…or: You Southerners Haven’t A Clue
Southern Fun Fact: “Snow blower” is not a synonym for “cocaine junkie”.
I’m standing next to my bike, putting my gloves on while letting the S warm up a little before I take off for work. It’s only 33F according to the radio-controlled clock in the living room. The outside temperature sensor is stuck to the wall under the front door’s eve and usually reads a little warmer than it should. I’m already shivering. As I jack myself into the temp controller velcroed to my bike’s tank I have to wonder how I even made it through my previous two winters: the first with barely appropriate riding gear, the second wearing nothing but UnderArmour ColdGear, two layers of clothing and my textile two-piece all-weather riding suit. I am older, skinnier, still anemic and probably turned into a Marshmallow Butt the moment I was first introduced to the modern marvel of agitated electrons that is heated motorcycle gear. I’m thankful this cold evening for being fortunate enough to have it.
During the commute my vest is eventually turned to “Full Blast Nuclear Winter” and my gloves end up somewhere in the mid-range of their dial. My neck is being bombarded with freezing cold air that somehow found a way through the tiny gap created by my earplug wire between my jacket’s collar and my Ninja/Bank Robber headwear also known as a balaclava. We’re talking the cap here, Mr. Slow, not the Turkish dessert! No mention of that yummy, honey-dripping, freshly ground nuts filled, rosewater infused, many-layered paper-thin phyllo-dough pastry that is a delightful piece of heaven on earth but so much sweeter. Hmmm… hmmm… *wipes the drool off the corner of her mouth* Where was I? Oh yes, it’s damned cold. I’m working on an acute case of precision frost bite on my neck, but I’ve got tunes! The wind chill alone drops the effective temperature from 26F to 16F; add to that my average speed of about 60-70 mph. Speaking of wind: it is gusting at even colder bursts of ice cold air and the bike is being pushed around side to side, so I opt for the middle third of my lane. This doesn’t scare me as much as it used to.
On the Harley it was a hair-raising experience. I remember the first time I experienced strong cross winds coming back from the International Motorcycle Show in Greenville, SC in February 2009. I had only been riding for five months and the wind pushed me all over the road. I managed to stay in my lane, but I was extremely nervous and didn’t like it much at all. I had to constantly remember to stay loose from the waist up, easy on the handle bars, lean into the wind, counter-steer and try not to focus on the visions my brain treated me to; visions of some Harley-riding chick running off the road and wrecking herself. The Hayabusa never wavered from her path. Unlike Kittyhog, The Fat Lady just cut through the crap weather, all I had to remember was to tuck in behind my Double Bubble windscreen and not let my body act as a sail. However, even sitting upright, the ‘Busa wasn’t much bothered by such annoyances as wind gusts. It seems the S1000RR, with all its aerodynamic wind-tunnel tested fairing panels, bobs around like a pirate ship in rough seas. Her precision handling and predictable manners make it a confidence inspiring rather than fear provoking experience; especially with a freshly mounted, properly scrubbed-in new front tire.
I really had forgotten what a precision missile the S1000RR really is. I suppose I had gotten used to riding around on front rubber sporting a flat middle and excessive non-use towards the edges. After my test ride in March of this year, I had excitedly exclaimed that I only had to think about turning and the bike would react! It was lust at first sight and love at first ride. I herewith apologize to all the Hayabusas in the world, especially to The Fat Lady, may her soul rest in pieces and her heart live on in someone’s SmartCar. *crosses herself in a moment of silence* I love you, always will; you are dearest to my heart, but you guys can’t corner worth a hoot!
When I arrived at work, I started shivering as soon as I parked and unplugged myself from the Pirate’s heat. I hurriedly went inside, ran up the stairs and loudly proclaimed: “Holy cow! It’s cold out there!” in lieu of the customary “Good evening, ya’ll!” I decided to stay in my gear until such time when I stopped shivering and felt warm again. I watched my co-worker run out the gate in a half-sprint, get in her car and all but lay rubber as she pulled out of the parking lot. Gotta get that engine cranked up to operating temp before the heater is going to work! I had to giggle. My fingers weren’t all that cold, but my legs and butt were chilling like Amaretto served on the rocks and my crotch was a frozen Winter Wonderland. My security officer promptly informed me that he wanted to play in my park and sing filthy Christmas Carols. He actually called me later and serenaded me over the phone, something along the lines of “Frosty the Snow Ho.” I informed him that my park was closed to through traffic from dusk until dawn. He almost fell down the stairs on his way out. This definitely calls for my specialty: Weapons Grade coffee with real cream. I put the pot on. Four hours later it’s still freezing in here. The heater is on full blast, but there is a definite draft in this building and the furnace just can’t keep up.
I swear I saw snow flurries. Later this sighting was confirmed by an external source. I can skip the Haldol tonight, I wasn’t hallucinating after all.
Photo Credits: Kudos and thanks go out to Jamie aka @jls1970 on Twitter. She graciously let me use her pic in this post. Visit her blog That’s What She Said. Tell her Miss Busa sent you and give her these. She’ll know what it means. *hands you a tube of lead-free solder and a push-up bra*
I really can’t help myself. It’s on a need to know basis, and I just needed to know! I had to do another Hayabusa vs. Pirate comparison. How else is a chica to appreciate the new toy and learn its personality? I was on the dam road again, and once I’ve passed Pollard’s Corner and disappeared over the crest of a left-hand sweeping turn, with no witnesses on my tail and seeing that I had the entire road to my lonesome self, the right wrist experienced a moment of squidly possession and gripped it and ripped it. Still, the DTC remained quiet and left me to my own devices as it has since I got the bike. Maybe I’m too much for a Hayabusa, but this bike is probably snickering behind my back: “That’s all you got, girly?”
I jam through the gears, but then decide to try the higher RPM range and bang down two to end up in fourth. I’m tucking in, just as the bike wants me to and go with it. Stable. Precise. Awesome. I feel like the female version of Speed Racer on a mission. I come through a few turns and a quick glance at the digital readout tells me I’m doing triplets. Good gawd! Really?!? Not only is this thing quick as hell, it’s also deceptively fast. My rational brain, which is trying to hang on to sanity and the last shred of maturity, tries to interject a message of reason into my wicked consciousness: high velocity equals jail time; but the thought is drowned out by the ferocious growl of the S1000RR’s inline-four fire-breathing heart. Fuck it! When the shift light comes on, I comply with another snick. 130s… carving through these sweepers like they’re nothing. As stable as the Hayabusa but I’m not feeling like I’m having to work to keep things under control. This is way too easy. Deceptively so. There is that word again! This bike could spell out more legal trouble for me than the ‘Busa ever did. It’s way too much fun. Hell, it almost rides itself. Or is this just my skewed perception of things, since my progression in motorcycles is somewhat backwards from the norm. Harley Sportster 1200 Low > Suzuki Hayabusa > BMW S1000RR. I’m definitely appreciating what the Pirate Bike can do and how it handles its business. It has also made me a better rider in some ways… dare I say it, but my crap weather riding is way better than it was… so are my braking skills… both of which I probably should attribute to more confidence in a skill I already possessed, but was mainly too afraid to use to its fullest; not to mention that the brakes on the Hayabusa really were shit. I can stop this puppy in roughly a third of the distance; without RaceABS intervention. What can I say? The tech is giving me a reason to let go of some of my self-doubts and execute what I’ve been practicing all along with more precision and authority. I still have no clue if the junk really works… for all I know they fleeced me for $1480 to make the pretty lights come on during startup self-diagnositics. 😉
As I round the next turn at hugely illegal speeds, I grab a handful of front brake and haul myself back down in a hurry (damn, I really do love these brakes… did I mention the thing comes with braided steel lines standard?) since I’m coming up on a hill which reduces my sight distance drastically. I’m going 50 in a 45 as I crest the hill and to my astonishment find myself staring down the business end of a radar gun stuck out of a Sheriff’s patrol car, parked in a church parking lot to my right. I smile (not that he can see it), and give him a cheery little nod, still tucked in nice and tidy from hauling Mach 3 pirate booty on a public road, as I vanish around the next curve. Holy shite! I’m glad that worked out, since I’m all out of K-Y and I fired my last traffic court attorney for scheduling issues.
Consider this Miss Busa’s version of CliffsNotes of Andrew Trevitt’s book “Sportbike Suspension Tuning – How To Improve Your Motorcycle’s Handling And Performance”. All the stuff online is confusing, and some of it is downright wrong. Buy the book, it’ll clear up any misconceptions and it’s actually easy to understand. It’s best to read it once all the way through to get a general idea of what you’re getting yourself into. Reread, break it down into parts, make notes or highlight the important stuff, get things straight in your mind, formulate your game plan, invite a couple of friends and just do it. I believe that this is just like any other thing a m/c newbie finds confusing at first, although it is way more involved that most stuff! Do it, and it will slowly become clear. It will start falling into place, and eventually there’ll be nothing to it anymore. I’m not afraid to screw things up and I have a game plan. Let’s get cracking:
SPORTBIKE SUSPENSION TUNING
- Make one change at a time.
- Document everything!!!
- Understand in technical detail how a suspension works internally and be better equipped to understand how adjustments affect the machine and why.
- Suspension setup is a compromise between several factors.
- Different situations (ideally) require different suspension settings, i.e. drag racing, track days, playing in the twisties, commuting, etc.
- Rider sag or sag is the amount the fork and shock compress when the rider sits on the seat.
- Free sag is how much the spring compresses under the bike’s weight.
- Rake is defined as the angle of the steering head relative to a line drawn perpendicular to the ground (usually between 20 and 25 degrees).
- Trail is the distance from where the steering axis intersects the ground to the front tire’s contact patch directly below the axle (usually between 80 and 110mm).
- Steep front-end geometry (with small rake and trail numbers) gives light, quick steering at the expense of stability.
- Relaxed front-end geometry (with high rake and trail numbers) results in heavier steering but more stability.
- Steep, aggressive geometry may lead to headshake when going over bumps or when accelerating out of a turn.
- Increasing ride height results in steeper rake and reduced trail.
- Raising fork tubes in the triple clamps results in steeper rake and reduced trail.
- Preload does not increase the spring rate, or the spring’s stiffness, for that the spring has to be replaced.
- Preload is a measure of how much a spring is mechanically compressed when the fork or shock is fully extended.
- Preload is mostly used to change the suspension’s range of operation within the total travel available.
- Topping or bottoming out the suspension will cause a loss of traction and upset the chassis.
- An ideal suspension setup uses almost, but not quite, the full range of travel.
- F = k * x (Force exerted = spring constant * distance) <~ linear spring rate
- The spring rate of a coil-bound spring is infinity.
- Damping controls the speed of the wheel’s movement; the spring controls the distance the wheel moves.
- Compression damping controls how quickly a spring can compress.
- Rebound damping controls how quickly a spring can extend back to its original length.
Part 1: Rider Sag, Free Sag, and Preload
Measure FRONT RIDER SAG:
- Have two friends lift the front of the bike by the clip-ons.
- Measure the amount of exposed inner fork tube, between the slider and the axle casting (for inverted forks). Call this measurement L1.
- While one friend supports the bike from the rear, sit on the bike in full gear, in your usual riding position.
- The other friend gently lifts up the front of the bike and lets it slowly settle on its suspension. Measure again. Call this measurement L2.
- Gently push down on the front of the bike, and let it slowly rise up. Measure once more for L3.
- Sag = L1 – (L2 + L3)/2
- Front rider sag should be no less than 25mm for a race bike
- Front rider sag should be no less than 30mm for a street bike
Below these numbers the fork is in danger of topping out on acceleration, which hinders traction and can cause tank slappers as the wheel continuously contacts the ground.
If your measurements fall out of range, adjust your preload: stiffer (clockwise) for less sag, softer (counter-clockwise) for more sag.
Measure REAR RIDER SAG:
- Have a friend hold the front fairing to steady the bike.
- Measure the distance from the axle directly up to a solid point on your bike’s subframe or bodywork. Call this measurement L1.
- While one friend supports the bike from the front, sit on the bike in full gear, in your usual riding position.
- The other friend gently lifts up the rear of the bike and lets it slowly settle on its suspension. Measure again. Call this measurement L2.
- Gently push down on the rear of the bike, and let it slowly rise up. Measure once more for L3.
- Sag = L1 – (L2 + L3)/2
- Rear sag should be 25-30mm for the race track
- Rear sag should be 30-35mm for street riding
If L3-L2 is more than 25mm for the front end, or more than 5mm for the rear end, there is too much friction. Investigate.
If your measurement fall out of range, adjust your preload: stiffer for less sag, softer for more sag.
ADJUSTING PRELOAD DIRECTLY CHANGES THE BIKE’S GEOMETRY!
- Adding preload to the fork springs will raise the bike’s front by the same amount. As long as the suspension isn’t topped out, dialing in more preload will not compress the spring more, but raise the bike on its suspension and equal amount, raising the ride height. Likewise, taking preload out will lower the bike on its suspension. Same goes for the rear shock.
- Add preload equally, front and rear, so that the front and rear sag numbers change by the same amount.
- Bumpy surfaces need more sag and less preload.
Adjusting REAR PRELOAD:
- As a measure of preload (on most Suzukis) record the distance from the top of the threads to the top of the two rings.
- Mark one of the tabs of the bottom ring with a Sharpie, then tighten or loosen it in one-turn increments as needed.
- Measure your setting after you lock the top ring in place.
Before riding attach a small zip tie to the shock shaft, if you can access it. It may be difficult do to the spring and bump stop. This will give you an indication of how much travel you use.
Adjusting FRONT PRELOAD:
- Some adjusters will move in relation to the cap as you turn them, you can record the number of lines showing on the adjuster as your measurement. Otherwise, turn the adjuster all the way in, clockwise, counting the number of turns until it lightly bottoms. This is full-stiff.
Before riding, put a zip tie around an inner fork tube and snug it up so that it doesn’t move on the tube. Slide it up against the outer tube’s dust seal. The zip tie will indicate how much suspension travel you use in each riding session. You can keep track of this number by measuring from the zip tie to the axle casting (inverted fork).
Checking FREE SAG:
- Take the measurements the same as for rider sag, but measure L2 and L3 with no rider on the bike.
- Free sag should ideally be between 5-10mm.
I’ve Got Her Number!
Here are my numbers. Everything is still at stock settings. What is painfully obvious is that The Fat Lady’s a little bit weak in the knees… or would that be her elbows? Something needs a little adjusting here. And I wasn’t even riding her all that hard. No time now, however, but I will post my progress as I continue on my quest to wreck a perfectly acceptable setup. ;P I still need to measure the threads showing above the top lock ring on the monoshock, I procured myself a metric ruler, just for that purpose and I couldn’t get the damned zip tie around the thing, I’m gonna try again with a longer and skinnier one, maybe I can get it in there, somehow, someway. I’m just too curious to let that one rest. *sigh*
Linkage to the entire series:
- Suspension Tuning – Part 1: Rider Sag, Free Sag, and Preload
- Suspension Tuning – Part 1: Plan ‘A’. Plan ‘B’. Plan ‘C’ It Is.
- Suspension Tuning – Part 1: Exploratory Surgery
- Suspension Tuning – Part 1: Let’s Go Shopping!
- The (preliminary) results: OMG! OMG! OMG! The Fat Lady Can Dance?
- Suspension Tuning – Part 1: The Fat Lady’s Got Slammed
- Suspension Tuning – Part 1 (Results): There’s a first time for everything…