Heavy steering

[stephen grant]

 

Had my 7 driven round Silverstone for a few laps yesterday, by someone who raced Caterhams for 10 years, in everything from Academy to CSR's. She commented that the steering on mine was heavier than on any other Caterham she'd driven.

 

It is heavy, but then again, not having driven many others, I thought they were all like that

 

I'd like to sort it out, since it's obviously not supposed to be like that. Where do I begin looking? It's a 1998 Roadsport 'A' on R888's, if that helps, and although i've tinkered with most of the car, I haven't touched the rack or associated bits.

 

Thanks,

 

stephen

[guilleracing]

Hi,

 

I would start with lubricating every joint and the rack itself.

 

Heavy steering can alos be caused by the column bushes being dry.

 

Finally check how much castor you have on the front uprights. Lots of castor will make the steering heavy.

 

Good luck!

 

 

Greg.

 

 

[Stationary M25 Traveller]

Jack the front of the car up and see if the steering turns freely with the wheels in the air. If difficult with the wheels unloaded, start with the steering rack ..... lubrication.

 

 

[NevDyson]

And tyre pressures, if you run a low pressure then it will make your steering feel heavier.

 

 

 

Q361 ANJ here

 

 

 

 

[Farreaster]

A quick rack will also feel heavier than a slower one

[Jason Plato]

money is on castor

 

 

here is my Duratec R .... C7 TOP

Taffia AO

[stephen grant]

 

Thanks all,

 

Yeah, i'm comfortable it isn't tyres, or the quick rack (if she's raced for 10 years, she'll be used to a quick rack). The car is also rather more understeery than one would want, even though I've dropped at least one bar thickness at the front. I'm starting to wonder if it is geometry (although it might well be lubrication; i've not lubricated the rack in the 6+ years i've owned the car). As I understand it, I should be looking for a washer/shim configuration on the front lower wishbone of 2-2-2, as detailed in the build guide, as a starting point? Or is there a simpler geometric way to measure the castor?

 

stephen

[Doug]

The simplest place to start is with the column bushes. These can dry out and make the steering a bit sticky. To begin with spray a little WD40 into the bushes and see if that helps. If it does then I would buy new bushes and lubricate them with silicon grease prior to fitting.

 

If the WD40 trick doesn't work, look elsewhere.

 

'Have you any idea what it's like to have the wind rushing through your hair!' (Quote:Sq Cdr the Lord Flashheart)

[Richard Price]

The car is also rather more understeery than one would want, even though I've dropped at least one bar thickness at the front

How does it wear its tyres on track?

What springs and dampers are you running?

How much camber do you have?

What front and rear ARB's do you have?

What size and compound of R888's are you running?

 

 

Is the steering "Heavy" or "Stiff" - If its stiff, it won't self centre, and will require constant corrections to hold it straight.

If it is "heavy" rather than stiff, then it will be castor. However, I run my narrow track car with full castor, and it seems to work for me.

 

 

 

[stephen grant]

Hi Richard,

 

Some not-very-good answers, I'm afraid;

 

Tyre wear; looks even to me, certainly there's no obvious asymmetry.

 

Springs & Dampers; not sure that there's anything to tell me. I'll look again in the garage this evening, but are there any identifying marks on the springs that tell me what spec they are?

 

Camber: no idea, unfortunately. I inherited whatever setup the previous owner (who raced the car) had. Sounds like I need to visit someone with some camber/tracking equipment?

 

Front ARB; pretty sure it's Red now, previously Green. Rear - not sure I have one? I have what I think is a Watts linkage (drop linkage, plate with 4 holes, currently connected to the 2nd from the back) - does that sound right?

 

R888's are the GG compound I think,13", 60 profile.

 

Steering self-centres just fine, so it's heavy rather than stiff.

 

Thanks again....

 

stephen

 

 

Edited by - stephen grant on 29 Oct 2009 12:02:45

[guilleracing]

Ahh,,,,,

 

Iv'e been thinking about this.

 

Make a list of things to look at as indicated on the posts, starting with the simple fixes first.

 

 

BE CAREFULL! I've seen people grease the steering on old MGs and the like, and have an off piste experience at the first series of bends they come to!

 

A simple test for castor is to measure the front ride height with the wheels straight ahead, turn them all the way one way and measure the front ride height again. If you have lots of castor, the two measurements will be vastly different.

 

Lots of castor actually lifts the front up, this is part of the reason that high castor settings force the steering to self centre. The weight of the car pushed the front back down an helps the steering return.

 

 

Again, please be carefull and do one thing at a time.

 

Proper castor settings can only be done with a Castor/Camber gauge and someone who knows exactly what they are doing.

 

Greg.

[stephen grant]

 

Much appreciated and, as you say, it sounds like it's boiling down to some careful lubrication (which I should be perdiodically doing anyway), and an investigation of the castor and the general geometry at the front.

 

Thanks all,

 

stephen

[Ash.Bailey]

Proper castor settings can only be done with a Castor/Camber gauge and someone who knows exactly what they are doing.

---

 

No need - its far simpler on a Caterham by reverting back to the number of washers on the wishbones in the build manual,but yes you will need to get the tracking rechecked after.

 

2-2 is my favoured but do a search on here and you will find lots of info

 

If ^It aint ^yellow, wonky ^and wobbly................ 😬

 

[guilleracing]

Hi

I would re-iterate my suggestion about doing the camber properly with a guage.

 

I have seen several people who have used the " Set it up like the build manual."

 

This is a good suggestion if the chassis is new, the uprights are new and the wishbones are new, oh and not forgetting the bushes and mounting bolts as well.

 

Unfortunately in the real world where stuff beds in and gets twisted and bent by pot hole, kerbs and anything else you run over on the road you actually do need to use a castor guage.

 

If you believe that you chassis stays the same shape throughout its entire life, just ask Arch. After all they have a well respected business that re-jigs Caterham and racing car chassis. They wouldn't have a business doing it if it wasn't regurlarly needed!

 

Sorry but that is life.

 

I once over a roof rack on an A road during 50 years of the 7 blat! .

 

 

Thankfully the luggage was somewhere else. 😬

[Paul Deslandes]

Stephen

 

if you have a reasonably flat and level garage floor or other hard standing, you can measure the camber to a reasonable accuracy yourself using a vertical spirit level and a steel rule.

 

Get the front wheels settled by rolling it back and forth a few times making sure the wheels are centralised. Measure the diameter of the wheel rim and cut a piece of wood (a piece of 1" x 2" is ideal) with parallel sides so that you can rest it vertically across a front wheel touching the rim at either end, i.e. across the diameter of the wheel. Hold the spirit level against the piece of wood, sticking it on with double sided tape makes it easier, pull one end of the piece of wood away from the wheel until the spirit level is vertical. Using a mm steel rule, measure the gap between the wood and the rim. If you pulled the top away from the wheel to get the level vertical. you have negative camber, if the bottom then you have positive. If your spirit level is the same length as the wheel diameter you won't need the piece of wood.

 

To calculate the camber angle, which is expressed for each wheel individually, not for both wheels like toe:

 

camber angle (deg) = (180/pi) x top or bottom gap/wheel rim-to-rim diameter.

 

1.5 to 2.0 deg negative camber is normal for other than cross ply tyres (ACB10 etc).

 

To give you an idea, 380mm dia wheel at 2 deg camber shows a gap of 13.27mm. A gap measurement error of 1mm either way is only +- 0.15 deg so don't get too hung up on accuracy.

 

Paul

 

 

 

 

 

Edited by - Paul Deslandes on 31 Oct 2009 15:59:38