# IsoSpeed Decoupler Maintenance?



## bobf

I've put about 6000 miles on my Domane 5.2. Does anyone know if the isospeed decoupler ever needs maintenance? Not that mine is acting up, but I've wondered how it will hold up over time.


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## Kerry Irons

bobf said:


> I've put about 6000 miles on my Domane 5.2. Does anyone know if the isospeed decoupler ever needs maintenance? Not that mine is acting up, but I've wondered how it will hold up over time.


Perhaps you need a recalibration of your flux capacitor?

In other words, what the heck is an "isospeed decoupler"? Oh, that's right - something of a marketing gimmick. If it does need maintenance it would be to clean and relube. Does it come apart with tools?


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## ibericb

That's about all you could do. It's pretty simple - a couple of sealed cartridge bearings make up the heart of it.









Source


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## looigi

It's a shaft with two cartridge bearings. Since they only rotate a few degrees at most, IDK what the symptom acting up would have. If the balls/races got trashed maybe there'd be some perceptible play in trying to force the seat tube fore and aft. Maybe they seize? Anyway, the cover pries off and the shaft is removable via hex headed screws.


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## bobf

Kerry Irons said:


> Perhaps you need a recalibration of your flux capacitor?
> 
> In other words, what the heck is an "isospeed decoupler"? Oh, that's right - something of a marketing gimmick.


Trek's nomenclature, not mine. Maybe I'll take it apart after I set the henweigh to 572 radians and bifurcate the jamflacket.

Actually, I like my Domane and I think the decoupling works pretty well. Not going to F with it if I don't need to.


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## Jon D

I have about 10,000 miles on mine still works just fine.


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## robt57

Jon D said:


> I have about 10,000 miles on mine still works just fine.


You need to get the dilithium crystal replenished. Unless you have or upgraded to the newer one with the Mr. Fusion option.


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## ibericb

robt57 said:


> You need to get the dilithium crystal replenished.


That explains my problem.


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## ghettocop

Kerry Irons said:


> Perhaps you need a recalibration of your flux capacitor?
> 
> In other words, what the heck is an "isospeed decoupler"? Oh, that's right - something of a marketing gimmick. If it does need maintenance it would be to clean and relube. Does it come apart with tools?


While I don't care much for Trek as a company nor it's business practices, I would not call the de-coupler a gimmick. That thing seriously works as advertised.


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## looigi

^^^ True.


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## bobf

OK, the reason I started the thread is that my Domane has been making clicking noises. I've been working through the checklist, and I'm to the point where I suspect either the brake cable where it routes inside the top tube or the iso decoupler joint. I wasn't able to change anything about the former (pulled it out, and yep, it's a cable), so I bit the bullet and opened up the decoupler. 

I'm not saying the cable is proven innocent, just that if it's guilty I don't know what to do about it. Kind of like the guy who lost something in the basement. When his wife asked, "Why are you looking in the kitchen?" he answered "Because the light is better up here."

The decoupler dust cover is held in place with an Allen bolt. As the pictures from Ibericb show, there are sealed cartridge bearings underneath. I can rotate the inner part of each bearing with a finger, and they feel surprisingly bumpy, as if the bearings are little boulders instead of round. They don't feel gritty, though. Rotating involves putting a little side-load on the bearing, so maybe that's the cause of bumpy feel? Or is it likely the bearings are shot?

If so, does anyone have experience with changing these out? They don't want to lift out of position so I wonder if they are press-fit. I'm real close to putting my LBS on the case.

Incidentally, the cable clearance inside the top tube seems to be microscopic. If I squeeze my rear caliper even slightly I get a very audible click from the top tube, as if a tiny bit of slack allows the cable to hit it inside. The click is tantalizingly similar to the one that's driving me batty on the road.

Thanks for the replies so far. I'm going back to the garage.


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## TJay74

My wifes Domane 4.3 was making a clicking sound as well, it was the chain. I am sure you have changed yours by now but just in case.

I could see the isocoupler causing issues as well, more so if you are somewhat bouncing on the saddle on bad bearings.

And as said that system works, so much to the point of when I wanted to upgrade my wife into a Giant Avail Advanced Di2 she refuse saying she loves her bike and is not interested in anything else. Full carbon, 105 group and she has the Bontrager RXL wheels.

Cant argue with her on that, means I can mod something else instead.


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## Srode

If the clicking is the coupler, it shouldn't make the noise riding out of the saddle. Try that as a test maybe?


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## looigi

Cartridge bearings should not feel lumpy. If they do, they're damaged, though the degree and consequence can vary over a wide range. Using ball bearings for the IS coupler is a questionable choice IMO as they don't rotate more than a degree or two so the ball always ride in the same place in the races and at the same point on the balls which can lead to lumpiness and notchiness, similar to can happen to headsets, though headsets often rotate much more than what what the IS coupler does. Any play between the shaft and the inner races can cause clicking, and if the bearings are very worn so as to be loose, they can click too. Replacement bearings should be cheap. The bearings are pressed in. Once the screws are removed from the end of the shaft, the shaft and drive side bearing is pressed out using an drift or (8mm screw works) and small hammer. The NDS bearing is driven out with a small punch working around the perimeter of bearing. In assembly, grease the outside of the races and use the bolts in the shaft ends to press the the bearings in. Bolts on each side are torqued to 8 NM. 

Using the bolts to press in the bearings via the inner race can itself damage the bearings, so this is kinda a bogus design/method, IMHO.


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## bobf

looigi said:


> Cartridge bearings should not feel lumpy. If they do, they're damaged, though the degree and consequence can vary over a wide range. Using ball bearings for the IS coupler is a questionable choice IMO as they don't rotate more than a degree or two so the ball always ride in the same place in the races and at the same point on the balls


I agree. I also wonder about the load on the coupler. If my butt on the seat forces the seat tube to bend, the top tube and seat stays will also flex, and the force to bend them transmits thru the coupler. That seems like a lot of force, though maybe no more than what the wheel and BB bearings have to carry. I wonder if a sleeve or roller bearing would be better, so long as the former is well-lubed to prevent squeaks.

For those with ideas of how to test my click noise, thanks, but I'd rather not take the thread down that rabbit hole. In a nutshell, I have an intermittent click that isn't 100% correlated to anything I do. I'm keeping track of the symptoms (how and when clicks do or don't occur) and of what I've tightened, greased, or inspected on the bike. It's getting to be a long list. That said, I'm not certain I've eliminated any of the possible causes!


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## TJay74

So as suggested and I am assuming this is only happening while in the saddle under a decent amount of pedaling effort?


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## Peter P.

If you think it's your brake cable, merely remove the cable completely and go for a ride.

It's not a death sentence. With a little common sense you'll survive and you might find the cable is the real cause.


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## bobf

TJay74 said:


> So as suggested and I am assuming this is only happening while in the saddle under a decent amount of pedaling effort?



Oops, whoa. Sorry, but I’d rather not get into this. I meant the thread to be about the isospeed decoupler. It’s my fault it has drifted to where people want to try and solve my clicking noise. But please don’t. I know it's well-meant, so thank you, but I don’t want a noise solution thread. See my “down that rabbit hole” comment from earlier.

The thing is, I can see a solution thread turning into a deal where a committee of advice-givers dreams up things to check while I spend a buncha time pursuing their suggestions or justifying why I ignore them. It would be a big internet game of WDYYB. Not going to go there. Would not be prudent at this juncture. Besides, I already have the Irons list to work with.

So thanks again, but I’ll be OK. I’m sure I’ll feel stupid when I find the answer, as in, “Why the **** didn’t I check that first??” For anyone who’s jonesing to track down a bike noise, you'll just have to come up with one of your own.


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## duriel

Well then, that is it, all you have to do is de-gause the in-futuro-tron and your good to go!


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## InBlack

Glad I came across this thread in my search for IsoSpeed Decoupler issues.
I've been having a pretty consistent "click" coming from the Decoupler for a good time now. It's definitely the decoupler (I've been able to recreate the noise while off of the bike).

I've also checked the bearings and have noticed that they are "notchy" which I'm thinking isn't normal, right?

I don't have a problem swapping out the bearings, which might be the culprit. looigi did a nice explanation on how to do it earlier in the thread. I'm just wondering if anyone knows the specs for the decoupler bearings?


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## tvad

bobf said:


> Maybe I'll take it apart after I set the henweigh to 572 radians and bifurcate the jamflacket.


Does that require a gangly wrench?


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## OldChipper

OK, I'll play the straight-man.... what's a henweigh? (you're welcome)


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## ogre

OldChipper said:


> OK, I'll play the straight-man.... what's a henweigh? (you're welcome)


African or European?


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## mfdemicco

looigi said:


> It's a shaft with two cartridge bearings. Since they only rotate a few degrees at most, IDK what the symptom acting up would have. If the balls/races got trashed maybe there'd be some perceptible play in trying to force the seat tube fore and aft. Maybe they seize? Anyway, the cover pries off and the shaft is removable via hex headed screws.


I'm still trying to figure out how this thing works. Is there an exploded view?


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## cxwrench

mfdemicco said:


> I'm still trying to figure out how this thing works. Is there an exploded view?


Basically it's like a pivot on a suspension bike. The top and seat tubes aren't rigidly bonded together, but they pivot allowing the seat tube to flex backward and absorb a significant amount of impact when the rider is seated. Definitely a noticeable improvement in ride quality.


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## deviousalex

Has Ceramic Speed come out with their Ceramic ISO Decoupler bearings that increases the torsional stiffness of your bike by 7% yet?


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## Chader09

Not and exploded view, but a good pic from the new hardtail MTB version that is easier to see the basic parts.
https://brimages.bikeboardmedia.netdna-cdn.com/wp-content/uploads/2015/06/S6O4224.jpg


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## looigi

If your frame in carbon fiber, you'll need to search on "assploded view".


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## ibericb

mfdemicco said:


> I'm still trying to figure out how this thing works. Is there an exploded view?


Try this from the patent:









More description here.


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## WormDevil

I've had a Trek Boone for a couple of years now and have ridden it hard on a variety of surfaces. For the second time this year i've had to service the IsoSpeedDecoupler. I can tell that is it due for service as the plastic cover on one side (drive side) is pushed out slightly and is not flush with the frame. I can also tell I need to service it because there is play at the TT / ST juncture. One of the bearings feels rough when I spin it with a finger after the bolt is removed (the other is very smooth). Because of the short travel of the bearing I'm not too concerned with it. I usually pull the bolts - both sides, and lube the bolt shoulder (where it meets the bearing) and re-locktite the threads of each bolt.
This small amount of maintenance is totally worth it however - this thing is like riding a naked Thai teen!


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## cxwrench

WormDevil said:


> I've had a Trek Boone for a couple of years now and have ridden it hard on a variety of surfaces. For the second time this year i've had to service the IsoSpeedDecoupler. I can tell that is it due for service as the plastic cover on one side (drive side) is pushed out slightly and is not flush with the frame. I can also tell I need to service it because there is play at the TT / ST juncture. One of the bearings feels rough when I spin it with a finger after the bolt is removed (the other is very smooth). Because of the short travel of the bearing I'm not too concerned with it. I usually pull the bolts - both sides, and lube the bolt shoulder (where it meets the bearing) and re-locktite the threads of each bolt.
> This small amount of maintenance is totally worth it however - *this thing is like riding a naked Thai teen!*


I'm not even going to ask...


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