Handling FAQ
Subject: [Fwd: Handling FAQ]
 
Since this was posted to the list for open discussion, I would like to comment.

shbaxter wrote:

> You know, I think our reading and riding public could benefit from a FAQ on
> how to screw up a gamma's handling.  I think my bike's previous owner
> started the draft, and I added a section or two, and Randy Norian found
> another jewel of a way to cock up the bike's chassis performance!  Here's
> some of the pearls discovered so far:
>
> 1.  Mess with the tires.  Put a wide rim on the back and mount a low profile
> radial.  Your bike's rear will squat like a dog taking a shit, and you will
> too when you want to slap the bike over into a turn.  However, with all that
> understeer you will have remarkable straight line stability.  You can
> achieve the same results with the front tire as well.  The bottom line is
> that if you maintain chassis attitude you need to beware of the bike's stock
> wheel diameters rubber and all, and if you choose to make changes do so with
> the express intent to change the handling characteristics, not to toss on
> some swayve new rubber.
>

Making changes to the chassis setup without thinking things through can be
counterproductive.  With performance tuned motors, however,  the stock wheels,
brakes and compatible tires are a little too exiting!  More traction, newer tire
technology and superior braking are a good thing.  Shorter rear tire profiles
can de-stabilize the bike if not compensated for by restoring ride height
through lengthening the shock or the strut link.  RG's with a "butt down"
attitude are unstable under most any conditions, including straight-aways.
Every sporting front tire profile known to Man (including all 17" 60 and 70
aspect ratios, as well as 80 series 16") is shorter in overall height than the
original 90 series 16"  Michelin.   Proper chassis attitude can be obtained by
adjustments in ride height to optimize stability and steering response when
using non-stock wheels and tires.

> 2.  Install RaceTech emulators without a real setup plan.  They're fantastic
> once configured properly, but they change everything in the forks.  If you
> just drill the damper rods and toss them in per the instructions you'll wind
> up with something that's scary in corners, but is a joy full upright.
> There's no dark secret on setup, but you need to consider how they work (the
> instructions describe that well), how forks in general work (like why oil
> level {or the air space above the oil} is important) and then you can begin
> to piece things together and work up a test plan.  In my case I had help
> from Rick Lance, which got me close to the mark, and I had to take a lot of
> notes and find specific road conditions to encounter at different speeds to
> finish the setup.  Like anything else the forks are not great everywhere;
> they just work best in those road sections in which I am otherwise the least
> comfortable (because I set them up that way).
>

Like Scott, I am very pleased with the performance of the RT-Es in the stock
front forks when properly set up.  Having used them since their release for the
Gamma, I am still learning more about the subtleties of  front suspension tuning
but I am convinced that the RT-Es are the best thing to happen to the Gamma
chassis since the Fox Shock.

> 3.  Mess with your sprockets and make big tooth changes.  You get the back
> end jacking around with the throttle and you can't get a drive out of the
> corners due to the changing effective lever ratios of the new sprocket
> radii.  To be fair I'm not good enough to feel this with the 15/42 ratio I'm
> now running  --  this is a recurring item I've found in my chassis setup
> research on the Web and elsewhere.
>

Perhaps I am not good enough to sense this phenomenon either but I would observe
that most any other Japan sportbike has a  greater leverage factor than the
Gamma (for example, '97 Gsxr 600 with 45/16 gearing stock) and are known for
their good handling.

> 4.  Gain 40 lbs, or 18 kg, or 3 stone.
>

I, too have gained 40# since I acquired my first Gamma (Sept. '86).  I would
like to think that I and my bike are faster now than then.  Still, I'd LOVE to
be 180# again!

> 5.  Loan Richard your chassis setup book.
>

I will take your word on that.

> 6.  And now for the latest, greatest, and most liver quivering revelation
> recently borne out of the West Coast gathering (given the lethargic response
> to prior attempts to generate some press for the bike I'm not surprised six
> were all that showed up) and handed down to me from on high by Randy Norian,
> INSTALL A FOX SHOCK ON YOUR BIKE.  I'm an idiot, and I never thought twice
> about my shock rocker tilting up at 15 degrees or so from horizontal.  I
> thought that was the way it should be.  Randy's sojourn to CA and
> Computrack, along with second opinions from other riders and the ability to
> cross reference rocker attitude on bikes with stock rear shocks, showed that
> the Fox shock is too long.  I immediately went to the garage, measured
> length on eye centers of the stock shock I still have, and compared to the
> Fox.  The Fox is around 38mm too long.  Well allrighty then...  The lever
> ratio is now shagged and the shock is artifically harsh.  You install a soft
> spring for your ass and the bike hunkers down on the gas giving you some
> wonderful understeer.  Get it right for the gas and you piss blood.  I'm so
> happy I could touch myself.  I'll be calling Fox tomorrow about this little
> news tidbit, and other parties are going to investigate this from the inside
> of the shock to see if its rod length can be dealt with.
>

The stock Gamma shock measures 310mm eye to eye.  The shock sold by Fox for the
Gamma measures 317mm.  The 7mm (approximately 1/4") increase in shock length was
not arrived at by accident.  Through much feedback from Gamma owners back 12
years ago, Fox concluded that the nearly 1" increase in rear ride height was a
benefit to the Gamma when using the stock (1986 era) wheels and tires.  How much
more so when using modern low profile radials with wide rims which require a
similar increase in shock or strut length just to restore original ride height.
On my personal RGs, I use the Fox shock along with my Lance Gamma adjustable
strut expanded another 7-8mm over stock along with raising my fork tubes to 16mm
above the T-clamp to drop the front end down to quicken the steering.  This
setup when used with 4.5x17 and 3.5x17 rims running 160x60 and 120x70 Michelin
radials alters the steering head angle from 25.1mm (stock) to mid 23dg with
about 98mm of trail (down from 110mm stock).  These are very contemporary
numbers and very effective with proper suspension tuning.  In my opinion, the
Fox shock is dimensionally ideal as designed for the RG500 Gamma.  As for the
Full Floater rocker being positioned in an improper angle relative to the
ground, I would like to add my testimony.  It has been my experience that the
bike does not display any rocker related ill behavior with the Fox shock being
longer than stock by 7mm.   When using a longer strut on the other end of the
rocker, whatever change in rocker attitude would be hard to discern at all.

> Who knows, if we can come up with some other choice upgrades that torpedo
> the bike's handling  we can make a top ten list.  I know I've got at least 3
> of the six already covered...

 I would not want to offend those who are running components and chassis setups
that I might find lacking.  In this post, I have not criticized anyone's choice
of how they choose to spend their time and money to improve their bike.  I have
my own opinion that I think is sound.  I am sure that many others feel the same
way about their own choices.

Rick Lance   Lance Gamma     
 
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