Another suspension thread

[k.rollin]

After two years of relaxed cruising and commuting with my GS500 on mostly well-maintained roads, I've come to a point in my life where I need to commute on not so well-maintained section of highway with higher traffic for work. This has brought the known shortcomings of the stock suspension that I had been living with into the light more clearly, and if I am to continue riding to work when I'm not carpooling, it needs to change. The thing is, I'm not sure what the best way of going about upgrading my suspension would be.

In my reading/searching, most of what I've run across has been along the lines of "replace the fork springs, use heavier viscosity fork oil, and install a Katana/SV650/R6R shock". Most seem happy with their changes, but without giving a clear description of what their performance goal was, and how well it was satisfied. As such, I am unsure as to whether or not such upgrades would actually help my situation or just result in a lighter wallet.

What I need then, is guidance/advice in setting up my suspension for the conditions that I ride in. My bike is a naked 2004 model and it has a bone stock front end. The rear has been lowered an inch, with the shock collar is set such that the stamped '5' faces the right footpeg. What I've found while riding is that my front end dives excessively under breaking, and that when traveling at freeway speeds along certain straight stretches of the road, it feels as though I'm sitting on a paint shaker. What I'd like to have is reduced front end dive under braking and a smoother ride over those rough sections. Having the bike feel more planted/confident in the corners would also be nice, but I don't ride particularly aggressively at the moment. I'm not sure how important it is in order to get appropriate upgrade suggestions, but I weigh about 175 lbs in all my riding gear. Any help as to how I should set up my bike's suspension to get the ride I want would be appreciated.

[Bluesmudge]

The SV shock won't give you a much better ride. Most people install it to raise the rear end. R6 and Kat shock should be similar in height to stock, maybe a little taller because you get less sag from the weight of the bike.

I think you don't weigh enough to use the Kat shock, given you are looking for a more comfy ride. I've never used a R6 shock myself buy I hear it is softer than the Katana. Also keep in mind there are a few different version of the Katana shock. I have the Kat shock without the remote reservoir, I am about 200 lbs and find it just right, but it actually feels even better with a passenger. That shock was meant meant for a much heavier bike. On the Katana it wasn't that great, but on the GS its an improvement, especially if you are 200+ lbs

For front forks, what is your budget? With the simplicity of the GS's forks its difficult to have a plush ride and also stop the brake dive. I find 15w oil and .90 sonic springs to be a good compromise. At your weight you will probably want .85 or .80 springs. Check Sonic or Racetech's website for recommendation.
If you have the money, throw a completely different front end on from a more modern bike, or at least get a set of Racetech's gold emulators.

[Watevaman]

 I'm ~5'9", 160 lbs without gear (so maybe 170/175 with) and I have a Katana rear shock and .90 Sonic Springs on the front. Granted, I haven't taken my bike over any particularly rough roads as I'm stuck to my neighborhood until I tag it, but with these mods it feels considerably more planted in the turns, which is what I wanted. Brake dive is essentially nonexistent at neighborhood speeds. However, there is the compromise of some comfortability with the setup I chose. The ride is much more stiff and you can definitely feel the road more. Over high speed bumps this may be better but as it stands now I think you'd be able to feel the road much better without the bike feeling like it wants to crawl out from under you.

[jestercinti]

Stick with stock shock. Ohio is slow to repair roads. When I switched to a Kat shock, I would hit frost heaves and have my rear thrust out of the seat noticeably. Scared the shaZam! out of me at first.

I weigh 210 and it was stiff. I have stock springs in the forks.

[Zwerski]

I like my R6 shock. I've gotten so I can adjust it to exactly where I need it pretty quickly.

[adidasguy]

As you know, I have a few GS500's in different configurations.
I am same weight.
I find the stock rear shock is fine for all my riding unless I have a passenger (which was done once to get someone to the bus stop in a hurry).

Front I have 0.85 Sonic's. That is great. No diving into turns or breaking.

One bike has progressives and I really can't tell the difference. The shocks are by nature progressive due to the compression of the air: the more compressed, the higher the air pressure and the more resistance.

Being the same weight, I suggest change the front springs with 0.85's and 15w oil. After you do that and ride for a week or more, you will be in a better position to decide if you want to change the rear.

One bike came with a Kat shock. After I changed the front springs the rear was way to stiff and high so I gave away that Kat shock and put on a new stock shock.

All my Gs500's have stock rear shock. My older ones (1992, etc.) I have replaced worn, old shocks with used stock ones from newer bikes (like 2006-2009)

[craigs449]

i have a 2001 gs500

i weigh 185 without gear

I put .90 sonics in the forks and swapped for an r6 shock......it doesnt bottom out or dive nearly as much as before and there is very little static sag in the rear.


on another note, anybody have proper sag measurements for the gs500?

[BockinBboy]

I have .85 springs and I'm the same weight with gear.  I stuck with 10w oil just so I could see the difference of changing one variable at a time... I plan on trying 15w next summer to see the difference.

I also have an R6 shock which I put on a couple rides before changing fork springs. The shock definitely smoothed out the ride and got rid of bottoming out two up.  You can adjust it enough that it is still similar to stock or on up to much stiffer than the stock shock can go. The adjustable dampening has been great for improving comfortability and stability and was worth the swap to me.  But it is probably one of those things you don't miss of you've never had it, but I'm definitely glad I do.

The springs were the most noticeable change for the better though.  It actually feels as if the bike is more solid compared to before, like it sticks to the road.  No wavering when I hit a bump on a turn, and it is much more stable, and lines are easier to maintain when riding the pace.  No diving when applying the brakes or during heavier engine breaking, so you are ready to get back on the throttle. 

- Bboy

[k.rollin]

I purchased an R6 shock to try, as I figure I can resell it and recoup much of my purchase cost if it isn't to my liking. Just thought that the increased adjustability might be helpful while tuning the overall suspension set up. To be completely honest though, I too have found the stock rear shock to be adequate until the paint shaker experience, which left me confused and uncomfortable. I didn't notice the forks pumping on that rough ride, but the whole bike seemed upset. I felt like I was being jarred through the seat and through the bars.

Regarding my budget, I'd like to keep things thrifty, but am willing to go as far as a swapping my front end for a cartridge fork set up if I can't get the ride I want from modifying the stock fork, as the GS500 is about the most practical bike for my needs. I reckon I'll start by replacing the springs and oil, but it'd be really nice to know that the parts I buy are going to do just what I want them to.

[slipperymongoose]

I started out with 85 sonics 15w fork oil at 90mm and had the spacer cut flush with the top of the fork, I even had it a bit more. My stock shock did me till it shat itself then went to the R6. The r6 gave me such better stability etc, then later on while bored I made up my own 16mm ally fork brace. Also search for a bloke on YouTube called Dave moss he is up with suspension set ups.

[Slack]

The only way to keep the bike more planted in turns, eliminate brake dive, AND keep the suspension plush over rough roads is to have suspension with separately adjustable high and low speed damping.  That way when your braking or cornering on a smooth road the suspension stays stiff, but when you hit a huge bump it softens up and doesn't launch you out of the saddle.  The R6 shock is what you want on the rear, I don't know why anyone uses the Katana anymore - it's no better of a shock then stock, just stiffer and slightly longer.  The R6 is 4-way adjustable so you can tune it to be soft on hard bumps and stiff through the corners.  On the front your only options are to replace the front end with a cartridge fork like a cbr600 or to add springs and gold valve emulators to your stock forks.  If you just add springs and oil without the emulators you will make your commute worse.  Check out my write up:  http://gstwins.com/gsboard/index.php?topic=59261.msg677615#msg677615

Edited because dampening is for squirt guns, not shocks!

[Funderb]

The kat shock is easy, but too stiff for regular riding on the GS. Maybe, with a kat shock on min preload and 1-2 damp setting for your weight may work. The r6 might be excessive technology-wise for your application.

Doing the front end, probably with either progressives or sonics with a set of gold valves, is going to be the best thing for your application.

[slipperymongoose]

I would take something with more adjustability over something without.

[k.rollin]

I had figured before starting this thread that I'd probably need forks and a rear shock that had independent adjustments for high speed and low speed damping, but I wasn't entirely sure. As luck would have it though, I've found a complete front end from a 2000 Honda CBR600F4 on the local craigslist site that will probably cost less than a new set of springs and cartridge emulators. It should swap right in with some new bearings and a spacer and will give me a cartridge fork.

I am curious as to how the handling will change as a result of the CBR front tire being 120 70/17 and my rear being 130 70/17, as compared to my current 110 70/17 front and 130 70/17 rear set up as well.

[gsJack]

I am curious as to how the handling will change as a result of the CBR front tire being 120 70/17 and my rear being 130 70/17, as compared to my current 110 70/17 front and 130 70/17 rear set up as well.

That CBR front end most likely has a radial tire mounted on the wheel and your current 130/70 rear must be a bias tire and a radial front with a bias rear is a bad mix.  Can cause serious oversteer when pushed to the limit so you should be changing one of the tires if you go ahead with the CBR front end.  A bias 110/70 should fit the CBR wheel or a wider radial on your present rear rim to go with the radial front if it's worth keeping.

I've run only one 120/70 front tire and didn't like it as well as the many 110/70 and 110/80 fronts I've used.  It wasn't that bad but just didn't feel as good as the 110's did on the GS's after it was half worn.  I ran the 120 front with 140/70 and 150/70 rears.  Tires I've used on my GS's:

http://img.photobucket.com/albums/v443/jcp8832/GS500tirelogs.jpg

I have rear links that lower about 1 1/4" and found they stiffened the rear suspension a bit due to the link geometry change and it felt better balanced with my Progressive front springs.  You might want to go ahead with your front changes and try it out before you decide on the rear.

[Funderb]

I would take something with more adjustability over something without.

To say the katana shock is without adjustment would be remiss. If you find you need more than spring preload and rebound damping adjustments for cruising to work, you're probably not actually "cruising" to work.   


For the op's problem, more than likely a katana shock in the back and heavier oil/springs in the front end will satisfy the problem. This will also provide the most cost effective and time effective upgrade. Spending time tuning a 4 way adjustable shock for a work commute is ... good for some people.

All that stated, there are some stretches of road in this world that will never be comfortable on a bike no matter what, and no amount of suspension tuning is going to give you a perfect ride over every terrain.

[slipperymongoose]

I would take something with more adjustability over something without.

To say the katana shock is without adjustment would be remiss. If you find you need more than spring preload and rebound damping adjustments for cruising to work, you're probably not actually "cruising" to work.   


For the op's problem, more than likely a katana shock in the back and heavier oil/springs in the front end will satisfy the problem. This will also provide the most cost effective and time effective upgrade. Spending time tuning a 4 way adjustable shock for a work commute is ... good for some people.

All that stated, there are some stretches of road in this world that will never be comfortable on a bike no matter what, and no amount of suspension tuning is going to give you a perfect ride over every terrain.

Ummm yeah kat shock does lack the adjustability. With the r6 you can properly tune and adjust your setup to make the bike do what you want, not adapt to what the bike does. It's a great tool for learning how suspension works on a bike and if you search YouTube you will find many videos to support this. In the end it's all about setting the bike up for the specific rider. And cause were all different I would take something that is more adjustable that I can tune to get what I need out of it. Plus the r6 shock is cheap as chips so why not?

[Bluesmudge]

The Kat shock does have more adjustment than the stock shock, which is good for people like me who can do more harm than good if I play with that many variables. However, I think that with the stock Kat spring, anyone under 200 lbs will find it to be too harsh for everyday riding, especially if you live in an area with bad roads.

[k.rollin]

I missed out on the CBR front end by a few hours today. Looks like I may be going with the full Race-Tech treatment instead.

[rebel_rocket]

I have gsxr 750 front forks and a stock rear shock. I'm 5'9 and 180 lbs. The bike feels about right for my tastes.