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Accidentally found a way to really test the dampening system on my Domane...

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Accidentally found a way to really test the dampening system on my Domane...

Old 06-29-13, 01:04 PM
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Accidentally found a way to really test the dampening system on my Domane...

Went on a 40 mile loop this morning and toward the tail end ran into milled asphalt being prepped for resurfacing. Turned out to be 16 stinking miles of it. That's what I get for not checking a road I've not been on yet this year. Anyway, it was a ridiculously rough, vibrating mess that made it tough to hold any speed over 15mph, but I really have to say that the bike did an awesome job of making it bearable. I don't intend to do that again if I can help it, but overall I really get the point of the seat post pivot system now.

I'm also suddenly very happy with the Boyd wheels I put on it last week. Not so much as a rattle over the rough stretch.
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Old 06-29-13, 02:06 PM
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I hear you're pain. One of my favorite rides has had the road milled for months. Not set to be paved untill the middle of July. I can't wait to head out that way.

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Old 06-29-13, 03:34 PM
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Originally Posted by SmellTheSmug
Went on a 40 mile loop this morning and toward the tail end ran into milled asphalt being prepped for resurfacing. Turned out to be 16 stinking miles of it. That's what I get for not checking a road I've not been on yet this year. Anyway, it was a ridiculously rough, vibrating mess that made it tough to hold any speed over 15mph, but I really have to say that the bike did an awesome job of making it bearable. I don't intend to do that again if I can help it, but overall I really get the point of the seat post pivot system now.

I'm also suddenly very happy with the Boyd wheels I put on it last week. Not so much as a rattle over the rough stretch.
It will be interesting to watch the evolution of the seat pivot moving forward. Its an interesting concept, however not without some controversy. Most say there is no question this design helps to smooth rough roads. A side note for me at least...the rear of the bike has never been a problem to discomfort. I guess this is because I have learned to rider lighter in the saddle over rough roads. A common countermeasure is to shift one gear up and mash and unweight a bit more. For many and certainly for me....It is the hands that get assaulted on rough roads. If designers could solve this issue and preserve weight and handling etc, they would have a gold mine. Of course they do what they can with carbon technology and slack hta's etc.

One criticism of the seat post pivot is...there is a perceived bucking affect on rough roads. This obviously would affect some riders more than others depending on the weight of the rider and riding style. What I would like to see moving forward is some tunability of this pivot for the simple reason that no two riders weight the saddle the same...even if they are the same weight. Some ride lighter or heavy in the saddle. So I am hoping to see Trek evolve this concept which has merit. Perhaps have different shim options with different elastomer grommets which would affect pivot resistance. I haven't had a Domane pivot apart to know what it consists of...if there is a target preload or torque to the joint for example. This pivot maybe dial-able with some clever engineering in the future....not unlike a simple analog to dually mtbs where the rear shock can be tuned based upon riding conditions and rider weight.

Last edited by Campag4life; 06-29-13 at 03:40 PM.
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Old 06-29-13, 03:41 PM
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There was about 1.5 miles of that on my ride today. That was enough for me.
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Old 06-29-13, 04:12 PM
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that means you have a nice smooth surface to ride on after it's done. Think of the positives. Around here they pearock roads as little as 2 years after they repave them so no road remains silky smooth for very long.... somewhat bumpy roads are par for the course out here.
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Old 06-29-13, 04:32 PM
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Woah. I rode about 1.5 miles on one of those corrugated surfaces. There was so much vibration, my vision started getting blurry from my eyeballs bouncing around. I can't imaging doing 16 miles of it.

Then it's pretty amazing when the road switches back to smooth! All the noise stops, and the road is like a dream.
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Old 06-29-13, 05:00 PM
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Dampening is when you wet yourself
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Old 06-29-13, 05:10 PM
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Originally Posted by jkuper
Dampening is when you wet yourself
Its damping of course and even that maybe a false reference technically. The reason is...a pivot doesn't damp. Although the resonant frequency of the seat tube maybe reduced by presence of the pivot because of decoupling from the higher frequency lower section rear chain stay. This could be construed as damping the rate of oscillation of the seat tube thereby instilling a more comfortable ride.
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Old 06-29-13, 06:48 PM
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Originally Posted by Campag4life
Its damping of course and even that maybe a false reference technically. The reason is...a pivot doesn't damp. Although the resonant frequency of the seat tube maybe reduced by presence of the pivot because of decoupling from the higher frequency lower section rear chain stay. This could be construed as damping the rate of oscillation of the seat tube thereby instilling a more comfortable ride.
After 16 miles of it, the damp part was almost correct.

I've been on that type of surface many times on my steel bike, just for not nearly as long, and the truth of it was there is no way I could have tolerated it for that many miles on my other bikes. The Domane is pretty amazing in that regard. I found myself weighting my seat more than normal and lightening my hands. Very little harsh shock or vibration came up through the seat. Obviously you have to feel something, but it really knocked it down enough that it didn't bother my butt or my back, and it saved my hands and feet. When I would load up either my hands or feet, the vibration was aweful for both.

I'm still wondering what got into my head to not just give it up and turn it around. Probably reading too many HTFU responses on here.
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Old 06-30-13, 05:58 AM
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Originally Posted by SmellTheSmug
After 16 miles of it, the damp part was almost correct.

I've been on that type of surface many times on my steel bike, just for not nearly as long, and the truth of it was there is no way I could have tolerated it for that many miles on my other bikes. The Domane is pretty amazing in that regard. I found myself weighting my seat more than normal and lightening my hands. Very little harsh shock or vibration came up through the seat. Obviously you have to feel something, but it really knocked it down enough that it didn't bother my butt or my back, and it saved my hands and feet. When I would load up either my hands or feet, the vibration was aweful for both.

I'm still wondering what got into my head to not just give it up and turn it around. Probably reading too many HTFU responses on here.
I believe you it works. Plus the overall design of the Domane is forgiving to vibration just like a Roubaix is. I have put the two bikes side by side and the geometry is strikingly similar and I can tell you first hand that the ride of the Roubaix over rough road is pretty amazing in particular for how racey the Roubaix is. The Domane is becoming a favorite for pros as well over the Madone and even pros like the the great Cancellara who has won on the Roubaix prefers the Domane to the Madone for overall ridability and his race bike of choice. I would love to see the FEA for the pivot which no doubt shows the kinematic displacement of the Domane under load. Decoupling the seat tube from the seat stay apparently is a game changer for ride quality. The question is why. I try to visualize how the pivot works. Seat stays are required for lateral stability of the rear triangle of course in support of the chain stays. Sta typically places the seat stay in compression over bumps. But in the case of the Domane this doesn't occur...or perhaps if it does at a fraction of the pressure because the seat stay rotates. So apparently this is the key. The top tube goes into tension and the seat stay doesn't compress. Perhaps it is the compression of the seat stay that contributes harshness and if this resistence can be removed, road shock isn't transferred up the seat stay into the rider's butt. In any event, those that own Domane's say it works and it isn't a gimmick. I know the Domane is a fast bike because I have ridden with guys that own them who are fast guys.
Enjoy it.
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Old 06-30-13, 07:19 AM
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Originally Posted by jkuper
Dampening is when you wet yourself
Originally Posted by Campag4life
Its damping of course and even that maybe a false reference technically. The reason is...a pivot doesn't damp. Although the resonant frequency of the seat tube maybe reduced by presence of the pivot because of decoupling from the higher frequency lower section rear chain stay. This could be construed as damping the rate of oscillation of the seat tube thereby instilling a more comfortable ride.
Oh, good - for a second there, I thought that you had missed the opportunity to turn a joke in to an platform for pedagoguery.
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Old 06-30-13, 08:05 AM
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Originally Posted by WhyFi
Oh, good - for a second there, I thought that you had missed the opportunity to turn a joke in to an platform for pedagoguery.
Sorry it went over your head. Well, not really...common on the 41 what gives us the background music. Look at it this way. I am not speaking to you as you can't possible participate.
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Old 06-30-13, 08:34 AM
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Originally Posted by Campag4life
Sorry it went over your head. Well, not really...common on the 41 what gives us the background music. Look at it this way. I am not speaking to you as you can't possible participate.
Of course it went over my head, starting from atop such towering intellect.
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Old 06-30-13, 01:14 PM
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Originally Posted by WhyFi
Of course it went over my head, starting from atop such towering intellect.
Point is, the pedantic put down is your self reflection. You have nothing to offer so you go there. If you want to talk about the merit of the Domane joint which is pretty unique in the industry, why don't you? I believe the answer is obvious. You don't have anything to offer or you would likely engage in more meaningful dialog...even if its shallow chatter. For example. What I wrote was technically flawed. There are a lot of engineers on this site. I was waiting for a counter point to what I wrote. Your drivel is just a waste of band width.
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Old 06-30-13, 01:23 PM
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Blah, blah, blah - yeah, I'm wasting bandwidth by informing you that this particular commentary is unwarranted, unwanted and a prime example of the source of the widespread disdain towards you. But go ahead - pretend that what you're offering is what others want. Ha.
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Old 06-30-13, 03:17 PM
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Originally Posted by Campag4life
This could be construed as damping the rate of oscillation of the seat tube thereby instilling a more comfortable ride.
Originally Posted by Campag4life
What I wrote was technically flawed. There are a lot of engineers on this site. I was waiting for a counter point to what I wrote.
Okay, rates arenít technically damped, amplitudes are. If the rate of oscillation changes, then simply the resonant frequency has changed. But Iím no engineer...
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Old 06-30-13, 03:20 PM
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Originally Posted by WhyFi
Blah, blah, blah - yeah, I'm wasting bandwidth by informing you that this particular commentary is unwarranted, unwanted and a prime example of the source of the widespread disdain towards you. But go ahead - pretend that what you're offering is what others want. Ha.
Here's the point you can't see in the very small lens you look through. You are not my audience. You don't have the intellect. You are a guy who prefers to live in a petty world and criticize others needlessly. It isn't necessarily your fault...or it may be. I don't believe much in free will. You are a victim of the DNA lottery. You got the short straw. You can't pick your parents. So carry on which you will because there are a lot of guys like you on the web. I am not speaking to you. I am talking to other guys who like to have a substantive conversation which does break out on the 41 from time to time. There is also a lot of comedy here which is entertaining. But your derision is a sad footnote...again what I refer to as background music.
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Old 06-30-13, 03:50 PM
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Originally Posted by robabeatle
Okay, rates aren’t technically damped, amplitudes are. If the rate of oscillation changes, then simply the resonant frequency has changed. But I’m no engineer...
But you play a pretty effective one on the internet and I believe you are helping define why the pivot works. I have looked at the pivot a bit closer since my previous post. I believe technically what the pivot does...saying it a bit different is...the pivot eliminates high frequency vibration of the seat tube/post felt by the rider. What is substituted is lower frequency but higher amplitude vibration which is more comfortable. To use an analogy it is Lincoln town car versus a Porsche 911. The pivot kills the buzz in other worlds. Comments have been made about feeling the seat tube move which I believe it does. What is substituted is higher amplitude and lower frequency oscillations for typical high frequency, low amplitude vibration when seat stay, seat tube and top tube are all connected conventionally. This maybe a watershed design in fact as many seem to like it including pros who have chosen it over the Madone.

Below is a pic of the joint. Where I mis-spoke earlier taking a harder look at the design is...the seat stay is connected to the top tube. They move together and will have both compression and tension relative to one another. But...the seat tube can pivot around both the seat stay and top tube. Trying to visualize how this works over bumps....the freedom of this joint I believe allows the seat stay to bow (concave up), the sta increases as the seat tube loads..over bumps the seat tube will want to rotate back...and the top tube goes into greater tension over bumps. The top tube of course is very strong in tension and a worthy restraint to the seat tube trying to rotate rearward about the BB and pivot as the seat stay goes into compression. The top tube keeps the seat stay from crushing under compression.

In summary, its a clever design. Again, there is no doubt this is dynamically modeled on CAD someplace by Trek engineers where the actual displacement of the seat tube as it angles can be seen with load and rebound and companion stress and strain. The real question is...is this the beginning of a larger trend that was really started with the Roubaix which has highly engineered seat stays to soften aka damp deflection. I hope so and believe it will be. Nice to have a road bike that is both fast and comfortable...what both the Domane and Roubaix are.
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Domane Pivot.jpg (61.1 KB, 15 views)

Last edited by Campag4life; 06-30-13 at 03:57 PM.
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