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Rear Axle alignment
Posted: Sat Dec 06, 2008 7:08 pm
by kevp
I have just checked my front wheels for toe in etc, & decided to check the rear as well.
The rear axle seams to be slightly twisted left. Making a difference of 3cm when measured at the centre line of the front axle.
Is this OK or should I try to adjust? If so how?
Re: Rear Axle alignment
Posted: Sat Dec 06, 2008 11:43 pm
by stylussprinter
kevp wrote:I have just checked my front wheels for toe in etc, & decided to check the rear as well.
The rear axle seams to be slightly twisted left. Making a difference of 3cm when measured at the centre line of the front axle.
Is this OK or should I try to adjust? If so how?
Kevin , I'm not sure what you mean by ''twisted'' left
Do you mean it literally OR do you mean that the axle is biased to the left BUT parallel with the front
What is your chassis number
Neville's chassis were pretty straight but the one's made by that Yorkshire twit were out at the front rockers which made the rear appear not straight.
If it's simply biased then make the panhard rod adjustable but don't get too close to the tunnel with the propshaft
Re: Rear Axle alignment
Posted: Sun Dec 07, 2008 12:26 am
by Antnicuk
i think i now what you mean, i put mine on a 4wheel diagnostic thingy and mine was a out. I'm going to replace bushes on the chassis ends of the trailing arms with rose joints so i can adjust each side of the axle and move it backwards or forwards.
Re: Rear Axle alignment
Posted: Sun Jan 04, 2009 1:19 am
by kevp
I have looked a little closer at my rear axle today.
The axle is not central to the car by about 15-20mm. I know it will travel whilst in use due to the panhard rod, but this will pull it even further out. Also the diff is pointing down. On full or near full suspention extention the diff nose sits on the panhard rod. As the suspention compesses the front of the diff is forced further down. This must be working the UJ on the prop realy hard. Finaly the axle as mentioned before does not sit square across the car.
I have decided to leave all alone at the moment but may end up following Antniuk & fit adjustable Rose joints when Rob (?) or Tim (??) decide to make a batch of the upgraded "bent" trailing arms.
Or has anyone converted to independant rear suspention? Should I even consider this?
Re: Rear Axle alignment
Posted: Sun Jan 04, 2009 11:43 am
by stylussprinter
kevp wrote:I have looked a little closer at my rear axle today.
The axle is not central to the car by about 15-20mm. I know it will travel whilst in use due to the panhard rod, but this will pull it even further out. Also the diff is pointing down. On full or near full suspention extention the diff nose sits on the panhard rod. As the suspention compesses the front of the diff is forced further down. This must be working the UJ on the prop realy hard. Finaly the axle as mentioned before does not sit square across the car.
I have decided to leave all alone at the moment but may end up following Antniuk & fit adjustable Rose joints when Rob (?) or Tim (??) decide to make a batch of the upgraded "bent" trailing arms.
Or has anyone converted to independant rear suspention? Should I even consider this?
I don't know by what method you checked the axle NOT TO BE PARALLEL with the front
Don't forget ----- that if the front rockers are NOT mounted parallel with the front chassis rail or not at the same angle each side , for instance , then the axle will appear NOT parallel with the front
You may regret quick decisions
Mine was definitely '' out '' at the front and so were many others but most people didn't notice including '' PETE ''
This being the MORE likely diagnosis to the axle appearing '' not parallel '' , the easiest route is to put ' rose joints ' each end of the panhrd rod as I did years ago. The other tweek ---- is to remove the panhard from it's chassis end mounting THEN weld a bracket plus bolt it directly underneath the existing BOLT THROUGH THE PASSENGER side seat pan . It needs to be 40mm x 50mm plus have plates welded at 90 degrees to the plate on two sides . One to bolt a 12.7mm bolt through and the other to strengthen that plate with the bolt hole
This way the diff nose clears the panhard plus the panhard sits level as intended , making it harder for ' g ' forces to shift the car across when cornering hard on track.(adjustment is limited due to needing to clear the tunnel/propshaft
)
You do need to be sure what is wrong first though . Frankly , for road use , I doubt anyone would notice a handling problem . It's only after developing the chassis/suspension in all other ways that that last little bit of accuracy will influence the car's dynamics and even then , only on track driving near the edge
If you want a photo of my '' bracket '' (panhard mount
) contact me directly Kevin then I'll take appropriate photos for you ok.
Anyone who bought a chassis from SSC since Tim took over the company will have a pretty straight chassis/mounting pick-ups because he stopped using that ' Yorkshire bodger ' and made his own jig .
Re: Rear Axle alignment
Posted: Sun Jan 04, 2009 8:36 pm
by Antnicuk
Just thinking a bit here (which is usually dangerous) if the rocker arms arnt parallel with the chassis, this would mean the top of the upright would be forward or backwards of where it should be which would alter the caster by moving the king pin (upright) and changing the angle in relation to the bottom B/J, but only move the wheel very slightly. ie, if the top ball joint was 20mm further back than it should be, that would only be a few MM at the centre of the hub due to the centre of the hub being a lot closer to the bottom pivot point(B/J) . So as long as the bottom wishbone pick ups are in the right place then wouldnt the distance between the back and front wheels be pretty close even if the rocker arms were as much as 20mm out??
Re: Rear Axle alignment
Posted: Sun Jan 04, 2009 8:50 pm
by Werner Van Loock
What are you talking about, have you seen the repairs that Colin McRae did to his subaru suspension after hitting a rock? He still managed to go fast. Believe me, a few mm here and there aren't going to change anything. Unless you have a very very stiff chassis and suspension otherwise this all compensates it.
I've raced modelcars long enough to know that unless something isn't seriously out, you won't notice a thing.
you should check out your tintop, then you will put up a face like this:
Re: Rear Axle alignment
Posted: Sun Feb 15, 2009 12:21 pm
by Cerberus
kevp wrote:I have just checked my front wheels for toe in etc, & decided to check the rear as well.
The rear axle seams to be slightly twisted left. Making a difference of 3cm when measured at the centre line of the front axle.
Is this OK or should I try to adjust? If so how?
I recently bought a four wheel alignment system as i didn't want to pay a garage between £30 and £80 to re adjust Toe etc everytime i changed something, plus i knew the T.A.D was wrong so i have just been through this with mine, mine was only offset though, by 15mm, plus all the springs were different poundages and the shocks were valved differently good ehh, oh and positive camber on the nearside and zero on the offside, so i spent yesterday(allday) sorting everything out and readying the car for a trackday and the MOT, at least everything is pointing in the right direction now, so it should now start to handle as its supposed to.
Kev, if you want to drive up here we can go through the car and point everything the way it should be.
Re: Rear Axle alignment
Posted: Fri Apr 17, 2009 9:45 am
by stylussprinter
Just thought some other Stylus owner , at some time , might find this handy to know
Ian Minki recently acquired a part built Stylus but in a little bit of a mess , axle wise amongst other things . He's having to grind off the pick-up points and remake them so not being able to ask SSC , he asked me for some info which I was happy to do
Looking at the axle from behind there are two measurements between the pick-up point bracket to the 8mm thick flange of the axle end.
1) 90mm ------ in front of the bracket/towards engine
2) 100mm ----- behind the bracket/towards boot
It's this difference that creates the slanted angle of the bracket.
Then he needed the measurement of the brackets from axle to bolting centre.
1) Top = 65mm
2) Bottom = 110mm
I hasten to say that these measurements are on an ENGLISH axle