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Can I do this ?
slopecombat - 18/5/07 at 10:16 PM

I've got a pair of SAAB 900 uprights. They look similar to Cortina ones except for the position of the arm that links with the steering bar.

In the Cortina's ones is in the front and in the SAAB ones is in the rear.

Can I rotate the uprights ?




regards,

Modesto

BenB - 18/5/07 at 10:37 PM

As long as the kingpin inclination angle isn't FUBARd it should be fine.....

scoop - 18/5/07 at 10:50 PM

FUBARD.... IVE ALWAYS LOVED THAT

Bob C - 18/5/07 at 10:59 PM

Find out what you can about "ackerman" then decide...
If you do it you probably won't be able to design out the resulting tyre scrub when cornering . . . . but some folk actually reckon that's a good thing!!
cheers
Bob

12a RX-7 - 18/5/07 at 11:20 PM

can you not fit a rear steer rack and make sure your engine is nice and far back to clear it ... or notch the sump to clear the rack.

some production cars run anti ackerman and allsorts of odd combinations .... they do spend a large fortune of money deciding on these things though.

BenB - 19/5/07 at 07:12 AM

King pin inclincation (KPI) = Ackerman

flak monkey - 19/5/07 at 08:26 AM

quote:
Originally posted by BenB
King pin inclincation (KPI) = Ackerman


Umm, no, not really.

KPI is the angle between the upper and lower balljoint from vertical with zero camber. (NOT camber). KPI helps with self centreing.

Ackerman is essentially to do with the angle of the steering arm from the upper ball joint when the wheels are pointing straight ahead. You can have positive and negative ackerman. It results in one wheel turning slightly more than the other in cornering.

Those arent the best descriptions, but I cant be bothered/dont have time to do a doodle at the moment.

David

dilley - 19/5/07 at 09:12 AM

flak where do you get your avatars from??

MikeR - 19/5/07 at 09:44 AM

hi g/f poses for him !!!

flak monkey - 19/5/07 at 10:30 AM

quote:
Originally posted by MikeR
hi g/f poses for him !!!



Yeah right

Thats Apena - google it with safe search turned off... Some more in my archive

Doug68 - 19/5/07 at 06:20 PM

I don't see that there's going to be any issues doing this.
The KPI will remain the same when swapped from one side to the other and the right castor - camber is a function of the wishbone design.

Look at this for the Ackermann definition.

This is good introductory reading too.

The importance of Ackermann appears to be minimal at anything other than slow speeds where tyre scrub is an issue due to the big steering angles that occur then.

slopecombat - 19/5/07 at 11:17 PM

I think it will be better if I don't contradict Mr. Ackerman, Mr. Toe, Mr. Camber & Mr. Castor.
I'm not sure if this configuration will displease Mr Disk Brake too.

I'll follow Mr. Saab design.

Thanks.

Modesto

MikeRJ - 20/5/07 at 12:05 AM

quote:
Originally posted by Doug68
The importance of Ackermann appears to be minimal at anything other than slow speeds where tyre scrub is an issue due to the big steering angles that occur then.


The problem with turning rear steer hubs around to get front steer is that you get anti-ackerman geomtery, i.e. the inside wheel will turn less than the outside one. This can't be conducive to good road manners...

[Edited on 20/5/07 by MikeRJ]

Doug68 - 20/5/07 at 04:49 AM

True.

rusty nuts - 20/5/07 at 07:50 AM

The Saab 900 was FWD doesn't look like a FWD hub assembly to me

slopecombat - 21/5/07 at 08:55 AM



cheers

Modesto

Peteff - 21/5/07 at 09:11 AM

With the cv joint cut down it looks like a good alternative and it looks to have an angle built in the wrong way round. Rescued attachment saab.jpg
Rescued attachment saab.jpg

rusty nuts - 21/5/07 at 04:54 PM

From that angle it's plain that it's FWD

t.j. - 21/5/07 at 08:20 PM

hmmm,

Not sure about it.
- there is probable an angle (castor) static in the upright which has to be compensated.
- watch out where you're rod ends come.
They are tapered! Otherwise your rack comes high mounted.