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Author Topic: Belt Tension (Getting tighter?)  (Read 2770 times)

stevenh

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Belt Tension (Getting tighter?)
« on: May 09, 2016, 03:22:18 PM »

When I got my DSR in late March the belt tension was at around 25kg.  I've checked it at around 750Mi this weekend, and it was at just under 45kg.  It still seemed to be aligned.  I backed off the tension to 25kg again and the belt got quite a bit quieter.  Has anyone else seen a belt get tighter over the first miles?  Seems very strange to me.  I am pretty sure I am measuring it correctly and the belt and pulleys look fine.

Steve
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JaimeC

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Re: Belt Tension (Getting tighter?)
« Reply #1 on: May 09, 2016, 04:59:43 PM »

Having ridden belt-driven Buells for years, it is not unusual for a belt to get tighter as it ages.  You didn't say how many miles you've ridden but belts don't age like chains.  As they get older, instead of getting looser (like a chain) they get tighter.

This is because the carbon fiber/Kevlar outer belt does not stretch.  Instead, as the rubber ages, it swells which reduces the inner circumference of the belt.  That reduction in inner circumference is what makes the belt tighter.
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MadwitTY

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Re: Belt Tension (Getting tighter?)
« Reply #2 on: May 09, 2016, 11:30:20 PM »

Is there a common mileage point where replacement of the belt is recommended?
I'm sure it's in the manual but I have lost mine  :-\
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JaimeC

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Re: Belt Tension (Getting tighter?)
« Reply #3 on: May 10, 2016, 12:13:51 AM »

Do what I did... load the PDF into your phone so it's always handy (even on the road).  I sure miss having a PRINTED manual, but I guess I need to get into the 21st century sooner or later.

Anyway, in answer to your question:  According to my 2016 manual, the DSR belt should be replaced every 16,000 miles (25,000 km) and the S/SR/DS models should have their belts replaced every 24,000 miles (37,000 km).
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JaimeC

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Re: Belt Tension (Getting tighter?)
« Reply #4 on: May 10, 2016, 12:15:35 AM »

By the way:  Go here to download the owner's manual for your bike:
http://www.zeromotorcycles.com/owner-resources/
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Kocho

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Re: Belt Tension (Getting tighter?)
« Reply #5 on: June 30, 2016, 07:15:44 AM »

Same here. Bought my bike at 500 miles, now at 1,100 I notice it has gotten gradually louder. The belt does feel tight by hand. Measured the tension today for a first time with a tool - it is off the scale. Will need to adjust it down.

When I got my DSR in late March the belt tension was at around 25kg.  I've checked it at around 750Mi this weekend, and it was at just under 45kg.  It still seemed to be aligned.  I backed off the tension to 25kg again and the belt got quite a bit quieter.  Has anyone else seen a belt get tighter over the first miles?  Seems very strange to me.  I am pretty sure I am measuring it correctly and the belt and pulleys look fine.

Steve
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Richard230

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Re: Belt Tension (Getting tighter?)
« Reply #6 on: June 30, 2016, 08:37:22 PM »

I am not convinced that the $14 Gates belt gauge is all that accurate. My new gauge shows that my belt is too tight (after 9,000 miles) at 50 kg, but when I used the old gauge that I gave my daughter with my 2012 S, that gauge read 30 kg. Not only is the gauge hard to use but it is also hard to read and sure doesn't seem like a very accurate and precision measuring instrument to me.  ???
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Kocho

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Re: Belt Tension (Getting tighter?)
« Reply #7 on: June 30, 2016, 10:15:15 PM »

It's a problem when we don't know which gauge is more accurate... I am getting very consistent readings with the $14 gauge. I did adjust my belt tension this morning - from "off the scale" on the gauge to 30kg. It took about 1/4 turn of the tension bolts to do that. And the belt is quieter than it was before. So I do think it was too tight to begin with. Am I at 30kg now? Who knows - I don't have a good enough feel in my hand for how tight is right (have not worked with belt tensions enough to know what a give tension feels like), so I have to rely on the gauge.
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Kocho

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Re: Belt Tension (Getting tighter?)
« Reply #8 on: July 01, 2016, 02:33:46 AM »

I did about 25 miles today with the new lower belt tension, and the belt is definitely quieter and with fewer resonance frequencies being felt as the bike accelerates. I might lower the pressure just a bit more to 25kg (currently 30) to see what that does ...
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quixotic

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Re: Belt Tension (Getting tighter?)
« Reply #9 on: July 03, 2016, 02:50:54 AM »

I ordered a Gates tension tester a few days ago.  However, it won't arrive for a week or two...and with Canada Post now on strike, who knows?

So is there some sort of spec which can be used without the tester?  (Doesn't seem to be anything in the manual.)   I remember on my ancient Honda 250, that a specific deflection (distance) on the belt was supposed to correlate with a specific pressure on the belt.  The pressure, of course, was a bit of a guestimate (eg, 20 pounds), but it was better than nothing, and it seemed to work just fine.
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quixotic

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Re: Belt Tension (Getting tighter?)
« Reply #10 on: July 14, 2016, 08:37:54 AM »

Well, the Krikit tension tester arrived today, and I have to say that I don't entirely trust it (or perhaps the Zero tension tester is a much more precise unit?).  Maybe I'm just old-school, but I prefer the method where a certain amount of pressure is applied up and down on the belt, and the resulting distance is measured (like on a motorcycle chain, or like the early belted  motorcycles...my old Honda 250 being an example). 

Anyways, on the Zero, when I put just 2 or 3 pounds of pressure on the belt (up and down), I get a resulting distance of about 1/2" to 9/16".  Does that sound about right?
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Richard230

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Re: Belt Tension (Getting tighter?)
« Reply #11 on: July 14, 2016, 08:38:09 PM »

I don't even bother with the tension tester anymore.  Now all I do is push the belt down with my finger and if it feels like it did when I bought the bike I call it good to go.  So far I haven't noticed any changes in belt tension on my bike. :) 
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Kocho

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Re: Belt Tension (Getting tighter?)
« Reply #12 on: July 14, 2016, 09:38:48 PM »

I did a quick measurement just now on mine. If use 5lb weight to press on the belt, it deflects about 1/4" in the same place where my Krikit tool measures 30kg. Deflection of 1/2" or even 9/16, I think is too much for only 2-3lb pressure - seems to me the belt might be lose in your case. I think it is better to measure on the bottom side of the belt with the Krikit tool, because there we can measure in the center of the belt (half-way between the motor and the wheel contact points of the belt), where on the top I think we are a bit off-center because of the belt guard plastics push us a bit towards the motor off-center.

Well, the Krikit tension tester arrived today, and I have to say that I don't entirely trust it (or perhaps the Zero tension tester is a much more precise unit?).  Maybe I'm just old-school, but I prefer the method where a certain amount of pressure is applied up and down on the belt, and the resulting distance is measured (like on a motorcycle chain, or like the early belted  motorcycles...my old Honda 250 being an example). 

Anyways, on the Zero, when I put just 2 or 3 pounds of pressure on the belt (up and down), I get a resulting distance of about 1/2" to 9/16".  Does that sound about right?
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quixotic

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Re: Belt Tension (Getting tighter?)
« Reply #13 on: July 14, 2016, 10:18:45 PM »

I did a quick measurement just now on mine. If use 5lb weight to press on the belt, it deflects about 1/4" in the same place where my Krikit tool measures 30kg.
Well, the Krikit tension tester arrived today, and I have to say that I don't entirely trust it (or perhaps the Zero tension tester is a much more precise unit?).  Maybe I'm just old-school, but I prefer the method where a certain amount of pressure is applied up and down on the belt, and the resulting distance is measured (like on a motorcycle chain, or like the early belted  motorcycles...my old Honda 250 being an example). 

Anyways, on the Zero, when I put just 2 or 3 pounds of pressure on the belt (up and down), I get a resulting distance of about 1/2" to 9/16".  Does that sound about right?

Is the 5 pounds just in one direction?  If so, that sound similar to mine (I was referring to up and down combined).

I like Richard's method.

It would be good to know what the 20-30 kg's refers to, since it's certainly not related to the force needed to make the krikit click. 
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Kocho

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Re: Belt Tension (Getting tighter?)
« Reply #14 on: July 14, 2016, 11:17:59 PM »

Just in one direction, down on top of the belt. Not too precise either - using a wood stick and a 5lb  exercise weight. I marked two notches on the wood stick for weight/no weight relative to the belt guard. Not too precise, but definitely not 1/2" deflection. 
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