Suspension - !985 GS450L

[Guest]

The rear shocks desperately need replacing but I worry that depending on what I select for new shocks, it will increase the seat height. I'm looking for a shock that will be good for a lightweight rider (100#) that rarely ever rides two up.

[steve murdoch]

I think they are 13" eye to eye on your bike?
It should be easy to find something in that size. Progressive makes decent, relatively inexpensive shocks.

[Tamara]

I think they are 13" eye to eye on your bike?
It should be easy to find something in that size. Progressive makes decent, relatively inexpensive shocks.

That sounds about right but I'm going to doublecheck it and make sure.

[Agemax]

double check your eye to eye measurement and have a scout through ebay. depending on your budget you will find some shocks that will fit,new or secondhand.
as long as the eye to measurement and the top and bottom mount is the same as yours any make/model shocks will fit, just make sure of the diameter especially around the top and bottom mounts,to allow for clearance (frame,chain guard etc...)

[pete]

A lot of people end up with Hagons and Progressives and are quite happy with them.

I stuck with the local Aussie stuff and went with Ikons and got their fork springs as well.

I'm very happy with them and they have transformed the bike compared to stock

[Tamara]

I just measured and the current shocks are 12 1/2" eye to eye.

[BentRod]

Why do the shocks need to be replaced?

If you like your current springs and they are in good shape you could always swap them into replacement shocks, if they fit

If you are looking for brand spanking new, there isn't a terrible amount of choice, and I have found a lot of the universal fit shock absorbers sold seem to be intended for bigger bikes. I was in your position a few years back with my gs400, and in the end I went to a vintage swap meet to find the right parts.

All that said, don't worry about the ride height too much. Chances are it won't change noticeably. What is more important is how the bike behaves going over bumps, accelerating and in the bends. In this regard just about any modern shock is going to be an improvement.

If you cannot find parts specifically for your bike, look for a shock with a progressive spring and make sure that it has at least as much travel as the stock equipment (I think it was 160mm for the 450?).
Good progressive springs are wound so that the spacing between each coil decreases at a steady rate from one end of the spring to the other. This is different from two step linear springs, which have about half the coils wound at a wide spacing and half at a smaller spacing. Two step springs should be avoided, as the handling characteristics of the bike change once the softer, narrow spaced coils become fully compressed... which is often... and in corners... and extremely irritating...

[Tamara]

Why do the shocks need to be replaced?

If you like your current springs and they are in good shape you could always swap them into replacement shocks, if they fit

If you are looking for brand spanking new, there isn't a terrible amount of choice, and I have found a lot of the universal fit shock absorbers sold seem to be intended for bigger bikes. I was in your position a few years back with my gs400, and in the end I went to a vintage swap meet to find the right parts.

All that said, don't worry about the ride height too much. Chances are it won't change noticeably. What is more important is how the bike behaves going over bumps, accelerating and in the bends. In this regard just about any modern shock is going to be an improvement.

If you cannot find parts specifically for your bike, look for a shock with a progressive spring and make sure that it has at least as much travel as the stock equipment (I think it was 160mm for the 450?).
Good progressive springs are wound so that the spacing between each coil decreases at a steady rate from one end of the spring to the other. This is different from two step linear springs, which have about half the coils wound at a wide spacing and half at a smaller spacing. Two step springs should be avoided, as the handling characteristics of the bike change once the softer, narrow spaced coils become fully compressed... which is often... and in corners... and extremely irritating...

They are 28 years old, the seals on the shocks are completely gone and there are piles of rust between the springs and the shocks. The last time I rode it, the shocks definitely were not absorbing anything. It was quite unpleasant.

[Agemax]

Why do the shocks need to be replaced?

If you like your current springs and they are in good shape you could always swap them into replacement shocks, if they fit

If you are looking for brand spanking new, there isn't a terrible amount of choice, and I have found a lot of the universal fit shock absorbers sold seem to be intended for bigger bikes. I was in your position a few years back with my gs400, and in the end I went to a vintage swap meet to find the right parts.

All that said, don't worry about the ride height too much. Chances are it won't change noticeably. What is more important is how the bike behaves going over bumps, accelerating and in the bends. In this regard just about any modern shock is going to be an improvement.

If you cannot find parts specifically for your bike, look for a shock with a progressive spring and make sure that it has at least as much travel as the stock equipment (I think it was 160mm for the 450?).
Good progressive springs are wound so that the spacing between each coil decreases at a steady rate from one end of the spring to the other. This is different from two step linear springs, which have about half the coils wound at a wide spacing and half at a smaller spacing. Two step springs should be avoided, as the handling characteristics of the bike change once the softer, narrow spaced coils become fully compressed... which is often... and in corners... and extremely irritating...

why would you want to go to all the trouble of refitting your old springs into a different set of shocks???? buy complete shocks!

ride height DOES make a LOT of difference...it alters the whole steering geometry of the bike, which affects bumps,acceleration and going round bends......and if not done right can be extremely dangerous.

[BentRod]

Agemax
I'm not going to argue that ride height isn't going to change the geometry of the bike. It obviously will, along with the height of the center of gravity, which in turn effects weight distribution under braking... the list goes on and on...rake angle, trail, etc.
However, whether the spring rate is 600 lbs/inch or 800lbs/inch, for example, the difference in ride height is a quarter of an inch. and the difference in stiffness can easily be accomidated by the adjustment of the preload setting, negating the difference entirely. The major difference, as I said before, is how it all works out with bumps and bends. There it is the spring stiffness that determines the geometry of the bike.
The original post concerns changes to the seat height. The suggestion to keep the original springs was made on the basis that the current springs provided a desirable seat height. All that being said, as rust has taken a bite out of the springs, I really cannot recommend keeping them.

For the sake of the original poster, I'm going to simplify this as whatever shocks you get, it will probably be an improvement over the rusty blown ones you've got now. The only safe bet is OEM parts, but if you cannot get them, there are a few tips you can follow, most of which have been said already.
- make sure the length from eye to eye is the same
- try to get equal or near equal stiffness and travel
- avoid shocks made for heavier bikes
- Decent pregressive springs. not riding two up makes these ideal

Agemax, can I get any agreement from you on these pointers?

This is a really complicated question, and the springs, travel, damping ratio and rebound are but a small part in a much more complicated system. Trying to pick the 'right' aftermarket shock is like asking if the greek debt crisis is resolved will 2 and 3 year mortgage rates drop.

[Agemax]

ok, calm down.......yes i agree with what you are saying now, except before you quoted "dont worry about the ride height" as if it doesn't matter.i think Tamara is well aware now that she has to stay with shocks the same height as originals, or maybe even a bit lower if she wants the seat height lowered a little, however i doubt there are many shocks available for GS450's with multiple adjustments for ride height or compression/rebound and damping