The Effects of Rear Roll Centre Height

[freddo__1]

Hey Bill, did you ever work out or do you know where the COG of the AE86 is?

[Billzilla]

Nope.
It's possible to work it out though.
Easier for you to read than me to try to explain.

http://www.jameshakewill.com/cg-height.pdf

Got your jack handy?

[mullett]

On the top pic (the watts linkage) how do you deal with the problem of the arms of the watts linkage effectively shortening when the whole axle moves upwards? is there simply not enough travel for it to be a problem?

-RM.

[Billzilla]

On the top pic (the watts linkage) how do you deal with the problem of the arms of the watts linkage effectively shortening when the whole axle moves upwards? is there simply not enough travel for it to be a problem?

-RM.

The Watts Link pivots, easy.

[mullett]

But it's fixed at both ends? So as the centre pivots upwards, it pulls the two ends inwards?

-RM.

[WDE_BDY]

Each end is joined on the opposite side of the pivot point so they are both move in opposite directions.

Callum

[Billzilla]

But it's fixed at both ends? So as the centre pivots upwards, it pulls the two ends inwards?

-RM.

Yep - and the Watt's Link pivots.

[freddo__1]

Nope.
It's possible to work it out though.
Easier for you to read than me to try to explain.

http://www.jameshakewill.com/cg-height.pdf

Got your jack handy?

Hmmm... apart from the fact that i have very little room in my current garage (damn single car garage), my sprinter is an empty shell sitting 800mm off the ground bolted to a trolley that was used to get it sandblasted and primed.

Am doing some suspension design at the moment for an independant rear end for it. The outboard points are courtesy of s13 silvia uprights, and i'm trying to figure out the best compromise between where the inboard points will physically fit, roll centre migration, roll centre height, camber gains, etc. Also doing stuff with the front end, but currently sticking with the mcpherson strut setup, which somewhat limits how good you can make the front end setup.

If i had a good idea of where the COG was, i'd have a better idea of where reasonable roll centres would be for the car.

Unfortunately i'm a bit of a noob when it comes to suspension stuff (more of an engine person traditionally).

Anybody else with a sprinter feel the need to find the COG?

[mullett]

Yep - and the Watt's Link pivots.

Ah, gotcha. That's the first time I've looked at one up close, it looked like the two inner ends were on the same bolt. Effective setup!

-RM.

[af300e]

my sprinter is an empty shell sitting 800mm off the ground bolted to a trolley that was used to get it sandblasted and primed.

How does that setup go? Bit flighty in corners?

[web]

Nope.
It's possible to work it out though.
Easier for you to read than me to try to explain.

http://www.jameshakewill.com/cg-height.pdf

Got your jack handy?

And while you're at it, change brake and clutch fluid - emptying the m/c reservoirs has never been easier

(Yeah, that's an implied warning to check any loose fitting caps before nearly turning your car on its side...)

[freddo__1]

How does that setup go? Bit flighty in corners?

lol, being on four pivoting castors it goes sideways really well!


(getting on the trailer to go to the sandblaster)