Another Ohlins Query (Johnnyboxer ?)

ferguscawley

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I have some questions regarding the ohlins set-up on my 94 1100GS.
I noticed on some of my friend’s (non-ohlins) GS’s that when on the centrestand, there is a gap of approx 1” between the front tyre and the ground, when back wheel is touching the ground.
On my GS, I cannot even get a finger underneath the front tyre when on the centrestand (with rear touching the ground).
There are probably a few reasons for this :

1 – Too much rear preload, thereby raising the rear of the bike so that the front gets closer to the ground, or …
2 – Too much front preload.

I suspect the latter because the bike tends to run wide on fast corners, which indicated to me that not enough weight is being transferred over the front causing the front to drift. (When I raced sportbikes, I would usually drop the forks down through the yokes by a few mm to stop this happening, albeit at the expense of some straight line stability. )

My friend's GS with standard (worn) shocks and with the 1" gap under the front wheel, handles superbly in the corners and doesn't seem to run as wide as mine does.

Yesterday, I took the tools out and tried to reduce the front ride-height by reducing the front pre-load. The only adjustability that is obvious is where the shock meets the telelever thingy, so I reduced this to a minimum, as you can see from the attached photo.






Contd................
 

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..Contd.....

This made no perceptible difference whatsoever to front ride height. Next port of call was the upper spring adjuster collar – from the picture there seems to be plenty of un-used thread which could be used to essentially reduce the front spring preload.

However, when I tried to adjust this, the collar just seems to turn but does not seem to move along the thread at all. Looking closer still (not visible in photo) there appears to be a type of ‘circlip’ between this collar and the threaded portion of the shock housing.
Is there some type of special tool required to remove this – or is this the preset location from Ohlins for the spring ?

In April 03, Johhnyboxer wrote :

“Tried out my newly fitted front Ohlins this weekend and on the first 180 mile ride,I found the handling to be far worse.
So,got some advice and backed off the front preload,to the bottom of thread,so that the double collar was flush with the shock body and threads.
This has made the shock softer and more responsive.
Now I will have to experiment with the rebound settings,to smooth things out.
Any recommended front rebound settings..........soft ~ ie very little is what I'm told.”

Johnny – did you make any adjustments to your upper spring collar/adjuster on your front shock ?. If so, how did you do it ?. Does the shock require removal to do this ?
Sorry for all the questions, but this thing is just driving me mad.
Thanks

Ferg
 

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tyre gap!!

Can't see what this has to with the shocks this is a weight thing,as the ride height/sag is set/adjusted whilst the bike is on the centre,then measured off the stand with both wheels on the ground.Winding your bottom collar up won't raise the wheel off the ground it will push the whole bike up from the bottom fixing point on the wishbone and winding it down will lower it.By the looks in the picture you have way to much sag!! have a look in your ohlins manual if you have one and set it up to that and then take it from there.When you measured your tyre gap with your friends did you have the same amount of fuel?.Andy
 
Andy
What I am trying to achieve is to reduce my ride height at the front of the bike. Right now, the front end of my bike is too high, by approximately 1 ". Moving my spring further back up the shock absorber body (i.e upper mount) will achieve this for me. As on any bike, the height of the bike is determined by the springs, nothing else.
I am aware on how to adjust sag and of it's importance - however, once I have the ride height in the right ballpark, I will adjust the sag to suit. Currently, I feel that my bike's geometry (rake and trail) is not what it should be - hence the bike pushing wide in fast corners.
The ohlins 'manual' that I got with the bike is not worth the paper it is written on - a sheet of paper with loads of disclaimers and a few words on how to install the shocks. By the way, the bike was bought used with the shocks already installed. Perhaps I did not get all the paperwork that I should have received.
Do you know if perhaps the ohlins springs/shocks perhaps longer than the standard BMW item ?
Any idea on what the sag figures for an1100GS with Ohlins shocks should be ?

Many thanks for your reply.

All the best

Ferg
 
Ferg
what's your weight ?

My ohlins springs are standard which are a bit stiff for my weight (150 lbs)
but i run with the same front settings as you, ie with the rings
on the minimum + six clicks off,back end pre load fully off,8 clicks out.

Have not touched upper collars

Gates ;)

Ohlins don't sag as much as oems, higher seat height :rolleyes:
 
weight

Gates

I am a 'healthy' 15 stone (210 lbs - 98 kilos) in my birthday suit. All kitted up I reckon I am a good 230 lbs at least.

I just downloaded some stuff from the ohlins website so I'll head down to the garage now and see where my bike is currently set.

Apparently, the front shock for a 1994 1100GS is type 46ER. However, the picture of the 46ER on the Ohlins site looks nothing like what is installed on my bike -

See below
 

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Fergus,
The second pic you posted is the adjuster ( top of the shock ) that you need to adjust to alter rideheight.

This is completely different from preload and sag.

Also the gap under the front tyre is a parameter of shock length - nothing else you do will affect this - at the front.
However - rear shock length will affect the gap under the front tyre.

if you adjust rideheights to how you think correct, the suspension will always drop to a stopping point of the shock or linkage - called static droop.

the important things are rideheight, preload and sag, not static droop.

Preload is the amount of initial compression applied to the spring by the adjusting collars from 'free length' ,.
The rideheight can be changed without affecting preload - provided you can move rthe spring along the shock body from each end.

I think you need to get the original shock length and start from there.

Phil
 
Apparently, the front shock for a 1994 1100GS is type 46ER. However, the picture of the 46ER on the Ohlins site looks nothing like what is installed on my bike -
Ferg
you have a 46er ;)
+ standard springs according to the No's
Oophs,standard
front 18 clicks out
rear 12 clicks out
Me
front 20 out
rear 16 out
 
cheers

Thanks for all your help guys. I will try to digest it tonight as I sleep !!

Anyway, I took some measurements according to the set-up guide I downloaded from the Ohlins website, i.e

F1 = height from axel to a fixed point on bike (beak) with bike on centrestand (no weight on suspension)
F2 = height from axel to a fixed point on bike (beak) with bike on its own weight (no rider)
F3 = height from axel to same fixed point with rider on board

Similarily,
R1 = height from rear axel to fixed point on bike (tailpiece) with no weight on suspension
R2 = height from rear axel to same fixed point with the bike unders it's own weight
R3 = height from rear axel to same fixed point with rider on board

According to the guide
F1-F2 (ie without rider) = 25 - 30 mm
R1 - R2 (no rider) = 5-10 mm
and
F1 - F3 (with rider) = 35-48mm
R1 - R3 (with rider) = 30 - 40 mm

My figures were way off this setting :-

F1 = 565mm, F2 = 520mm, F3 = 498mm
R1 = 515mm, R2 = 484mm, R3 = 443mm

So, I have

F1 - F2 = 45mm
R1 - R2 = 31mm
F1 - F3 = 67mm
R1 - R3 = 72mm

By setting my rear preload to the max, I got the following figures (for the rear only)

R1 = 515mm
R2 = 493mm
R3 = 457mm

Giving me R1-R2 (no rider) = 22mm and R1-R3 (rider) = 58mm

These are still way off the mark. Also, the bike now feels harder to sit on (even though it isn't).

Are these figures really relevant to a GS with long travel suspension ?.
Anyone know what the sag settings should be for this bike ?

Thanks !

I'm off for a well-earned beer now

Ferg
:beer:
 
Fergus

I chased my tail for nearly a month tryng to set mine up (on an S, not a GS) and although I got reasaonable results never really got it to the point where I was happy.

Sag and preload were the problem for me, I'm ok playing with damping but if the other settings are wrong to start with (and mine were way out) you don't stand a chance.

In the end I bit the bullet and took it to a specialist, in my case Motorcycle Technics in Suffolk, coughed up £75 and in return had a bike that was transformed. The price even includes free tweaking for life should I need it.

The bit that really threw me was more preload gives a softer ride (or something to that affect) and not harder. This is a common mistake apparently. I found it quite amusing (not to say confusing) to see the preload wound off front and rear, the damping reset and then end up with a firmer ride than when I'd 'set it up'.

Not much help I know, but there's only so many times you can measure all the settings and adjust the shocks.

Adam
 
any updates ?

Anyone with ohlins suspension who can contribute their current set-up (preload - rebound damping etc) would be greatly appreciated .

Thanks

ferg
 
initial setting of spring rates and preload should be to give static movement of 1/3 of full movement with rider on board in kit.

this means knowing full suspension movement from std sources - ie BMW.

lets say 150 mm front full travel -i'm guessing - but you need to have an
f4 figure- axle to fixed point on bike at full travel.( 565 -150=415)
then

f3 should equal 565 - 50 = 515

adjust spring compression (preload ) to get this figure.
Rideheight is independant of these figures - it still uses the 150mm but a different starting point.

adjust damping from minimum upwards

siimilar for rear after determining full travel

does that make sense ?

Phil
 
That's my original post..............however I subsequently realised I was doing it wrong......DOH........when I went to an Ohlins suspension specialist and he set the bike up............,so now I have more spring preload on front,than I had previously ( and now rides firmer and better)..........never had a problem with ride height.........but my bike is a 1150,so geometry mike be different
 
Thanks

Thanks Phil

That makes perfect sense. I have actually been experimenting with the preloads (increased the rear substantially)and the bike is definitely better than it was.
I will get the full travel figures and adjust accordingly.

Many thanks to all who replied :beerjug:

Ferg

motomartin said:
initial setting of spring rates and preload should be to give static movement of 1/3 of full movement with rider on board in kit.

this means knowing full suspension movement from std sources - ie BMW.

lets say 150 mm front full travel -i'm guessing - but you need to have an
f4 figure- axle to fixed point on bike at full travel.( 565 -150=415)
then

f3 should equal 565 - 50 = 515

adjust spring compression (preload ) to get this figure.
Rideheight is independant of these figures - it still uses the 150mm but a different starting point.

adjust damping from minimum upwards

siimilar for rear after determining full travel

does that make sense ?

Phil
 
Hello Ferg,

Did you stick with the 1100 and Ohlins, and if you did what settings did you finally end up with? I'm going through the same process that you did.

Cheers,

Chris
 
phone Clarance Bell..... a 2 minute phone call should have you sorted :thumb


Clarence Bell
Pro-Link Racing Services
9 Cardy Road
Greyabbey
Newtonwards
Co Down
BT22 2LS
Tel: +44 28 4278 8854 Tel 028 4278 8854

Fax: +44 28 4278 8841 Fax 028 4278 8841
Official distributor for Ohlins in Ireland
Suspension Suppliers Shock and Fork Rebuilds and Re-valves for road bikes and motocrossers. Can rebuild nearly every make of shock. Bit hard to find if you don't know were it is!!
 
We're Missing The Point Here???

All this talk about pre-load etc is absolutely irelevant to the original question about clearance under front tyre on the centre stand.
The Ohlins fitted to GS's have NO ride height adjustment - only pre-load, which has no effect on the centre stand :nenau .
Did you buy the Ohlins new or s/hand?. They sell them in THREE lengths for a GS (this is the length the shock would be even if it wasn't fitted to the bike and is the EFFECTIVE height sitting on the centre stand.
They do a standard length as per O.E.- standard clearance under f/wheel,
a shorter one to help short-arses reach the ground - more clearance under wheel, and a longer one for the 1150 adventure. Now I'm sure the 1100 and 1150 use the same front Ohlins, so if the one you have was for an 1150 ADVENTURE then you would lose the gap under the front wheel :confused:

I ran mine as supplied by Ohlins on my 1150 for a year, then, like many others I had to admit defeat and get Harris to rebuild the rear with a heavier spring - 160 I think, instead of 140??. Standard was ok solo, but no good with luggage, passenger or both :eek: - but it's now spot-on :bounce1

Cheers......................Grizzly :beer:
 


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