[slimshady]

https://www.pinkbike.com/news/trek-presents-reaktiv-thru-shaft-technology.html

Less room for heat-induced oil expansion, but NO IFP!!! We are finally free from that opression!!

I'm reading all this marketing bukakke as "you won't be able to take any downhill run longer than 4 minutes without your shock becoming a pogo stick"

EDIT: The RS version actually has an IFP

 

[SkaredShtles]

Solution: remove air shock, install coil shock.

Profit?

 

[jlindy86]

Both the Fox and Rock Shox versions have IFP's for thermal compensation - Rock Shox in the little piggy-back and Fox has it housed in the slave shaft.

 

[Sandwich]

Solution: remove air shock, install coil shock.

Profit?

Haha, this is trek. Proprietary eye to eye or custom yoke.

Both the Fox and Rock Shox versions have IFP's for thermal compensation - Rock Shox in the little piggy-back and Fox has it housed in the slave shaft.

who are you and where did you come from?


my first question was: no IFP, what happens for thermal compensation? As we all know, more seals means less stiction, particularly when they are external and keep oil from leaving the shock body. There's a little known secret to getting rid of the IFP though...a bladder.

 

[slimshady]

Solution: remove air shock, install coil shock.

Profit?

Behold, Occam's razor in its magnificent glory!

my first question was: no IFP, what happens for thermal compensation? As we all know, more seals means less stiction, particularly when they are external and keep oil from leaving the shock body. There's a little known secret to getting rid of the IFP though...a bladder.

Yeah, I thought their complete dismissal of the bladder solution was at least lousy. But then again, they are Trek. DRCV should have taught something to those poor guys buying their trail bikes.


EDIT: Cant't wait for their "engineers" to post to twitter laughing at our Monkey lucubrations!!!

 

[Olga_icannot]

EDIT: Cant't wait for their "engineers" to post to twitter laughing at our Monkey lucubrations!!!

Holy shit! I love the level of nerdery on RM but that's the first time I've had to the google the definition for a word. Lucubration =
I can't wait to hear the explanation from Trek as to why an IFP is bad yet they ended up including one anyway to deal with thermal expansion. This feels like Trump/Russia without the vitriol.

 

[jlindy86]

I can't wait to hear the explanation from Trek as to why an IFP is bad yet they ended up including one anyway to deal with thermal expansion.

Some type of thermal compensation is necessary to prevent blowing seals, but with the thru-shaft the IFP isn't dealing with shaft displacement every time the shock extends/compresses. Both IFP's and bladders that have to deal with shaft oil displacement inherently add some lag to the system, but that whole part can be eliminated with a thru-shaft layout.

 

[StiHacka]

This is going to work great in forks.

 

[Sandwich]

Some type of thermal compensation is necessary to prevent blowing seals, but with the thru-shaft the IFP isn't dealing with shaft displacement every time the shock extends/compresses. Both IFP's and bladders that have to deal with shaft oil displacement inherently add some lag to the system, but that whole part can be eliminated with a thru-shaft layout.

honest question: how does a bladder, which doesn't slide but rather compresses, create lag/friction/hysteresis?

I won't deny that the idea has merit, but knowing trek it will only be available on a few models for a few years and won't be cross compatible with anything else on the market.

 

[djjohnr]

I'm liking the potential applications for continuous bong hit technology.

 

[StiHacka]

How many extra seals are there needed for the shaft to exit the shock ass?

 

[Westy]

Some people just like to look down and watch their shaft go in and out of the can.

 

[Olga_icannot]

Some type of thermal compensation is necessary to prevent blowing seals, but with the thru-shaft the IFP isn't dealing with shaft displacement every time the shock extends/compresses. Both IFP's and bladders that have to deal with shaft oil displacement inherently add some lag to the system, but that whole part can be eliminated with a thru-shaft layout.

Yup, I understand the basics. And I'm sure the Trek guys gave us the USA Today media version of how it works but from the interview he seems to make a blanket statement as to how IFPs are bad and then glosses over the fact that the shock has one anyways. Admittedly the IFP in their new shock doesn't move much (oil doesn't expand much when heated) or often but it still has one, it's still subject to the same manufacturing tolerance, wear, complexity, and service restriction (I don't yet have my own nitrogen tank to recharge the IFP if I try to service the shock myself).

I'm going to date myself here a bit and go ahead and admit that I owned several iterations of the AMP Research frame in the early/mid '90's with a through shaft coil shock (with titanium spring!). That thing constantly leaked from its ass end.


Cool story, eh?

 

[jlindy86]

honest question: how does a bladder, which doesn't slide but rather compresses, create lag/friction/hysteresis?

Bladders do avoid the IFP seal friction, but in the case of the design you pictured, it still requires pushing fluid through a tube/hose in and out of the reservoir. Fluid friction occurs that you can't really do anything to easily tune/adjust. Controlling damping via that displaced fluid (ie remote/base valves) works off of a relatively small amount of fluid, compared to the amount of oil being forced through the mid-piston on a thru-shaft shock. The real benefit to thru-shaft shocks isn't removing the IFP seal friction, but really the piston working against a solid column of fluid that isn't supported by a spring (IFP/bladder). The lack of oil displacement also allows for lower pressurization and seal friction...granted you're adding a seal for the slave shaft so the net friction change is minimal.
Interesting article that's a bit dated from '02, but still relevant - http://www.f1technical.net/features/10660

 

[Westy]

That thing constantly leaked from it's ass end.


Cool story, eh?

Just like Kidwoo!

 

[trib]

I can see the benefits of this system, but am rather frustrated by the lack of true innovation in the suspension industry at the moment.

The issues the "Reaktiv" system is trying to solve could be completely negated if suspension companies used some kind of high tech elastic polymer to control rebound and compression.

 

[Olga_icannot]

Just like Kidwoo!

I'm so glad someone jumped on that.

 

[Westy]

I'm so glad someone jumped on that.

Just like Toshi's mom!

 

[roflbox]

I smell lizurds

 

[jonKranked]

I smell lizurds

Definitely lizard physics.

 

[Tom Ritchey's Moustache]

Should have made that extra pokey shaft a nice shade of pinkish red for maximum arousal.

 

[Udi]

I support the new coil version of that shock:

[/img]

 

[jonKranked]

Should have made that extra pokey shaft a nice shade of pinkish red for maximum arousal.

I'm gonna call it the trek probiscus

 

[Westy]

I'm gonna call it the trek probiscus

 

[toodles]

(oil doesn't expand much when heated)

Wait - what? Yeah it does - it expands something like 4 times more than water does. We had massive issues with it when we converted a water tube boiler to a thermal oil heater for a work project a few years back.

As an aside, I know the extra shaft seal might seem like twice as many opportunities to leak but I wonder if the through shaft design will prevent twisting and align the shaft better through the seals.

 

[Olga_icannot]

Wait - what? Yeah it does - it expands something like 4 times more than water does.

Oh, who knew? RM educating me again. I suppose I was thinking that most of the IFP movement is due to displaced oil, not thermal expansion. But I could easily be wrong about that too.

 

[jonKranked]

Oh, who knew? RM educating me again. I suppose I was thinking that most of the IFP movement is due to displaced oil, not thermal expansion. But I could easily be wrong about that too.

Why not both?

 

[toodles]

Oh, who knew? RM educating me again. I suppose I was thinking that most of the IFP movement is due to displaced oil, not thermal expansion. But I could easily be wrong about that too.

Nah you're right, the shaft displacement would be much, much more than thermal expansion. But I still wouldn't want to heat up a hydro-locked damper. Apparently it has a mechanism to deal with thermal expansion anyway.

 

[kidwoo]

Wait - what? Yeah it does - it expands something like 4 times more than water does. We had massive issues with it when we converted a water tube boiler to a thermal oil heater for a work project a few years back.

It's like shimano brakes. I'm just going to blame your bleed job.

Try it meow.

 

[toodles]

It's like shimano brakes. I'm just going to blame your bleed job.

Try it meow.

Nah we flicked all the hoses. That should do it right?

 

[xy9ine]

my god.

 

[Jm_]

Because America, F-yeah.

 

[TrumbullHucker]

I saw that pinkbike vid of the shock showing lag and it tripped me the fuck out

then i went into my local woods and rode my bike. it was an awesome day.

 

[troy]

So... 6pot calipers from Hope are back, so is the Pro Deluxe shock. Still waiting for the URT suspension to come back to its glory (with some BOOST "technology" ofc)

 

[slimshady]

So... 6pot calipers from Hope are back, so is the Pro Deluxe shock. Still waiting for the URT suspension to come back to its glory (with some BOOST "technology" ofc)

Isn't the GGDH a URT? We might be just a hair away from the 90s awesomeness!

 

[jonKranked]

Isn't the GGDH a URT? We might be just a hair away from the 90s awesomeness!

Single pivot.

 

[slimshady]

Single pivot.

I stand corrected. Mistaken it for the old Morpheus DH.

 

[norbar]

EDIT: Cant't wait for their "engineers" to post to twitter laughing at our Monkey lucubrations!!!

I don't follow them on Twitter. Can you post once they do? I really love to see that.

 

[Flo33]

So if finally a bike with through shaft damping technology, speed balanced geometry, supermegahyperboost and automatic telescope seat post emerges from the Atlantic ocean's capital, I will spend serious money again.

Plus: Bonuses for 32.7" wheels can be obtained.

It's your turn, lizards.

 

[slimshady]

I don't follow them on Twitter. Can you post once they do? I really love to see that.

Don't you remember their previous rant? My laptop's disk just died (literally!) and searching from the phone is a PITA, but I know there is a thread from maybe 4-5 years ago about that.