Which is a better replacement shock?

[not2slow]

Hiya,
I'm looking for some advice about a replacement shock for a 2008 Hyosung GT250R. My stock shock is pongo-ing at the moment (Needs more rebound dampening...i think??) and its only limited to preload adjustment (currently on 2 clicks). The shock sags about 80mm when i sit on it as well.

I have been looking at replacements and have some up with a list potential shock replacements but i am unsure, of the potential replacements, which shock is better and which is rebuildable.

A few details: I weight 100kg (in bike gear) ride on the motorway daily and the Hyobag weights 160kg (i think?).

So i have found these shocks as potential replacements:
88 gsxr 400 (some mods)
95 gsxr 750 (some mods)
91-93 CBR 600RR and may be the CBR 900RR (same year)
1991 ZZR 1100

Of the above shocks, which is better (e.g. would suit my weight), which has better rebound dampering and whether any can be reconditioned and the costs?

I'm not wanting to spend a shitload on the shock as this would be mad considering the hyobag is only worth $4k so an Ohlins shock would be over kill on the old wallet. But if i can get an older shock and use it then may be get it rebuilt this could be a price friendly option. Also been eying up YSS and Hagon shocks and these are quite well priced (~$500NZ) along with a heap of shocks listed on Ebay.
So if anyone (Mr R. Taylor?) can offer some input i would be happy to listen to someone with more knowledge then me about shocks.

Cheers

[DMNTD:Me]

I would consider simply having your stock shock re-valved/sprung

[CookMySock]

It's not worth trying to do anything with the stock shock - it's a sealed/welded unit.

As you have discovered, a couple of other shocks will fit. Recommend you just fit it and try it. If it has a remote resivoir, then pump that up hard and see if its in the ballpark. If not, then you will need to buy a spring for it.

A standard 88-91 gsxr1100WP shock is okish for a really skinny girlie rider, but it does sag the arse a bit. The ride is a big improvement over stock.

[Mental Trousers]

I have been looking at replacements and have some up with a list potential shock replacements but i am unsure, of the potential replacements, which shock is better and which is rebuildable.

A few details: I weight 100kg (in bike gear) ride on the motorway daily and the Hyobag weights 160kg (i think?).

So i have found these shocks as potential replacements:
88 gsxr 400 (some mods)
95 gsxr 750 (some mods)
91-93 CBR 600RR and may be the CBR 900RR (same year)
1991 ZZR 1100

Anyone of those will probably do the job. However, don't put it in the bike until you've sent it off to be reconditioned and preferably resprung. If you can get one for a good price, once it's reconditioned you'll have what feels like a brand new bike that actually does things like handle for very little money. The cheapest way to get a new bike is to upgrade the suspension, it makes that much difference.

Unfortunately the shocks on the Hyobags are a bit notorious for losing all of the Nitrogen in rear shock and turning into undamped pogo sticks. I rode one with a friend on the back cos she wasn't sure if there was something wrong with the bike. That bike scared me in a couple of corners. It's no wonder she had 3 offs just before she got rid of it. Talk about a scary handful.

[avgas]

Hagon / IKON / KONI will give you good value for money. Especially if all you want is a stiffer shock (like me).
Rebound rates etc are awesome if you give a fuck (and if you do then get an ohlins).....but for the rest of us that just want an "upgrade" and you can't do it to the shock on the bike - the above suit perfectly.
I preferred my Koni's on the GB over the Ohlins I tested even but that was just personal preference.

[DEATH_INC.]

So i have found these shocks as potential replacements:
88 gsxr 400 (some mods)
95 gsxr 750 (some mods)
91-93 CBR 600RR and may be the CBR 900RR (same year)
1991 ZZR 1100

Forget the gixxer shocks, they are rubbish.
CBR would be a lot better, at least they have decent internals.
Dunno about the zzr one's.

[Robert Taylor]

The internal damping calibration and the selected spring and its preload must be within a window that is dictated by the motion ratio that is imparted to it. Also the load that is applied to it by the rider, the disposition of any added loads and the engine torque imparted to it.
Damping is velocity dependent, the faster / further you move the suspension shaft for any given rear wheel movement the more damping it develops, just like pushing that humble fire door with a damper on it! So it follows that factors such as swingarm length and the mounting points of that shock ( plus in many cases rising rate linkages ) will all have a dramatic affect on the spring rate and damping required.
The shocks you have quoted are all dramaticaly different, the Suzuki shocks are calibrated for a very aggressive linkage and the Honda shocks have much heavier rate springs fitted with different damping as the shock shaft gets moved a lot more slowly than many other models.
There was some flippancy about ''giving a f..k'' abour rebound damping. Over slow rebound damping is in fact one of the biggest causes of motorcycle accidents, injuries and fatalities. As is little or no rebound causing instability.
Having a shock installed that gives a safe level of performance ( and Im not wearing my Ohlins hat in saying this ) is not something that should be sneered at.
Sorry I have no data for this model, as is the case with many or most lower cost commuter models.Everyone chips in with their five cents worth on many forums, you just have to be wary of bad advice that might suit your pocket but may impinge on your personal safety.
If however there is a wide sampling of consensus on what actually fits BUT ALSO ACTUALLY WORKS then it startrs to become plausible.

[Robert Taylor]

Forget the gixxer shocks, they are rubbish.
CBR would be a lot better, at least they have decent internals.
Dunno about the zzr one's.

Thats a pretty bold all encompasing statement. Ive seen more than a few of those shocks over many years, Showa and KYB all have their average and better shocks. If you look at the current CBR600 shock ( for example ) its a very low cost and not so flash example. The Triumph 675 shock has good bones but nothing is going to work very well with such a dog of a link curve. The Soqi made R6 shock has some good engineering but they dropped the ball in another couple of areas. Etc......

[Maha]

Its flogged out after a couple of years of primarily motorway riding?...

[not2slow]

The shocks you have quoted are all dramaticaly different, the Suzuki shocks are calibrated for a very aggressive linkage and the Honda shocks have much heavier rate springs fitted with different damping as the shock shaft gets moved a lot more slowly than many other models.

Mr Taylor; since i'm not the smallest of blokes, I am assuming a heavier spring rate be more suitable for me? Also (excuse my ignorance here) what do you mean by an aggressive linkage? And what would be the cost (a rough estimate would suffice) to rebuild a GSXR or CBR shock?
Cheers

[Robert Taylor]

Mr Taylor; since i'm not the smallest of blokes, I am assuming a heavier spring rate be more suitable for me? Also (excuse my ignorance here) what do you mean by an aggressive linkage? And what would be the cost (a rough estimate would suffice) to rebuild a GSXR or CBR shock?
Cheers

Absolutely, but also the high speed rebound needs matching to the spring force. An aggressive linkage is one that ramps up aggressively in its link curve as the suspension gets deeper into its stroke, raising the shock shaft speed more and more and therefore the damping force.
If you ride a Triumph 675 Daytona on a bumpy road you will well understand aggressive links!
I wouldnt attempt to even give a rough quote sight unseen as this is such a one off job, and if anyone attempting such a job is completely honest, they like we would insist on having the whole bike to do so properly.

[CookMySock]

[...] but also the high speed rebound needs matching to the spring force.

Robert is right, but I can confirm that the 1990's GSXR1100WP shock on a GT250R is light years better than stock for a 55KG rider, coz I tried it. Only slight mods to the shock are needed.