The noise from my Fortius Brake roller is caused by

Fortius, i-Magic , Cosmos, Flow , upgrade kits
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Techno
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The noise from my Fortius Brake roller is caused by

Post by Techno » Thu Apr 10, 2008 7:52 pm

The steel sleeve on the roller is loose so that it is constantly being made to chatter under tyre contact.
Has anyone found or improvised a remedy??

mcorn
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Post by mcorn » Thu Apr 10, 2008 8:08 pm

Tacx (FMM) has identified this as a problem that requires replacement of the entire motor unit. The motor unit is relatively easy to disassemble. Unfortunately, the half of it with the stainless steel covered urethane roller has at least one press-on bearing (which can be removed with some effort), but also has a press-on plastic fan which I don't think you can remove without destroying. It would be nice if Tacx made some of these things available as relatively inexpensive spare parts. If they did, it would not be hard to replace the shaft with urethane roller.

Techno
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Post by Techno » Thu Apr 10, 2008 8:29 pm

Thanks
I've just partially dismantled and concluded the same.
It's just cost me £145 for a replacement :evil: I hope Tacx have sorted this problem with the part or I'll be finding another make of trainer next time.

Techno
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Post by Techno » Fri Apr 11, 2008 5:36 pm

While waiting for the new unit I decided to try a repair.
I've drilled out all the holes in the stainless steel sleeve 10mm deep and countersunk the hole slightly. Filled all with rapid epoxy resin 4 at a time.
Will let you know how it goes.
Link to picture
http://techno.smugmug.com/Cycling/Bikes ... 4vrV-L.jpg
P.S. It would be usefull and much cheaper if Tacx made this as pictured available as a spare rather than the WHOLE damn unit :evil: :evil: :evil:
Last edited by Techno on Mon Oct 26, 2009 12:54 am, edited 2 times in total.

Techno
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Post by Techno » Fri Apr 11, 2008 8:43 pm

Repair held up ok.
65min session with 4x5min @270/280 watts.
noisiest thing was cooling fan then my breathing then my chain, roller inaudible against all other.
Why oh why dint they just make a solid roller instead of trying to be clever?
Last edited by Techno on Mon Oct 26, 2009 12:55 am, edited 1 time in total.

mcorn
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Post by mcorn » Fri Apr 11, 2008 9:58 pm

Techno wrote:Repair held up ok.
65min session with 4x5min @270/280 watts.
noisiest thing was cooling fan then my breathing then my chain, roller inaudible against all other.
Why oh why dint they just make a solid roller instead of trying to be clever?
Graph of ride
http://techno.smugmug.com/gallery/35147 ... XJpWk-O-LB
I will be interested in seeing how your repair holds up as it is very difficult to get a permanent bond on cured urethane.

The earlier models did not have the steel band, only the urethane roller. My understand is the urethane by itself wore out too quickly from friction and heat. But I agree that the banded approach is pretty flimsy as evidenced by a fairly large number of reports of problems with it coming loose. I think that a roller of the type used on the CompuTrainer is much better and more durable. It also provides good traction.
Last edited by mcorn on Sat Apr 12, 2008 4:51 pm, edited 1 time in total.

Techno
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Post by Techno » Fri Apr 11, 2008 10:09 pm

I don't think it especially needs to bond. There are effectively 12 spikes of set epoxy embeded in the urethane. As long as it stops the steel sleeve moving it should remain silent. FINGERS CROSSED :lol:

One more thing! now the sleeve is stabilised, there is no tyre residue or beading at all.
Conclusion is that the poor design has also been responsible for wrecking our tyres :?:

mcorn
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Post by mcorn » Sat Apr 12, 2008 4:55 pm

I think a loose steel band is only one of a number of potential causes of noise problems. I know that my first orange Conti trainer tire wore out very quickly while the second one did not. Both of them were used on the same resistance unit, but the rubber on the first tire seemed to be very soft and shredded easily. I returned it to the US distributor who provided a replacement that has worked much better.

Techno
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Post by Techno » Tue Apr 15, 2008 10:41 pm

Been ill 4 days but repeated the 65min interval session tonight. Still whisper quiet. :D

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Post by Techno » Fri May 02, 2008 10:39 pm

A great number of sessions now and I'm quite confident my repair is not going to fail.

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Post by Techno » Sat May 10, 2008 4:03 pm

Luckily SBR/Bonthronebikes did not deliver the new unit either so I cancelled and saved a load of wonga. :D
Maybe I should go into business doing repairs :lol: 8)

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Post by mcorn » Sun May 11, 2008 3:05 pm

Glad to hear your repair is holding up. That's a good tip for folks to put in the notebook. It looks like you could do it without diassembly of the unit. In fact, it could probably be done with the motor-roller mounted on the frame. (Just use a vacuum to cleanup the drillings from the urethane roller.)

Techno
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Post by Techno » Sun May 11, 2008 5:48 pm

Yes no need to strip the unit but it's easier on a bench.

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Post by hmronnow » Mon Sep 22, 2008 3:01 pm

I have been reading forums to help decide which trainer to get. It seems if the Tacx fortius works, it would be my choice. However, this and other threads have brought me in serious doubt. Therefore, some questions to those of you who have much experience:

- Does the above described repair still hold (last post was in may)

- Could the 'choppiness' perhaps be reduced by attaching a flywheel on the right-side of the roller (seen from behind). I.e. a) does it seem possible to make such a modification? (I have only seen pictures of the product) and b) do you think this would help with the choppiness?

- can you nail the 6% issue: Does it essentially mean that it behaves badly above a certain power-value? (that power-value may depend on rpm). I am a weak rider with FTP of only 240. Is it possible that I would not be able to push the unit into the range where it works poorly?

Thanks
Henrik

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willy
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Post by willy » Mon Sep 22, 2008 4:05 pm

Techno wrote:Thanks
I've just partially dismantled and concluded the same.
It's just cost me £145 for a replacement :evil: I hope Tacx have sorted this problem with the part or I'll be finding another make of trainer next time.
:shock: it's almost half the price of the Fortius, isn't it ?

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Post by Techno » Mon Sep 22, 2008 6:36 pm

My repair is still going strong so unlikely to need a replacement. Done 1000 miles easily and quieter than when it was new.

tri-xy68
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Post by tri-xy68 » Mon Sep 22, 2008 7:15 pm

willy - what do you mean half the price of the fortius - here in Canada the Fortius costs Can$1400, which is ~ £700?? You must be talking about the just the replacement motor brake or something??

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willy
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Post by willy » Mon Sep 22, 2008 8:19 pm

tri-xy68 wrote:willy - what do you mean half the price of the fortius - here in Canada the Fortius costs Can$1400, which is ~ £700?? You must be talking about the just the replacement motor brake or something??
In France it costs 600€ so it's about 475£, I've got mistaken, not a half, "just" a third of the price...

tri-xy68
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Post by tri-xy68 » Mon Sep 22, 2008 8:38 pm

yeah that is more like it - Here in Canada it is very expensive and the Fortius has the 110V speed and choppiness issues.

I just bought an I-magic from the States for US$850=574€ =457£, which is about Can$500 cheaper than here in Canada.

You can probably do much better in on-line shops, or e-bay, as well.

Cheers Peter.

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Post by hmronnow » Tue Sep 23, 2008 10:21 am

OK, so if one is willing to perform Techno's fix, the noise issue can be eleviated.

Any feedback on whether the choppiness will occur for a mediocre 240W FTP rider like myself, or only for superfit +300W guys?

And, the question as to whether one could attach a flywheel with some inertia to dampen that choppiness.

Since I haven't seen unit and hence not experienced the chopiness, this is complete guesswork. But my guesswork is that the chopiness is relted to the fact that the motor is not continuous. Inside there must be an array of magnets and coils (they probably use a so-called DC brushless motor/generator). Let us assume there are 32 magnets along one revolution, and assume a 3" roller (with 0.24meter circumference) and assume the problem arrise at a speed of 16kmh=10mph=4.4meters/second. This means the roller would spin with 18 revs/minute, hence passing about 600 magnets per minute, or 10 per second. This would give a 10 Hz choppiness. Now, these numbers are guesswork, but if the chopiness is between 5 and 20 Hz, it could be an explanation. And, there would be nothing to be done about it.

There could on the other hand be a different explanation. The unit feeds the produced electric power into the grid. This is in principle very clever, since instead of producing heat in the exercise room (the rider produces plenty of that himself), the power is not only disposed but even 'recycled'. However, this requires converting the DC power produced by the generator to AC power synchronized to the powergrid. Firstly, there can of course be poor engineering of conversion or synchronisation. But even with perfect conversion and synchronization, it is a fact that for a single phase AC, the power is in fact modulated with 100Hz. Hence, the load on the DC motor would also be modulated with this frequency, and could lead to a 100Hz chopiness. The solution to this would be either electronic damping, but at >300W this probably requires some rather beefy capacitors. Or, one could forego the nice idea of sending the power back into the grid. Instead have a large variable resistance (one capable of receiving up to 1000W). That would be a much simpler design, with the only draw-back that the energy gets converted to heat - but that's how all the other trainers work.

Given that Tacx seem unable to solve any problems themselves, they could opt to provide enought information on the engineering that the user-group can come up with the solutions.

Thos of you who have had the unit open, can you see any indications of make and model of the motor?

ATB
Henrik

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