Prof's Patch: Suspension troubleshooting
PHOTOS BY SIMON MAKKER
THE STORY SO FAR
If you’ve taken note of last issue’s article, you’ve now set the rear suspension free sag to exactly 35mm for all PDS systems (KTMs) or 25mm for linkage-type Japanese bikes, you've checked the front sag is between 35-50mm, the front fork is 5mm through the top of the triple clamp, all clickers are set 10 clicks out from fully in and the rear high-speed compression nut is fully anti-clockwise. This is called the “base setting”; it’s always the same, so that if you get lost in your settings, you can go back to base. Adjusters can be “tightened”' (more damping) by turning them clockwise or “loosened” (less damping) by turning them anti-clockwise.
You may already be pretty happy with your settings, and if that’s where you’re at, record your own base settings. It’s important to keep records so if you go to another comp, ramp or track, your set-up is already done.
It’s also important to have a balanced riding style and bike set-up: even Ricky Carmichael went faster and smoother when his mechanic convinced him to roll his bars forward. Individual style can be dialled into a bike, but it’s easier suspension-wise if the rider has a neutral style. Years ago when Maddo and Jono Porter were on factory CR80s, JP rode a stock front, hard rear, and had his bars sitting in his lap, RC-style. Maddo rode a hard front, stock rear, and with upright bars. Despite being identical size, weight, age and speed, they couldn’t stand each other’s bikes!
On the next two pages, we outline some common handling problems and their cures to get your bike feeling like a factory ride.
CORNERS
If your bike won’t get around corners easily, they can be a right mongrel, and one of the keys to being a good FMX rider is linking the corners quickly and efficiently. Ever wonder why all the best FMXers are former racers?
Problem
- Front wheel lifts out of ruts
Adjustment
• Tighten front rebound
• Lower front ride height
• Tighten rear high-speed compression
• Loosen front compression
Problem
- Excessive dive/front wheel catches rut
Adjustment
• Tighten front compression
• Loosen rear high-speed compression
• Tighten rear rebound
• Raise front ride height
JUMPS
Problem
- Rear flies low
Adjustment
• Loosen rear rebound
• Tighten front rebound
Problem
- Front flies low
Adjustment
• Tighten rear rebound
• Loosen front rebound
STARTS
Obviously, these are critical to motocross and supercross, but they're also important in FMX, when you have a short run-up and need optimum traction.
Problem
- Front lifts (too much traction)
Adjustment
• Tighten front rebound
• Tighten rear low-speed compression
• Lower front ride height (slide forks through triple clamp)
• Stiffen rear spring preload
Problem
- Rear fishtails (no grip)
Adjustment
• Loosen front rebound
• Loosen rear low-speed compression
• Loosen rear rebound
• Raise front ride height
• Soften rear spring preload
FAST STRAIGHTS
Winding it on sounds easy … until the bike spits you off.
Problem
- Headshake
Adjustment
• Loosen front rebound
• Loosen front compression
• Raise front ride height
• Tighten rear rebound
• Lower rear ride height
Problem
- Skittery rear end
Adjustment
• Loosen rear high-speed compression
• Soften rear spring preload
• Tighten rear rebound
WHOOPS
Great whoop bikes have factory suspension. It’s another league above stock suspension, but here’re some tips to help you get through the technical sections easier.
Problem
- Rear end packs down
Adjustment
• Loosen rear rebound
• Tighten rear low-speed compression
• Tighten rear high-speed compression
• Stiffen rear spring preload
Problem
- Front end packs down
Adjustment
• Tighten front compression
• Raise front ride height
• Loosen front rebound
IMPORTANT NOTE
Remember to only adjust ONE THING AT A TIME, and once free sags are correctly set, don’t move them if you can help it.
Clickers should never be moved more than two clicks at a time. If you have to go in tighter than five clicks from fully in, the suspension needs re-valving and/or new springs.
All I can say is don’t be afraid to experiment with it: I’m a miles worse rider than all my buddies, but after hours in the saddle I can pass them easily because my bike is completely dialed to me.
Remember you’re riding a fully adjustable machine that can be turned from a pig into a gem with a couple of clicks (and vice-versa), so why not learn to get the most out of it?
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