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Beta Xtrainer stock shock rebuild R16V OLLE - valving update

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I started the process of rebuilding the Xtrainer shock. 

I've been doing DIY suspension service for years, started on road bikes in 2000'.  I'm an average rider and an average mechanic and not an experienced suspension tuner.  

I highly recommend the Racetech Motorcycle Suspension bible if you've never rebuilt suspension before.  It has a great illustration section for how to disassemble / assemble standard forks and shocks.  I picked this up on a whim and enjoy the book. 

The Olle / R116 shock seems more similar to a KTM type non-pds shock as it uses a piston (not a bladder) in the reservoir, but there is no bleed screw in the top of the shock. 

Disassembly Process: Standard.  It disassembled like a normal shock.  If you need step-by-step with glossy pictures this is detailed in the Racetech book for a standard shock (pp 200 +).  Remove spring, depressurize reservoir, remove dust cap from bottom of shock body, push seal piston down into shock body, remove circlip, remove shock shaft, seal piston, etc as a unit.  The reservoir piston isn't threaded, not sure of the best way to remove it (if I wanted to).  For assembly  I'm going to push it all the way down and assemble the shock per racetech standard instructions.  (fill with 50 psi, assemble shock shaft into body, depressurize as pushing shock seal down).  

Once the shaft / valving is out you can re-shim if desired.  The shock uses standard 12MM ID shims and a traditional valving setup.  For shims:  https://mx-tech.com/shop/valving-shims/12-mm-id/

Assembly is the reverse, ensuring that air is bled from the shock is a critical part of the assembly process.  I'm not there yet. 

Outside of being a little thinner diameter body than a traditional shock, the unit looks to be reasonably built and capable of tuning / adjustment.  It is using single stage stacks. 

The valve itself is Aluminum (edited).  It looks to have relatively restrictive porting compared to other design's I've seen.  

The shock fluid is relatively thick compared to other fluids I've used in shocks.  I ordered redline 5wt for this and it is thinner than what is in there.  My guess is 7wt.  

If anyone wants to, please provide feedback for potential mods while I have this apart. I'm going to stew on it a little, no rush to get it put together (it's snowing). 

I'm 205lbs with gear, have a 5.6 spring in the back. 

My Feedback on the stock shock:  For my skill and riding level not bad, I ride tight rocky single track, ATV trails and connecting roads.  It has enough rebound dampening stock for the uprated spring and enough compression dampening.  If anything it feels sluggish.  Rebuilding the forks on this bike is mandatory, but the shock I'm doing more for fun and to see if I can make it better, it was adequate for trail / light enduro work (for me)... now that said I've never ridden a fox shock on the bike so maybe I have no Idea what good is ???   

My current thoughts for modifications:  

-Thinner Fluid: I plan on using Redline 5wt fluid, as I saw another rider swapped to this fluid and had success

- drilling out the valve for more flow:  This combined with lighter fluid should help higher speed harshness

- Uprating the shim stack:  Not sure here what I want to do, comments welcome.  Not sure I want to do too much at once.  

Shim Stacks: 

Stock Compression Stack
12MM ID
34 x .15
32 x .15
30 x .30
28 x .20
26 x .30
24 x .30
22 x .30
22 x .30
20 x .30
22 x 1.0 clamp
 

Stock Rebound Stack
12MM ID
34 x .15
32 x .15
30 x .30
28 x .20
28 x .30
26 x .20
26 x .30
24 x .30
24 x .30
22 x .30
22 x .30
20 x .30
22 x 1.0 clamp
 

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5a74c7e0954f6_IMG_20180202_150950720(Large).jpg.760757745f3d40e71f43cd3d1c2ab63b.jpg

 

Edited by bikesandcars
sticky shims, updated pic and stack
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bikesandcars...

Your suspension posts are good stuff! Thanks for taking the time to put together a narrative on this shock work.   I recently bought a second, like-new Xtrainer shock to play around with - so I'll wait to see what your results are with the lighter oil as a base before I start to play with the shims.  I think you're on the right track with that -

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Messing around with ReStackor, this is what it shows for stock.  I'm not really good on this software yet, let me know if I messed it up. 

I tried to model the stock valve / geometry the best I could, I sat at my PC with my calipers and put the data in.  

compression stock on ReStackor.jpg

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This quote attributed to Yogi Berra certainly seems hold true for suspension tuning: "In theory, there's no difference between theory and practice. In practice, there is."

So, in theory, you could just box up your suspension and send it to the tuner of choice, telling him what you weigh all geared up, what your approximate skill level is (aren't we all experts?), what sort of riding you do, and get your parts back and enjoy riding nirvana. In practice, it's going to take a few (or more) iterations to get it right, but how many of us are going to send our parts back for follow-up tuning (it's expensive and time consuming)? 

The aura of mystery surrounding suspension tuning keeps most of us from even thinking about trying it ourselves. Your posts have given me hope. I just spend an hour on ReStackor's web site and my head feels like it is exploding from all the physics. But the bottom line is that they have (mostly) verified their model against dyno data. Very impressive. And with an appropriate investment in learning to use it, it promises to make the tuning process into a straight forward engineering protocol. I can do that!

Thank you for making your adventure public. I'll be following every step, and maybe emulating your process when the time comes.

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1 hour ago, Old Plonker said:

This quote attributed to Yogi Berra certainly seems hold true for suspension tuning: "In theory, there's no difference between theory and practice. In practice, there is."

So, in theory, you could just box up your suspension and send it to the tuner of choice, telling him what you weigh all geared up, what your approximate skill level is (aren't we all experts?), what sort of riding you do, and get your parts back and enjoy riding nirvana. In practice, it's going to take a few (or more) iterations to get it right, but how many of us are going to send our parts back for follow-up tuning (it's expensive and time consuming)? 

The aura of mystery surrounding suspension tuning keeps most of us from even thinking about trying it ourselves. Your posts have given me hope. I just spend an hour on ReStackor's web site and my head feels like it is exploding from all the physics. But the bottom line is that they have (mostly) verified their model against dyno data. Very impressive. And with an appropriate investment in learning to use it, it promises to make the tuning process into a straight forward engineering protocol. I can do that!

Thank you for making your adventure public. I'll be following every step, and maybe emulating your process when the time comes.

Nice quote :).  In practice, a good tuner that can also ride the setup has a HUGE advantage over a hobbyist like me, but what I have on my side is time and ambition.  My local Beta dealer where I got the bike is actually a great tuner and I wouldn't hesitate to use him again, he had previously improved my Xtrainer quite a bit with springs, a custom fork damper valve and re-shim.  I'd be happy to send him my K9 kit and shock and ask him to do more.  But, I have an affliction.... I like to tinker and I like to learn, and it sends me down all kinds of boondoggles like this.  

I think the value of restackor for a person like me is that I can test different shim combinations against each other... I can't validate it's a good absolute simulation...i.e. I don't have my stuff on a dyno and I doubt my measurements are down to the .01mm of accuracy (garbage in garbage out).  The value is I can change viscosity of fluid, enlarge valve ports, change stacks, etc and at least have an idea of how it will respond.  I just think it's fun as a side-hobby to riding.  

There is a huge lack of information on the xtrainer suspension given how many have been sold, there is more out there about swapping KYB-SSS or other suspension parts into an xtrainer... in all my searching I only found one facebook thread on actual revalves for the front forks (back to 2015) and nothing on the shock.  I think the sharing of information is good for us enthusiasts and the hobby and the brand.  

 

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I don't know if you remember this, but moto9 posted this thread back in 2015. My first look at the shim stack of the XT:

 

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I don't know if you remember this, but moto9 posted this thread back in 2015. My first look at the shim stack of the XT:
 
That's a great post, once again good info is thin, or at least diluted in the 400+ posts. I'll run that 2 x 34x.15 stack for comparison

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More information, this time for the base valve on the shock:  

 

stock base valve stack top to bottom.  8MM ID besides check plate.  Note this is the same valve as in the forks, but the check plate is a totally different design.  

Note the needle, got a little buggered on the tip. 

I'm not sure what (if anything) to do to this valve, any comments welcome.  

nut

13 x .30

13 x .30

16 x .30

16 x .30

19 x .30

13 x 1.71 (preload shim in valve)

27 mm valve

18 ID x 27 OD check plate

spring

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I used ReStackor and played around with different stacks.  

I have made more digressive compression and rebound stacks and ordered the shims, I'll let you know how it works out. 

Compared to stock I ordered thicker large shims and thinner small shims, the overall stack height / number is similar.  Staying with the Redline 5wt fluid, though thicker fluid would help the digressive nature and the excessive bleed of the shock so I may try that too.  I feel the main issue with these is the lack of "plushness", which to me means it needs stiffer slow speed compression and softer high speed... i.e. a digressive stack.  Just adding thicker big shims moves the entire stack up.  

If it works I'll post my results and the restackor print-outs.  I hesitate to post anything until I know what will happen.  

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I got the shock back together.  

Strangest thing happened, the piston was seized at the bottom of the reservoir, it wouldn't move and I couldn't get the shock together.  I used a Tusk motorcycle bearing puller to extract it and after cleaning it moved free again, allowing assembly.  There is in general a lot of stiction with it.  It's a strange size reservoir: 41.5 mm, so I didn't see any bladders or SKF pistons available for it.   

After getting that straight it went together well, and it bled really well after removing the reservoir piston, I recommend doing that as part of the procedure.

I stiffened up the stacks and shuffled sizes to get a little more digression on the mid-valve.  After debating on fluid I finally decided to go to 3wt, which may counter-act my theory of stiffening up low speed and lowering high speed compression, but I've always liked the other benefits of a thinner oil.  

 

IMG_20180218_152328008 (Large).jpg

Edited by bikesandcars
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Nice work, good to see guys doing and discussing this. I'm working with Restackor on an RR Sachs shock/Gold Valve setup.

 

I've had a piston stick slightly in a Sachs shock. Also leaked a little as the anodizing on the wall was slightly damaged. I don't know if the res dia is the same as the shock body on that shock, but on the Sachs to remove the piston I use the res cap in the body temporarily with compressed air. Just holding it by hand is enough and a rag over the res to catch the piston.

 

With this shock I went with a bladder, but found nitrogen bleed through the rubber into the oil on following services. Now I'm back on the piston with a new shock body/reservoir. Working on a way to unthread the shock body from the casting so I can have it hardcoated.

 

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This shock could benefit from hard coating for sure, but the general consensus seems to be it sucks so bad it's not worth it.

Right now fox shocks are unavailable, tfx or ohlins are $1000 to $1200.

Other shocks can be adapted to fit, but that's the cost of the used shock plus revalving and respringing.

So, in the end I don't mind fiddling with it, I may upgrade in the future.

If I got this shock working well I wouldn't be opposed to dlc / hard anodizing it to make it last and work better

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Got everything back together. Initial impressions are the rebound is much more responsive and the bike feels very plush.

 

I really notice the combo of lots of bleed (due to design) and the lighter oil when it comes to low speed compression and adjusting compression..it is very soft on low speed comp even with more base and mid valving. This shock feels like it could really benefit from a check valve on the shaft. When I set rebound how I want the base valve adjuster doesn't have much impact and the low speed compression is soft. Thicker fluid should help this, that may be next.

 

So far the changes are what I was looking for except for the soft low speed comp...need to think about that....but first things first the weather is clearing and I'm riding this week.

 

 

 

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First ride report:  I've spent some time off the bike since last fall and I'm a low-C rider, so take this with a grain of salt:   I really like the improvements so far.  The shock is much more plush.  I need the bike to be controllable but also soak up trail junk.  Stock the bike was soft AND harsh.  After re-springing it was much better.  It is now another level better.  

I rode a mix of rocky northeast PA single track at a low C pace.  Wet rocky "streams", trails, dual track, haul roads.  The ride was much smoother.  the rear end hooked up well and combined with the BPS-K9 kit the xtrainer was definitely smoother and more comfortable and more fun.  I run a SOFT setup, I am not racing and I want control and comfort.  

The low speed compression adjuster is not very effective with this setup.  It seems to give it the rebound speed I want it's not pushing enough fluid through the low speed stack to make that needle / valve very effective.  That said, with the rebound in the range I want the compression felt pretty good, soft but controllable.  The ratio seemed OK to me.

I tried some different settings in the field, adding more rebound clickers to slow it down was worse, so my initial settings and valving seems to be in the right direction. 

My notes were HORRIBLE on the shock rebuild, I lost my restackor file / settings (over-wrote by mistake) and I was trying to get done, but here's the best I had from the notes I was able to take: 

Sag set at 3.5" (90mm) without riding gear, which puts me in the 95 to 100 mm range depending on load-out.  

Oil:  Maxima 3wt shock oil

Reservoir pressure: 150 psi

compression midvalve updated

1    34    0.3
2    34    0.3
3    32    0.3
4    30    0.2 (error above, the 30 x .2 is stock, it is not 30 x .3 stock)
5    28    0.15
6    26    0.2
7    24    0.2
8    22    0.2
9    22    0.2
10    20    0.3
11    22    1

rebound midvalve updated

1    34    0.3
2    32    0.3
3    30    0.3
4    28    0.25
5    26    0.3
6    24    0.3
7    22    0.3
8    20    0.3
9    22    1
 

Base compression updated

preload    13    1.71
1    19    0.3
2    18    0.3
3    16    0.3
4    16    0.3
5    13    0.3
6    13    0.3

 

Edited by bikesandcars
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Good job.  With Restackor, did you model the comp adjuster as well and run it as a system, calculating shaft velocity from bump sizes?  I would really like to do this with my Sachs/GV setup, to see just how the pressure balance is.  I see you removed the preload shim under the face in the comp adj (base) valve.  If its like a Sachs or KYB, the valve is undercut so doing this you are increasing preload on the stack.  I imagine you know this and was your intent, why I'm curious.  With the Sachs, which has an adjuster that preloads the 14mm shim in the stack, I added .1mm to reduce preload as the adjuster is mostly unusable past a few clicks in from full soft.  It helped, and I'd like to try even lighter settings, but you can run into cavitation issues if the balance is off.

I had Restackor pro for years and got a replacement key from them after a crash and rebuild of a new PC, but it only works with std features, sucks.  Not happy about spending another $83 for something I paid for already.  I w

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Great feedback GP, unfortunately I got LAZY (and/or short of time) for running restackor simulations.  In my spare time I want to model the entire shock using the midvalve program, but I didn't get there yet.  I ended up modeling each stack independently, coming up with an optimum stack based on the stock curves and what I wanted.  Then I ordered shims.  Then I lost my entire notes.... then winged it together.... I know, not very scientific. 

I didn't remove the compression adjuster shim It measured 1.71), good catch. 

From what I understand adding preload is a great way to add digression (stiffen low speed and maintain high speed).  The OLLE shock only has low speed compression adjustment (external), though it would be easy to add / subtract shims in place of that standard preload washer.  

I still have the opinion that it could benefit from a shock check valve (similar to what race tech sells for other shocks).  I have thought about that mod but it seems time/cost intensive because of the OLLE design of the bleed circuit / needle.... the shock shaft has a threaded insert for bleed so that would have to be modified, in addition to finding a 12mm x 1.0 pitch check valve nut.  

Edited by bikesandcars
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You can model that, or get a feel for it anyway by changing the bleed factor.  If you go that route it likely means substantial valving changes.  The Sachs seems to work well with the crosstalk,  actually works best IMO with a stiffer rebound stack and the reb adj run farther out.  Some older original GG Sachs had RSVs stock, but it was done away with in following years.

BTW where are you in PA?  I ride the ECEA harescrambles and also do some riding with my buddy near Jim Thorpe.

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Second ride in, compared back to back with my 2006 KTM 200 xc-w (PDS shock). The xtrainer is on par or better, I'm really happy with the traction and performance on single track and connecting rocky trails.

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Good work.  So it looks like a significantly stiffer compression stack is keeping it up in the stroke and making it feel better.  Did you run the new stack using stock as a baseline? 

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