Trek rail rear shock upgrade ideas please

[Slapbassmunky]

Interested in selling one of theses yoke?

No, sorry, that was a one hit wonder. It was done between tooling changes for a much bigger job.

 

[Hob Nob]

Just a thought with these home made yokes to make shorter shocks fit - are you not effectively changing the start / end point of the travel for the bike?

The kinematics of the suspension (pivot placements, size of rocker create the curve of progression as the shock cycles through its travel, but with this you are hitting a mechanical stop before the suspension is designed to.

The Rail hasnt got a lot of progression to its suspension & if you are ‘ending’ the travel earlier you are potentially losing even more of it.

Just a thought/theory.

 

[JMD]

Just a thought with these home made yokes to make shorter shocks fit - are you not effectively changing the start / end point of the travel for the bike?

The kinematics of the suspension (pivot placements, size of rocker create the curve of progression as the shock cycles through its travel, but with this you are hitting a mechanical stop before the suspension is designed to.

The Rail hasnt got a lot of progression to its suspension & if you are ‘ending’ the travel earlier you are potentially losing even more of it.

Just a thought/theory.

The yoke's change the eye 2 eye length not the shock stroke (measured shock movement)

 

[Hob Nob]

The yoke's change the eye 2 eye length not the shock stroke (measured shock movement)

Yep, I understand that, but the shock is sat in a different position, at the full travel point (mechanical stop) it is in a totally different position to the standard shock size (and this at a different point in the suspension curve).

Not quite so critic on an eeb, but I would guess it also totally screws up the anti-squat values too, as you are effectively sitting at a different point in the bikes theoretical travel.

 

[JMD]

Yep, I understand that, but the shock is sat in a different position, at the full travel point (mechanical stop) it is in a totally different position to the standard shock size (and this at a different point in the suspension curve).

Not quite so critic on an eeb, but I would guess it also totally screws up the anti-squat values too, as you are effectively sitting at a different point in the bikes theoretical travel.

You might be correct, but more likely over thinking it?

 

[Slapbassmunky]

Just a thought with these home made yokes to make shorter shocks fit - are you not effectively changing the start / end point of the travel for the bike?

The kinematics of the suspension (pivot placements, size of rocker create the curve of progression as the shock cycles through its travel, but with this you are hitting a mechanical stop before the suspension is designed to.

The Rail hasnt got a lot of progression to its suspension & if you are ‘ending’ the travel earlier you are potentially losing even more of it.

Just a thought/theory.

The standard rail shock is 230mm overall. A standard trunnion shock is 205mm overall. The custom yokes are 25mm center to center, or at least my one is.

The total length stays the same. Otherwise you'd have all sorts of issues.

 

[Hob Nob]

The standard rail shock is 230mm overall. A standard trunnion shock is 205mm overall. The custom yokes are 25mm center to center, or at least my one is.

The total length stays the same. Otherwise you'd have all sorts of issues.

Yes I get that - I think you’re totally missing my point however. I’ll try and dig the other picture out with it mounted up to help visualise with some doodling on it

 

[Slapbassmunky]

Yes I get that - I think you’re totally missing my point however. I’ll try and dig the other picture out with it mounted up to help visualise with some doodling on it

It literally makes no difference. A frames kinematics are determined by where the pivot locations are l. As long as the shock is the correct length and has the correct(ish) stroke it dosen't matter.

By your reasoning mounting a shock upside down would cause all sorts of suspension issues, yet countless frames allow you to do just that.

 

[Doomanic]

The Rail hasn't got a lot of progression to its suspension

You keep saying this and I'm wondering what you're basing this supposition on? The only review I've seen that goes into suspension kinematics is by that Spaniard who has done literally hundreds of bikes and he says the Rail is progressive (2.9-2.6). As I asked previously, how much progression is needed?

 

[coregrind]

Yep, I understand that, but the shock is sat in a different position, at the full travel point (mechanical stop) it is in a totally different position to the standard shock size (and this at a different point in the suspension curve).

There are two stock shock design specs for the Rail: standard eyelet 230x57.5 and trunnion 230x57.5. The trunnion mount option from Trek has the Thru Shaft. The Thru Shaft shock is a yoke added to a trunnion 205x57.5 Metric shock, making it 230mm in overall length. What @Slapbassmunky (or others) created has identical start and end points, not that it even really matters. I say it doesn’t matter since the other shock spec (with standard eyelets) does indeed move the shock body lower in the system without any issues. The eye-to-eye and stroke are the same in all of these situations so the swingarm and related bits still move through the travel as intended from 0-100%.

 

[Slapbassmunky]

You keep saying this and I'm wondering what you're basing this supposition on? The only review I've seen that goes into suspension kinematics is by that Spaniard who has done literally hundreds of bikes and he says the Rail is progressive (2.9-2.6). As I asked previously, how much progression is needed?

"That Spaniard" as you so call him, mostly analyses pictures to locate the pivot points and his findings should not be taken as gospel, just a guide. Either way 2.9 to 2.6 is very mild progression. My last DH bike went from 3.2 to 2.0. MX bikes have very progressive linkages for good reason.

The rail should be just fine on a coil as you guys have found. But personally I'd run a progressive spring for hard charging.

 

[zaykay]

That Spaniard had it 2.9 - 2.375 which is 18%. I would categorise it lower end of middle ground when comparing to another linkages. For sure not the best linkage ratio for coil but can be made work really well especially if you keep adjusting the clickers and shock tune is not too light. Running the compression full open will cause bottoming in faster g-outs and drops. For me it does not make sense since you loose the control provided byt the damping. I’m running stiffer clickers than Fox recommends for DHX2 and it works great. I’ve learned it’s the HS rebound which is finicky with the abs linkage.

 

[zaykay]

Just to give another perspective, new Commencal Meta AM has 11% progression on linkage. That is in the more linear end of these. YT’s are usually very progressive and typically around 33%

 

[Stray cat]

Has someone fitted a regular Rock Super deluxe with Meg neg (or without) on a L size? Thanks

 

[Doug Stampfer]

I'm not getting this at all. On that terrain it's so much smoother than the air shock it's almost unbelievable.

Update - I talked to the tuner/dealer who said the damping should be 3 clicks from wound up so wound it right up & back one & it is much much better. I was on the verge of throwing it away however now I can't really fault it - well apart from the blingy bits which I'll have to deal with with some matt black paint....

 

[Stray cat]

This is interesting:

 

[Doomanic]

It is? I think you misspelled incomprehensible, because that’s what it is without some idea of what the column headers are referring to.

 

[Stray cat]

The last column refers to the progressivity of the system. For the others, go to the page linkagedesign.blogspot.com

 

[Railingit187]

Will a RS Super Deluxe 230x57.5 work on a medium Rail 7? I can get this one for 100 USD. Would it be worth it compared to the stock Deluxe Select+ shock?

TIA

View attachment 49771

Did anyone ever get back to you on this? I am in the same boat and wanting to swap out my less than stellar deluxe on my ‘21 9.7.

Cheers

 

[tyspap]

Considering swapping out the super deluxe for the jade x. Any feedback from someone who has done this?

 

[zerofunds]

Considering swapping out the super deluxe for the jade x. Any feedback from someone who has done this?

Just ordered mine today, should be here early next week. Hardware is the biggest issue. Thanks trek ?

 

[Railingit187]

Just ordered mine today, should be here early next week. Hardware is the biggest issue. Thanks trek ?

What is wrong with the thru shaft super deluxe? Is it not what trek wants it to be? I just have the deluxe on my 9.7 and trying to swap it out with a super deluxe ultimate non thru shaft. I like the progressiveness, the reason I do not want to go to coil.

 

[Railingit187]

Anyone on this thread have the RS Super Deluxe thru shaft for sale from the 2021 rail in the USA?

 

[zaykay]

Thru shaft relies only to active piston shim stack on damping. It feels livelier but in reality it’s harder to control damping with only active piston since it basically sees about three times more oil flow than typical passive piston on typical shock. Normally both active&passive are used together under pressure to allow lower cavitation and finer tuning capabilities. To be honest I think thru shaft is a cost reduction initiative, not performance. A more simple and cheaper to manufacture. Thru shaft shock feels typically very free on initial movement, but then hard to fine tune and feels hard on high speed hits when on attack. For leisure type of trail riding it’s very smooth and nice.

 

[Railingit187]

Thru shaft relies only to active piston shim stack on damping. It feels livelier but in reality it’s harder to control damping with only active piston since it basically sees about three times more oil flow than typical passive piston on typical shock. Normally both active&passive are used together under pressure to allow lower cavitation and finer tuning capabilities. To be honest I think thru shaft is a cost reduction initiative, not performance. A more simple and cheaper to manufacture. Thru shaft shock feels typically very free on initial movement, but then hard to fine tune and feels hard on high speed hits when on attack. For leisure type of trail riding it’s very smooth and nice.

Thanks for putting this together.

 

[zerofunds]

Anyone on this thread have the RS Super Deluxe thru shaft for sale from the 2021 rail in the USA?

I'm selling mine, have no problems shipping to the US, have shipped Motox parts often

 

[Railingit187]

I'm selling mine, have no problems shipping to the US, have shipped Motox parts often

How much are you wanting for it? Next how much is shipping from the land of Kiwi’s?

Cheers

 

[Railingit187]

How much are you wanting for it? Next how much is shipping from the land of Kiwi’s?

Cheers

Also is this the shock you would be getting rid of? This is the one I would be wanting.

 

[Doug Stampfer]

Just ordered mine today, should be here early next week. Hardware is the biggest issue. Thanks trek ?

Be interesting to hear your feedback. Is Jesse tuning it to your weight? I'd like to hear how it goes straight out of the box before you do anything to it.

 

[Bronzo]

hello, sorry my english, in Italy the creek kitsuma spring shock absorber is nowhere to be found, someone from the forum has mounted creek kitsuma air on a medium trek rail?