Ah, so you have Karon's Ambro. Your laser setup is trick. I did this
back in 2003 and did everything with a homemade bumpsteer gauge and shop
tools. I was able to measure a camber curve that matched the Triumph
specs and get good agreement between the calculations and measurements.
I spent a lot of time going back and forth between the shop and the
computer. My report gives all the numbers I got, including when I
compared moving the inner pivot versus shortening the A arms.
Bill Babcock wrote:
> I also used FSGP but I prefer SusProg3D, it's how I set Peyote up. I don't
>have my notebook here (in Hood River) but from memory, the amount of camber
>gain with the upper arm shortened increases substantially from an already too
>high value. I also directly measure camber gain and bump steer using a laser
>reflected off a very flat mirror onto graph paper stuck on the wall. The
>results are pretty shocking for stock TRs and most racing set ups. I'll take a
>look at the Ambro today (I'm on my way to Portland) --current owner is well
>known to me--it's me. I don't think the shock tower was modified. The Ambro
>has many handling problems and the suspension is more than a bit of a bodge.
>I'm in the process of peyotifying it.
>
> I ran hundreds of roll/bumps with suspension tweaks with FSGP and had a very
>hard time getting them to fit directly measured results. The biggest challenge
>seems to be that the trunnion cannot be properly represented in FSGP so you
>have to run two runs of every tweak and approximate. If the trunnion were a
>heim or ball joint the lateral pivot plane would be the same as the vertical
>plane--but it is offset by about 3/4". That's a big issue. Beven Young, who
>wrote SusProg3d added trunnion suspension options at my request, though
>looking at the marketing info for current version it seems to have slipped
>away--but I bet it's still really there. It's a lot better software, but it's
>expensive: A$335 though updates are always free and the support is terrific.
>I've had it since it first came available and Beven has never charged for
>anything since--even adding trunnions.
>
> As you say, the biggest challenge is getting the measurements. I had to build
>all kinds of tools to get them accurately. You also need a very flat floor.
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