GSXR1000 Suspension Upgrade

Sorted the Basics

I spent the first 6 months after buying the bike getting it serviced turning her into a fine running motorcycle. At the end of December 2012, she has had all necessary wear and tear parts replaced. Areas where riders often neglected (such as valve clearance adjustments, greasing of bearings etc) have also been done. Irritating electrical problems have also been ironed out (fingers crossed). Lemozuki/Changi Express has never been better.

Making Her More Usable

I had previously thought of selling her as the low clip-ons were killing me. With the Convertibars installed, the riding position is now more bearable. At least I can now ride in a more upright position and it also gives me better leverage to counter steer into turns.

I have also attached my saddlebags to the bike permanently, so that I have more storage space. They are a used set of Bagster Sprint saddlebags. I noticed that the inside of the bags were relatively dry even after a heavy down pour. They got a bit damp in some areas, but did not become like a fish tank. I have also found that spraying them periodically with the Scotch Guard Outdoor Silicone Weather Shield helps to improve the waterproofing noticeably. So now I basically leave it on the bike all the time and keep my rain coats and other bits in there. It is also a good place to keep my riding jacket so I don’t have to carry it with me all the time. Before using the saddlebags, I bought a big sheet of plastic with an adhesive on one side and pasted it over the rear plastics where the saddlebags sit. This prevented the plastic from being scratched.

Relatively waterproof saddlebags helps to increase storage
Relatively waterproof saddlebags helps to increase storage

I also had to replace the original rear winkers with shortened ones as the saddlebags will sit on the standard ones and bend them.

Shorter winkers due to clearance issues
Shorter winkers due to clearance issues

I have also bought 2 combination cable locks to lock my helmets to the bike if I do not want to carry them around when out and about. They probably won’t deter a determined thief but it is good enough to deter a casual opportunist.

With the basic maintenance and repairs done and the usability improved, my mind now turned to improving the suspension of the motorcycle.

Considerations for Improving Suspension

The GSXR, as I bought it, was an 11 year old motorcycle that still had the original shock and springs. While I have set up the motorcycle the best I could, I still could not get it to ride the way I wanted. All the clicks in the suspension worked and every change can be felt, no question about that. However, while I have narrowed down the settings, a change of a click resulted in either a more compliant, but a vague feeling bike in the corner or a bike that turns in nicely, but has a harsh ride. No matter how I tried, I just could not find the sweet spot. Have you ever had this problem?

Now, there are probably some riders out there who will just ride through the bumps mid corner and ignore them. There are probably also riders who have supple bodies and can ignore the bumps. Being deficient in the cornering skills department and having a life preserving nature, I cannot ride like the GP gods. I would like the best of both worlds, both 1) Confidence and 2) Comfort.

This is a 160bhp machine (when new anyway – I would be more than happy if the dyno reads 120bhp at the rear wheel now) that weighs only 170kg dry. It is made to go 280kph and around corners rather quickly. Remember the ad by Pirelli? “Power is nothing without control”? With a machine that goes so fast so quickly, I don’t want something that goes like the Kawasaki H2. I want something that is precise, consistent, and most importantly that doesn’t scare the s%^& out of me (at least not until it goes above 200kph). Good suspension will give the rider the confidence to enjoy the bike. If you are scared of the bike, you are not going to be able to enjoy it (there are probably others who enjoy getting scared witless, but I’m not one of them. If you are one, let me know in the comments section! LOL!).

The 2nd thing, comfort, is also important. I made the wrong decision when buying the GSXR as it was never meant to be a sports tourer (or daily transport for that matter), but with the Convertibars and saddlebags, at least the bike can now be a passable, comfort wise, a bearable (fast! fun!) transport tool. The thing is, if the rider is not comfortable on the bike, he will not keep it (hence its actually a rather silly thing for people to buy GSXRs to ride in city traffic). If one is constantly feeling the backache or the wrist pain, then one will be distracted from riding and enjoying the corners. If that’s the case, what’s the point of riding the bike? Good suspension and more importantly, a well set up motorcycle, will give the rider the comfort and the confidence to enjoy it. Remember, this bike is not a weekend bike for me. I only have 1 bike, she has to serve as a daily transport (including pillion duties), long distance tourer as well as a track/cornering tool.

Ohlins and Bitubo

Naturally, for the suspension upgrades, I turned to Ohlins first. However, I quickly found out that Ohlins no longer made any rear shocks for the K1 or K2. I searched around and finally decided on Bitubo’s XXF31 rear shock. Interestingly, the same model can be used on K1 to K4 GSXR1000s. Hmm…do I detect some kind of compromise here? This shock came with high/low speed compression damping, rebound damping, ride height adjustment and hydraulic preload adjustment. There was a cheaper and equally well made XXF11 that comes without the hydraulic preload.

Initially I wanted to save some money by going with the XXF11 but in the end, I bit the bullet as I wanted the hydraulic preload adjuster. This bike has to do everything, including pillioning my wife. The hydraulic preload adjuster will allow much easier preload adjustments then the c spanner and notched collar set up. If this was purely a toy for the track, I would have gone with the XXF11.

There 2 stickers are very expensive...ouch.
These 2 stickers cost me many coins…ouch!

While the front forks were generally ok, I knew that once I changed the rear shock, the balance of the motorcycle will be upset as the rear shock comes with a stiffer spring than the standard shock. The front was also under sprung based on the information on Race Tech’s website. The website recommended at least a 9.5N/mm spring which I got the local Ohlins agent to install. A few months back, I also came across someone selling a used 20mm Supersports Fork Piston Kit which I bought, so I also asked the agent to install it at the same time.

Suspension Set Up

After the items were installed, I knew that I would probably have to set them up. The initial ride was disappointing. While the front seemed good, the rear was harsh and my body was pitched more forward. It was tiring and totally not confidence inspiring.

These are my best friends ever. 3mm hex key not here.
My best friends, the suspension adjustment tools.

I remembered the seller of the 20mm FPK kit mentioned that Bitubo shocks are harder to set up, so thought that I probably needed some time to get to the right settings.

Front Ohlins

The front were already quite nice after I took the bike from the shop. Immediately, I noticed that the dive was more controlled and I could feel the front in the turns. It also turned in smoothly. Its hard to describe in words, but it reminded me of the time I fitted my rear Ohlins shock to the FZR1000 EXUP. It had the similar compliant but firm and controlled feel.

As there were no recommended settings in the 20mm FPK for my bike, I asked the mechanic at the Ohlins agent what settings he recommended and he said 8 clicks out for both rebound and compression. He added that he had set the forks with 4 lines showing for preload (standard settings in the Suzuki manual) and the above mentioned settings for rebound and compression.

This was where it got interesting. Ever distrustful of mechanics, a few days after I got the bike, I made a point to check the actual settings on the forks. Here was what I found.

From Ohlins Agent:

  • Preload: 4 lines showing
  • Rebound: 3 clicks out
  • Compression: 6 clicks out

Eight clicks out for each? Yeah right! What’s even stranger was that there was only 6 clicks of adjustments for my rebound damping where previously, there were at least 9 or more! A check with the guys at Gixxer forum revealed that the mechanic probably did not install the cap properly. There should be an 11mm space from the top of the nut at the damper rod to the top of the rod, but this was probably not done properly. In addition, looking at the Suzuki workshop manual, the rebound settings should be all wound out (softest position) when the cap is installed.

However, the bike’s front end was already quite nice, so I was not really bothered. In the end, all I did was to reduce the compression damping by adjusting it to give me 8 clicks out and reducing the rebound damping to give me 2 clicks out. The reason was that the bike was too twitchy after I changed to Pirelli Angel STs. The reduced rebound damping was to give me more feel for the bike in mid turns.

Rear Bitubo

As mentioned before, the rear was trying to bash my spine into pieces with the standard settings.

Bitubo XXF31 Standard Settings:

  • Hydraulic Preload: 1 to 2 turns in
  • Rebound: 16 clicks out
  • High Speed Compression: 12 clicks out
  • Low Speed Compression: 14 clicks out

With the Angel STs fitted, the bike was super flicky. Initially, I was careful not to really corner the bike as the tyres were new and needed some scrubbing in. After a few days, I tried cornering the bike and found her to be very very sensitive to handlebar inputs. She was more eager than the rider was to tip over. I knew this could not be right. In mid turns you felt the road, but if she encountered a bump, I get kicked in the butt and the bike became unsettled. Due to the hypersensitive handlebars, I could not really settle down on the bike and was tensed up. In addition, the rear did not like to compress during acceleration.

It took a Sunday morning and the subsequent week for me to set up the Bitubo. The first thing was the sag. With me sitting on the bike, there was less than 10mm of sag. Dejavu…just like the time with the previous owner’s silly set up. No suspension movement is not a good thing. With the hydraulic preload all wound down, I could only get 23mm of rider sag. Ideally I should get at least 30mm of sag for road use. A ride around my area still showed that the rear was still too harsh.

Over the bigger bumps, the rear suspension did not seem to compress. So next up was the high speed compression. I reduced it from 12 clicks out to 14 clicks out. Better already.

The biggest culprit was the rebound. With each click, she was kicking me less in the turns. Finally, I increased the rebound damping from 16 clicks out to 20 clicks out. This was one of the main causes of the harshness. The final touch was to reduce the low speed compression damping from 14 clicks out to 15 clicks. Another click out resulted in slightly slower turn in than I liked and less feel when doing side to side transitions.

The final result was a bike that felt balanced, turns quickly in a controlled manner. The feel of the front is fantastic. The rear is still firm, but no longer harsh. The rear does not have that Ohlins feel I mentioned about the FZR1000 EXUP but is firmer than I remembered on the FZR. However, the handling is fantastic and she has never felt better. Now, I want to lean the bike over at every corner and have to control myself. She is settled in turns and she makes you want to just lean over more and more while you go faster and faster. She is also neutral in mid lean and only leans over more when you push the handlebar a bit more. If you don’t do anything, she just stays there. Beautiful!

My current settings are as follows:

Tyres

  • Front: Angel ST 120/70 – 35psi
  • Rear: Angel ST 180/55 – 41 psi

Front (Ohlins 9.5N/mm Springs and 20mm Supersports FPK)

  • Preload: 4 lines showing
  • Rebound: 2 clicks out
  • Compression: 8 clicks out

Bitubo XXF31 Standard Settings:

  • Hydraulic Preload: all wound down
  • Rebound: 20 clicks out
  • High Speed Compression: 14 clicks out
  • Low Speed Compression: 15 clicks out

Nitpicking on the Bitubo

I’m going to nitpick on the Bitubo shock. Its not a big deal, but thought that the finer details could have been improved. I am referring to the adjustments.

Firstly, the hydraulic preload adjuster is mounted at the back of the shock body with the knob pointing to the RIGHT side of the bike. That means, in order to adjust it, I have to use my LEFT hand to go under the seat and turn it CLOCKWISE to increase the preload. When gripping the adjuster, the left hand cannot be placed over the adjuster, but can only be placed under it. As you can imagine, this makes turning the knob rather awkward. In addition, the knob has NO markings so I have no idea how many turns I have made. I used some liquid paper to mark the knob. Lastly, for Ohlins’ products, they have some kind of rubber grip to make turning the knob much easier. The XXF31 only has plastic all around with some groves at both ends of the knob. It is not very grippy and is more difficult to turn.

Awkward way to adjust using left hand due to the position.
Awkward way to adjust using left hand due to the position.

Secondly, for some reason, the designer decided to use 3 different tools to adjust the damping and hydraulic preload settings. There’s a 4mm hex key for the low speed compression and rebound adjustments, a 3mm hex key for the hydraulic preload adjustment (its at the end on the knob and easier and quicker to turn than by hand), an a 14mm socket to adjust the high speed compression. Couldn’t they have used all 4mm or 3mm hex keys for the low speed compression, rebound and hydraulic preload adjustment?

Rebound damping uses a 4mm hex key
Rebound damping uses a 4mm hex key
Low speed compression (the center hole) uses 4mm hex key, while the high speed compression uses a 14mm socket
Low speed compression (the center hole) uses 4mm hex key, while the high speed compression uses a 14mm socket
You can use a 3mm hex key which is easier and faster, but why not a 4mm one to standardise everything?
You can use a 3mm hex key which is easier and faster, but why not a 4mm one to standardise everything?

Lastly, it is impossible to adjust the ride height with the fairing on. It uses a 27mm spanner, which I do not have. I tried using an adjustable wrench, but could not get it to turn. There was just not enough space to lock onto the nut and turn it.

Pirelli Angel ST Update

I would like to post an update on the Angel STs. Previously, with the Diablo Stradas, no matter how I fiddled with the settings, I could not seem to get the right feel for the bike. Perhaps I did not try hard enough before the puncture occurred and I had to fit the Angel STs. After changing to Pirelli Angel STs, the bike became a whole new beast. At the time of writing, I have used the tyres for about 1 month and I can attest that these tyres really really suit the GSXR1000. Its as if they were specially made for her.

Combined with the new suspension and the tyres, I think I have finally gotten the bike to be where she should be. I am no racer, but even a mere mortal like me can notice the difference. She is no plush long distance tourer, but she is definitely more comfortable and very confidence inspiring in the corners. I have to restrain myself from being carried away in the turns and endangering myself on the roads.

I would love to hear your stories about your suspension set ups and woes and especially any one who are using or have used the Bitubo XXF31/XXF11. Cheers and ride safe!

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