Caster Angle

Moderators: theelanman, nitroman, Specky, clemo, dapinky, Dave Eds, GeoffSmith, Nige, DaveT, Sy V, Elanlover, muley, Enright, algirdas

Caster Angle

Postby Bern » Wed 07.03.2018, 21:38

Can somebody let me know what the Caster angle should be?

I see in the manuals it has:

+1°; +0.5°, -0

But I don't understand, does it mean that it should be between 1° and 1.5°?

Cheers,

Bern.
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK

Re: Caster Angle

Postby dapinky » Wed 07.03.2018, 21:49

Bern wrote:
But I don't understand, does it mean that it should be between 1° and 1.5°?


Basically, yes - but as close to 1 deg as possible
Dave

Just the one now, but this one's mine! - and it will be finished eventually.....

go on - click this link - you know you want to!
User avatar
dapinky
Moderator
 
Posts: 8013
Joined: Sun 15.10.2006, 12:54
Location: As far west as you can get in West Wales before you become Irish (Pembroke Dock).

Re: Caster Angle

Postby Bern » Wed 07.03.2018, 22:02

Great, thanks for clearing that up Dave.
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK

Re: Caster Angle

Postby Simon_P » Thu 08.03.2018, 01:51

The way it is written is as a value with a tolerance.

The value is +1o. It The tolerance from 1o is +0.5o but - 0o

Ie 1o is good, up to 1.5o is equally acceptable, but less than 1o is not acceptable.

With a tolerance all values within the tolerance are considered equally acceptable. With 1/2o shims this indicates that 1" 29' is preferable to 59'

Personally I'd go for the middle of such a tolerance, but in practice it is down to whatever shim puts it in the range and you are unlikely to have a choice.
Simon_P
God
 
Posts: 1006
Joined: Fri 06.08.2004, 12:33
Location: Kent UK

Re: Caster Angle

Postby Bern » Thu 08.03.2018, 09:33

I'd have expected it to be 1.25° +0.25° -0.25°, but I guess the way it's written adds more weight to the 1°, as in it has to be at least 1 and then anything up to 1.5 is fine.

I currently have 1°10' on the left and 0°50' on the right. The people that did the alignment decided (or the machine decided) that this was in tolerance.

I'm going to move one of the shims over which I believe should make it 1°20.

I'm also going to try checking the caster angle myself, I've got one of those camber angle measuring tools. I was going to do it 30° in either direction, but I think I saw on here somewhere that it should be 20°, anybody know for certain? Though I'm not sure that the tool is sensitive enough to show such small angles. But no harm in trying it.

At the moment all all the shims at the front of the joint on the left and all bar one on the right, does this sound correct? I guess if it gives those measurements it must be! I'll take them out and count how many I have in case some are missing.
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK

Re: Caster Angle

Postby Giniw » Thu 08.03.2018, 14:29

Bern wrote:I'd have expected it to be 1.25° +0.25° -0.25°, but I guess the way it's written adds more weight to the 1°, as in it has to be at least 1 and then anything up to 1.5 is fine.

I would say it's not equivalent, as the target is 1°, not 1.25°

Bern wrote:anybody know for certain?
I would stick to the data written in the workshop manual if I were you.
User avatar
Giniw
God
 
Posts: 1108
Joined: Sat 21.04.2012, 20:46
Location: France

Re: Caster Angle

Postby Bern » Thu 08.03.2018, 15:46

Giniw wrote:I would say it's not equivalent, as the target is 1°, not 1.25°


You're right not an equivalent at all, but whenever I've seen tolerances before they have always been either side of a central value. But I'm a software engineer rather than a mechanical engineer!!

Giniw wrote:I would stick to the data written in the workshop manual if I were you.


Unfortunately it doesn't say in the manuals, or not that I can see. Looking around on the web it looks like 20° is the standard. Not sure where I got the idea of 30° from!

Also the manual says a shim is about .25° rather than .5°, so I should get +1°05' if I move it.
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK

Re: Caster Angle

Postby Simon_P » Thu 08.03.2018, 17:22

My reason for suggesting the middle of the tolerance is that it requires less accuracy of measument and equipment ie more likely to always be correct, allows for play, wear etc.

The manual says that moving 1 shim is equivalent to 1/2o

There should be 8 1mm shims.

You need the instructions for the tool to confirm the test method.

For one sided tolerances consider a peg fitting in a hole a tight fit being best but if the peg is to big it won't fit in the hole
Simon_P
God
 
Posts: 1006
Joined: Fri 06.08.2004, 12:33
Location: Kent UK

Re: Caster Angle

Postby lotusflasherman » Thu 08.03.2018, 21:45

Had mine checked by Hanger 111 who do a lot of setting up for the Elise/Exige trackday and racer brigade. Their computer has Elan dimensions shown in degrees and minutes and has 1°15' (1.25°) as the target for Castor Angle.
Picture below as other target settings might be useful.
geo ls.jpg

I asked for just a check, as I was going to remove any shims if needed rather than pay them for a time consuming process, but front track was a bit out so I got them to adjust that so got 'Before' and 'After' readings. Nothing was changed on rear but 2 measurements changed by 1' (1°/60) and 1 by 2' (1°/30) so a bit of 'measurement accuracy' with their lasers maybe, or a minor movement in rear wheel bearing - but I run mine tighter than Simon likes going from previous 'technical debates' ... :lol: Hate to think what changes occur on cars with MOT "Slack Rear Bearings" Advisory Notes.

Oh.. by the way ... I see Bern knows that to type ° you hold down Alt key and hit 0176 on the numeric keypad and release and there is a ° (numbers along top of qwerty keypad don't work as they have different ASCII codes so no idea how you do it on a tablet or phone) but you can also type ± with Alt 241 using same process...
You do not have the required permissions to view the files attached to this post.
Phil

Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Elan+"S.... and now a Collapso SE
User avatar
lotusflasherman
God
 
Posts: 2172
Joined: Fri 05.09.2008, 00:14
Location: Hadleigh, 15m west of Ipswich or 800 miles south (Cap d'Agde)

Re: Caster Angle

Postby dapinky » Thu 08.03.2018, 22:12

:offtopic: :offtopic:

There are many different ascii codes (most of which are just allocated a key sequence in MS Word etc, but work with many/most typing interfaces - TBH, although 0176 gives a superscript "O", I prefer the sizing by using 167 (but I'm a sad git who learned them before Word Processor programs got advanced!!!)

0176 = °C
167 = ºC

A useful table here
Dave

Just the one now, but this one's mine! - and it will be finished eventually.....

go on - click this link - you know you want to!
User avatar
dapinky
Moderator
 
Posts: 8013
Joined: Sun 15.10.2006, 12:54
Location: As far west as you can get in West Wales before you become Irish (Pembroke Dock).

Re: Caster Angle

Postby Giniw » Thu 08.03.2018, 22:15

(Oh, you don't have the° on the qwerty keyboard?! For us it's just over the ')', so shift+')'='°' ^^)
User avatar
Giniw
God
 
Posts: 1108
Joined: Sat 21.04.2012, 20:46
Location: France

Re: Caster Angle

Postby Simon_P » Thu 08.03.2018, 22:22

Never one to miss an opportunity Phil :roll:

Let's have an old gits ASCII athon.

Having thought getting a ° would be impossible on a phone I looked it up. I don't have an alt key but there is one with symbols in its place and it's there!

iOS. From the iOS keyboard on your iPhone or iPad:
Android. Switch to the numbers and symbols keyboard and press the ALT key. The degrees symbol is on the second row.
°°°°°°°°°°°°<>°°°°°°©®¬
Simon_P
God
 
Posts: 1006
Joined: Fri 06.08.2004, 12:33
Location: Kent UK

Re: Caster Angle

Postby Bern » Fri 09.03.2018, 08:50

I used the ASCII code the first time I used it, then copied it. Once it was in the clipboard I just did a ctrl-v every time I needed it, so no need to remember the code. I even copied it from my first post for the subsequent posts, largely because I'm forgetful and lazy!

The last time I had my alignment done it was at my local tyre place, and they are probably just guys that know how to operate the machine rather than enthusiasts that care about what they are doing. I ought to take it back to the guy in Bristol who did my MX5, he inspired confidence. But I'm going to check the number of shims I have on each side, move the one on the left where the reading was low, and see if can measure the caster angle with what I have. The latter is just to see if I can!
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK

Re: Caster Angle

Postby Bern » Sat 10.03.2018, 14:04

There are 6 shims on the RHS, 5 infront and 1 behind the balljoint.

And 5 on the LHS, all infront of the balljoint!

I've just ordered 5 from SJs.

I've recently replaced the the bushes on the top wishbones, they were really quite soft and worn. Perhaps this was to blame, or at least not helping?!
'90 Elan SE Turbo
'03 Land Rover Discovery TD5
'03 VW Transporter
'03 VW Lupo
'87 Mini
'80ish Kubota B5100E
User avatar
Bern
Fanatic
 
Posts: 271
Joined: Sat 21.05.2016, 19:16
Location: Wells, Somerset, UK


Return to Chassis & Steering

Who is online

Users browsing this forum: No registered users and 1 guest