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zomething different
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8,430 Posts
Discussion Starter · #1 · (Edited)
I got the following information from Andrew Trevitt's Sportbike Suspension Tuning. It is a great book and I highly recommend it. Hope you find this useful :cheers


ENTERING A CORNER

Symptom:
Steering is heavy and slow
Likely Cause:
Excessive trail
Possible Remedy:
Reduce trail by raising the rear ride height, adding rear preload, raising the fork tubes in the triple clamps, reducing front preload, or increasing triple-clamp offset

Symptom:
Steering is quick and flighty or unstable
Likely Cause:
Insufficient trail
Possible Remedy:
Add trail by lowering the rear ride height, reducing rear preload, lowering fork tubes in the triple clamps, adding front preload, or decreasing triple clamp offset

Symptom:
Steering is slow in side-to-side transitions
Likely Cause:
Center of gravity is too low
Possible Remedy:
Raise center of gravity by lowering the fork tubes in the triple clamps and raising the rear ride height an equal amount

Symptom:
Chassis is unstable in side-to-side transitions
Likely Cause:
Insufficient rebound damping is allowing the chassis to unload excessively
Possible Remedy:
Add front and rear preload damping

Symptom:
Chassis resists leaning while trail braking
Likely Cause:
Insufficient rake
Possible Remedy:
Increase rake by lowering rear ride height, reducing rear preload, lowering the fork tubes in the triple clamps, or adding front preload

MID CORNER

Symptom:
High-frequency chatter
Likely Cause:
Tire is out of balance or out of round
Possible Remedy:
Check tire condition

Symptom:
Footpegs or chassis parts drag
Likely Cause:
Center of gravity is too low
Possible Remedy:
Raise center of gravity by lowering the fork tubes in the triple clamps and raising the rear ride height an equal amount, or increase front and rear spring rates

Symptom:
Ride is harsh and rough
Likely Cause:
Suspension is packing or bottoming
Possible Remedy:
Reduce rebound damping, increase spring stiffness, or increase preload

Symptom:
Ride is bouncy and loose
Likely Cause:
Insufficient rebound damping
Possible Remedy:
Add front and rear rebound damping

Symptom:
Limited traction over bumps
Likely Cause:
Suspension is too stiff
Possible Remedy:
Reduce rebound damping, reduce low- or high-speed compression damping, or reduce preload

EXITING A CORNER

Symptom:
Bike runs wide or is unstable over bumps
Likely Cause:
Excessive squat is causing the front tire to lose traction
Possible Remedy:
Reduce squat by adding rear low-speed compression damping, adding rear preload, adding rear ride height, raising the fork tubes in the triple clamps, adding front rebound damping, or raising the swingarm pivot

Symptom:
Sudden loss of rear traction on acceleration
Likely Cause:
Insufficient squat
Possible Remedy:
Increase squat by reducing rear low-speed compression damping, reducing rear preload, reducing rear ride height, lowering the fork tubes in the triple clamps, reducing front rebound damping, or lowering the swingarm pivot

Symptom:
Excessive wheelies
Likely Cause:
Center of gravity is too high
Possible Remedy:
Raise the fork tubes in the triple clamps and lower the rear ride height an equal amount

Symptom:
Excessive chassis pitching
Likely Cause:
Excessive weight transfer
Possible Remedy:
Add rear low-speed compression damping, add rear high-speed compression damping, reduce front rebound damping, or lower the center of gravity

STRAIGHT

Symptom:
Wallows over rolling bumps
Likely Cause:
Insufficient compression damping
Possible Remedy:
Add low-speed compression damping

Symptom:
Bottoms out in depressions
Likely Cause:
Insufficient high-speed compression damping
Possible Remedy:
Add high-speed compression damping

Symptom:
Harsh over sharp-edged bumps
Likely Cause:
Excessive compression damping
Possible Remedy:
Decrease high-speed compression damping or low-speed compression damping

Symptom:
Wobble (high-frequency headshake) on smooth pavement
Likely Cause:
Insufficient trail
Possible Remedy:
Add trail by lowering rear ride height, reducing rear preload, lowering the fork tubes in the triple clamps, adding front preload, or decreasing triple-clamp offset

Symptom:
Wobble (high-frequency headshake) on rough pavement
Likely Cause:
Excessive squat is allowing the front end to unload
Possible Remedy:
Reduce squat by adding rear low-speed compression damping, adding rear preload, raising rear ride height, raising the fork tubes in the triple clamps, or raising the swingarm pivot

Symptom:
Weave (low-frequency headshake)
Likely Cause:
Insufficient rear damping is allowing the rear end to oscillate
Possible Remedy:
Add rear rebound or low-speed compression damping

Symptom:
Suspension gets progressively harsher over a series of bumps
Likely Cause:
Excessive rebound damping is allowing the suspension to pack down
Possible remedy:
Reduce rebound damping

Symptom:
Chassis feels loose and loses traction or is unstable over rough pavement
Likely Cause:
Insufficient rebound damping
Possible Remedy:
Add rebound damping

BRAKING

Symptom:
Rear wheel comes off the ground or slides sideways
Likely Cause:
Excessive rear rebound damping is allowing the wheel to leave the ground
Possible Remedy:
Reduce rear rebound damping

Symptom:
Excessive chassis pitch
Likely Cause:
Insufficient damping to control brake dive
Possible Remedy:
Add front low-speed compression damping or add rear rebound damping

Symptom:
Excessive chassis pitch (cont.)
Likely Cause:
Center of gravity is too high
Possible Remedy:
Lower the center of gravity by raising the fork tubes in the triple clamps and lowering the rear ride height an equal amount

Symptom:
Front end feels harsh at maximum braking
Likely Cause:
Fork is bottoming
Possible Remedy:
Add front low-speed compression damping, add fork oil, add front preload, or increase front spring rate

Symptom:
Lack of feel from front end
Likely Cause:
Not enough weight is transferring to the front tire
Possible Remedy:
Remove fork oil, reduce front low-speed compression damping, or reduce front preload

Symptom:
Lack of feel from the front end (cont.)
Likely Cause:
Insufficient trail
Possible Remedy:
Increase trail by lowering the rear ride height, reducing rear preload, lowering the fork tubes in the triple clamps, adding front preload, or decreasing triple clamp offset

Symptom:
Front end bounces when the brakes are released, giving a momentary loss of traction
Likely Cause:
Insufficient front rebound damping
Possible Remedy:
Add front rebound damping
 

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Yamaha Blue in any color
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3,254 Posts
Very nice. I'll post a link in the Suspension 101 Thread.

This is EXACTLY what people should be looking for after a basic suspension setup.

Good work bro :fact
 

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crashing aint so bad
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2,271 Posts
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Thats a new one I haven't seen. Looks like a pretty good trouble shooter. It has some different problems than others I have seen.
 

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zomething different
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8,430 Posts
Discussion Starter · #5 ·
Very nice. I'll post a link in the Suspension 101 Thread.

This is EXACTLY what people should be looking for after a basic suspension setup.

Good work bro :fact
thanks dan :cheers

and thanks for posting up that pic colin. haven't seen that one before :cheers
 

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Yamaha Blue in any color
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3,254 Posts
No worries. Thank you guys for posting this stuff. I have been asked to cover troubleshooting/fine tuning as a thread, but I've avoided it for the longest. There are too many folks (like I mistakenly did) that will try to troubleshoot to a proper setup, although the basic sag etc has not been done. I had gotten to a point where I had run out of clicks and still couldn't get the handle I wanted. Finally checked my sag and it was at 62mm front, and 38mm rear. Turns out I needed springs. No amount of troubleshooting would have fixed my setup. It was this experience that sent me off and running to understand chassis adjustment.

What copyright of Andrew Trevitt's book do you have? I don't recall seeing that section, but it's very good :fact
 

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zomething different
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8,430 Posts
Discussion Starter · #7 ·
'08 David Bull Publishing. This guide is Chapter 12 in the book.
 

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Blowing fuses one wire at
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110 Posts
love this, so much
 

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Registered
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2,198 Posts
I have a copy of sportbike Tuning and it is a great book. i understand andrew is now in a wheel chair. happened i belive testing bikes on a public road. someone correct me if im wrong. great book, and we should all buy it ,not just for ourselfs but i am pretty sure i saw somewhere where he had a sack of medical bills too pay. Peace and stay safe.
 

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YZFR6... ooodles of HP
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1,296 Posts
What is excessive front end dive? Say I'm using 50mm fork travel and feels relatively decent. Hard braking not even activating abs on dry assphalt then compresses to about 100mm. More or less making me run more compression to not bottom out.
 

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9 Posts
Hi can anyone help me out here.
this is stock suspension 2018 R6.
I got clip ons and triple clamp at the top of the forks. This are SC1 with 32psi hot. What should I do ? 80kg rider with gear can anyone recommend me a setup that I can go for ?
376567

376568
 

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Touchdown!
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1,409 Posts
do you have any setting that been working good on 2018 r6. rider is 85kg
Go see someone who does suspenion set-ups. It should cost you that much; between $25 - $100 USD depedning on your location. They'll dial it in properly for you based on your weight.

If you do not want to go that route, use the baseline setting in the manual. They will be in the 'okay range' for a person of your weight.The setting aren't ideally perfect, but they'll work.
 
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