Ride height/rake,camber and tracking

[weeman]

Doing some rudimentary measurements on my car it's fairly obvious that it has never been 'set up' properly.

I've been doing a little research and I'm confident to undertake this myself, but I would like to know which order to tackle the various adjustments. From what I've read I'm guessing that the title of this thread is the correct order 🤔.

I know that many of you may recommend having the car professionally flat floored, but I would like to tackle it myself and so add to my limited knowledge.

All input will be very welcome, feel free to treat me like a numpty 😬

 

Edited by - weeman on 8 Mar 2011 12:26:00

 

Edited by - weeman on 8 Mar 2011 12:57:16

[James_Russell]

So many don't bother but it makes such a difference!

If you have adjustable platforms, setting ride height and rake isn't difficult. 'flat flooring' is quite a different exercise and you'd need scales for that.

I'm sure some de-dion owners will happily lend some hints with regards to geometry measurements.

[weeman]

thanks James,

I use the term 'Flat floored' as a generic term for a 'professional set up'.

I'm fairly sure as to how to go about making the adjustments and what settings I want to achieve. It's more a question of what order to do them. e.g if I were to set the front and rear camber first would these settings be affected by then setting the ride height?

Should have mentioned my car is a CSR so there are Camber/track adjustments to be made at the rear as weel as te front, though I imagine that the 'order' will be the same on a De dion as on IRS

[weeman]

 

 

Edited by - weeman on 8 Mar 2011 12:56:55

[James_Russell]

I don't know if this is the 'rule' as such, but our race cars have a minimum ride height- so we begin by setting the front ride height at 120mm. Then you set the rear with the requisite 15mm of rake.

Geometry and corner-weighting effect each other to an extent but usually I'd set the corner weights (being careful not to lower the front below the minimum), before setting the geometry. Remember that corner weighting may leave the offside rear ride height much higher than the other three corners- so you may choose to set the geometry with the driver on board too.

So basically the order in your title is spot-on as far as I know!

EDIT: measurements taken from under chassis rails! Sump clearance may be more important to you as SM25T says below...

 

Edited by - James_Russell on 8 Mar 2011 13:39:02

[Stationary M25 Traveller]

Assuming your sump is the lowest point, you want to start with getting something like 75mm clearance under there once you have played with camber, etc. Then measure gap under chassis rails just behind front wings, then look for +15mm at the front of the rear wings.

 

I did it with the equivalent of driver + passenger in the seats, using concrete blocks (with the seat bases removed).

[myothercarsa2cv]

Ian (SM25T) helped me do a rudimentary set up on mine, using me in the drivers seat - lots of hopping in and out! We set the ride height and rake, making sure that the car was level (measured with a spirit level across the roll bar and headlamps) with me in the driver's seat. I don't know what the result of a flat floor would be, but it was such a massive improvement, I was kicking myself for not doing it sooner! Would recommend that as a good starting point.

 

Don't forget to take your other half into consideration, though

[Pendennis]

Why do you set rake and why at 15mm

[Revin Kevin]

Weeman,

Chassis set up is a massive subject which I can and do bore people to death with (just ask the west hants lot) and now after 25 years of it I still consider myself an amateur. BUT a Flat Floor set up is easily achieve with a few simple tools at home (with the correct knowledge), but the basics can be picked up quickly and it's great fun to experiment and learn.

I think we have met before, I came across to one of your meets last year and we spoke at Gurston. I am more than happy to talk/show you through a set up (bore you to tears before anyone else says it) if I can help.

 

Pendennis,

Rake is to do with skew roll and the roll centres of the front and rear suspension and how they effect each other. 15mm is a ball park figure that has come about over years of experimentation, testing etc for each individual chassis set up/driver is the only way to determine the exact correct figure.

 

Cheers

Chris

 

Edited by - Revin Kevin on 8 Mar 2011 18:47:21

[MADMALC]

Hi W

 

If you blatmail me I can send you a 'method' for adjusting corner weights. It relies on you having a rear anti-roll bar and requires no weighing. Obtained a while ago from this forum and it it very useful.

 

 

[Pendennis]

And that is why I raised the point of why everyone says you need rake

 

As a rule, you don't want rake but if the c.o.g means you have to make a compromise then so be it, but keep it as low as you can Me, I don't go with "ball part figures"

 

Malc, your right scales are not necessary to get your Caterham geometry almost there, a tape measure, camber and toe gauges are though

[weeman]

Thanks to all for your suggestions (via your posts and B/M).

 

Chris YHM. We did meet at Gurston and at the Brigadier Gerard.

 

MADMALC. AFAIK there is no rear anti roll bar on the CSR (well I can't find one on mine anyway) . Wouldn't mind reading the method to which you refer though, so YHM.

 

Thread still open if anyone else wants to 'chip in'

 

Be lucky!!

 

Martin.

[Revin Kevin]

Martin,

YHM

Cheers

Chris

[Jason Plato]

rake will vary depending on rear spring rates

 

nice 200lb rear springs require little rake in my experience , STD springs require a little rake