Rear shock help K75... non stock

[ronbuell]

I'm still learning about this bike...'88 K75...
It appears to have a rear shock that is not stock... rather stiff.
It has a threaded lower part with 2 lock rings that you jam together to keep adjustment.  There is an air fitting on the bottom as well.  And there appears to be a compression adjustment at the top numbered 1-5 and you fit an allen wrench in to turn it.  It was set to 3, and I turned it back to 1 to try to soften it some... which it did.
The adjuster wrench (spanner) in the tool kit does not fit the jam nuts, and besides, they are located down at the bottom where the side bags go.  So I would have to remove the bracket to adjust it... bad location....  I think stock adjuster is on top.
There are no manufacturer markings on it......... Any ideas?

[johnny]

greetings ronbuell...

gonna needs some photos...

j o

[ronbuell]

OK Johnny
Do I have to post it to photobucket and put the link here?
Or Will the Insert Image actually post from me to here?

[johnny]

you can post an off site photobucket image link in the body of a post... or you can post an attachment from your device to the bottom of a post...

j o

[ronbuell]

OK, trying this again, with pics this time.
Top shows adjusters lock rings with inlet for gas, and bottom show either compression or rebound... not sure.

[johnny]

what brand is that shock... looks upside down to me...

im thinking the bottom rings would set ride height aka sag... and there is no other adjustment... butts hard to say without more info... caints see whats you gotts circled at the top... and the bottom nubbin is either a charge port or port for remote reservoir... butts caints see much of it either...

j o

[TimTyler]

That looks very similar to my Progressive 465, like maybe an older version. Mine has an orange bumper, not purple. I think yours is upside down too.

If it is a Progressive 465, you'll probably want to adjust those threaded rings to about the middle of their range.

[beachcomber]

"Most" shox are designed with different rates of dampening - compression vs extension, and as such have a harder compression rate [ obviously ] than extension. UNLESS the valving has been designed otherwise, fitting a shock "upside down" from it's designed orientation is asking for trouble.

I would say in this instance the SPRING is upside down, but the shock is in it's correct orientation.

Here's an over simplification - let's say the shock has 70 / 30 dampening [ just a figure plucked out of the ether ]. That is to say 70% of the dampening effort is on the compression stroke. Now fit it upside down - you have 30% of the dampening effort on the compression stroke.

The control at the bottom looks like dampening adjustment, but it's not clear if there is two way dampening adjustment.

Not foolproof, but let's assume the control is for dampening - set it to it's lowest setting [ usually anti / counter clockwise ], remove the spring and see if their is a significant difference in effort to open / close the shock manually.

While you're at it, you could gradually adjust the control to see what / how much difference it makes.

BTW all the above given I have NO idea of the shock manufacturer, but I DO have 35 year's experience with shox and their application [ race and road ] and having been involved in the design / development of the RAMSHOX for the past 9 years !!

TT - what orientation is your Progressive shock on the bike ?

BTW - the threaded rings adjust the sag / or pre-load and there is a specific proceedure to do that it is dependant on the loaded and unloaded static weight of the bike / bike + rider - the shock manufacturer will have that info. on how to set it up.

[Inge K.]

Here's an over simplification - let's say the shock has 70 / 30 dampening [ just a figure plucked out of the ether ]. That is to say 70% of the dampening effort is on the compression stroke. Now fit it upside down - you have 30% of the dampening effort on the compression stroke.

Please explain, my little head don't quite get this.............

When the shockie being compressed, I thought that the oil was forced through the same valves and openings
whatever position it is mounted in.

[TimTyler]

I just called Kyle at Progressive Suspension and he said the 465 was designed to be mounted on a K75 with the nitrogen port on the bottom facing the rear.

He said it was designed that way to offer the best clearance options, and that the shock's functionality would not change whether it was mounted right-side up or upside down.

[ronbuell]

I'm with you guys.. . looks like it's upside down to me too.
Almost all of my shock experience is with off-road bikes... the later model WR250F and YZ250F is what I have the most experience with.  So I'm familiar with compression and rebound, free sag, laden sag, preload etc.  I have a rebuilder I work with here and we actually re-stacked and changed the shims to change the damping for my bikes.  With 12 inches of travel available, I like to use most of it and still have a soft ride.... getting older, not younger.

Some shocks are position sensitive.  My off-road bikes have a bladder in the pressure chamber and its connected to the shock by hose to the fitting on the valve body.  Usual mode of failure is the baldder gets a hole in it and the gas mixes with the fuid and doesn't work properly any longer.  They will also develop a leak around the seal at the shaft, which makes the failure visible.

I didn't see any manufacturer marking or stickers on it, but will look again.  I can try flipping it and see if that changes anything too.

Geting back to this one... with only 5+ inches of travel, right now, it is too stiff for sure.  Does make for very controled ride when the surface is smooth, but really have to slow down when the surface is ruff.... not good at all.

[beachcomber]

Here's an over simplification - let's say the shock has 70 / 30 dampening [ just a figure plucked out of the ether ]. That is to say 70% of the dampening effort is on the compression stroke. Now fit it upside down - you have 30% of the dampening effort on the compression stroke.

Please explain, my little head don't quite get this.............

When the shockie being compressed, I thought that the oil was forced through the same valves and openings
whatever position it is mounted in.

Hope this is simpler. However here's an analogy, IF you are familiar with Drag Race cars - you will note that in the good old days the front end would lift violently. The shox typically fitted would be "90/10"s - That is to say 10% of the resistance was on extension - to allow the shock / wheel to fall rapidly and the 90% of the resistance was in compression allowing the front to come back to earth safely [ 'ish ! ].

The same  [ less extreme ] is true of roadgoing shox - they manufacturers want to ensure that your wheel is in contact with the road for as much of the time as possible. Standard valving is designed with such ratios [ not 90/10 ! ] - that's why some of the more complex shox have an adjustement for both compression and extension.

TT - did your tame Progressive guru mention the orientation of the spring in the pic ?

[TimTyler]

He's not "my guru". I just called Progressive's support number. I did not show him the photo.

[beachcomber]

He's not "my guru". I just called Progressive's support number. I did not show him the photo.

My money's on spring USD     :2thumbup:

[TimTyler]

The spring is at its loosest position and since you dialed the damping down to #1, the shock should be in its least stiff operational condition.

I'd send it off to Progressive for a rebuild, or just replace it.

FYI - The instructions for the 465 specify that the damping adjustment should never been turned from 1 to 5, or 5 to 1. Only 1-2-3-4-5-4-3-2-1.

[Inge K.]

Here's an over simplification - let's say the shock has 70 / 30 dampening [ just a figure plucked out of the ether ]. That is to say 70% of the dampening effort is on the compression stroke. Now fit it upside down - you have 30% of the dampening effort on the compression stroke.

Please explain, my little head don't quite get this.............

When the shockie being compressed, I thought that the oil was forced through the same valves and openings
whatever position it is mounted in.

Hope this is simpler. However here's an analogy, IF you are familiar with Drag Race cars - you will note that in the good old days the front end would lift violently. The shox typically fitted would be "90/10"s - That is to say 10% of the resistance was on extension - to allow the shock / wheel to fall rapidly and the 90% of the resistance was in compression allowing the front to come back to earth safely [ 'ish ! ].

The same  [ less extreme ] is true of roadgoing shox - they manufacturers want to ensure that your wheel is in contact with the road for as much of the time as possible. Standard valving is designed with such ratios [ not 90/10 ! ] - that's why some of the more complex shox have an adjustement for both compression and extension.

That didn't answer my question..........
I wonder how the damping resistance can change from 70% to 30% by just turning it upside down.........
normally the oil is forced through the same valves and openings whatever position it is mounted in.

[ronbuell]

"I wonder how the damping resistance can change from 70% to 30% by just turning it upside down......... "
My guess would be NOT if it works like a dual chamber shock.

I may have found it... or what looks close:
Ikon Suspension 7614
http://ikonsuspension.com/content/product_ranges/7614_series_shocks.shtml

[beachcomber]

Here's an over simplification - let's say the shock has 70 / 30 dampening [ just a figure plucked out of the ether ]. That is to say 70% of the dampening effort is on the compression stroke. Now fit it upside down - you have 30% of the dampening effort on the compression stroke.

Please explain, my little head don't quite get this.............

When the shockie being compressed, I thought that the oil was forced through the same valves and openings
whatever position it is mounted in.

Hope this is simpler. However here's an analogy, IF you are familiar with Drag Race cars - you will note that in the good old days the front end would lift violently. The shox typically fitted would be "90/10"s - That is to say 10% of the resistance was on extension - to allow the shock / wheel to fall rapidly and the 90% of the resistance was in compression allowing the front to come back to earth safely [ 'ish ! ].

The same  [ less extreme ] is true of roadgoing shox - they manufacturers want to ensure that your wheel is in contact with the road for as much of the time as possible. Standard valving is designed with such ratios [ not 90/10 ! ] - that's why some of the more complex shox have an adjustement for both compression and extension.

That didn't answer my question..........
I wonder how the damping resistance can change from 70% to 30% by just turning it upside down.........
normally the oil is forced through the same valves and openings whatever position it is mounted in.

Inge ...........................I am talking fluent cobblers of course.

The point I was trying to make referred to an experimental shock that was being developed for a Trike we were building - and NOT of course to mainstream shox as you rightly pointed out.

My apologies to all those who were scratching their heads like you - good job I don't design the shox, just develop them.

Sitting in the corner on the naughty step with my dunce's hat on.

[mjydrafter]

It would be my understanding that with a shock that was meant to be run in a certain orientation; if it were run upside down, wouldn't the valve pack be upside down?  Meaning whatever the ratio that BC is talking about, would be reversed between rebound and compression.

[beachcomber]

It would be my understanding that with a shock that was meant to be run in a certain orientation; if it were run upside down, wouldn't the valve pack be upside down?  Meaning whatever the ratio that BC is talking about, would be reversed between rebound and compression.

It really does depend on the internal design, and there's so many options this debate could go on forever !

Meanwhile - I still think the SPRING is upside down !!!!!!!!!!!!   :dunno2:

[Inge K.]

Inge ...........................I am talking fluent cobblers of course.

Thanks, got the answer I wanted.

[mjydrafter]

I think that's a Progressive 420 shock.


It's not upside down, check this thread: http://www.motobrick.com/index.php?topic=4501.0

[ronbuell]

And the winner is: 
Progressive 420  :clap:  Congratulations to all those who voted Progressive.  Your prize is waiting at the door!
They don't make this one any longer, discontinued.  I did find some bad press on it.  They came out with another low end, and the 465 which is impressive.  The one they designed for the GS models is quite good.
So now its time to loosen the preload a little so it will have some usable travel.
Seriously, thanks for point me in the right direction. :2thumbup:

[TimTyler]

That looks very similar to my Progressive 465, like maybe an older version.

What door? Where's my prize???    :yes

[Motorhobo]

Start putting some change in your piggybank daily -- 420 isn't rebuildable and when it fails you're riding a hardtail. I know...ask my coccyx.

http://www.motobrick.com/index.php?topic=5284.msg32939#msg32939