Sunday, 7 June 2015

Setup & Shakedown: Solo suspension & Tyres

Time to get busy setting up the Yammy.

It's no secret the stock suspension on the MT09 leaves most riders wanting, however it is adjustable - both front and back - so before a final assessment can be made, some tweaking is required.

As always, the first step is to record the default setup.
As per my previous post Setup: Solo Suspension my shorthand is as such:

R - Rings visible on suspension crown for preload
C - Clicks closed from fully open on rebound.

For the uninitiated, here is a very simplistic explanation of preload and rebound:

The suspension spring is statically compressed to increase preload tension, thereby requiring more force to further dynamically compress the spring. End result - stiffer suspension.

Suspension rebound refers to the rate at which the suspension oil returns to 'rest'
The rebound adjustment manipulates a valve aperture which increases or reduces the rate at which the suspension oil can flow.

Open the aperture and you reduce rebound damping, thereby providing less resistance to oscillation.
Close the aperture and you increase rebound damping, thereby proving more resistance to oscillation.

The stock MT09 front-end settings were:
R = 6.5
C = 7

There is no doubt in my mind that I need to add preload and increase rebound damping.

After some adjusting, measuring and static tests I arrive at the following settings.
R = 4
C = 13

14mm Spanner - Preload adjustment (required evenly on both fork legs)

Flathead screwdriver - Rebound adjustment

Time to dial in the rear. Again first step is to record stock settings:

The rear shock has stepped notches ranging from 1 - 7 and a rebound screw without clicked internals. As such, my shorthand is as follows:

N = Notches from setting 1 preload
T = One full revolution of the screw head from fully closed

The stock MT09 rear-end settings were:
N = 4
T = 4.5

Again, after some fettling I arrived at:
N = 6
T = 1.5

Using the supplied C-Spanner to add preload

The rebound screw can be accessed via the left side of the bike through the frame

Finally I checked the tyre pressure - oh dear!
(F/R) - (38/40) psi

That won't do - especially if I'm going to kill these Dunlops. 

I reduce the cold pressure to:
(F/R) - (30/31) psi

After completing my setup and rechecking my work to ensure everything was cinched down I set off for a shakedown. Let the fun begin.

Day 2 - photo roll.

I stopped mid way through the ride to readjust the rear-end. She was chattering about.
I reduced preload and rebound to the following:

N = 5
T = 3.5

I think there is still room for improvement. I will let things bed down for a week or so of daily use and adjust as necessary. 

That said, the chassis is much more compliant after these changes. She is still a little misbehaved in the Hills, however in the Urban environment the adjustments have improved stability dramatically. 

Preloading the Yam whilst on the Rebound from the Ape......

1 comment:

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