Suspension geometry and setup - DIY?

Chris_in_the_UK · 24 Mar 2016

Demort said:
I agree , but is not the purpose to spend as little money on equipment as possible

I was - and it still is!.

Current expenditure over what I already had:-

Alloy scaffold poles - £30

Digital angle Gauge - £20

Parachute cord - £5

:mrgreen:

poppopbangbang · 24 Mar 2016

How we used to do it:

All that fancy billet is essentially recreating axle stands and string.

We've back to backed a mobile hunter against our string and poles ability and the hunter read exactly the same as our setup sheet. This is very much one of those things that gets quicker with experience - if this is the first time you've done it expect it to be a long job!

Chris_in_the_UK · 25 Mar 2016

Ok folks - long day need!.

Spent a good while setting this up as I do not have the F1 bespoke stuff!.

Basically this is one corner of the 4 on the car. What you are looking at is an axle stand at each corner equip distant and the height set to as near as dammit to the centreline of the wheels. The car is on 4 blocks of wood to make access underneath a bit easier whilst allowing the car to loaded with it's weight on the suspension.

Across the front and back are 2 metre long alloy scaffold poles, again set perpendicular to the car and equidistant down the centreline - secured by a bungee cord at each corner. Importantly, the scaffold poles are exactly the same length (more on this later).

I'll post a close up shortly, but the tyres are sat on two pieces of numberplate placed one of top of the other - these are slightly larger than the contact patch but importantly allow the tyres to slip easily as the suspension/toe is adjusted.

The parachute cord is set exactly 50mm from the end of each pole and, importantly checked to be exactly parallel to each other.

deMort · 25 Mar 2016

If your going to crawl underneath to adjust the setup then you be Bloody carefull mate .. id like to see some kind of wheel chock to stop the car from possibly moveing .... with number plates under the tyres it will easily move side to side.

Dont want to be seen as nagging but ive seen far too many accidents in my time to not say anything .. forgive me

Chris_in_the_UK · 26 Mar 2016

Demort said:
If your going to crawl underneath to adjust the setup then you be Bloody carefull mate .. id like to see some kind of wheel chock to stop the car from possibly moveing .... with number plates under the tyres it will easily move side to side.

Dont want to be seen as nagging but ive seen far too many accidents in my time to not say anything .. forgive me

Not nagging - been there done that many years ago - all bolts loosened off before number plates went under - I replaced the lower arms/springs/shocks and CV boots a few weeks earlier so all suspension related fastenings were off, cleaned/replaced and coppaslipped before reassembly.

The rear end has wheel chocks both sides of the wheels :thumbs:

Been a long day getting everything set up so the picture is missing a few stuff as it's only one corner.

More to follow......

stasis · 26 Mar 2016

i tried the same thing a couple of weeks ago, I gave up for two reasons, firstly its hard to work on a garage floor tightening the eccentrics without moving them out of adjustment as there is not enough room, to get both arms in. Second as proved by my local who ended up doing it, without rotating plates under the wheels and more importantly sliding plates that allow the wheels to properly move whilst adjusting the camber, the drag of the floor with the weight of car make it pretty impossible to adjust it. I ended up adjusting, moving the car back and fowards to allow it to settle, , repeat, repeat, in the end I was chasing my tail thought I had it spot on, only for the actual measurement on an optiflex was to show it was miles off.

Chris_in_the_UK · 27 Mar 2016

Ok folks - interesting process indeed.

Everything went quite smoothly in the end.

Following the principles used in setting up the Cup cars, the stages that the Cup manual suggests is rear camber first, followed by rear toe, followed by front camber then front toe. This is the sequence I followed.

Firstly a recap on the finer details of the setup - here is a close up of the home made swivel plates made from 2 pieces of perspex number plates on top of each other - very slippery and very necessary, without this you have little chance of making any meaningful adjustments TBH.

First off - check and set the camber. I used a digital angle gauge to make life a little easier.

Couple of considerations...... the reason that I ended up doing the whole alignment thing was a result of me shaping all 4 lower arms, shocks and lowered springs. The lowering of the suspension itself would have been reason enough but the arms I sourced were Meyle items and there have been hints that these can cause problems with geometry set ups.

Rear camber is adjusted by an eccentric bolt/washer combo on the inner lower suspension arm mounting. The arrangement on the rear means that the toe and camber need quite a bit of juggling since one affects the other. The Meyle arms clearly are slightly different to TRW (OEM) ones and the rear camber could not be set less than 1.4 degrees negative. Bit more than I set out for but it's not extreme and if it becomes an issue I'll swap the inner bush for an eccentric one. The toe setting could not be set to zero due to this so I am contemplating putting some adjustable toe arms together to get to zero rear toe as opposed to the 0.5 degree toe in it's currently maxed at.

Front camber is relatively easy to change using the elongated top mount holes.

As a starting point I set the front camber to 1.4 degrees of negative camber.

It's important the set the steering and fix it at the straight ahead position before front toe is attempted. I used a wooden block to facilitate this.

Quite an involved process doing the toe adjustments and small adjustments is the way to go measuring the distance form the wheel rim front and rear to the cords on each wheel. End result - 0.03 degrees of toe in on each front wheel
:thumbs: .

All data entered in here - really helps with the process!.

https://www.robrobinette.com/DIYAlignmentCalculator.htm

So - for now this is pretty much as good as it gets for now.

Just looking at some bits to make up some rose jointed adjustable rear to arms to take the rear toe out to zero (be less than £100 for both sides).

Hugely satisfying if not a little intense.

deMort · 29 Mar 2016

:thumbs: from me , id not even herd of this before untill you posted and im actually impressed ... and that dont happen very often.

Chris_in_the_UK · 23 Apr 2016

UPDATE - All done after a recheck just to make sure everything is settled.

Home-brew adjustable rear toe arms in place.

Results - I had another week after this screen shot and the front settings are now identical.

Screen%20Shot%202016-04-23%20at%2014.28.56_zpslknag2jp.jpg

Was it worth it? - For me it was a good learning exercise and I understand suspension geometry much better than I did before.

Time for a cold beer........

deMort · 23 Apr 2016

Chris_in_the_UK said:
UPDATE - All done after a recheck just to make sure everything is settled.

Was it worth it? - For me it was a good learning exercise and I understand suspension geometry much better than I did before.

Time for a cold beer........

Excellent job , you did it along with sorting out problems along the way , you should be working in a garage .. wasted talent doing any other job

ultegra · 23 Apr 2016

I use the same method on my BMWs.

The only tip I would offer is to use a product called SHOCK LEADER rather than paracord. It's a sort of semi-elastic fishing line that stays really taught.

http://www.ebay.co.uk/itm/WARBIRD-S...932104?hash=item25b276fbc8:g:H6IAAOSwAKxWYZHq

Chris_in_the_UK · 23 Apr 2016

ultegra said:
I use the same method on my BMWs.

The only tip I would offer is to use a product called SHOCK LEADER rather than paracord. It's a sort of semi-elastic fishing line that stays really taught.

http://www.ebay.co.uk/itm/WARBIRD-S...932104?hash=item25b276fbc8:g:H6IAAOSwAKxWYZHq

:thumbs:

Just ordered some - thanks for the heads up!.

MNC911 · 23 Apr 2016

Well done, I like people who think outside the box and have a good engineering mind & put to use their abilities.

You should pit your ability by then putting it onto a Hunter afterwards. If it transpires you can get it near bob on, you could be onto a business idea for DIY enthusiasts :thumb:

BHZ661 · 25 Apr 2016

Excellent , fantastic work, :thumbs:

MNC911 · 25 Apr 2016

Chris_in_the_UK said:
UPDATE - All done after a recheck just to make sure everything is settled.

Home-brew adjustable rear toe arms in place.

Results - I had another week after this screen shot and the front settings are now identical.

Was it worth it? - For me it was a good learning exercise and I understand suspension geometry much better than I did before.

Time for a cold beer........

That looks like a Hereford & Worcester tan colour fire jacket hanging up in the garage Chris. See us ex-fireman spot these things.

Suspension geometry and setup - DIY?

Chris_in_the_UK

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