andrews_45
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| posted on 16/12/06 at 10:46 AM |
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Are these wishbones adequate?
I have got problems with my mk wishbones as they have zero caster. I have remembered I had this Luego set lying around, this is how they
measure...
Will these enable me to get the 5 degree castor that I have been told I will require?
Ta
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MikeR
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| posted on 16/12/06 at 11:10 AM |
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probably (looks approx right) ........
daft question, have you got the current wishbones on the right way round?
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thunderace
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| posted on 16/12/06 at 11:20 AM |
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its only a daft question if you know the answer.
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andrews_45
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| posted on 16/12/06 at 11:23 AM |
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TBH, I have not checked so cannot say for certain.
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907
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| posted on 16/12/06 at 11:31 AM |
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Hi
I am building a +4 wide book chassis.
I made my first bones to the book, about 8mm off set (Tina uprights)
When I test drove it on a flat straight road it needed my full concentration to keep it in a straight line.
I made new ones with 22mm of off set and it transformed the car.
On a flat straight road I can now let go of the wheel and it stays in a straight line.
The steering still doesn't return from full lock like a tin top but it does try.
I'm happy with my setup and think it will pass SVA.
Below is a pic of my jig with the book bone on top and my new one underneath.
I can't comment on an MK but I would have thought Martin knows what he is doing.
Hope this helps
Paul G
 
Rescued attachment wb-jig-s.jpg
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andrews_45
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| posted on 16/12/06 at 01:17 PM |
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I can confirm, that they are the right way round. MK also confirmed that they are designed to have zero castor
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oliwb
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| posted on 16/12/06 at 06:03 PM |
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How does it actually drive? Have you tried it??? If MK's didn't handle I'm sure we'd all know by now! Take it for a drive
and see what you think before playing too much. Its easy to get too worried by numbers when actually its the feel of the car thats more
important....Oli.
If your not living life on the edge you're taking up too much room!
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andrews_45
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| posted on 16/12/06 at 06:25 PM |
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quote:
Originally posted by oliwb
If MK's didn't handle I'm sure we'd all know by now! Take it for a drive and see what you think before playing too much. Its
easy to get too worried by numbers when actually its the feel of the car thats more important....Oli.
Thats my point exactly, how can you expect to get a feeling for a race car on a track with zero castor. This is fine on a road car. I dare say that
MK's handle great compared to any tintop you'll ever drive, but for a track car you need positive castor. I have tried looking for info
to back up what MK say but the internet, the carol smith book and a handling book, a westfield race team and a locost car prep company, all say for
positive feel on handling you need positive castor, while MK say I dont...
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procomp
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| posted on 16/12/06 at 07:18 PM |
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Hi just about sums up MK's attitude. All the other manufacturers of chassis for the locost race championship certinaly DO have castor on
them.
Cheers matt
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procomp
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| posted on 16/12/06 at 09:57 PM |
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I dont quite know what you are trying to say SNOOPY as the early LA GOLD setup you show on the first pic has 7degs of castor . Our LA LOCOST chassis
certinaly has castor wont say what though.
MK have already said that thier locost kit is jigged for ZERO castor.
ST locosts have 4 degs.
And the luego ones also have 4 degs of castor but have brackets that enable this to be achived.
So what are you comparing a Mk locost with.
cheers matt
(edit)PS the LA GOLD uses sierra uprights.
And how the hell can you work out castor angles from picture's.
[Edited on 16/12/06 by procomp]
[Edited on 27/12/06 by procomp]
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procomp
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| posted on 16/12/06 at 10:03 PM |
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Hi it also looks like you are also only looking at the top wishbone offset on it;s front and rear legs.
And not taking into account the possition of the brackets themselves relevant to the lower wishbone brackets.
cheers matt
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907
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| posted on 17/12/06 at 07:49 AM |
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I'm no expert on this, a trial and error man me, but I think you can photograph castor.
The pic needs to be taken from directly above though.
Paul G
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NS Dev
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| posted on 18/12/06 at 04:03 PM |
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think that is what matt meant, that the photos need to be from above, and then its only an indication, as optical illusions make accuracy tricky.
as for the zero castor, seems strange, but then there were a lot of folks on here having issues with self centring for SVA..........which seems
equally strange!!! 
Once sva'd, I'll be re-wishboning the front of my ST car for a little more castor amongst other things.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Peteff
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| posted on 18/12/06 at 06:50 PM |
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My Locost which was built before internet to book measurements and SVA passed in 2000 does make an effort to self centre and, compared to a kit that I
helped with last year, is a lot nicer and easier to drive. I think the tendency to stick on the widest wheels and tyres you can find spoils the idea
of the car as they tramline and make the steering too heavy and don't improve the handling (which is not the same as the roadholding) I'd
go for the wishbone change before SVA if you have any doubts Nat, every little helps.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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GParkes
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| posted on 19/12/06 at 08:14 AM |
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Interesting, I'd never worried about castor before, or really understood what it was!
I checked my car last night, and the top and bottom balljoints are in line, so no castor. Like Matt says it all depends on where the brackets are.
Got to re weld the brackets anyway to comfortably be within the new regs, so looks like an opportunity to add some castor, though I don't expect
it will change my lap times!
Gavin
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procomp
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| posted on 27/12/06 at 06:47 PM |
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Hi the reason that none off the above reads correctly is because SNOOPY(charlie) has removed his posts as he did on the mk forum with the CAR SETUP
thread he posted.And the mk chassis desighn thread also.
cheers matt
[Edited on 27/12/06 by procomp]
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Uphill Racer
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| posted on 24/1/07 at 11:12 PM |
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As Procomp has said, the wishbone isnt the problem, make the chassis bracket wider so you can shim the wishbone for whatever castor works or feels
good.
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