Calculate belt length!

BoomboxLover48

Member (SA)
Dec 3, 2010
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Chicago, IL
:-D If there is no belt reference chart available for a specific model this calculation can become handy. :yes:

Actually I always calculated belt length by measuring the distance between the center of flywheel to the the center of the other drive pulley and measuring the diameter of both. After getting the length, I multiplied it with 0.95 to accomodate for some tension from stretching. The calculation always came right to select the belts.

Measure the diameter of each pulley/flywheel and divide by 2 to get the radius of the pulley
Measure the distance from the center of the pulley/flywheeel to the center of the other pulley

Total length of the belt = [(2 X distance from the center of the pulley/flywheel to the center of the other pulley + 3.14 X radius of the flywheel/pulley + 3.14 X radius of the other pulley)] X 0.95

Basically we are adding the 1/2 of the circumference (2Ï€r) of two pulleys, and adding twice the distance between the center of two pulleys, then reducing the total length by 5% to get the snug fit.

If the diameter of the flywheel is a lot bigger than the other drive pulley, then another calculation will come onto play. The belt messurement becomes a little smaller in that case. I will soon come with another calculation to accomodate that.
 

BoomboxLover48

Member (SA)
Dec 3, 2010
5,738
252
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Chicago, IL
baddboybill said:
Good to know :thumbsup: or you could use the old string trick. I also save my old belts and have used them for measuring ;-)
:-D That is correct Bill :yes: :yes: :agree:

The string trick only works when they are fixed on the same plane on the chassis.

FH-11W double cassette deck got one pulley mounted on the top plate that comes off when you take the plate off. The top plate slides into a lock position hiding both teh flywheel and the drive pulley. This is where I had to take measurements. There was no way to use a string in this case.

This time I was not lucky to get an old belt there.

I got my like new Sony FH-11W new in box with belts sticking on the flyweel and the motor pulley like a rubber glue. It took me some time to clean the mess.

Imagine this is a unit that had the blue seal tape on it. :-D

 

BoomBoomBlaster

Member (SA)
Jan 24, 2012
208
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0
Germany
BoomboxLover48 said:
BoomBoomBlaster said:
I might have the best link for calculating belt sizes but it's all in german :-/

there is a calculator and everything is explained :yes:

http://www.die-radiowerkstatt.de/antriebsriemen.htm
This is nice! :yes: :yes:


I can also ask my German friends at work if I have a problem!. :lol: :lol:
oh yeah forgot that your employers have a german branch office in bremen :-D but tell them not to drink that much becks before :lol:
 

BoomboxLover48

Member (SA)
Dec 3, 2010
5,738
252
83
Chicago, IL
BoomBoomBlaster said:
BoomboxLover48 said:
BoomBoomBlaster said:
I might have the best link for calculating belt sizes but it's all in german :-/

there is a calculator and everything is explained :yes:

http://www.die-radiowerkstatt.de/antriebsriemen.htm
This is nice! :yes: :yes:


I can also ask my German friends at work if I have a problem!. :lol: :lol:
oh yeah forgot that your employers have a german branch office in bremen :-D but tell them not to drink that much becks before :lol:

I enjoy the beer over there. World's best beer!

When I am there they give me a bath in beer! OMG.... Love the beer over there... I don't have to worry about driving because they take me around. :yes: :yes:
 

baddboybill

Member (SA)
Jul 14, 2009
11,091
84
48
55
Hudson Florida
BoomboxLover48 said:
baddboybill said:
Good to know :thumbsup: or you could use the old string trick. I also save my old belts and have used them for measuring ;-)
:-D That is correct Bill :yes: :yes: :agree:

The string trick only works when they are fixed on the same plane on the chassis.

FH-11W double cassette deck got one pulley mounted on the top plate that comes off when you take the plate off. The top plate slides into a lock position hiding both teh flywheel and the drive pulley. This is where I had to take measurements. There was no way to use a string in this case.

This time I was not lucky to get an old belt there.

I got my like new Sony FH-11W new in box with belts sticking on the flyweel and the motor pulley like a rubber glue. It took me some time to clean the mess.

Imagine this is a unit that had the blue seal tape on it. :-D

:agree: this is why I save old belts. They come in real handy to get closest possible size ;-). Then I usually order one size up and down and always have a nice supply :-)
 

BoomboxLover48

Member (SA)
Dec 3, 2010
5,738
252
83
Chicago, IL
baddboybill said:
BoomboxLover48 said:
baddboybill said:
Good to know :thumbsup: or you could use the old string trick. I also save my old belts and have used them for measuring ;-)
:-D That is correct Bill :yes: :yes: :agree:

The string trick only works when they are fixed on the same plane on the chassis.

FH-11W double cassette deck got one pulley mounted on the top plate that comes off when you take the plate off. The top plate slides into a lock position hiding both teh flywheel and the drive pulley. This is where I had to take measurements. There was no way to use a string in this case.

This time I was not lucky to get an old belt there.

I got my like new Sony FH-11W new in box with belts sticking on the flyweel and the motor pulley like a rubber glue. It took me some time to clean the mess.

Imagine this is a unit that had the blue seal tape on it. :-D

[ Image ]
:agree: this is why I save old belts. They come in real handy to get closest possible size ;-). Then I usually or one size up and down and always have a nice supply :-)

:-D :yes: :yes: :yes: :yes: :yes: :yes: :-D