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Vorsprung Smashpost: Violent top-out with 50/55lb spring. Anyone else?

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NewYawka

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Discussion starter · #1 ·
Hey there. Currently running either a 50 or 55 lb spring set to 150mm on my Smashpot converted 2021 Lyrik RC2. I am fine with some extra noise that one gets with a coil, and the fork feels wonderful EXCEPT for the fact that it tops out like all get out when yanking up on the front, and sometimes even when punching through rough high speed square edge hits. If I use the low speed adjuster to eliminate top out the rebound is too slow for my taste and does not track well. I know Vorsprung mentions 60lb and heavier springs may need a different rebound stack but though i should be in the clear with the 50/55lb (FWIW the 55 lb is what I need to run, tried the 50lb to see if the lighter spring eliminated the top-out issue). I have adjusted the spring perch to get exposed threads anywhere from 7mm (which is 1mm less then called for, this I know) to 10mm to no avail.
Any insight is appreciated, thanks!
 
#2 ·
The most obvious one: is your damper working properly? I've opened one fork with similar symptoms, and the fault was a blown out damper that did not offer any rebound (or compression) damping.

How's the preload with the 7mm setup? If the spring is set in a way that just the slack has been taken out, then excessive preload should not be the culprit.
 
Discussion starter · #3 ·
Jukka4130 said:
The most obvious one: is your damper working properly? I've opened one fork with similar symptoms, and the fault was a blown out damper that did not offer any rebound (or compression) damping.

How's the preload with the 7mm setup? If the spring is set in a way that just the slack has been taken out, then excessive preload should not be the culprit.
Click to expand...
No issue with damper. All adjusters work as should, no air in bladder. No top out issues when original air spring was installed, although I know it would not be as pronounced with the neg air acting as a top-out bumper off sorts. Preload seemed fine, just enough to keep spring from moving vertically.
 
Discussion starter · #5 ·
Staktup said:
What did Steve/Vorsprung say to you?
Click to expand...
Vorsprung was very helpful when I had initial issues with my install; I installed the Smashpot on the damper side in order to save the inner stanchion walls should i decide to go back to air. Did not realize the lowers are different lengths on certain Lyrik's until Steve pointed it out (never would have thought to look...).
Once i got that sorted and got rid of a knock/spring seating issue when lightly compressing from full extension (I just flipped the spring upside down and the perch fit a bit better alleviating the knock).
I reached back out regarding the top out issue during the busy holiday season and got a reply that did not really address my inquiry so I just let it be. I purchased the smashpot second-hand and did want not to come across as pestering, nor continue to bother to try and diagnose a possible problem from a used unit over email.
 
Discussion starter · #6 ·
I do have a second rc2 damper that, i believe, has slightly stiffer rebound valving to see if that makes a difference. But, as I type this, I do not know if it will matter since the top-out is present even when not coming out of deep in the stroke.
 
Discussion starter · #8 · (Edited)
Staktup said:
Is top out bad? Will it harm any internals? If not and it's just annoying or concerning I understand, but if I knew it wasn't bad then I'd just ignore it...
Click to expand...
Ha, I would say it is pretty bad, personally: It feels like metal-on-metal; like the lowers want to blow off from the CSU. I can feel it through my hands and if the rebound LSC is set to wide-open (which I of course do not ride as such) , or close to it, the front rotor will resonate from the force. Again, I can dial in LS rebound but even set where it seems to track well (I need check how far out I am from fully closed in order to avoid top-out) there is still the very noticeable mechanical top-out sound/force.
I have ridden a number of coil sprung forks over the years and cannot recall ever having such a noticeable top-out which is why I am wondering what is going on, or if this is to just be expected.

One thing I had noticed when setting travel is that the top-most 10mm travel spacer seemed to sit a bit deep under the seal-head, almost covering some of the outer tubes threads. Not sure if this could result in something with the exposed length that is causing it to fully extend BEFORE hitting the top-out spring thus causing the metal-om-metal sensation. I would need to look at the assembly diagram again to see if that was even possible but it is something that I have wondered about.
 
Discussion starter · #10 ·
Jukka4130 said:
This might or might not be helpful.

Vorsprung Smashpot Coil Conversion
Click to expand...
Hey, thanks for the link. I have read through that thread quite a bit before picking up a smashpot. Issue sounds different to me. I do not have noise when compressing from full extension but rather very harsh top out once the fork fully extends.
 
#11 ·
I could never get rid of the top out on the one had, It was in a Lyrik and then a ZEB.

I went for as minimal preload as possible, lower than what Vorsprung recommends. It would still noticeably top out against the little negative spring. Very annoying when riding, mostly occurred when climbing or flat trail when I would lift/unweight the front wheel to get up something. Tonk..tonk..tonk.

Finally went back to an air spring with a DSD RUNT installed and life is good, and silent. ;)
 
Discussion starter · #12 · (Edited)
ARider said:
I could never get rid of the top out on the one had, It was in a Lyrik and then a ZEB.

I went for as minimal preload as possible, lower than what Vorsprung recommends. It would still noticeably top out against the little negative spring. Very annoying when riding, mostly occurred when climbing or flat trail when I would lift/unweight the front wheel to get up something. Tonk..tonk..tonk.

Finally went back to an air spring with a DSD RUNT installed and life is good, and silent. ;)
Click to expand...
Dang. Pretty much sounds like my experience thus far.
You mention the "little negative spring ( I will assume you mean the top-out spring) "; I cannot help but wonder if a stiffer/larger neg spring would help. Hard to believe that one spring rate would be sufficient to control top-out across 10 different spring rates, but I am not designing aftermarket suspension upgrades so I may be off base with that thought.
Out of curiosity, what spring rate are you using?
 
#14 ·
I dealt with this also with the Vorsprung unit I had and I don't weigh a ton or run really fast rebound (45lb spring). Their response was to point fingers at the damper, but this condition doesn't happen with ANY stock air springs at REALLY high pressures and fast rebound settings. The problem lies with their top-out mechanism not having any kind of rubber bump stop or isolator, or simply too weak of a spring, or too short of engagement. Any explanation that directs the attention to other components is plain and simple BS.

I thought the whole cartridge was kind of a joke after using it. The HBO system had a silly engagement that just locked things up regardless of the setting, and the fitment into a 38mm leg was crazy tight and just bound everything up in the mid stroke. So it didn't handle top-out well, didn't handle bottom-out well and didn't handle the mid-stroke well. I didn't run it for very long.
 
#15 ·
GH28 said:
I dealt with this also with the Vorsprung unit I had and I don't weigh a ton or run really fast rebound (45lb spring). Their response was to point fingers at the damper, but this condition doesn't happen with ANY stock air springs at REALLY high pressures and fast rebound settings. The problem lies with their top-out mechanism not having any kind of rubber bump stop or isolator, or simply too weak of a spring, or too short of engagement. Any explanation that directs the attention to other components is plain and simple BS.

I thought the whole cartridge was kind of a joke after using it. The HBO system had a silly engagement that just locked things up regardless of the setting, and the fitment into a 38mm leg was crazy tight and just bound everything up in the mid stroke. So it didn't handle top-out well, didn't handle bottom-out well and didn't handle the mid-stroke well. I didn't run it for very long.
Click to expand...
The majority of the experiences I've heard are quite the opposite. I would go as far as saying that the Smashpot is a splendid product. The top-out problem is weird though, and not common.

When talking about fit, did you mean the interface between the PVC sleeve and the inner surface of the stanchion? If yes, that's been remedied with the new spring isolator.
 
#16 ·
Jukka4130 said:
The majority of the experiences I've heard are quite the opposite. I would go as far as saying that the Smashpot is a splendid product. The top-out problem is weird though, and not common.

When talking about fit, did you mean the interface between the PVC sleeve and the inner surface of the stanchion? If yes, that's been remedied with the new spring isolator.
Click to expand...
Yes, the PVC sleeve interface. Unaware of any updates as this was a couple years ago. That seems like the most simple of the 3 issues to fix since it's just clearance.

The bottom-out system issues are common and well-documented on here with people chasing a solution to it and not really getting anywhere, and so is the top-out issue (like this thread). It's to the point where I bet if anyone with a Smashpot, regardless of springrate, backed off their rebound damper a ways, they could replicate the issue and put it into an aggravated state.
 
#18 ·
NewYawka said:
Vorsprung was very helpful when I had initial issues with my install; I installed the Smashpot on the damper side in order to save the inner stanchion walls should i decide to go back to air. Did not realize the lowers are different lengths on certain Lyrik's until Steve pointed it out (never would have thought to look...).
Once i got that sorted and got rid of a knock/spring seating issue when lightly compressing from full extension (I just flipped the spring upside down and the perch fit a bit better alleviating the knock).
I reached back out regarding the top out issue during the busy holiday season and got a reply that did not really address my inquiry so I just let it be. I purchased the smashpot second-hand and did want not to come across as pestering, nor continue to bother to try and diagnose a possible problem from a used unit over email.
Click to expand...
This is interesting... seeing as you are able to install the coil into the damper side and move the damper to the air spring side, if you had want to go back having run the coil spring in the air spring side could you have just installed the air spring to the damper side if it had messed up the inner stanchion walls? Just curious since this is a concern of mine if I do not get along with the coil spring. I have a Push coil/damper on the way.
 
Discussion starter · #19 ·
EliminatorMTB said:
This is interesting... seeing as you are able to install the coil into the damper side and move the damper to the air spring side, if you had want to go back having run the coil spring in the air spring side could you have just installed the air spring to the damper side if it had messed up the inner stanchion walls? Just curious since this is a concern of mine if I do not get along with the coil spring. I have a Push coil/damper on the way.
Click to expand...
You cannot run the air air spring on the damper side as the stanchion does not have the "dimple" on the inner wall that allow air to transfer into the negative air spring chamber.

I actually just ordered the PUSH coil as well. Curious as to how that coil setup behaves compared to the smashpot.

It is so odd to me that some folks have top out problems, some not at all. I also read that looong thread where numerous folks were having difficulty getting full travel and/or finding an effective range for the HBO. I myself have had no problem getting full travel on either spring rate and do find the HBO effective. Wonder what the variable at play is.
 
#20 ·
NewYawka said:
You cannot run the air air spring on the damper side as the stanchion does not have the "dimple" on the inner wall that allow air to transfer into the negative air spring chamber.

I actually just ordered the PUSH coil as well. Curious as to how that coil setup behaves compared to the smashpot.

It is so odd to me that some folks have top out problems, some not at all. I also read that looong thread where numerous folks were having difficulty getting full travel and/or finding an effective range for the HBO. I myself have had no problem getting full travel on either spring rate and do find the HBO effective. Wonder what the variable at play is.
Click to expand...
Thanks for the info. Interesting to see you're switching to PUSH and what you think, your thread is the first negative thing I've read about the coil conversions which made me second guess my purchase and wanting to be able to reverse it if needed. I was actually leaning towards Vorsprung for the HBO but went with PUSH since it was on sale along with damper, it gets her Saturday and due to rain probably won't be able to give it a decent run for a couple of weeks.
 
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EliminatorMTB
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