roller vibration/noise dampening?

[joe.e]

anyone have any tricks for limiting the amount of whirring/vibration noise coming from a set of (cheap) rollers? Drums are metal, all the hardware is tightened, and the rollers are absolutely level (I used a level to check). I set em up on a really thick towel, and that deadened the noise a bit, but not to a level I'm comfortable using them when its not light out (I'm in a duplex, and we share a wall). I'm trying not to be a jerk neighbor, basically.

It only really gets bad when I'm spinning a big gear (53x12) and the drum is movin quick. The noise isn't even that much of an issue, its really the vibrating (that you can feel in another room) that I want to make sure our neighbor doesn't have to deal with.

help?

[11.4]

If it isn't the noise and just the vibration, it's almost certainly the drums themselves. Cheap rollers rarely have them turned with any precision.

But do they have band grooves on both sides? If so, here's a likely way to make it work for you. It's tedious but usually works pretty well. First, try to get a sense from the vibration on the bike whether it's front or rear. If front, swap that drum to the rear. See if it goes away. If your drums aren't great, you at least want the best one on the front to keep stuff quiet and stable. Then if the rear is still vibrating, reverse a drum, one drum at a time (this is where you have to have band grooves on both sides; if not, this doesn't work). You can have two drums that are vibrating each time the two unbalanced points get aligned. You may have to try three or four different combinations, but you'll usually find a way that works. This usually has to do with uneven weight distribution in the drums rather than with one actually drilled off-center.

Do check each drum to see if you can perceive any out-of-roundness or eccentricity -- just rotate each drum slowly and hold a business card or whatever against the frame to see whether you have high or low spots on the drum. I've seen drums drilled out of round, but drilling is pretty hard to mess up, while an uneven weight distribution is pretty easy to do. If out of round, you may not really have a choice, but still flip the drum around to try to minimize it.

Your frame typically shouldn't be a problem, but do lay the rollers out on a flat hard floor, lay a long straight edge from front to rear on each side and down the middle, and rotate drums slowly. If you see the middle rising and lowering (measured with a ruler up from the floor), the frame is actually not drilled right. At that point you can see if it's small and fixable with some filing, or you may want to build up one foot a little extra and then swap around drums to get the best result.

If you were telling me that the rollers were shrieking, I'd say to work on bearings. But with vibration only, it's most likely a matter of alignment and concentricity (of both dimensions and mass) which is more easily fixed but tedious to do.

[Peter P.]

I had similar experience even with Kreitler rollers. You're correct that it's vibration and not noise. While it's possible your rollers are out of round, information I received from a Kurt Kinetic tells me tire tolerances are 10x worse than roller tolerances. I realize you said your rollers are cheap but there's no telling without measuring if they're worse than the tires.

I was told the typical quality roller (on a KK Road Machine) will hold tolerances of 0.003", while the typical tire is 0.030". To prove this, think of it this way: If you could rotate your rollers at 25mph WITHOUT a bicycle could you imagine them creating such a vibration? Now add the bike...

There are two ways to mute that vibration; mass and damping. If you could add mass to the floor, more mass than the rollers could excite, you would not have the vibration. Think-a concrete floor.

Damping absorbs the vibration, turning it into low-grade heat. Some electric motors and HVAC equipment are mounted on isolation pads made of cork and ribbed rubber (http://www.supersoundproofingsales.com/products.asp?dept=25) which do the job.

Part of the problem is, your rollers are coupled to the floor at probably 6 points.That's a lot of pressure per foot. Distributing that pressure would also help. The towel isn't going to do much because it's only coupled to the floor under the feet, and getting severely compressed at that.

I would try a carpet scrap or two stacked, on the floor, a sheet of cork, a sheet of plywood, then another carpet scrap. Cork is very effective at damping vibration. You might have to make a multi-layered "sandwich" of cork tiles and plywood on a carpet base. Using a variety of materials, all with different resonant frequencies and absorptive properties will damp the vibration as well. I wouldn't be surprised if an effective vibration damping platform is +2" thick.

I bought several of the materials suggested at soundproofing.org (http://www.soundproofing.org/) . The web site even mentions using certain products (http://www.soundproofing.org/sales/vibrationpads.htm) under Kurt Kinetic trainers.

I gave up on my effort quickly, partially because I bought the wrong materials, and experimentation is expensive!

[Louis]

The simplest way is to leave them down in the basement and not use them. (which, btw, is what I do)

[bikerider888]

dynamat

or buy better rollers. Cheap rollers are a total waste of everyone's time.

[thwart]

or buy better rollers. Cheap rollers are a total waste of everyone's time.

Unfortunately not everyone wants to drop $400-$800 on something they may not like and use frequently (see the comment from Louis above). So newbies to rollers usually want something inexpensive.

My experience: new Nashbars (IIRC $120) > used Kreitlers (~ $200) > new e-motions (~ $600).

The e-motions now have several hundred hours of use... just did 60 minutes in my garage a few hrs ago with the sun shining in... made 30° F feel a lot warmer.

Back on topic, the carpet remnant and cork solution sounds like it would be very effective. Lowering tire pressure a bit would probably help somewhat as well.

[frank_h]

Not to thread-jack, but what about if its the opposite... More noise than vibration?

My tacx galaxia are crazy loud.

[11.4]

I had similar experience even with Kreitler rollers. You're correct that it's vibration and not noise. While it's possible your rollers are out of round, information I received from a Kurt Kinetic tells me tire tolerances are 10x worse than roller tolerances. I realize you said your rollers are cheap but there's no telling without measuring if they're worse than the tires.

I was told the typical quality roller (on a KK Road Machine) will hold tolerances of 0.003", while the typical tire is 0.030". To prove this, think of it this way: If you could rotate your rollers at 25mph WITHOUT a bicycle could you imagine them creating such a vibration? Now add the bike...

There are two ways to mute that vibration; mass and damping. If you could add mass to the floor, more mass than the rollers could excite, you would not have the vibration. Think-a concrete floor.

Damping absorbs the vibration, turning it into low-grade heat. Some electric motors and HVAC equipment are mounted on isolation pads made of cork and ribbed rubber (http://www.supersoundproofingsales.com/products.asp?dept=25) which do the job.

Part of the problem is, your rollers are coupled to the floor at probably 6 points.That's a lot of pressure per foot. Distributing that pressure would also help. The towel isn't going to do much because it's only coupled to the floor under the feet, and getting severely compressed at that.

I would try a carpet scrap or two stacked, on the floor, a sheet of cork, a sheet of plywood, then another carpet scrap. Cork is very effective at damping vibration. You might have to make a multi-layered "sandwich" of cork tiles and plywood on a carpet base. Using a variety of materials, all with different resonant frequencies and absorptive properties will damp the vibration as well. I wouldn't be surprised if an effective vibration damping platform is +2" thick.

I bought several of the materials suggested at soundproofing.org (http://www.soundproofing.org/) . The web site even mentions using certain products (http://www.soundproofing.org/sales/vibrationpads.htm) under Kurt Kinetic trainers.

I gave up on my effort quickly, partially because I bought the wrong materials, and experimentation is expensive!

I've had vibration due to tires that was painful to endure, but the vibration tends to be into your saddle, not a vibration that transmits through the floor and that kind of thing. And if it's the tires, you can figure that out quickly with a different pair of wheels or even just changing tire pressure for a few minutes. Short of having a quarter-inch high spot at your valve on a tubular, the kind of irregularity we talk about on tires actually tends to disappear when you get up to higher speeds anyway. If a tire vibration is so significant that it transmits a vibration through the floor, there are two issues: you are pounding your butt into a bloody pulp, and at speed the vibration becomes a hum and you actually float the low spots on the tire and it evens out. It's worst at about 10 mph on rollers. The reason I was focusing on the drums was because if it feels like a vibration, it is likely to be something that occurs not every drum revolution but once every several turns.

I'd definitely do clinchers on rollers, both for cost and because clinchers naturally end up a big rounder than tubulars.

[Peter P.]

I've read of some people erecting sound absorbing boxes around their trainers; I suppose you could do the same with rollers but it would be a big box.

I think in your case the cause is the bearings and the rollers. The bearings make the noise and the hollow chamber of the roller resonates much like a hollow body acoustic guitar ports the sound. I'll also bet the frame rails are hollow which is another resonant chamber.

If you could stiffen up the rollers with internal discs you could change the resonant frequency but I anyone would go to that trouble. You could try spraying Great Stuff foam inside the rails. If the bearings are standard size and readily removable, you could try a higher quality bearing.

[frank_h]

I've read of some people erecting sound absorbing boxes around their trainers; I suppose you could do the same with rollers but it would be a big box.

I think in your case the cause is the bearings and the rollers. The bearings make the noise and the hollow chamber of the roller resonates much like a hollow body acoustic guitar ports the sound. I'll also bet the frame rails are hollow which is another resonant chamber.

If you could stiffen up the rollers with internal discs you could change the resonant frequency but I anyone would go to that trouble. You could try spraying Great Stuff foam inside the rails. If the bearings are standard size and readily removable, you could try a higher quality bearing.

Great ideas. Hadn't thought of the spray insulation approach. The bearings are removable and actually had to loctite on install to keep things together.
I'll give these two tips a go. Thanks!

For vibrations I've had success using a yoga mat that also served go collect sweat. Granted, my vibrations weren't too bad, but it did help quite a bit.

(Also an apartment roller. Roll in a closet to try and minimize the damage.)