Trek Koppenberg - Where Emonda and Domane meet

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Mr.Gib
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by Mr.Gib

Not sure that I would have the nerve to grind material away from a bottom bracket shell. Again though, I guess you know your specs, identified the problem, and came up with the fix. One of my Treks has an out of spec non-drive side that requires the special oversized bearing that Trek can supply. But my problem was too big as opposed to too small. I basically have an oversize bearing shoved in BB that is oval as opposed to round. Interestingly there is no binding or strange noises, spins very free.

I still have doubts about the Iso-Speed de-coupler and it's relationship to movement of the seat stays. If the seat tube can only flex from the BB cluster pivot point then it is basically moving backward. In order to drive the seat stays downward there would have to be some sort of ramp system in the Iso-Speed junction. I have taken mine apart and everything is round. I get that the seat tube at the Iso-Speed in not moving perfectly horizontal but the degree of downward tangent is very slight. Perhaps this is enough to cause your rear brake to hit a close fitting tire.

I really like all three of my Treks but I must admit I have never been a fan of the de-coupler - a complication without real benefits. While they do add comfort I find they are not necessarily superior in terms of saddle stability and comfort when compared to a conventional 27.2 carbon seat post with lots showing as is the case with a compact geometry frame. Much as you noticed the greater rear end compliance of the Giant Defy.

I have a Trek Cronus (the road version) which is some ways was the pre-curser to the Domane, and it is by far the most comfortable bike I have ever ridden - no de-coupler, just a lot of 27.2 seatpost showing. I guess one advantage is that a de-coupler could create as much compliance as one could want on a frame with a horizontal top tube where the amount of seat post showing is minimal.

Did I miss your ride impressions? Curious about how the Koppenberg feels is all situations. Most curious about the steering feel when climbing out of the saddle. Does it want to flop a bit? Or does it stay dead straight no matter how much you throw the bike around? What about tight curves at the limit? Does it take more lean to get it to carve your line (like my Parlee) or does it hook right away with the slightest effort (like my Colnago)?
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

hlvd
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by hlvd

SilentDrone wrote:
Mon Jan 08, 2018 6:35 pm
Thanks, Cal. I appreciate your thoughtful and careful analysis of the former rear iso speed compared to the new rear SLR. Great pic! Even better write up! I'm looking forward to your thoughts about the new front iso speed. . . .

With regard to the rear, I see an advantage to the new design in that the front triangle is now a solid structure. What I mean is that it does not rely on the bolt and bushings at the seat tube/top tube junction to provide lateral rigidity. I think that's a design improvement in so far as I've always been a little curious about whether the bolt and bushing can provide sufficient rigidity. With the new design that's no longer an issue. The seat post piece (i.e., the removable mast down to the bolt where it attaches to the seat tube) no longer has to play any structural role in the frame. The engineers are free to design a stiff frame and as much or as little compliance in the removable seat post piece as they wish.

And by the way, I had a chance to speak with a trek rep last year about the evolution of the domane. He mentioned the Koppenberg's role and pointed out how thick and stiff it had been made. He said this was done specifically to accommodate the massive power that Cancellara produced and his need for solid power transfer. He said the off-the-shelf domane would have been far to flexible.

Thanks again!

I so miss Cancellara! What a rider having to have a beefed up bike made to cope with his power.

hlvd
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by hlvd

I've been waiting for this thread for a long time, thanks Calnago, great and envious reading!

stormur
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by stormur

Nice bike ! I really like the main idea of it.

My only concern ( as all Slip in ) is bottom bracket. bearings seat directly and loosely in carbon shell ( loose fit ). From the long term point of view is "asking for troubles". For Shimano crank Trek has "oversized" bearings ( admitting issue is real and not so isolated ), but what with UT bearings ?
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Calnago
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by Calnago

Great posts @SilentDrone and @Mr.Gib... you've both raised points that I want to address in a bit more detail, in separate posts, hopefully today... it's good to see people actually thinking about this stuff instead of just swallowing up marketing spin as fast as can be thrown at us.
SilentDrone wrote:
Mon Jan 08, 2018 6:35 pm
...And by the way, I had a chance to speak with a trek rep last year about the evolution of the domane. He mentioned the Koppenberg's role and pointed out how thick and stiff it had been made. He said this was done specifically to accommodate the massive power that Cancellara produced and his need for solid power transfer. He said the off-the-shelf domane would have been far to flexible.
hlvd wrote:
Mon Jan 08, 2018 7:45 pm
I so miss Cancellara! What a rider having to have a beefed up bike made to cope with his power.
It wasn't only Cancellara that was on this frame in Grand Tour Events; quite a few others rode it as well. But Cancellara was definitely "The Man" that this frame revolved around for sure, and probably the pro rider most directly involved in its development. At the 2015 Tour Down Under, most of the Trek team were on the Domane (Koppenberg I presume), at least according to this quote from an article at the time...
"Most of the Trek Factory Team would normally ride the Emonda or Madone road bikes, but Trek Australia told Bike Radar that the majority of the team rode the Domane at the Tour Down Under, because of Australia's generally poorly surfaced roads". Source: https://www.bikeradar.com/us/road/gear/ ... erg-43524/


Mr.Gib wrote:
Mon Jan 08, 2018 6:53 pm
Did I miss your ride impressions? Curious about how the Koppenberg feels is all situations. Most curious about the steering feel when climbing out of the saddle. Does it want to flop a bit? Or does it stay dead straight no matter how much you throw the bike around? What about tight curves at the limit? Does it take more lean to get it to carve your line (like my Parlee) or does it hook right away with the slightest effort (like my Colnago)?
No, you didn't miss it @Mr.Gib... but as you can see I kind of got mired down in the nitty gritty of the bike itself, perhaps a little too much. I really want to finish up my part of this thread in the next day or two. And yes, I'll give you all my detailed thoughts on its ride in all circumstances and conditions (at least those that I've encountered).
Last edited by Calnago on Mon Jan 08, 2018 9:19 pm, edited 1 time in total.
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Calnago
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by Calnago

stormur wrote:
Mon Jan 08, 2018 9:18 pm
Nice bike ! I really like the main idea of it.

My only concern ( as all Slip in ) is bottom bracket. bearings seat directly and loosely in carbon shell ( loose fit ). From the long term point of view is "asking for troubles". For Shimano crank Trek has "oversized" bearings ( admitting issue is real and not so isolated ), but what with UT bearings ?
Well, would I have preferred to be able to use Campy cups directly? In a word, Yes, I would. But I've gotten over wishing the pressfit thing would go away as it's not likely to happen anytime soon imo. And with a good install it works, the trouble is always getting a good install.

Trek's BB90 is in fact a "slipfit", and not an interference "pressfit". In fact, I discussed that with Trek when I was building my emonda as they would say to use a press, and others would call it a pressfit. So while my Emonda seemed to have a very good shell, similar to that of campy cup tolerances, I was not so lucky with my Koppenberg. It's not hugely out of spec, but it's certainly not as perfect as a campy cup. At this point I'm not even talking about whether the cup is pressed in or threaded, I'm just talking about how round it is. I would have been a lot more concerned if I had gotten any measurements over 37.00mm in the diamter of the cup, and while I don't possess a true "bore measuring" device, with three simultaneous points of contact etc., I do possess very accurate vernier calipers which enabled me to get a good idea of where things were a bit out.

I think the issue Trek had early on with BB90 is largely a thing of the past, and I am not predicting or expecting any long term issues with this setup. Time will tell of course. Unlike shimano cranks, where the bearings are slipfit both on the crank and in the shell of BB90, Campy's ultratorque bearings are pressed on the spindle, and when things are locked down with hirth joint, everything is aligned and square. But if the cup surfaces that the outer bearing surfaces seat in are out of alignment, then there could be issues. Hence why it's so critical to get those cups in straight and aligned. But in the campy cups, those bearings are fixed on the spindle, with just enough slip fit that they could slide a teensy bit laterally if required. The wavy washer and the c-clip help keep everything where it should be. But you don't want BOTH the inner race fixed (which it is as it's pressed onto the spindle), and the outer race fixed (which it kind of was since it was binding a bit), since unless both races are fixed in exactly the perfect position they will be fighting against each other. So, the outer race needs to be free to float in the cups a teensy bit, and then all is good, and that is what I was trying to achieve with my slight sanding of the BB inner bore in a couple of areas. I think I did just that.

Shimano bearings on the other hand, are placed into the BB90 on their own, before sliding the crank spindle through. On my Emonda, I could have seated Shimano bearings by hand, and all would have been good. On the Koppenberg, I doubt I would have been able to do that, hence the recommendation by Trek to use a press, even though it's technically not a pressfit BB. Using a press will ensure that you do get the Shimano bearings seated properly in the shell, before you install the crank. Without the bearings being fully seated, which may happen if you do not use a press, then that's where potential issues may arise. The other thing with Shimano, is there is no wavy washer system invovled and it relies on mechanical preload (tightenting the non-drive side crank just the right amount to fix those bearings in their correct locations. Shimano says to "hand tighten" the preload but that will probably not get you to where you really want to be. A little help here doesn't hurt to make sure you've really got a properly preloaded set of bearings in there. But I'm getting into another topic now.

I think the BB90 system is ok. I've kind of focused on the bearing/cups interface above, and not so much the cup/BB shell interface which is really the source of so many other pressfit application woes. In those cases, Loctite 609 and primer is usually your best friend. As you mentioned, Trek had some oversize bearings to address cases where the shell became, or was produced, slightly "ovalized" or not perfectly round to spec. In extreme cases, you could actually, if very careful, apply a retaining compound between the outer race of the bearing and the inner surface of the BB90 shell, but I wouldn't even attempt that except in extreme cases. But different topic.
Last edited by Calnago on Mon Jan 08, 2018 9:52 pm, edited 3 times in total.
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Calnago
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by Calnago

A word on the H1 Geometry vs Koppenberg:
As I mentioned somewhere in an earlier post, the Koppenberg is H1 geo, meaning it has the same angles, wheelbase, fork rake, eff top tube, etc as the Emonda. But there is one important difference in the actual numbers if you're looking at the H1 geo chart for comparative purposes. The headtube dimension is incorrect from an absolute perspective as it relates to the Koppenberg. If you look at my size 60 for example, the headtube is supposed to be 180mm according to H1 geometry charts. But in fact it is only 170mm. Your stack still ends up being the same, but the axle to crown measurement on the Koppenberg fork is 380mm, vs 370 on the Emondas. So, if you’re comparing headtube lengths you need to consider that. When I actually made a physical measurement of the headtube and found it to be 170mm instead of the 180mm I expected it to be, I almost said right then “well this will never work. I'm ok with two centimeters of spacers but three would be getting to be too much, might as well just stick with my H2 geo". So that’s when I compared axle to crown measurements to figure out what they had done. Just one more datapoint you need to look at when comparing things like fit.

In sum, what this means is that the headtube on my Koppenberg is a whopping 4cm shorter than on my H2 60cm Emonda SL. Basically, it's my H2 headtube with 3cm cut off the top and 1cm cut off from the bottom to make room for the fork with a longer axle to crown dimension and buckets of tire clearance (lot of good it does a the front however, when the rear is still limited). Since the H2 headtube was always about a centimeter higher than I'd prefer, I figured by adding two centimeters of spacers to the Koppenberg it could actually work out quite nicely, as I knew the rest of the geometry was spot on to what I like. And from a looks point of view, even with the two centimeters of spacers that I have underneath the stem it's a good look. When I sent some pics to a friend, his comment was "since when did you start riding such an aggressive position?" and I told him that the fit setup was exactly the same as most of my other bikes. Even the gap between the top tube and the downtube as it flows with the headtube is imo a lot sexier than even the current H1 Emonda in this size...
Image
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stormur
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by stormur

How both systems works I know.

Shimano ( to which BB90 has been designed for ) has possibility to lock bearings in place by 609( optimistic scenario ) or 648 ( better solution ) to avoid bearing rubbing cf shell. Campy set up a priori is bereft from that feature. That setup in particular would be my only concern about this frame. Left just hope that weavy washer will deliver enough pressure on outer bearing race vs shell to hold in in place regardless load applied and shell ID imperfections, to not mention thermal sizing so different for cf and steel... .
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Calnago
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by Calnago

Works a treat. I've had my Emonda/Campy setup since 2014, as a dedicated rain bike. Not a peep, perfectly smooth. Like I said, you do not want to lock the bearings outer race to the inner surface of the BB shell in Campy's case, but you do want a good tolerance on the dimension, ideally 36.98-37.00mm. Even in a properly installed Campy only system, using Campy cups etc., there is a very slight lateral play (the c-clip stops any excess). Grease is what you want between the outer race and the BB shell in the BB90 case, as is the case between the Ultratorque bearings and the inner surfaces of the Campy cups. I knew it was too tight initially when I couldn't push the crank laterally (from the non drive side) and get any amount of movement whatsoever. Now I get the same tiny amount of lateral movement that you would get performing the same exercise in a properly installed 100% Campy setup, which immediately returns due to the wavy washer, same as Campy. If the outer surface of the bearings races were loctited to the shell, the wavy washer would be rendered completely useless. Trek has thought it through and locates the bearings perfectly and supplies their own wavy washer for the setup. It's good. So far (fingers always crossed, but I'm pretty confident on this one).
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FIJIGabe
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by FIJIGabe

Cal, seriously, never let me borrow your bike. If you do, you aren't getting it back!
Madone 9 https://goo.gl/7UwZpV
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Madone 4, Cobia. I own a lot of Treks.

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Calnago
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by Calnago

Ha... well it’s only N-1 for me going forward. So you never know. :)
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Calnago
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by Calnago

Mr.Gib wrote:
Mon Jan 08, 2018 6:53 pm
I still have doubts about the Iso-Speed de-coupler and it's relationship to movement of the seat stays. If the seat tube can only flex from the BB cluster pivot point then it is basically moving backward. In order to drive the seat stays downward there would have to be some sort of ramp system in the Iso-Speed junction. I have taken mine apart and everything is round. I get that the seat tube at the Iso-Speed in not moving perfectly horizontal but the degree of downward tangent is very slight. Perhaps this is enough to cause your rear brake to hit a close fitting tire.
Ok, we're talking about a very small amount of movement here and yes, with the 27mm Vlanderens it is very close to the rear brake bridge (my one gripe about the bike in all honesty). Whereas with your Boone (presuming discs), you would never even notice this flex since there's no brake bridge, correct? But yes, as the seatube flexes and pivots, that entire joint around the seatpost cluster has to move slightly as well, meaning some flex in those slender seatstays all the way through to the top tube. If you can acknowledge a slight bowing in the seattube below the pivot, then you also have to acknowledge that the pivot point has to be moving downwards a bit to accommodate that. I actually had a friend put his finger between the brake bridge and the tire while I tired to push down on the seat to see if it actually was moving. At the time I wasn't sure if what I was hearing was the brake pads touching the rim every now and then due to lateral flex of the wheel or something, or whether it was vertically touching the underside of the brake bridge. My friend let out quite a yelp followed by sucking his finger to confirm that there was indeed some vertical flex. And this was also later confirmed by marks on the underside of the brake bridge where the tire would hit every now and then.

Mr.Gib wrote:
Mon Jan 08, 2018 6:53 pm
I really like all three of my Treks but I must admit I have never been a fan of the de-coupler - a complication without real benefits. While they do add comfort I find they are not necessarily superior in terms of saddle stability and comfort when compared to a conventional 27.2 carbon seat post with lots showing as is the case with a compact geometry frame. Much as you noticed the greater rear end compliance of the Giant Defy.
I'm kinda with ya on this, and the only way I was going to figure this all out was to try it, which I did and still am. The saving grace here is that the rear decoupler doesn't really seem to add a whole lot of complexity (at least on the Koppenberg), it looks sleek, and if it does what they say it does, then well... ok. I'm much less convinced of the need or added benefit of the front iso-speed however. But back to the rear... like you noted... a skinny long seatpost in a "compact" style frame can produce a whole lot of compliance, as I found out with the Giant Defy I rode, more so than the standard Domane even. But quite frankly, the mushiness of the rear of the Defy I rode was a bit disconcerting to me, and didn't match up well with the stiffness of the front end, which seemed solid and planted. Just didn't really care for it, plus I've always hated the look of "compact" road frames.

There was a thread on the forum a little while ago where someone was saying he thought the ride of the Dogma (F10 or F8, can't remember) was more plush than the new Madone with it's iso-speed. He was met with "Not possible... the Madone has iso speed". Now, I have not ridden one of the new Madones, but having ridden this Koppenberg with iso-speed and looking at the tube shapes of the new Madone, I could very easily believe that the Dogma could feel plusher for all kinds of reasons, not the least of which may even be the layup schedule and the sheer amount of carbon and/or resins used. More material tends to dampen vibrations better in my experience. A lot of the jarring in the Madone is going to be coming from the front end, with little reprieve from the rear iso-speed. And that downtube etc... well, a 2x4 is going to be a lot stiffer in the 4" plane than the 2" plane, typical complaints when it comes to talking about the ride quality of many aero bikes. Rarely is there a free lunch to be had. Gain something, lose something. Point is, his opinion whether real or imagined, even though he had actually ridden both frames, was being shot down simply on the basis of the marketing spiel of iso-speed and a few reviewers that said it really worked in taking the edge off the Madone. Which I'm sure it does, but when you take the "edge" off a 2x4 on it's edge, does it really end up feeling better than a 2x2 oriented either way. I don't know, but I'm sure you get the drift.

So back to the Koppenberg, the ride is very nice, but if I didn't know iso-speed was there, I wouldn't be saying "Wow, how come there's so much more compliance with this frame than my C60". I'd be hard pressed to tell a huge difference. But it is there, and it doesn't feel bad, so by default... I guess that's good because I might think a frame built this solid could end up feeling like a boat anchor, but it doesn't. My Emonda SL for example, with no iso-speed, has more vertical compliance than my Colnagos. I could hit a good bump with that and actually feel it give a bit. But Trek gets that compliance with the layup schedule. They've done a good job me thinks.
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Calnago
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by Calnago

SilentDrone wrote:
Mon Jan 08, 2018 6:35 pm
Thanks, Cal. I appreciate your thoughtful and careful analysis of the former rear iso speed compared to the new rear SLR. Great pic! Even better write up! I'm looking forward to your thoughts about the new front iso speed. . . .

With regard to the rear, I see an advantage to the new design in that the front triangle is now a solid structure. What I mean is that it does not rely on the bolt and bushings at the seat tube/top tube junction to provide lateral rigidity. I think that's a design improvement in so far as I've always been a little curious about whether the bolt and bushing can provide sufficient rigidity. With the new design that's no longer an issue. The seat post piece (i.e., the removable mast down to the bolt where it attaches to the seat tube) no longer has to play any structural role in the frame. The engineers are free to design a stiff frame and as much or as little compliance in the removable seat post piece as they wish.

And by the way, I had a chance to speak with a trek rep last year about the evolution of the domane. He mentioned the Koppenberg's role and pointed out how thick and stiff it had been made. He said this was done specifically to accommodate the massive power that Cancellara produced and his need for solid power transfer. He said the off-the-shelf domane would have been far to flexible.

Thanks again!
@SilentDrone: You raise an excellent discussion point on the new iso-speed design. With that "shroud" as I call it, coming down from the top tube to the BB junction, it is very structural and it must do as you say, and stiffen up the front triangle. I just don't know which is better quite frankly. With the new design, the seat mast seems more strictly limited to pivoting on the pivot junction, but that sole single point of support strucutre concerns me a bit, versus the way it was before with the entire seattube providing support for the seat and weight of the rider. I haven't felt a problem with lateral flex at all on the Koppenberg, but do see how the addition of that solid support structure completley detached from the pivoting system could add to the rigidity of the front triangle, especially in the veritcal plane. And they compensate for the lesser lack of compliance in the front triangle with a detached/pivoting seat mast which coupled with the sliding elastomer provides an amount of adjustability which was not possible in the old design. I think that is the biggest selling point of the new design. People like adjustability, and like I'm here to confirm, the older iso-speed, especially on the Koppenberg, can be a little hard to even detect. But that's actually what I wanted, I didn't want to feel any "bounciness", just maybe take the edge off a chattery road. And I'm sure if I had the new Domane iso-speed I would be sliding that elastomer all the up as far as it could go, at least for the pavement I ride on. Maybe on rougher gravel roads, a softer setting would welcome. I guess there's arguments either way for sure. So good point.

But the new front iso-speed... I look at that and think... really? Now that's complex, at least compared with a traditional setup as we know it, with all kinds of things to get loose and wear and cause "knocking" sounds in the same way that a loose headset would. I'm sure that Trek's engineering and sensitive testing instruments can show that it does indeed dampen vibration somewhat, but any more than losing a few pounds of air pressure... I'm not so sure.

Here's a blowup from Trek's website of the inner workings of the new front iso-speed...
for what... so the fork can flex a tiny bit between the two bearing spans in the headtube?
Let's take a 20cm long head tube... how much flex can really happen in that span? And it would be even less for a shorter headtube. I think the Complexity/Benefit ratio may be too high here. Especially since this is probably technology that is only really warranted on their "gravel grinders" at best. And if they are going to go all in with discs... well hell... just throw on a 30mm tire or bigger and lower that pressure a bit and my intuition says you're going to get more vibration dampening than this setup could provide on it's best day. Why add the complexity? I guess I'm not a fan of this one. Those are my thoughts, and I obviously haven't tried it. But seeing these changes before I bought the Koppenberg only served to hasten my decision as to which system I wanted going forward.
Image
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Mr.Gib
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by Mr.Gib

That front Isospeed is insanity. Just build a good fork and leave it at that. Could you imagine chasing down a headset creak?
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

SilentDrone
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by SilentDrone

Calnago wrote:@SilentDrone: You raise an excellent discussion point on the new iso-speed design. With that "shroud" as I call it, coming down from the top tube to the BB junction, it is very structural and it must do as you say, and stiffen up the front triangle. I just don't know which is better quite frankly. With the new design, the seat mast seems more strictly limited to pivoting on the pivot junction, but that sole single point of support strucutre concerns me a bit, versus the way it was before with the entire seattube providing support for the seat and weight of the rider. I haven't felt a problem with lateral flex at all on the Koppenberg, but do see how the addition of that solid support structure completley detached from the pivoting system could add to the rigidity of the front triangle, especially in the veritcal plane. And they compensate for the lesser lack of compliance in the front triangle with a detached/pivoting seat mast which coupled with the sliding elastomer provides an amount of adjustability which was not possible in the old design. I think that is the biggest selling point of the new design. People like adjustability, and like I'm here to confirm, the older iso-speed, especially on the Koppenberg, can be a little hard to even detect. But that's actually what I wanted, I didn't want to feel any "bounciness", just maybe take the edge off a chattery road. And I'm sure if I had the new Domane iso-speed I would be sliding that elastomer all the up as far as it could go, at least for the pavement I ride on. Maybe on rougher gravel roads, a softer setting would welcome. I guess there's arguments either way for sure. So good point.

But the new front iso-speed... I look at that and think... really? Now that's complex, at least compared with a traditional setup as we know it, with all kinds of things to get loose and wear and cause "knocking" sounds in the same way that a loose headset would. I'm sure that Trek's engineering and sensitive testing instruments can show that it does indeed dampen vibration somewhat, but any more than losing a few pounds of air pressure... I'm not so sure.

Here's a blowup from Trek's website of the inner workings of the new front iso-speed...
for what... so the fork can flex a tiny bit between the two bearing spans in the headtube?
Let's take a 20cm long head tube... how much flex can really happen in that span? And it would be even less for a shorter headtube. I think the Complexity/Benefit ratio may be too high here. Especially since this is probably technology that is only really warranted on their "gravel grinders" at best. And if they are going to go all in with discs... well hell... just throw on a 30mm tire or bigger and lower that pressure a bit and my intuition says you're going to get more vibration dampening than this setup could provide on it's best day. Why add the complexity? I guess I'm not a fan of this one. Those are my thoughts, and I obviously haven't tried it. But seeing these changes before I bought the Koppenberg only served to hasten my decision as to which system I wanted going forward.
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Great points, @Calnago.

Regarding the new design in the rear, when I first saw it and gave it some thought it occurred to me that his new design isn’t really a “decoupler” at all, or at least not in the sense of the original design. In the original, like yours, the pivot ingeniously freed up the seat tube from the top tube-seat stays to allow movement in the vertical plane, while keeping that junction rigid in the lateral plane. But with this new design the “frame” itself, i.e. the front and rear triangle, is a completely solid unit just like with any frame. The design simply bolts on a really long seat tube to that frame with a slider to adjust its flexibility. I’m sure I’m not the only one to find it interesting that the new design comes full circle back to the rigid two-triangle-design that was eschewed when the original iso speed was implemented.

Regarding the front, I too have wondered how it could be that this design provides some humanly perceptible benefit that isn’t equally available to a bike with wider tires. Did the engineers design some special flex into the fork steerer tube to take advantage of the pivot? (There is no mention of that anywhere that I’ve seen.). And what about riders who will be slamming the stem onto the headset bearing cover? I think that would diminish whatever benefit the pivot provides, and yet with the tall head tubes on these bikes it would be natural to want to slam the stem. Maybe I’m just being too skeptical. Trek would never release a marketing gimmick, right?

All of that said, I hasten to disclose that I’m in the process of spec’ing a project one Domane SLR 8 Disc (endurance geo) for my next ride. Hence my interest in all of this at this time. The thing that draws me to the Domane for my next bike is, first and foremost, the endurance geometry and tire clearance. But I will admit that I’m also interested to try the iso speed system myself, and I’m hopeful the advertised benefits with manifest themselves. We shall see.

I will add also that I was able to carefully test ride an 2018 Emonda SL against a 2018 Domane SL Disc, and the Domane was of course much smoother and slower in steering, ie. stable, as one would expect. So as a system it is “as advertised.”


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