommended minimum cold running pressure is usually 18 psi. In my experience this can be adjusted either way by maybe 1-2 psi to get the car 'feeling' right. 17 psi is my target cold pressure.

Hot pressure is important but not having experience of R888R cannot really comment. Best guestimate is 22-24 PSI. This is important if on track all day & experimentation is the only way to get the car 'feeling' correct.

You could increase camber a touch, maybe to 1 degree 30. A small amount of toe out, 5 to 10 minutes will aid turn in but the penalty is feathering of the inside edge.

I have run 10 minutes toe out for some years but have decided to reduce it to 5 minutes or if possible less, but not parallel, as I still want good turn in but a reduction in the width of the feathering. 

[aerobod - near CYYC]

I have found with the AR-1 tyres I'm running with relatively stiff sidewalls for a 7, that track cold pressures are 15.5 PSI front (185/60-13 tyre) and 13.5 PSI rear (235/45-13 tyre). This gives the optimum tyre roll and typically around 19 to 20 PSI hot pressure (usually 17.5 PSI after a cooldown lap, slow pit track-out and the time it takes to get out the car and check the pressures).

[p.mole1]

Hi,

Many thanks for all your help, I may have to bite the bullet and pay a professional  to set it up. I much prefer to do everything myself as I Iike to able to understand the cause and effect of adjustments so I can then do all the work myself.

I used Dave Gemzoe to set up my engine on the rolling road and he is a great guy. 

I have no idea what type of anti roll bars I have, I have Nitron dampers but I am not impressed with the fronts they have very little  travel and seem drop onto the bump stops as soon as you turn into a corner and  that is with quite a high ride height. I think the damper bodies could be too long? I am not sure if this could be an issue. the rears are absolutley fine 

Front springs are 200lbs and rears 130lbs  

 

[p.mole1]

I think I need to speak to Dave Gemzoe 

[Tom_Arundel]

Where are you?

[Amos91]

Also worth speaking to Simon at Meteor Motorsport. My Nitrons are fantastic on road and track. 

[Dannyboy]

To be fair, I'd personally get someone to give you a baseline set up. You can then refine it to suit your particular style. It sounds like you are a million mikes from where you want the car to be. 

camber- on circuit I'd be expecting 2-2.5 degrees but as stated, this isn't hard and fast and doesn't suit everyone so also don't always listen to the crowd. 
 

Of concern is your dampers, they shouldn't really be sitting on the bump stops. Norton's when set up are bloody lovely ( and out of my meagre race budget). What year us the car, is it wide/ narrow track.. do you know anything about the dampers etc.. Simon could probably tell you in 10 seconds whether they are the right ones for your car- ie open/ closed length which varies certainly pre and post 96 as well as between normal and sidetrack. Not sure if post 96 anti-time dive are any different in length to metric those on metric chassis cars. However, if wrong they would make the car bloody awful. This would be my start point..deduce they are the correct length first before you move forward on anything else.

Anti-roll bars- the norm is red and soft / disconnected at the rear. I personally prefer the green bar but for some reason that just suits my driving style and setup. 

Your tyres look fine! In fact given you said you got understeer I'm surprised they haven't 'blued' on the outer edge, always a good sign you've been trying hard when that appears.. 

[Wrightpayne]

In earlier post I think Richard was referring to castor not camber. The castor is adjusted with washers on the lower wishbone. The rear bush needs 4 spacer washers that can be placed either side to adjust the castor. The front fixing needs varying amounts of washers depending how the rear bush is set. The build manual describes the fitting process.

The castor setting determins the propensity for the steering to self centre.

[SM25T]

Are the dampers hitting the bump stops or the springs becoming coil bound. ? I have seen some springs that are really short with coils close together.

[Richard Price]

"In earlier post I think Richard was referring to castor not camber."

Oops. Yes. I've now edited my post. 

[Nigel Blandin]

There is loads of advice here and the beauty of Sevens is that you can learn lots as you go. However, I would suggest a pro baseline set up and ask them lots of questions as you go along.

Then you can play as you go along. 

what ever you do though - only ever adjust one thing at a time. If you do more, how do you learn what does what? 

I find that leaving it until you have real time helps. Then note your current setting on whatever you are looking at. Go one way (bump, rebound, castor, whatever) note down your observations. Then go the other way and do the same.

Put it back where you started and note your observations again - this refers you back to your baseline. Then have a think and choose a direction. If you are happier then great, move to the next item on the list.

If not, go back to baseline, then move to the next item. use the same process and see what effects this change has.

 

It takes forever, but you will learn what you like, what you don't and usually learn that what you originally thought was wrong!

Have fun.

[Golf Juliet Tango]

Excellent advice Nigel. 

And explains why I got mine set up and have left well alone.

[7 wonders of the world]

Castor does impact on camber as it alters the dynamic camber which is applied during turns, it also affect turn in.

[Nigel Blandin]

Words of painful experience Stephen! I was then taught by Ducati racer Geoff Baines at Silverstone the mystic art of...patience.

[p.mole1]

Hi,

Many thanks for all the posts, Plenty to think about. I had many issues with my front Nitron shocks, They had to go back twice because the body was too long. I think the issue is my car is a pre 96 and I don't think they had ever supplied any before, I also had to machine down the top spacers as they are narrower on the top mounts. I have managed to find a set of adjustable spring seats for the original Bilstien dampers so I may re-fit them. 

The spring is not getting coil bound, but as you can see the ride height is quite high and almost all of the travel is used up on the offside although I don't think this is an issue as the bump stop seem quite thick and compliant . Absolutely no problems with the rear it is almost impossible to unstick the back end even with my ham-fisted driving