How to tune your ShermanS / Patton / Lynx suspension 101

[onkeldanuel]

5 minutes ago, Rawnei said:

Dunno what to tell you guys, I've adjusted at least 6 different LeaperKim wheels and they all behaved the same, left (counterclockwise) gave less rebound (rebound will not spring back as fast) and right (clockwise) gave more rebound (rebound will spring back faster) on every single one of them, same thing with compression dampening.

Mine has the same markings as pictured above yet the results that I wrote.

Seems ridicoulus odd,  since clockwise should always add damping, both compression or rebound and so are the markings (clockwise -->S = slower rebound-->add dampening to rebound circuit) 

Im pretty sure it was also correct like that on my sherman S same as on every for example mtb-shock like on S22 or Extreme im aware of...

Edited December 14, 2023 by onkeldanuel

[Rawnei]

It's super strange, I just had to test and confirm the behaviour just now and you guys are right, turning it clockwise gives less rebound and counterclockwise more, it's very confusing almost feels like I've gaslighted myself. 😂 I can't explain it.

I will update the original post.

[Planemo]

So what about the other 5 wheels you mentioned?!

[RagingGrandpa]

Hehe give him a break, the message was still good... There are a lot of changes possible, and the change in extension damping ("rebound") is subtle. 

I liked the advice of 'start with it at minimum (fully unscrewed CCW) and notice how bouncy the ride feels, then tighten it until it stops being too bouncy.'

Even on a smooth surface, I can feel the difference while riding at "minimum rebound damping" (very easy to get undulating continuous bouncing), and "a nice amount" (bounces die down quickly). It's good. 
 

Edited December 15, 2023 by RagingGrandpa

[RagingGrandpa]

On 12/3/2023 at 10:29 PM, RagingGrandpa said:

Another datapoint:

Today we measured sag for a 215 rider on Lynx with the 70lb spring. 
Static sag was 32mm or 1.25".

It agrees with the table data above: about 40% sag for the 215lb man.

So, we cranked in another 0.4" of preload and enjoyed slamming it around  

 

Edited December 31, 2023 by RagingGrandpa

[stizl]

Another data point:  I went to set the sag on my Lynx today.  I am 180lbs geared and have the 66lb springs.  With zero added preload (preload adjusters all of the way out), I was at 24% sag...in other words, this is the minimum sag I can get.  I read this result as indication that I would have been better off with the 62lb springs, as I would then would likely have been able to get about 30% sag without adding preload.  I also have tried getting the Lynx to bottom out both by jumping in place as hard as I can on it and dropping off 2ft drops to flat, both with the compression damping set to full soft (full counterclockwise).  So far, I have yet to use the last 16mm of travel. On the 66lb Patton with 0 clicks of compression damping, I can bottom it out just by bouncing in place.  The Lynx suspension is much stiffer. 

Perhaps the Lynx has more "permanent preload" (as named in the above table) then the SS or Patton.  Regardless, I am completely satisfied with the Lynx so far.  

Edited January 1 by stizl

[onkeldanuel]

2 hours ago, stizl said:

Another data point:  I went to set the sag on my Lynx today.  I am 180lbs geared and have the 66lb springs.  With zero added preload (preload adjusters all of the way out), I was at 24% sag...in other words, this is the minimum sag I can get.  I read this result as indication that I would have been better off with the 62lb springs, as I would then would likely have been able to get about 30% sag without adding preload.  I also have tried getting the Lynx to bottom out both by jumping in place as hard as I can on it and dropping off 2ft drops to flat, both with the compression damping set to full soft (full counterclockwise).  So far, I have yet to use the last 16mm of travel. On the 66lb Patton with 0 clicks of compression damping, I can bottom it out just by bouncing in place.  The Lynx suspension is much stiffer. 

Perhaps the Lynx has more "permanent preload" (as named in the above table) then the SS or Patton.  Regardless, I am completely satisfied with the Lynx so far.  

Nice important Sag-Data , thx, this helps very very much...facts instead of the usual Feelings

i think you are on the edge weight-wise...like i am too...Im 185 lbs geared and ordered the 66lb too...

So for our usecase 30% sag is the very very max one should aim for imo....perfect for streetriders tho....

In the Mtb World where all this numbers are coming from of course there also is the max 30% recommendation..but depends strongly on usecase..(light trails)

There it can vary from 25-30% recommendations, but they have 2 Wheels with 2 dampening mechanisms...in general a little less sag should be preferred for us...imo!

My target would be about 27% sag for mixed riding, but mostly trails and jumping around too...

In general you should be able to use your shock stroke fully on your hardest rides , thats also part of the truth...

Also its good to not need to use any preload and also no compression dampening 

Now if it should be a little little bit softer one can change the stock oil in the dampers to a lighter one (stock was 5wt on the SS/patton and should be same on Lynx...), so you could use 2,5wt fork oil (motul) , (also can experiment with a little less amount of oil (SS was 150ml per shock for example))

Lower viscosity Fork oil should increase your sag by about 2-3% i would say...

 

The Lynx has progressive spring-ends as far as i know and can imagine thats that exactly last 20mm of the stroke/travel

Edited January 1 by onkeldanuel

[stizl]

7 hours ago, onkeldanuel said:

In the Mtb World where all this numbers are coming from of course there also is the max 30% recommendation..but depends strongly on usecase..(light trails)

There it can vary from 25-30% recommendations, but they have 2 Wheels with 2 dampening mechanisms...in general a little less sag should be preferred for us...imo!

... Now if it should be a little little bit softer one can change the stock oil in the dampers to a lighter one (stock was 5wt on the SS/patton and should be same on Lynx...), so you could use 2,5wt fork oil (motul) , (also can experiment with a little less amount of oil (SS was 150ml per shock for example))

... Lower viscosity Fork oil should increase your sag by about 2-3% i would say...

 

Agreed, I was aiming for 25% sag as a starting point.  I ride mostly rooty trails.  I am happy with it as is, but being able to adjust from 20-30% would be better than my current range of maybe 15% to ~25%

Good idea about the fork oil weight change to adjust the damping range.  Nobody I know runs these LK wheels with high levels of compression damping, as it just kills the small bump compliance that makes these suspensions so great, especially on the rocky and rooty trails where I live. I run my Lynx at 0 clicks so far and my Patton at 2 clicks.

I don't see how the oil weight would meaningfully affect the sag though.  If you overfilled the oil then you could get less air volume inside the tubes and a bit of air spring effect, but that is probably a bad idea. 

Edited January 1 by stizl

[onkeldanuel]

4 hours ago, stizl said:

Agreed, I was aiming for 25% sag as a starting point.  I ride mostly rooty trails.  I am happy with it as is, but being able to adjust from 20-30% would be better than my current range of maybe 15% to ~25%

Good idea about the fork oil weight change to adjust the damping range.  Nobody I know runs these LK wheels with high levels of compression damping, as it just kills the small bump compliance that makes these suspensions so great, especially on the rocky and rooty trails where I live. I run my Lynx at 0 clicks so far and my Patton at 2 clicks.

I don't see how the oil weight would meaningfully affect the sag though.  If you overfilled the oil then you could get less air volume inside the tubes and a bit of air spring effect, but that is probably a bad idea. 

https://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid

If interested here is an informative link for the shock oils...

You may be right regarding this might not change sag, i dont know for sure, but it could benefit the whole dampening characteristiks , especially also for a little to light rider for the spring...and or lowcompression-characteristics, small bump compliance

I know that 5w oil is used in the ss shock and most likely so in the Lynx...

But the 5w Nr doesnt tell much as you can see in the table from my link (and unfortanatly LK nor Fastace are able to tell the important nrs for recommendation regarding the oil)

The more relevant Nr would be the viscosity Index at 40° temperature and there are huge differences at the different oils.

I want to try a 2,5w oil , most likely silkolene or red line from the table, along with this seals (already mounted them to the ss and they work really great and smoother then the stock ones...

https://www.maciag-offroad.de/skf-gabeldichtsatz-showa-37-mm-honda-cr-85-crf-150-r-suzuki-rm-85-sid54746.html

Edited January 1 by onkeldanuel

[onkeldanuel]

On 1/1/2024 at 3:29 PM, stizl said:

I don't see how the oil weight would meaningfully affect the sag though.  If you overfilled the oil then you could get less air volume inside the tubes and a bit of air spring effect, but that is probably a bad 

If you fill in lets say 10% less oil your springrate gets softer in essence (at least the progression ramp up)...then there is more air in the chamber which can be compressed, where the oil cant get compressed..

Edited January 6 by onkeldanuel

[onkeldanuel]

Also i want to ask: how your rebound behaves with your weight and the 66lb springs? Is it rather fast (to fast) when dialed to fully open setting (no additional rebound dampening applied)

Because the LK Wheels have the rebound in one leg and the compression in the other you can use different cst oils for each leg , i.e lower cst in the compression side to make it softer and higher Cst in the rebound side to make rebound slower 

Fastace uses 17 CST oil stock  in there Forks...as far as i found out 

In my mind this makes highly sense to tune/finetune in general and  especially if youre on the edge weightwise between two springrates...(66lb for 180lb rider could give a little to harsh comp and little to fast rebound i would guess....)

They are bound to one wheel and act together so there is no downside to doing so...imo

I would love to try 12cst oil in the comp leg and 22cst in the rebound leg for example...or even lower in comp as i have an 7cst fork oil here...(basically like water)

Edited January 6 by onkeldanuel

[daniel1234]

I have 190 lb / 87kg and there is just 70 lb variant available. I would go with 66 lb if I could .

I hope spare suspension slider will rarely be available. I will probably need to eat more and exercise ...

 

[Cyberwolf]

I just rebuilt my Patton suspension, swapping the original 66lb springs out (after ~3500mi) and replacing them with 70lb Progressive springs.

The process to swap springs was super easy, and just required a couple extra steps beyond what was required to change the seals and oil.

Haven't had a chance to ride it yet, but felt a bit stiffer during initial adjustments, and a single full-turn back from full-preload put me just a hair over 30% sag (at ~215lbs without gear, currently).  Wasn't able to bottom-out during a quick initial "jumping in place" test (no dampening), but I'll have to get some miles in and see how it behaves...

One thing that suprised me was how ugly the original oil had become - it looked like metallic syrup. 

Replaced that with Red Line 5wt (16 CSt; VI:560), and new SKF seals; figure that alone should make a big difference, even before considering the heavier (and progressive) springs...

Edited March 19 by Cyberwolf

[stizl]

19 hours ago, Cyberwolf said:

I just rebuilt my Patton suspension, swapping the original 66lb springs out (after ~3500mi) and replacing them with 70lb Progressive springs.

The process to swap springs was super easy, and just required a couple extra steps beyond what was required to change the seals and oil.

Haven't had a chance to ride it yet, but felt a bit stiffer during initial adjustments, and a single full-turn back from full-preload put me just a hair over 30% sag (at ~215lbs without gear, currently).  Wasn't able to bottom-out during a quick initial "jumping in place" test (no dampening), but I'll have to get some miles in and see how it behaves...

One thing that suprised me was how ugly the original oil had become - it looked like metallic syrup. 

Replaced that with Red Line 5wt (16 CSt; VI:560), and new SKF seals; figure that alone should make a big difference, even before considering the heavier (and progressive) springs...

Nice!  I think you’ll be happy with the results. I did the same on my Patton…66lbs to 70lb progressive, SKF seals, and 5W oil. The 70lb “progressive” springs (they’re technically dual-rate springs) are actually less stiff than the 66lb springs in the upper 60% of travel. I had to use less preload than with the 66lb springs to achieve the same sag, and they’re actually slightly more plush than the 66lb in the upper part of the suspension stroke  

Once past 60% (iirc) of travel, the second, stiffer rate portion of the spring takes over. I’ve never noticed the transition point, but it being there makes a huge difference. I could bottom out the 66lb springs by jumping in place on flat ground, but I’ve never felt the 70lb bottom out, even off 2ft+ drops to flat. 

The 5W oil also makes a meaningful difference in bringing the compression damping adjuster into a more useful range. I now prefer 5-ish clicks from full open instead of 0-2 with the stock 10W oil. On the rebound leg (only), I ended up going back to 10W oil, as the 5W felt so light that the full range of the adjuster screw felt nearly the same to me, but the 10W felt more tunable. 

[UniVehje]

I just tested my new 62 lbs Lynx. With 0 preload and 74 kg riding weight I get barely 22 mm of sag. Just about enough but I think I should have gone with 58 lbs version. Dampening at softest setting still feels a bit hars or “sporty.” If I don’t do drops, jumps or stairs and want a plush ride, I maybe should change to 58 lbs? My tuned up S22 felt better than this. 
I left rebound and almost fastest and will tune it on the next ride. 

[Rawnei]

2 hours ago, UniVehje said:

I just tested my new 62 lbs Lynx. With 0 preload and 74 kg riding weight I get barely 22 mm of sag. Just about enough but I think I should have gone with 58 lbs version. Dampening at softest setting still feels a bit hars or “sporty.” If I don’t do drops, jumps or stairs and want a plush ride, I maybe should change to 58 lbs? My tuned up S22 felt better than this. 
I left rebound and almost fastest and will tune it on the next ride. 

Tuning rebound can make a big difference in how it feels so try tuning that as well and ride it in a bit and you can make a more informed decision.

[UniVehje]

1 hour ago, Rawnei said:

Tuning rebound can make a big difference in how it feels so try tuning that as well and ride it in a bit and you can make a more informed decision.

I did go for another good ride and tuned it a bit and it made it better. Now it’s a really good sporty ride. I like this feeling also. I will just enjoy this feel and maybe do the seal upgrade you mentioned. I’d like a bit more small bump compliance. 

[Rawnei]

1 hour ago, UniVehje said:

I did go for another good ride and tuned it a bit and it made it better. Now it’s a really good sporty ride. I like this feeling also. I will just enjoy this feel and maybe do the seal upgrade you mentioned. I’d like a bit more small bump compliance. 

Yeah SKF seals help a lot with that since it removes stiction, smoothens out small bumps.

[hikky]

Hello all, I have made a quick chart FOR REFERENCE PURPOSE ONLY. 

1. Find your Spring lb/in (62, 66 or 70)

2. "Riderlbs": Find the total weight that will be on the Lynx (your body + gear)

3. "max lbs": See how many lines should be visible to be at "theoretical 20%" sag. 

4. "#lines visible": How many lines should be visible for given Rider (lbs) to be at 20% sag. 

 

62lbs/in

Rider(lbs) | max lbs | #lines visible

88.0      131       7

98.0      141       6

108.0     151       5

118.0     161       4

128.0     171       3

138.0     181       2

148.0     191       1

158.0     201       0

 

66lbs/in

94.0      140       7

104.5     151       6

115.0     161       5

125.5     172       4

136.0     182       3

146.5     193       2

157.0     203       1

167.5     214       0

 

70lbs/in

99.5      149       7

111.0     160       6

122.5     172       5

134.0     183       4

145.0     195       3

157.0     206       2

168.5     218       1

180.0     229       0

Brief notes:

For a 62lbs/in spring, if the suspension pre-load is set to 20% sag at baseline, you can carry an additional 43.4lbs of cargo in your backpack and still be at 30% sag.

For 66lbs/in spring, you can carry an additional 46.2lb

For 70lbs/in, 49lbs. 

I decided to have this value so that a rider can keep in mind where they are on the travel to adjust riding style based on how much additional cargo you are carrying. If more weight is carried than the above value, then you should keep in mind that you have exceeded 30% sag and thus will risk bottoming out more than what you might expect. 

 

 

How to get this chart yourself: 

1. find "20%" and "30%" travel = 90mm x 0.2 and 90mm x 0.3. This gets you 18mm and 27mm.

2. convert this to inches: 20% sag = 0.71in, 30% sag =1.06in. 

3. Find how much sag you will be at with your weight: [your weight] ÷ ([spring lbs/in] x 2springs). For example, I am 150lbs with 62lb/in spring: 150÷(62 x 2) = 1.21in. 1.21" is how much I will sag with a 62lb/in. 

4. How much do you need to go up in order to be at 20% sag (i.e. 0.71in): [value from #3 above] - 0.5". For my example: 1.21" -0.71" = 0.5" I need to go up 0.5" (or aka "not-go-down" 0.5")

5. Convert 0.5" into metric: *note, I convert this back to metric because "1 line" on the pre-load indicator lines on the Lynx is 2mm apart, so having a metric value is helpful.: [in] x 25.4. For my example 0.5in x 25.4mm/in = 12.7mm. 

6. convert metric to "lines": [metric distance] / 2. For my example 12.7mm/2 = 6.35 lines. 

This means that I need to go down 6.35 lines from the factory setting of 7. Therefore, I should only be able to see1 line, and then some. 

What this really tells me is that I was really close to getting a Lynx that was NOT suited for my weight. I was almost maxed out. 

After making this chart, it became apparent that I would have been fine with 70lbs/in. 

Again, all this is just theoretical ballpark for your own reference only. fine tune based on your own riding style and typical load that is carried.