Minimizing chain noise

[Solcar]

Any other tips or strategies for minimizing chain noise

I use plastic chain in the first stage, which has greatly quieted down my drive train.

https://sdp-si.com/eStore/Direct.asp?GroupID=447

https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=5231&GroupID=447

The links pry apart, which makes setting the length relatively easy.

 

[swbluto]

Any other tips or strategies for minimizing chain noise

I use plastic chain in the first stage, which has greatly quieted down my drive train.

https://sdp-si.com/eStore/Direct.asp?GroupID=447

https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=5231&GroupID=447

The links pry apart, which makes setting the length relatively easy.

Very interesting. I've calculated I need at least 26 pounds from the tensile rating, and I found good ratings on regular roller chain ratings at http://en.wikipedia.org/wiki/Roller_chain, but I found that the "working load" rating was often 4-5 times less than the tensile strength rating. Is the "Ult. tensile strength" supposed to mean the working load rating or just regular tensile rating? If the tensile rating, it seems like none of them will work reliably(The high rating versions also required like .5" pitch. That'd be a big sprocket.). (Either that, or I have to stick below 1-2 kw, which is why I was going with chain in the first place.)

 

[Solcar]

swbluto, I can give my results from experience, which should help some, at least. My motor sprocket is able to apply 20 pounds or more to the plastic chain and after a few thousand miles, it hasn't failed. That seems to give me some confidence that your 26 pound situation could work as well.

Edit: my reckoning is based partly on the fact that for about the past 1000 miles I was running an 8 tooth .25 pitch sprocket, that was metal, on the motor. If possible, I recommend plastic sprockets to ease the wear on the plastic chain. I have since changed the motor sprocket to an 11 tooth plastic one.

 

[swbluto]

swbluto, I can give my results from experience, which should help some, at least. My motor sprocket is able to apply 20 pounds or more to the plastic chain and after a few thousand miles, it hasn't failed. That seems to give me some confidence that your 26 pound situation could work as well.

Are you using the .25" pitch type?

 

[kenkad]

Hello,
I have been watching this thread with quite some bit of interest. I am particularily curious about the comment by Papa 'that he plans to CNC some sprockets from 7075T6'. I have looked all over Gates website and have never seen the critical dimensioning that goes along with specifying the machining of the sprocket teeth, regardless of which tooth pattern one chooses. Where did Papa get this dimensioning? I would have assumed that this is proprietary information. If this information is available, can we get a link to this info? It certainly is not in the PDF referenced by Miles.
kenkad

 

[Solcar]

Are you using the .25" pitch type?

yes (please see my edit on last post)

 

[MitchJi]

Hi,

How does one minimize chain noise?

According to one place, a slower chain speed (like feet/minute) results in less noise. So does a smaller pitch. So does a larger tooth count.

So, the solution to reduce chain speed there is to decrease the tooth count at the jack-shaft sprocket or go with less teeth on the motor sprocket (But, then below 12t or whatever, chordal noise comes into play).

Those statements contradict each other and I think the second statement is incorrect. I think the main issue is that a sprocket with more teeth is closer to a straight line (which is less noisy) so I think more teeth is always going to be quieter (easy to test before you build a drive). Also agrees with the quote I'm posting below from Ramsey.

Ok, let's sum up:

8M PowerGrip GT and HTD profiles are the same.

8M PolyChain GT profile is different.

PolyChain has a significantly higher torque handling capability than PowerGrip. The belts are also much more expensive than those for PowerGrip.

Moving from 5M PowerGrip to 8M PowerGrip is itself a significant change in torque handling capability.

Does anyone know if 5mm x 15mm PolyChain belts and sprockets are available? Decent assortment?

Does anyone have ratings on the HTD belts greater than 5mm? Like 8mm, 14mm, 20mm or something else? It seems that Gates doesn't make this information so easily accessible/findable from their site.

The problem with 8mm and larger is with decent reduction ratios you end up with pretty large driven pulleys. Going to 5mm pitch and 20mm width might be a better option?

BTW the Ramsey Silent Chain Design Tips page and Calculator are pretty useful.
http://www.ramseychain.com/eng_design_tips.asp

Minimizing Noise and vibration
Use smaller pitch chains and sprockets with larger numbers of teeth to reduce noise and vibration.

Sprockets
Increasing the number of teeth in sprockets will decrease noise and prolong sprocket life. Whenever possible sprockets should have a minimum of 21 teeth.

Shaft Center Distance
The distance between shafts should be great enough that the chain wraps the small sprocket at least 120 degrees. Generally, center distances should not exceed 60 pitches.

I don't know the prices but the Calculator results look good:
http://www.ramseychain.com/chain_calc.asp

 

[swbluto]

Hi,

How does one minimize chain noise?

According to one place, a slower chain speed (like feet/minute) results in less noise. So does a smaller pitch. So does a larger tooth count.

So, the solution to reduce chain speed there is to decrease the tooth count at the jack-shaft sprocket or go with less teeth on the motor sprocket (But, then below 12t or whatever, chordal noise comes into play).

Those statements contradict each other and I think the second statement is incorrect. I think the main issue is that a sprocket with more teeth is closer to a straight line (which is less noisy) so I think more teeth is always going to be quieter (easy to test before you build a drive). Also agrees with the quote I'm posting below from Ramsey.

Yes, they are contradictory. What I meant was that a larger tooth count reduced the "chordal action", which should reduce sound. However, less teeth on the motor sprocket will reduce the chain speed at a given motor RPM. Overall, though, I think I would agree that a larger sprocket would reduce overall noise. As you said, it's pretty easy to test.

 

[Papa]

Does anyone know if 5mm x 15mm PolyChain belts and sprockets are available? Decent assortment?

5m and 15m PolyChain are NOT available. Only two PolyChain pitches available; 8mm and 14mm. The 8mm comes in 4 widths; 12mm, 21mm, 36mm, and 62mm. There is approx. 30 different belt lengths available in each width.

 

[Miles]

I have looked all over Gates website and have never seen the critical dimensioning that goes along with specifying the machining of the sprocket teeth, regardless of which tooth pattern one chooses. Where did Papa get this dimensioning? I would have assumed that this is proprietary information. If this information is available, can we get a link to this info? It certainly is not in the PDF referenced by Miles.
kenkad

Hi Ken,
I think it is proprietary. I haven't seen it published anywhere. The exact tooth form is less critical for the large sprocket, though.

 

[Miles]

I'll try to pay attention, this time

Does anyone know if 5mm x 15mm PolyChain belts and sprockets are available? Decent assortment?

5m and 15m PolyChain are NOT available. Only two PolyChain pitches available; 8mm and 14mm. The 8mm comes in 4 widths; 12mm, 21mm, 36mm, and 62mm. There is approx. 30 different belt lengths available in each width.

This wasn't always the case... Old stock PolyChain 5M GT belts are still available, here: http://www.royalsupply.com/store/pc/Poly-Chain-GT-Belts-5M-c1032.htm I'm not sure if they would perform significantly better than PowerGrip 5M GT3, though...

 

[Miles]

The problem with 8mm and larger is with decent reduction ratios you end up with pretty large driven pulleys. Going to 5mm pitch and 20mm width might be a better option?

You can have belts cut to any width you want. Wider belts require more critical alignment and have greater bearing overhang....

 

[Papa]

I'll try to pay attention, this time

uh oh!... now i'm in trouble! :wink:

This wasn't always the case... Old stock PolyChain 5M GT belts are still available, here: http://www.royalsupply.com/store/pc/Poly-Chain-GT-Belts-5M-c1032.htm I'm not sure if they would perform significantly better than Powergrip 5M GT3, though...

My response was governed by current availability from Gates. Obviously, some 5m's are still available through select dealers, but for how long since I can't locate any 5m PCGT within Gates' parts finder: http://www.gatespowerpro.com/Comergent/en/US/adirect/gates?cmd=GRCPartInterchangeSearchFrame&CFID=21578220&CFTOKEN=65801839

Also, in pertinent part: "Sprockets for the Poly Chain GT belts are available in 8mm and 14mm pitches." at: http://www.gates.com/brochure.cfm?brochure=3150&location_id=3878
Assuming that's the case, I'd be hesitant to build around 'seemingly' discontinued parts.

 

[Miles]

Papa,

Yes, I agree. I wasn't intending to contradict you I think (needs checking...) that the 5M PolyChain used the same sprockets as PowerGrip GT. Anyway, it's history...

 

[Papa]

I think I've butchered swbluto's thread far too much. I think I'll go sit in the corner now. :wink:

 

[Miles]

LOL. He's started so many threads.... I wouldn't worry about it..

 

[Miles]

Re. PolyChain tooth form, I found this:

http://www.cnczone.com/forums/showthread.php?t=102033

http://www.practicalmachinist.com/vb/general/polychain-sprocket-cutters-174162/

 

[Papa]

http://www.google.com/patents/about?id=VwwvAAAAEBAJ&dq=toothed+belt+and+sprocket+westhoff

 

[Miles]

Thanks Papa,

You beat me to it.

 

[Papa]

Geee.. I wonder who MVHPV is?

 

[Miles]

Geee.. I wonder who MVHPV is?

You?

Initials M. V. Anybody?

 

[Papa]

I'm currently running 75t/28t, highly modified steel (actually, one cast and the other stainless), feeding an iM9. By month's end, I should be spinning 7075-T6. After spending 40 years 'in chains', this setup is pure unadulterated bliss..

 

[Papa]

Geee.. I wonder who MVHPV is?

You?

Initials M. V. Anybody?

Magic Valley - do east of Treasure Valley. Pretty helpful, huh?

 

[Miles]

I'm currently running 75t/28t, highly modified steel (actually, one cast and the other stainless), feeding an iM9. By month's end, I should be spinning 7075-T6. After spending 40 years 'in chains', this setup is pure unadulterated bliss..

8) Look forward to the pics

 

[Papa]

8) Look forward to the pics

Soon. Got a pedal party to crash in Kellogg on the 27th first. Premature leaks would be detrimental to the cause