I now know why I never went racing.
John Kipping
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: "'John Kipping'" <johnkipping@inet.net.nz>; "Larry Young"
<cartravel@pobox.com>; <fot@autox.team.net>
Sent: Friday, January 24, 2003 11:32 AM
Subject: RE: Suspension/Handling Questions
> If it were only that easy. Other stuff happens, for example, if you lower
> a car by shortening or weakening the springs then the suspension arms
> angle more upward (or less downward depending on how you want to look at
> it). Moving the rack up changes the relationship of the rack to the
> inboard upper and lower suspension fixing points and the relationship of
> the tie rods to the steering arms. That will change the amount of camber
> angle variation as the suspension travels (it will probably increase it,
> but there is no way of saying for sure). You might wind up with way more
> bump steer at the bottom of travel than at the top (or vice versa), which
> makes for interesting handling differences, especially when one wheel
> travels up and the other travels down against the resistance of the roll
> bar. It will also change the amount of tire scuff induced by differential
> camber (front wheel to front wheel) since that will change too. You might
> lengthen or shorten the tie rods to try to compensate, but that will
> induce a whole 'nother cycle of unintended consequences.
>
> I started getting serious about modeling this stuff when I saw how many
> things change when you tweak anything in a front suspension. Most of the
> time people get their suspension to work by stiffening the front springs
> to the point that it only travels when you hit a pothole at 85. That's not
> the best way.
>
> When you model a stock Triumph TR3 front suspension and put it through a
> roll/bump you can't help but wonder how anyone can drive one to the store,
> much less race one.
>
> -----Original Message-----
> From: John Kipping [mailto:johnkipping@inet.net.nz]
> Sent: Thursday, January 23, 2003 1:26 PM
> To: Larry Young; fot@autox.team.net
> Subject: Re: Suspension/Handling Questions
>
>
> I'm not an expert on bump steer but.........AFAIK the whole steering rack
> should be straight in its normal rested state so that as it moves with the
> suspension the effective length change is very small. Lowering a car would
> then suggest either the steering rack has to be raised or the the steering
> arms effectively lowered so the inner ball joint assemblies are again in
> line with the rest of the rack and parallel to the road. No idea how you
> do it though. John Kipping
> ----- Original Message -----
> From: "Larry Young" <cartravel@pobox.com>
> To: <fot@autox.team.net>
> Sent: Friday, January 24, 2003 4:33 AM
> Subject: Suspension/Handling Questions
>
>
> > I've been doing a lot of work measuring and analyzing the suspension
> > in my TR3 race car. I've spent quite a bit of time going through the
> > archives. I can't say that I've read every post, but I think I have a
> > pretty good idea of what has been posted. My questions are:
> >
> > 1. I've got a ride height (to bottom of frame rails) of about 4 1/2
> > inch in front and 6 inches in back. What is the stock TR3 ride height
> > and is it the same in front and back, i.e. frame rails parallel to the
> > ground. What ride heights do most TR3 race cars have front and back?
> > I know lower is better, but how low can you go?
> >
> > 2. I appear to have a horrible bump steer problem, with toe out
> > increasing on a bump and decreasing with droop. To correct this I
> > believe either the steering arm and idler arm must go down or the
> > steering lever attached to the vertical link must go up. I'm thinking
> > heating and bending the steering lever will be the easier approach.
> > Is this the right thing to do? Do I have to worry about hardness of
> > the arm? Any suggestions will be greatly appreciated.
> >
> > Larry Young
> > Forever Young Racing
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