Suspension setup - final installment (I think..)
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Since I covered all the terms, and how to setup your spring preload, I'll try to briefly cover setting the damping on shocks that allow this..
First - you need an afternoon, good weather, plenty of time. You need to check and adjust your tire pressure. Carry the load on the bike you normally carry. And you need a course. I have a loop that I use that has the following features:
- Long straight section
- Washboard section
- Pavement cuts - poorly filled
- Light traffic
- Safe place to pull over to make adjustments
The loop is about 5 miles in length, and takes me about 8 minutes to do. It has a decent spot to pull off to the side where I can make adjustments without worrying about a car running into me, and it has little traffic usually.
I first start out making 2 loops of my route - just to get the feel of how the suspension now feels and determine what I think could be improved. I'm looking for:
- High speed stability in the straight section - I can hit about 70 on the straight section, not terribly fast, but fast enough to feel if the bike feels "stable" and "planted" at speed
- Comfortable ride - the washboard section and the pavement cut (badly filled - nice sharp edges about 2' apart) will tell me if the suspension is compliant. The washboard will tell me if the rebound damping is too high and "packing down", the sharp edges will tell me if the compression damping (especially on shocks with two compression adjustments - the high-speed adjustment) is correct.
- The twisties section tells me if the control feels good - and control is really changed with rebound damping on twisties. Too much rebound and the bike feels wooden and starts to compress and run wide (rake increases), too little and the bike will have an unsettled feeling - not-planted feeling. Too much low-speed compression damping will result in the suspension jacking up, and the bike turning in quicker - again - not-planted feeling.
What do I do to make the adjustments?
IMPORTANT - only adjust one thing at a time. ONE THING. Making more than one adjustment will lead to rampant confusion, I know, I've done it.
First a note on how to make any adjustment:
Start out with a large adjustment so you can FEEL the effect the adjustment has. On compression adjustments, I usually turn the adjuster 3 or 4 clicks higher, which should make a very noticeable difference in feel. Once I make the adjustment, I circle the loop, as many times as needed to be sure I feel exactly what the adjustment did.
IF the adjustment made things feel better (in this case - high-speed compression might make the sharp edge of the pavement cutout feel less sharp) - then I continue making adjustments on that adjuster until things feel worse - and I make smaller (1-2 clicks) adjustments. Once the adjustment starts feeling worse - reverse direction and work back toward where it felt better. Continue in that direction until it feels worse - then reverse again and narrow it down to the single click position that feels "best"..
If your initial big adjustment immediately made it feel worse - go back to where you started - and go for a big adjustment in the other direction. Then work your way in to where it feels best.
Doing ONE adjustment at a time will teach you what adjustments change what feeling in the bike..
In general:
High speed compression - changes sharp shock response, the badly patched pavement-cut with a sharp edge. Too much will shock you, too little feels unstable.
Low speed compression - does the bike feel "planted" - especially in curves? If not - increase low speed compression until it does. Too much low speed compression can make the bike start to hike-up, with the rear suspension jacking upward over undulating pavement, or a series of curves. In that case the bike will start to turn sharper into turns as the rake on the front end is decreased by the rising rear suspension.
Rebound - the washboard section is usually good to adjust this - if the bike seems to "pack down" - compress the rear suspension over the washboard, it will become harsher as you travel through the washboard, it will also become slower to respond on curves (tend to run wide) since the rake is increasing with the lowered rear suspension. Rebound also can cause sharp impacts to feel harsher if the wheel isn't recovering (rebounding) fast enough due to too much rebound. Too little rebound can give a pogo sort of feeling, especially in the twisties section as the suspension loads and unloads.
That's the basics - and using a course, giving yourself plenty of time will give you a chance to learn how the adjustments change the bike. The adjustments DO interact to some degree.. you may find adding more rebound might mean you also need a bit less compression damping..
It's sorta fun to do if you attack it as a puzzle, and do it very methodically. Make ONE adjustment at a time is the biggest rule! Doing otherwise will lead to brain-fog. BTDT.
Must have been my buddies K1200R, or just the Akropovic without the baffles that made me sound fast...
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