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 Tyre Rubbing /Steering Geometry
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 30 Sep 2018 :  11:41:44 Show Profile Reply with Quote

Hi
I have an Fn/s tyre rubbing on the inner wing and It did it was doing so prior to the recent work carried out during project Dilemma.
When rebuilding the suspension I noticed that the lower F n/s had been repaired, welded up and thought that this was the problem, so I changed it for an undamaged one I have, assuming that this would solve the problem. It didnt.
When the car is suspended, level on axle stands the tyre doesn't touch the wheel arch.
I replaced the trimming shims as I had found them about 6mm worth in all four locations.
Nothing is obviously bent i.e. Track control arms, steering arms etc.
I havent yet renewed the wishbone bushes.
I read in a post by Derek - Even the standard 155 can rub on the rear of the inner wing on some cars.
Derek, do you or anyone else have more information on this?
I knocked up what could loosely be termed a camber angle gauge, just to try and see in very crude terms whats going on.

[/url]

In terms of settings this is what I found:
Camber:
OSF -1 degree
NSF +1 Degree
Caster:
OSF +1 degree
NSF +1.5 degree
Any advice?



Dynorog

Mos6502
V4 Fan

USA
133 Posts

Posted - 03 Oct 2018 :  07:46:39 Show Profile Reply with Quote
Rubbing where? Front or back of the inner fender? Tire size? Steel wheels?
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 03 Oct 2018 :  07:55:58 Show Profile Reply with Quote
Low level at rear of inner wing,155 80s @ 24 psi, Steel 4Js.
Ill take a photo.
Cheers

Dynorog

Edited by - Dynorog on 03 Oct 2018 07:57:29
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 03 Oct 2018 :  10:58:35 Show Profile Reply with Quote

Here's the Rub



Cheers

Dynorog
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Derek
V4 Guru

United Kingdom
1872 Posts

Posted - 03 Oct 2018 :  11:56:28 Show Profile Reply with Quote
This seems to affect some cars and not others. Sometimes it's only on one side. An MOT tester might spot it and be rather unhappy about it. If the rubbed area is smooth with no jaggies, rust etc it's probably not dangerous being that it only happens on full lock. Unlikely to happen when you are driving but you may have to do a lot of full lock manoeuvering in the road or in and out of your garage for example. Don't remember anyone offering advice on a cure for it. If it concerns you maybe try 1/8" spacers and see if that helps. I think I remember running about 28 psi, mostly to lighten the low-speed steering and that might help. Some cars have adjustable stops to prevent it but not in this case I think.
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Mos6502
V4 Fan

USA
133 Posts

Posted - 04 Oct 2018 :  06:28:17 Show Profile Reply with Quote
You might try swapping front wheels. If one is warped it may be the reason for rubbing on the side.
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 04 Oct 2018 :  08:44:32 Show Profile Reply with Quote
Thanks both.

Mos - I have already tried the wheel swop to no avail.

Derek- Your thoughts are similar to mine, that it's not likely to be of any real concern,not dangerous but things like this just annoy me.
I hope to get the castor and camber properly checked today and take it from there.
Your mention of stops though has given me food for thought. I'm wondering if the axial movement on the rack in the direction in question is greater than it should be, so I will have the steering angle checked today as well. Maybe it's wear in a spacing washer or something in the shaft bearing cap.I have a spare rack and I will compare the travel.
I may also look at putting some sort of split collar on the rack to act as a stop if possible.
If all this fails I will probably go for the spacers as you suggest.
I'll let you know the outcome.
Cheers

Dynorog
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stevebod
V4 Fanatic

United Kingdom
336 Posts

Posted - 04 Oct 2018 :  14:10:23 Show Profile Visit stevebod's Homepage Reply with Quote
Hi Guys,
Just catching up with this discussion.
I haven't fully thought this through but could this be reduced by centring the steering rack?
What I mean is, your tracking could be correct but if one track rod was significantly shorter than the other, could this cause one wheel to "tuck-in" more at full lock due to ackerman geometry?
I could imagine this happening if the steering wheel was removed and put back a few splines different. Then you would adjust track rods to get the car running straight with the steerng wheel straight but the track rod legnths would different.
My brain is not clever enough to work out if this matters.

Edited by - stevebod on 04 Oct 2018 14:11:14
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 04 Oct 2018 :  15:43:53 Show Profile Reply with Quote
Hi Steve, Im not sure because my head is starting to hurt now, but the rack would only travel the same axial distance at whatever point on the steering wheel position the tracking was set up at. I think #129300;
Not having camber etc. Checked until tomorrow now.
Cheers

Dynorog

Edited by - Dynorog on 04 Oct 2018 15:48:00
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digger
Starting Member

40 Posts

Posted - 04 Oct 2018 :  20:19:53 Show Profile Reply with Quote
Hi, I fitted the car with 165 Vredestein snow classics on 5J HSP compomotives and they rub on both sides. Looking on the bright side the steering and suspension geometry must be similar on both sides. They only just touch on full lock so it's something I'll live with unless someone has a clever solution.


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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 06 Oct 2018 :  11:10:48 Show Profile Reply with Quote
No real progress. Wasnt able to have camber castor set, the guys equipment must be connected to all 4wheels to work even when youre only concerned with the front wheels and the kit wont fit in the rear wheel arches. The kit cost him 10K and it looks like it did.
I know a guy who has a supper tracker rip off copy of the old super tracker kit and I try him. A mechanic mate of mine is convinced its down to something inside the rack. Ill investigate that as well.
Cheers

Dynorog
Ps wheels look great Digger

Edited by - Dynorog on 06 Oct 2018 11:11:44
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andydeans3
V4 Guru

United Kingdom
1192 Posts

Posted - 07 Oct 2018 :  10:55:13 Show Profile Reply with Quote
Roger
I had the same problem with trying to get my wheels aligned.
I did finally find an outfit called Farmer Autocare, who have the equipment shown in the photos below.

In spite of the fact that the manager told me that he couldn't hang his measuring devices on the back wheels, a little bit of ingenuity, did the trick.
Downside is that Farmer Autocare only exist in Scotland.
You can see the brand name of the equipment in the photos. perhaps try and track down a local tyre place that has this equipment?
Worked very well in the end.

Andy









1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro
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stevebod
V4 Fanatic

United Kingdom
336 Posts

Posted - 08 Oct 2018 :  15:02:54 Show Profile Visit stevebod's Homepage Reply with Quote
Hi Roger.
Well I had to draw it out in the end to satisfy my own curiosity. I'm posting the sketch here in case it helps with the problem you are seeing.
I agree that rack movement left and right is the same, but the angle change I get at each wheel is different if the track rod ends are different lengths. Hopefully the drawing is clear and ignore the actual values because this is not to scale, but it looks like the side with the shorter track rod end tucks in more for a given rack motion than the side with the long track rod end. This might apply to Derek's comment about some cars rubbing one side only, I dunno.



Yawn.....sometimes I bore myself.

Edited by - stevebod on 08 Oct 2018 16:36:13
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RhysN
V4 Fanatic

United Kingdom
273 Posts

Posted - 08 Oct 2018 :  19:22:38 Show Profile Send RhysN an AOL message Reply with Quote
Thanks for posting Steve, it's a very good way of showing something difficult to put in words.
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 14 Oct 2018 :  16:03:33 Show Profile Reply with Quote
Just testing to see if a drawing I've done re steering geometry comes out like.
I may delete it depending on what it looks like.






Screen shot of pdf didnt come out very well.
Must try harder.

I still cant read it Properly and I drew it!
I'll try again. Its not bad if you open it in a new tab though.
Cheer

Ill put the others on.
cheers

Edited by - Dynorog on 15 Oct 2018 19:58:59
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Dynorog
V4 Fan

United Kingdom
134 Posts

Posted - 15 Oct 2018 :  19:57:41 Show Profile Reply with Quote
Hi Steve, Youve got me at it now with the steering drawing, I think Im becoming obsessive in my retirement.
I took some basic measurements on a spare rack I have and I drew it out to scaleish
My drawing doesnt concur with yours for some reason. If anything, mine shows the longer track
length side giving a shallower angle.
On further reading the workshop manual I noted that that when referring to checking the overall turning angle , the offside side should be 20o and the nearside 22.5o with a tolerance of +/- 1.5o.

What it has shown me however is that either way it doesnt make a lot of difference to the problem I have. I am pretty sure its wear in the rack which has altered the stop position.







Cheers

Dynorog
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