Unfinished Business 7 – Suspension Set Up (Making Goldilock’s Porridge)

The Perfect Ride

Risa is purring at 4500rpm at 6th as we slip between two columns of traffic. The highway is filled with traffic at knock off time. She is nimble. Changes in direction are immediate and accurate. Bumps and undulations of the road surface are absorbed by the taut but well damped suspension. I push the left handlebar slightly to move her left as we come up to a daydreaming driver. The precise handling left nothing to be desired. She is a scalpel.

My exit is coming up. A quick check over my shoulder, winkers on and we go into the next “motorcycle lane”. Accelerating smartly past a truck, we move left into the lane towards our exit. We spot a taxi in front and the start of the turn is about 70 meters ahead. No matter. A slight drift towards the right and we are riding on dotted lines. Risa is transmitting the bumps but not upsetting her composure.

We have to get past the taxi and set up to enjoy the corner. We shifted down a gear and start to wind the throttle and in a moment, we are past the taxi and in front of him (with the left winker on. Must be courteous).

The corner is coming up swiftly. Stay a bit on the right, roll off, no need to brake, pressure on the left foot peg. The turn in point is….Now. I push on the left handlebar, lean forward and Risa rolls over on her side. The horizon rotates clockwise. Eyes to the front and left. The turn tightens up a bit and we roll the throttle off a tinny bit to stay in line. Risa does not stand up and remains neutral.

Almost through the corner now. We roll on the throttle while standing the bike upright and she howls through the exit. It is beautiful…. then I wake up.

Challenges In Setting Up the Suspension

I would have loved the dream to be reality, but unfortunately, I have had a hard time setting up Risa’s suspension. Due to the torturous riding position, I swapped out the original bars for my old set of Convertibars. Without these, the GSXR’s riding position is just too tiring for me. These handlebars are multi adjustable but they also compounded the problem as they shifted the weight distribution backwards and changed the characteristics of the bike.

In addition, the tires she came with are old and the rear is squared off. This also did not help with matters.

Squared off rear tyre

Lower Tyre Pressures = Better Comfort?

When I first got the bike, I set the tyre pressures to 33psi front and 36psi rear. The logic was that Elsa’s recommended tire pressures were 33/36 instead of 36/42. It didn’t make sense to me that a bike that is lighter by 30kgs should have 36/42 instead of 33/36 for road use. I thought I was onto something. However as I was adjusting the suspension, I could not get rid of the harsh ride.

Then one day, I decided to just pump them up to the recommended 36/42 and what do you know? The bike immediately felt better. The ride was bumpy, but harshness (the crash like feeling) was reduced. The added bonus was the bike turning much better. I was confused but thought that perhaps more air in the tires help the tires to absorb the bumps on the road better.

Suspension Related Variables

Throughout the process the following were the variables that I have to deal with:

1) Tyre Pressures
2) Convertibar Positions – higher than stock, maybe wider and drawn further back towards the rider
3) Front and Back Preload
4) Front and Back Compression Damping
5) Front and Back Rebound Damping
6) Old Suspension – Needs New Oil and a Refresh. Unknown Spring Rates
7) Rider Factor – I was still getting to know the bike

The settings on the bike when I first got it were way too hard. The front preload was showing 2 lines (stock was 4.5). The rebound was 4 clicks out (6 was standard) and the compression damping was also increased. The rear has an unknown Bitubo rear shock with preload, rebound and compression damping. The preload was also wound up and there was little movement with me on it. So I wound them down to what I thought was a reasonable amount and set the damping adjustments to somewhere in the middle of the range 15 clicks out or so.

The initial ride was poor. The bike was bumpy, harsh and my handlebars were set a bit too wide and back. I fiddled with the damping adjustments especially for the rear and actually wound out the compression and rebound damping almost all the way out. I have no idea what was the spring rate of the Bitubo and was wondering if I was trying to compensate for it like I did with the K1.

I was also trying different handlebar positions at the same time. One week, I may set it to be in a sportsbike position, another week a very upright position that I called the “Super Bandit” riding position. And another week, a sports tourer kind of position. Trying to do these all the same time also added to the confusion and difficulty.

This is one position I tried. Its wider than stock and drawn backwards towards the rider
The “Super Bandit” riding position. Very comfy, almost no wind protection. Front feels remote and lacking in feel.

Through out the time, I noticed that it was not too difficult to set it up so that the bike can turn quickly. What was difficult was to make it adequately comfortable, balanced front and back AND make it turn like a Zero Fighter at the same time.

Restart and Reset

I decided to restart the whole thing.

First I set the tyre pressure to 35/41psi as 36/42psi was too bumpy (you will be surprised what a 1 psi and even a 0.5 psi difference can make).

Next, I got my brother to help me set the sag. I set it to 25mm for the front (around 5 lines) and 30mm for the rear.

Then I set the front damping back to stock settings at 11 clicks out for compression and 6 clicks out for rebound. The rear was left at its quite extreme settings as I have no idea what are the standard settings.

The result was a harsh ride from the rear but better from the front. The front was pitching down a bit too much when braking and the rebounding a bit too much. I knew that the back was pushing up the bike from behind and still giving a harsh ride at the same time.

I looked for help online and realise that I might have increased the rebound damping too much causing a harsh ride. In such a scenario, basically the shock compresses but the rebound damping is so great that it does not extend quickly enough before another bump comes along and gives the compressed shock another whack. So that causes the rear of the bike to feel harsh. Conversely, if I reduced the damping too much (ie. screwing the adjuster in), the shock will extend too quickly and the front will pitch down and the rear will feel like its kicking up.

I also tried increasing the compression damping cos it could be that the shock was compressing too quickly and then rebounding back quickly too. It kind of helped but the harshness still remained. I also tried winding up the preload in front to balance the rear and while it helped with the dive, it made the front harsh, telling me that too much preload was added.

I was then thinking to move the handlebar backwards a bit (again) to ease the pressure on the hands and also thought of playing around with the tire pressures (again). I was going back and forth trying to find a good balance. I even reduced the preload to try to get some comfort back but it was never ideal.

The above illustrates the problem of balancing the bike front and back. You may get a nice set up in the front for say comfort, but the rear feels low and reluctant to turn. As your stiffen up the rear the front feels too low and twitchy and so on. I don’t have a race track to use to tweak the suspension and can only do so on usual rides around so it took a while to get to where I am.

I restarted again and this time I realised that I should have set the rear preload to 35mm instead of 30mm (which the article said was for track). This was immediately much better. All it took was a 1/8th turn of the preload adjuster. The harshness was mostly gone and the bumps were soaked up much better.

In the end, the following are the current settings that I have decided to leave the bike at:

1) Tyre Pressures: 35/41.5psi. Lowering the rear pressure made the bike feel sluggish or reluctant to turn. I tried lower at 34.5/40psi and 34/38psi and didn’t like them. Perhaps the lower tyre pressures will work with fresh pointy tyres. Mine are a bit squared off. I could be compensating for their flatter profiles.


2) Convertibars: About 30mm above the triple clamp (from triple clamp to about middle of the handlebar rod). The angle and forward position is almost the same as the original handlebar position I think. At this position, the front feels good but the bumps can sometimes be a little tiring (it feels better if you ride faster though hee). I realise that the GSXR’s geometry requires a more forward rider position. Moving the bars even up by another notch (on the tube) makes the bike more comfortable, but less planted and flighty.

Back to a rather sporty riding position
About 30-35mm above the triple clamp, measured from top to the middle of the handlebar nut. Preload is 5+4×1/4 turns (looks like stock’s 4.5 lines)

3) Front Preload: 5 lines + 4 x 1/4 turns harder (looks like 4.5 lines). Sorry about the strange description. I had to slowly tweak the suspension settings little by little as I get near the desired set up so sometimes its one click here or there for the damping and quarter turns for the preload. With 3 x 1/4 turns, the front feels more comfortable with less of the bumps transmitting through the bars (its comfy really), but the front uses up too much travel and it is also a bit too twitchy for my liking.

4) Front Damping:
– Compression (the lower screws): 11 clicks out as per standard
– Rebound (the top screws): 6 clicks out as per standard
Risa is very sensitive to these adjustments and each click make a difference. One click harder for the compression and the bike doesn’t like to turn in. One click less and she’s twitchy. For the rebound, one click in made the front feel like I’m using stone for tyres and in the turns, she wants to stand up run wide if I reduce throttle mid corner or apply some brakes. One click out and the front feels low and I can’t feel the road.

Front Compression is 11 clicks out

5) Rear Preload: Marker points towards the right front foot peg. Another strange description here. I made a marking on the preload ring so that I know roughly where to turn to do minor adjustments. Currently, Risa’s rear sag is about 35mm. If I turn anticlockwise by 1/8th of a turn, she’s about 40mm sag and the bike feels like a boat and doesn’t like to turn.

The white markings for quick identification – around 35mm sag

6) Rear Damping:
– Compression (upper screw): 16 clicks out
– Damping (lower screw): 16 clicks out
Again, Risa is very sensitive to the damping. At these settings, the rear is slightly harder than I like, but it turns much better than if I were to reduce the compression by 1 click (ie 17 clicks out). Any more compression damping and the rear feels like a rock. One click more rebound damping (ie 17 clicks out) and the bottoming harshness returns, and one click less (ie 15 clicks) made the rear feel like its kicking me back and upsets the front/back balance.

The rear rebound adjuster is really a pain to adjust. I need to use a small ratchet connected to a flat head bit to get to it while minding the hot exhaust pipe in the way.

7) Rider Adjustment: On going adjustment...

The above settings may or may not work for you. Risa’s suspension has old oil and needs a refresh so the settings might change after that is done. Risa is riding well at the moment. Even with the squared out tires, she is easy to turn into corners and holds her line well. She is quite neutral mid turns but I would still prefer the front to be slightly better damped. The bumps still get transmitted to my arms but between the secure front end with quick turning nature and a plusher ride, I have to choose the slightly less comfy ride. I would like the bars to be one notch higher, but again I didn’t like the “looser feeling” front end. Still, the current position is better than the original handlebars.

Tyres

Risa came with Metzeler Roadtec 01 tyres which I read are highly rated sports touring tyres. Initially, I did not like them, but after I settled on this set up, I must say that they are quite good. Even though squared off, they seem to allow the bike to turn quickly. I may just change a pair of the same once the time comes. I liked the Pirelli Angel STs for the pointier profile but since they moved production to China, I do not see them for sale locally. Shops are pushing for the GTs which I have also used and liked, but the profile is rounder. The Roadtec 01s seem to have a pointier profile like the Angel STs.

Once other thing. After the ECU was changed and the problem solved, I have been riding the bike more regularly. As I got more comfortable and confident on it, I realised that I did not escape the infamous grabby clutch of the early GSXR1000s. It is much better than the K1 that I had, but if I were to move off from stand still just a bit more enthusiastically, the clutch will grab, making that awful noise and judder the bike. I am a bit annoyed, but it will be a simple fix with the ZX10R clutch plate. The parts have been ordered and I should be able to get to work on in sometime end Feb or March. In the meantime I am a courteous rider when moving off from the junction. Just don’t judge me after we get going.

Isaiah 40:3-5
New King James Version

The voice of one crying in the wilderness:
“Prepare the way of the Lord;
Make straight [a]in the desert
A highway for our God.
Every valley shall be exalted
And every mountain and hill brought low;
The crooked places shall be made [b]straight
And the rough places smooth;
The glory of the Lord shall be revealed,
And all flesh shall see it together;
For the mouth of the Lord has spoken.”

John 1:14-18
New King James Version

The Word Becomes Flesh

14 And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.
15 John bore witness of Him and cried out, saying, “This was He of whom I said, ‘He who comes after me [a]is preferred before me, for He was before me.’ ”
16 And of His fullness we have all received, and grace for grace. 
17 For the law was given through Moses, but grace and truth came through Jesus Christ. 
18 No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, He has declared Him.

John 1:22-26
New King James Version

22 Then they said to him, “Who are you, that we may give an answer to those who sent us? What do you say about yourself?”
23 He said: “I am
‘The voice of one crying in the wilderness:
“Make straight the way of the Lord,” ’
as the prophet Isaiah said.”
24 Now those who were sent were from the Pharisees. 25 And they asked him, saying, “Why then do you baptize if you are not the Christ, nor Elijah, nor the Prophet?”
26 John answered them, saying, “I baptize with water, but there stands One among you whom you do not know.

One thought on “Unfinished Business 7 – Suspension Set Up (Making Goldilock’s Porridge)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s