DDK - Die Deutschen Klassiker

Good write up Mark

My race car runs almost square - front is 3 minutes toe in, rear is 5 minutes to out


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Love the greasy/oily bag for the skid plate substitute.
Never read that before.
Every day a school day!

For the slip plates I decided to splash out a bit and bought these for about £200



Below are tow platforms I made of exactly the same height for the rear wheels to sit on.

I wondered if I could use the lift to lower them on



That didn’t really work - the wheels splayed out as I was lowering them on. Also then when I tried to turn the wheel through 20 degrees to measure the castor it wouldn’t stay there and I had to hold it in position to take the measurement which I don’t think is right.

I looked at the manual for a pukka set of slip plates and that advised driving the car onto one set of blocks and then rolling them forward onto the slip plates

So I made 4 more platforms (initial platforms). Next need to make a bit of a ramp to be able to drive onto them. Then I’ll be able to use them properly - drive onto the 4 initial platforms and then roll onto the slide plates.

So, measuring castor and camber….

I bought these - about 115 each



The frame on the left clamps onto the wheel and fits very well - consistently and quickly



And then the other part - the red sealey tool in its box - magnetically fixes onto that disc in the centre.

It then uses a series of “level bubbles” and adjusters to measure the camber and the castor

What are you setting the caster too Mark?
I set mine to max but equal, not sure that was right looking back.

I haven’t got the figures with me at the moment but I’m going to aim for the “after” figures from the last visit to centre gravity.

From memory the castor was 5 something and my first attempt at measuring showed they are now 3 something.

Before I change anything at all though I want to be able to do repeat measurements at least twice to satisfy myself that I’m measuring consistently

Hi
What make of camber / castor gauge did you buy please. Also, having used them, would you recommend them?

Thanks

Colin

sladey wrote: ↑Sat Apr 12, 2025 11:38 am

Nice turntable, is it a custom build?

COLIN58 wrote:Hi
What make of camber / castor gauge did you buy please. Also, having used them, would you recommend them?

Thanks

Colin

I went for the sealey one - think it was about 115, and then the clamp to mount it on - again I think about 115.

From preliminary measurements it seems ok but I’ve not yet used it in anger.

Will post again when I’ve got the corner weight stuff ready to go

Nige wrote:

sladey wrote: ↑Sat Apr 12, 2025 11:38 am

Nice turntable, is it a custom build?

It’s a Hardon Carton if I remember correctly

OK time for another update.

This week-end I’ve tried to push ahead with the corner weighting. I’d ordered 6m of 40x40 angle iron and cut it down into lengths that I needed




I then started to make a jig to weld in the first cross-bar. This is the bar that is going to rest on the bathroom scales (with a bit of foam underneath to avoid cracking the glass top). I wanted to get it so that with the car on these were roughly level.

I made this jig to put it into the right place


And then welded them all (just on the one end)



I then started positioning where the fulcrum was going to be. Again I wanted to make the whole thing reasonably level (it doesn’t have to be bob on but close enough)



After moving it all about a bit I realised I needed the fulcrum angle iron to be sitting below the side bars. This was a bit of a bugger as I’d cut them assuming they were going to slot in between the two - so that wouldn’t leave me much (or anything!) to weld onto.

So I ended up making these little corner pieces which let me hold it in place securely



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Next came the plates the wheels are going to sit on. These have the edges folded for rigidity, and then a piece of angle iron welded across the bottom so that the weight of the wheel sits along one particular line - letting you calculate quite accurately how much to multiply the indicated weight by to get the actual weight

I was able to re-use the previous jig to position the angle iron in place


And soon they were all welded up




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Then I needed to weld in one last piece of angle iron (this time sitting vertically if you see what I mean) - this is the piece that the wheel plate is going to balance on.

I was concerned here to get each one as identical as possible so again I made a jig to help with this - the end of it slots into the top of the fulcrum and the piece clamps onto the other end so you can then weld it into the right place each time



I realise the 50x50 square tube is overkill for this but I had a load of it lying around already so that was the obvious choice. Also I know it all looks rusty and crap but the focus today has been actually making it and seeing if it works. Later on I can paint them up so they look a bit smarter

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So let’s give them a go!!!!

I decided to drive onto the platforms I’d already made first and then drive/roll from there onto the scale frames.

It took me two goes to drive onto the platforms - really I need to build a bit of a ramp onto them. This won’t be a big deal but it was the end of the day and I just wanted to give it a try

A couple of goes, a bit of a run up and quick braking and I ended up here



Then I put the scales into place and carefully drove onto them



It worked well!

I was able to go around and push the scales and got a reading.

I’d worked out what multiplier I needed to use (I thought). The wheels would be sitting 198mm from the fulcrum and the bar on the bathroom scales was just under 595 from it. Initially I thought I would need to double the reading and then I thought I’d need to treble the reading.

After working it all out though my car apparently weighed 860Kg in total. Which would be lovely but I know isn’t accurate.

I then realised that I could get the correct multiplier accurately by weighing myself on the wheel plate and then weighing myself directly on the scale.

To make it even more accurate I did this for each corner and got different multipliers for each corner (reflecting my inaccuracies in making the framework). I wrote the multiplier onto each frame. They ranged from 2.61 to 2.70

I got confused part way through as I managed to write down numbers wrong and also re-did a couple of the weights.

Finally I ended up with this


So as I understand it the key weights that you can and should adjust are the opposite corners. So The Porsche requirement is that FL + RR should be no more than 20kg different to FR+RL

Mine came in at 10.6kg difference. Which I’m happy with.

When I go to centre gravity they generally get this down to 2-4 kg difference. For the moment I’m not planning on changing that necessarily - as I’m going away in May I don’t want to risk buggering anything up but I’m reassured that it’s not far out.

For all the above measurements I out 80kg in the drivers seat

It also showed the overall weight of the car - I subtracted the drivers weight and ended up with 1072kg which I’m pleased with. That fits in with previous weighing at centre gravity plus the weight of the air con that I fitted last year

I’m currently waiting for the DIY smartstring brackets to arrive from California (they are currently in Canada) - they should make it easier to measure the toe-in accurately and consistently.

Once I’ve got that I’ll re-measure everything and then decide if I’m going to change anything prior to the road trip - or maybe leave well alone. I’m not sure yet.

From initial measurements the only things that seem materially out from the last good settings are the front castor.

It felt good today to get those weights, and also to prove that the concept of using cheap bathroom scales works fine.


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