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paul091085

Castor Setting

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Just got my car back from GBSC with its new wishbone coversion and took it yesterday to the garage to have the toe, castor and camber setup properly. Toe is now set to 0 and 0.5 of negative camber. However the castor was not so good. The guy showed me the computer screen and the right has 4 degrees and the left has 7.5 degrees. What can i do to get them both even and what should they ideally be set as?

 

Paul

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Probably not worry about it too much. I doubt if any of us mere mortals are able to genuinely detect those castor differences by the way the car behaves. I know I can´t. And I´m not slow.

There is a gap between what we know the suspension settings to be and what we can feel when we drive the car. Unless you are a Lewis H you won´t be aware of the difference side to side and the car will still be potentialy way faster than you can drive it.

You can use shims/washers to move the top/bottom wishbones forward or back to alter the castor figures if you wish. I don´t believe you will detect any difference but you might feel happier.

 

Nigel

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depends if you notice if it feel heavier to steer one way more than the other, or get uneven tyre wear

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Castor angle affects self centering doesn't it? If so if they weren't balamced wouldn't the car pull to one side or have heavier steering in one direction? My Superspec was bang on 4.5% on both sides. There are shims (panney washers I believe) that can be moved around to adjust the setting. Can't be much different on your car. I think it would be worth getting right.

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The way Paul asked the question was that the computer said his car was wrong, not 'I drove it and it felt strange'.

Lots of questions come up such as what is the accuracy of the garage measuring equipment in perfect condition and correctly used? Were these conditions met in the measuring process? What is the experience of the garage and operator in use of the equipment? Have you noticed any difference in the car handling, pulling to one side, more tyre noise or change in turn in or steady cornering on left or right turns?

I have to stand by my own experience of a 250 mile trip with toe set by eye, positive camber on the right and negative on the left, no idea of what the right castor was and the shockers were mounted at different inclinations after my Barkstone bump and I couldn't feel any real difference. Most was motorway admittedly but the last 40 miles was A road at about eight tenths effort. Sadly I can't tell stork from butter.

 

Nigel

 

You can use shims/washers to move the top/bottom wishbones forward or back to alter the castor figures if you wish. I don´t believe you will detect any difference but you might feel happier.

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I havn't really driven it yet. Since getting it back from GBSC ive been to the MOT centre, garage to get the suspension setup and the 5 miles to my lock up. I will have a drive next time im up there and see if its heavier turning one way or another. Can't say ive noticed it yet. Will be going down the garage to do some work on it tomoz so will put my comments on here after that

 

Paul

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Um am i missing something as ive heard it said a few times now that you can adjust the caster by shimming the wishbones back or forward?!

 

i dont understand how as on my 2b the top wishbones sit into box section front and back and the lower one into a box section at the front. I dont see where you can move it? Sure my car has shims on the lower wishbone but that is because RH welded the back mounting in the wrong place by 1/2 inch. Ive just assumed that castor is set, hopefully iam not missing anything important :huh:

 

cheers

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I've found it difficult to sort out my front end because there has been so much wrong with it, i couldn't see the wood for the trees. There are so many settings that can compensate for others, but ultimately lead to acceptable tyre wear and relatively normal feel, but less grip. A 'computer says no' attitude works for me cos i can make small improvements and leave it for 6 months to get used to how it feels before making another improvement, but i do have the luxury of using it for 10k miles a year!

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What you could do is cut out one side of the box where the wishbone end is bolted in. Shim then between the remaining side and the wishbone till the castor was what you wish. Then reweld the missing side of the box section in it's new position.

This would require you to get it all checked first so you know which way you want to move the wishbone. Cut and shim. Remeasure and then repair the box.

Pic is supposed to be left hand lower front wishbone mount and the process for moving it forward to increase castor. Decent weld required of course and appropriate materials!

 

Nigel

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What you could do is cut out one side of the box where the wishbone end is bolted in. Shim then between the remaining side and the wishbone till the castor was what you wish. Then reweld the missing side of the box section in it's new position.

This would require you to get it all checked first so you know which way you want to move the wishbone. Cut and shim. Remeasure and then repair the box.

Pic is supposed to be left hand lower front wishbone mount and the process for moving it forward to increase castor. Decent weld required of course and appropriate materials!

 

Nigel

Seems a hell of allot of work Nigel for something as you say we would never notice I haven’t a clue how mine is I only know the camber is about 1.25 degrees negative and that is only about due to the fact that one turn of the top ball joint is well over 0.25 degrees. But it seems OK to me.

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I did say 'leave it alone' would be my first choice as I believe there are very few drivers in robin hoods who would be able to tell from driving it that there were different castor readings on the front wheels.

I've found it difficult to sort out my front end because there has been so much wrong with it
Well yes to a certain extent. None of it is to the standard found on a cateringvan but it's still hugely better than your average tintop.

 

If the castor on a 2b is not what you want it to be then you can change it by moving the the wishbone mounting points or remaking the wishbones. (I had the wishbones remade when I built, but not by me as I did not have the skills at that time)

 

I still think I'm the weak link and the car could go a couple of seconds faster round Barkstone with a better driver than I can. I don't think I could go a couple of seconds faster round Barkstone with a better car. (similar powered cateringvan, say). I guess that half the Sevens on the road don't have more accurate castor settings.

 

I also think that Paul should drive it and stop worrying.

 

Nigel

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I took it out yesterday for 5 mins and didnt notice any difference in the steering from right to left, it all seems as it should be and like Nigel said, i think i am unlikely to be able to tell the difference the way i drive it. Only thing i might do is change the springs as im not getting a lot of movement on the front or rear. what lb springs have people got on front and rears??

 

Paul

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I im not getting a lot of movement on the front or rear. what lb springs have people got on front and rears??

 

Paul

You don’t get allot its supposed to be a tight sports car

Anyway I think most have 300 to 350 on the front I have 325 and 300 on the rear.

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The front is better than the rear. It just feels a bit strange as the rear seems to jump/skip out when i hit any bumps or potholes. didnt get it when i had the old RH springs and shocks. Maybe it needs time to settle down and for me to get used to it :unknw:

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Strangely enough Ive just found the same thing.

I had Sierra springs with new (sprung) standard shockers, & the rear was very compliant.

 

Ive just fitted AVOs with 300lb springs, & with the shockers on click no 2 (from softest) the back

seems to skip all over the place. Bit early to tell, only taxed it yesterday, & done 140 miles "trying it out!!"

 

I'll see if it feels any better with different shocker settings over next week....I may be imagining things....

Bob

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