Thuoght that people might this article interesting...

LINK

Although it's written for the Mini, the weighing device does look very easy to build.

Apart from the gauge, I could easily make the other bits. Anyone know where I can get a suitable pressure gauge at a ridiculously low price?

Not sure how to calibrate it though - my knowledge of dry-horlicks is abysmal.

David

Great link!

I didn't have a clue what corner weighing entailed - but I do now

There is another way..

If you go and poke your head round a race car supplies shop you'll see lots of corner weight scales for a for £k's.. these give the weight in Kilo's of each wheel, so its very easy to see what happens when you adjust something.

But you can replicate this method the Locost way!

Using (and I kid you not) some old school mechanical bathroom scales..

They'll need to weight up to about 160kg for our purposes and be spring based, not digital.
Got mine for about £30 the pair from the local discount superstore.

To use

Fisrt find a flat floor.

Secondly put the rear corners of the chassis on stands - ensure its the chassis NOT the axle/suspension

Disconect ARB's

Ensure scales read the same - stand on them - adjust the start point on 1 until they agree- they'll not differ much anyway.

Put under each front wheel, orientated so you can see the gauge... been there done that...

Insert suitable ballast into drivers seat (Missus plus tool box... )

Give the suspension a bounce to settle the car.

adjust front spring platforms until you get to the point you're happy.

Remove stands from under rear of chassis.

Have the scales alltered out of synch? (NOTE the weight will alter but has the balance?)

If so adjust the rear spring platforms until you get the front back to where you wanted it.

Re-connect ARB's - if these change the balance adjust ARB mounts until they don't..



If like me you this sounds too locost to work the first time you here it, now borrow some big bucks digital kit to check..

It'll not be far out, certainly close enough, apparently this method was first used by a certain Mr Mallock and his race cars were none too shabby..

The only thing I've found is that if you're aiming to get the weight different across the front down to Nil. It's very difficult to get too (assuming no passenger) without the spring platform heights getting radically out. However its quite easy to get it close and then you start to see an expontial rise in adjustment versus kilo change - so I would recommend you only aim for the 'getting it close' and stop when you start to see huge changes for little benefit.

Hope this helps

Good point - as long as you could get accurate numbers off the scale, it doesn't matter if it's displayed as "carats per square cubit" or, more likely, a "bar" value these days. You just want "the same value" on each side.

As for weighing scales - my car weighs 600kg without people on board. Assuming a 60/40 split, the front wheels will be carrying 360/2 = 180Kg each. I'd need to get a pair of 200Kg scales to be sure that I won't break them! Not sure how common they would be.

I just thought the pressure gauge thingy would be a simple way to get the same effect quite cheaply.

David

How about this?

http://cgi.ebay.co.uk/HYDRAULIC-PRESSURE-GAUGE-BASE-ENTRY-63MM-2000-PSI-NEW_W0QQitemZ140016259564QQihZ004QQcategoryZ48718QQrdZ1QQcmdZViewItem

£10 sounds suitably locost.

I dont see how it would need to be calibrated as long as you always used the one tool for all 4 corners. t will be a suitable comparitor and as the article says you calculate front to rear split by percentages so wether the pressure readings is accurate or not is irrelevant.

I wonder if an old axle stand could be adapted fo rthe leg? This would give the height adjustment and keep it vertical and secure. The tricky bit would be making the cylinder back plate so it will all fit inside the wheel.

[Edited on 10/8/06 by DarrenW]

Might be too great a range - ideally you want to be about 2/3 to 3/4 around the scale when lifting, so that you get a decent number of graduations to work with.

Still, at that price, it would be ideal for playing with.

David

UPDATE: I just bought me one of these from the same seller - LINK - "That'll do nicely, Sir!"

[Edited on 10/8/06 by David Jenkins]

I tried making a hydralic gauge like that a few years ago after seeing one like it made by Pace. I made mine out of a caliper and gauge, but never used it as the garage wasnt wide enough and I couldnt get good repeatability.

I ended up with a balance beam and spirit level.

http://www.beardmorebros.co.uk/website%20pages/update_16th_June_2004.htm
Describes the method.




I now have some ex F1 digital scales.......

John

quote:

---

Originally posted by robocog
Well spotted that man
Just got one myself :-)

Now for the clutch slave cylinder....

---

cheapest new clutch slave (and one of the longest stroke oe ones) is a mini one, still £30 tho!

quote:

---

Originally posted by David Jenkins

If anyone has a good suggestion for a clutch slave cylinder that can be bought new quite cheaply then I'd like to know about it. Why new? It means that I can put any suitable fluid in it, rather than brake fluid (as long as it won't corrode the bore or rot the seals).

David

---

That was Plan B!

I've seen one of these Caraven nose weight

It has definiate potential although I can't currently work out how.... any suggestions?

best I have come up with is using two (due to the scale only going to 80kg) next to each other as a fulcrum and a long lever across the top....

its Friday afternoon so brain bnot working, but i wonder if the caravan nose weight gauge at 80Kg range would work if you used a lever and pivot point between the gauge and the wheel?

I was thinking about the top sketch but probs no good. Bottom one replicates the cylinder idea but gets back to the problem of the gauge possibly not reading high enough or maybe too big to fit under rim.

What about a load cell?

http://cgi.ebay.co.uk/PHILLIPS-WEIGHING-LOAD-CELL-PR-6201_W0QQitemZ250017189387QQihZ015QQcategoryZ50964QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Diagrame 1 would require you to have a very long lever, you have to lit the car + compress the nose weight.


load cell looks very interesting, assume you need another devise to be able to read it?

I can't see how the hydraulic one could work well. The fact one tire must be lifted 1/4" or so changes the loads on the other three wheels... Reminds me a bit of the Heisenberg Uncertainty Principle, where the act of measuring something changes what you're measuring.

Reaching into the wheel:

I'm planning to make a swinging arm with a 1:1 ratio, leaving the master cylinder back near the upright. This means that the size of the cyclinder is irrelevant (within reason). Good tip on the Landy parts!

Amount of lift:

That's mentioned in the article - but I was thinking of a piece of card or plastic on an elastic: you'll know when you've lifted it just off the ground when the card moves. Even so - the auther suggests that it isn't necessary.

It may not work - but it's a cheap project so it's worth a bit of experimentation!

David

I think with a car as light as one of 'ours' tends to be, getting one wheel off the floor will alter the loads a lot. As the article says a 3mm or so gap won't affect things, I think it will with these type of cars. Whilst slightly different, when I jack mine up from one corner that end of the car is very quickly off the floor. The idea with the card is quite sensible and has been told to me by many others in the past.

Good link there
The Castor / Camber Gauge looks interesting, but £80 for a piece of board and couple of string is eee..... not locost.
I “computer-generated” something similar but you will have to make up you own “easy to use directions”.

CAMBER GAUGE

If you manage to figure out how to measure caster with it, please post here.

Cheers!

[Edited on 06-8-18 by leto]

I would suggest if you are using the hydraulic type guage blow the tyres up hard to minimise the amount lifted before clearance, also make sure tyre pressures are equal. Back off all shocks to full soft & loosen all bolts through suspension pivots if using bushes to eliminate sticktion, this is not necessary with rose joints.
We always use proper corner weight scales as it is easier & more accurate, plus the factbwe have them.
HTH
Ian

I would suggest if you are using the hydraulic type guage blow the tyres up hard to minimise the amount lifted before clearance, also make sure tyre pressures are equal. Back off all shocks to full soft & loosen all bolts through suspension pivots if using bushes to eliminate sticktion, this is not necessary with rose joints.
We always use proper corner weight scales as it is easier & more accurate, plus the fact we have them.
HTH
Ian

lifting the wheel 3mm off the ground will add around 30lbs to the apparent corner weight, obviously depending on springs etc. Thats quite a large percentage of the total i suppose.

To avoid the uncertainty of the tyres flexing, you could replace the wheels with bare steel wheels (ie no tyres). It should still clear the deck, and will be a lot easier to judge the moment at which lift off occurs.

Very good point Joel P. Dummy setup wheels will make all suspension alignment so much easier.

If you are rich make them out of aluminium plate (or carbon or honeycomb) otherwise some stout plywood will do the trick.

They will make corner weighting, camber and tracking so much easier. If you get clever you can add bearings, wheels, rollers on the bottom to take out side loads after you have lowered the car to the ground (on independant set ups)

I must make some before my next setup.

John