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SACHS SHOCK REBUILD
- Thread starter Denz0
- Start date
Spring rate question
Denzo
I have a 2017 GS which has the 'automatic' suspension. I've always felt that the bike could do with a bit more preload or a stiffer spring. I weigh some 95kg and also often take a pillion but she weighs next to nothing probably only 55kg and we also often have luggage on as well
Do you know if you can put a firmer spring on the back to help with this or would this just confuse the auto setting?
Denzo
I have a 2017 GS which has the 'automatic' suspension. I've always felt that the bike could do with a bit more preload or a stiffer spring. I weigh some 95kg and also often take a pillion but she weighs next to nothing probably only 55kg and we also often have luggage on as well
Do you know if you can put a firmer spring on the back to help with this or would this just confuse the auto setting?
I've just had my rear 1200GS LC rear shock refurbed by Firefox Racing in Keighley.
I figured that after 27000 miles, failure could happen at any time and potentially ruin a foreign holiday or mean that I have to buy a standard shock from BMW whilst away.
The cost was £450 for them to remove the rear shock, replace the seals and oil and make sure all is good and fit a heavier duty spring.
I did 270 miles yesterday and whilst the ride seems slightly plusher and it doesn't sag as much when I sit on it, I'm hard pressed to find a difference...which is a good thing.
I figured that after 27000 miles, failure could happen at any time and potentially ruin a foreign holiday or mean that I have to buy a standard shock from BMW whilst away.
The cost was £450 for them to remove the rear shock, replace the seals and oil and make sure all is good and fit a heavier duty spring.
I did 270 miles yesterday and whilst the ride seems slightly plusher and it doesn't sag as much when I sit on it, I'm hard pressed to find a difference...which is a good thing.
Yes I can install a custom spring to them units in any color you like. The cost of service and new spring would be about 210 for LC models.
Spring will be calculated to your weight.
Like the gentlemen above said" stronger spring gives plusher ride" yes I know it doesn't make sense, but that's how the suspension works...plus your sag is right that way you get more usable suspension travel.
One more fact about ZF/Sachs by 30K guide bush in the sealed is worn to the limit or already rubbing or the bare metal. Simple service can extend the shock lifetime drastically.
Look on the picture below 35K LC guide bush completely gone.. next 20k doesn't look much better
60K 2010 ESA RT guide bush and shaft but that was too late
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Yes I can install a custom spring to them units in any color you like. The cost of service and new spring would be about 210 for LC models.
Spring will be calculated to your weight.
Like the gentlemen above said" stronger spring gives plusher ride" yes I know it doesn't make sense, but that's how the suspension works...plus your sag is right that way you get more usable suspension travel.
One more fact about ZF/Sachs by 30K guide bush in the sealed is worn to the limit or already rubbing or the bare metal. Simple service can extend the shock lifetime drastically.
Look on the picture below 35K LC guide bush completely gone.. next 20k doesn't look much better
60K 2010 ESA RT guide bush and shaft but that was too late
Sent from my SM-G960F using Tapatalk
When replacing spring only, what is cost please, and if only rear spring is changed, is that ok, or must front and back be change to heavier load spring, thank you, sorry I cannot send pm.
If you not going mad with the rear spring front could be adjusted normally you have two extra positions for your front spring adjustment you just can't see them when spring is mounted needs to be compressed.
Spring change is not mandatory springs are calculated to your weight and needs.
measuring suspension SAG is the only way to find out if you in the range. Typically this be 33% Of your total suspension travel.
If you travel off-road and constantly bottoming out then that's another reason for the upgrade.
Normally spring alone will cost £ 75
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Spring change is not mandatory springs are calculated to your weight and needs.
measuring suspension SAG is the only way to find out if you in the range. Typically this be 33% Of your total suspension travel.
If you travel off-road and constantly bottoming out then that's another reason for the upgrade.
Normally spring alone will cost £ 75
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Thank you I am not understanding the part about 2 positions on front, do you mean I can manually change that, and my weight is 110kgs and pillion will be 80kgs so what spring you think will be needed for front and rear thank you.
Yes, there is a manual preload adjuster on the front shock but only accessible when the spring is compressed 3 position adjustment.
I would have to check that but with that kind of weight 60N/mm on the front and 175N/mm or 185N/mm rear would work here.
I guess hardest part here would be getting the shock out.
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I would have to check that but with that kind of weight 60N/mm on the front and 175N/mm or 185N/mm rear would work here.
I guess hardest part here would be getting the shock out.
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Thank you, youtube video helps good to remove.
I have some nice 
photos to share
Recently I've made couple of changes and updates to the service now most seals is made of Viton rubber O-rings as well
And scraper seal was upgraded to the PU virtually undetectable seal. SOME DRAMA FIRST and then some nice photos
Front shocks get fitted with dust seal that is missing for some reason.
All the shocks are vacuum bleeded and dyno tested then I compared them to the 3K mils shock that I've done for someone.
ESA range is also tested and can be adjusted.
Hopfully someone will find this interesting
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photos to share Recently I've made couple of changes and updates to the service now most seals is made of Viton rubber O-rings as well
And scraper seal was upgraded to the PU virtually undetectable seal. SOME DRAMA FIRST and then some nice photos
Front shocks get fitted with dust seal that is missing for some reason.
All the shocks are vacuum bleeded and dyno tested then I compared them to the 3K mils shock that I've done for someone.
ESA range is also tested and can be adjusted.
Hopfully someone will find this interesting
Sent from my SM-G960F using Tapatalk
Menshock, I believe that you have to be a subscriber to send and receive a PM, it’s only £15 per year, then you will have access to the whole site. It’s £15 very well spent imo.
Welcome to the site......
T-Tech have a Facebook page.
I have sent quite a few shocks to T-tech on behalf of my customers.
He's always done a great job.
I have sent quite a few shocks to T-tech on behalf of my customers.
He's always done a great job.
Wow, this looks interesting. I've hung on to the OM Sachs shop form my X-Country since it went loco about 2015 and I replaced it with a Wilbers unit, never had the heart to just throw it away ...
Could it be refurbished?
Could it be refurbished?
schneazle weazle
Registered user
I did exactly the same, I replaced my rear unit after it failed at 32,000, with Wilbers, it failed on the day of the first lockdown. I kept the old unit in my shed for 18 months or so, then decided to get Denz0 to perform his magic. when I put it back on my bike I could not get the electronics to work. I even took it to BMW to see if they could plug it in to the mothership, but still, it would not work. so that was £250 wasted as I asked him to upgrade the spring.
I was gutted, and still to this day do not know why it wouldn't adjust, now done close to 20,000 on my wilbers, happy with it, but it's a ball ache adjusting the pre-load castle nut, from solo to pillion with luggage. but it's what we used to do years ago, just got out of practice I suppose.
please note I am not saying this was caused by Denz0,
if I ever get a new bike the first thing I will do is send the new units down to him for upgrade.
There is no mentioning of year and model here, but generally speaking, the so called electronics in these shocks are not really containing any electronics as such.
There is a motor that adjusts the preload (unless your bike is a paralell twin) and either a small motor or solenoids controlling the damping.
If the shocks cause a fault message, something is stuck. Most likely, it is the preload motor that is causing the issue, as the preload also contains a potmeter that gives the system feedback of the chosen rideheight.
The preload, if not used on a regular basis, has a history of getting stuck. If so, when the ZFE tries to operate the preload, the stuck motor draws a heavy load in order to try to get things moving. The thing is, there is a built in resettable fuse in this circuit, and if the load is too high, it just shuts down.
The procedure is to unplug the shock and power it from an external source, and offering the unfused current is usually enough to get the preload system unstuck.
I don't have the description for this procedure right now, but someone in here surely has it, and I'll look for it my self.
schneazle weazle
Registered user
2016 gsa, like I said I took it to Williams bmw and they couldn’t sort it, I spoke at length to the engineer and he always helpful but this time could not offer any advice except to tell it would not work.
I was just replying to some else’s thread telling of what I did.
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