How do I measure the pitch of a sprocket???

exrm193 · Post by **exrm193** » Mon May 14, 2012 4:06 pm

Not the chain, but a rear sproket??
The chain I don`t need to do, it's a 520. But I need to check the pitch of the rear sprocket 45 teeth

Any ideas?

Cheers

davsato · Post by **davsato** » Mon May 14, 2012 4:26 pm

how do you mean, the pitch, 520 or the teeth?

the pitch of a standard #520 chain is 5/8", to fit on a 1/4" wide sprocket. to know the number of teeth, count the teeth!
its usually stamped on the sprocket side but also usually covered in filth

exrm193 · Post by **exrm193** » Mon May 14, 2012 7:24 pm

It`s a 45 tooth rear sprocket
I need to check that it is for a 520 chain.
It came as a pair. Front & rear obviously. The front is definatly NOT a 520 pitch as it doesn't fit the brand new 520 chain I have. So I need to confirm that the rear sproket is for a 520 chain.

If you follow all that..

Still Gotta Pulse · Post by **Still Gotta Pulse** » Mon May 14, 2012 7:47 pm

On the sprocket you will need to measure at a point in the centre of the radius at the bottom of where the chain roller sits to the same point two further radii along.

So that's in the first radius , miss one, then at the third one are your points of reference and then divide this figure by 2.
For a 520 (5/8 pitch) to fit your sprocket this distance should be 1.25"

What is the (precise) thickness of your sprocket?

exrm193 · Post by **exrm193** » Mon May 14, 2012 8:21 pm

Thanks....I'll do it on the morning and let you know. Gives me an excuse to use my new digital vernier gauge....happy days!!

exrm193 · Post by **exrm193** » Tue May 15, 2012 8:32 am

OK...distance between the radius is 30mm
Thickness is 6.4mm

my maths is shite, but doesn`t that work out about right 1.25" = 31.75mm???

Still Gotta Pulse · Post by **Still Gotta Pulse** » Tue May 15, 2012 5:27 pm

exrm193 wrote:OK...distance between the radius is 30mm
Thickness is 6.4mm

my maths is shite, but doesn`t that work out about right 1.25" = 31.75mm???

Having something work out 'about right' isn't the same as it being right. Perhaps you weren't quite so accurate with your measurement because at 30mm you will be a long way out after a full revolution of your sprocket.

I am surprised you have a 6.4mm thickness of the sprocket as opposed to either 5.7 or 7.2mm . I'm not entirely sure that a 6.4 actually exists!

exrm193 · Post by **exrm193** » Tue May 15, 2012 6:21 pm

Deffo 6.4 mm....brand new digital vernier gauge :laugh:
Again Definatly 30mm between the bottom of the U bit of the sprocket.

The front is certainly NOT a 520. I just need to know if the rear is the same. I rang the supplier & he double checked the part number saying it was a 520. But I went in and showed him it with my chain & it Don`t fit.....DOH!!

Still Gotta Pulse · Post by **Still Gotta Pulse** » Tue May 15, 2012 6:45 pm

A 520 chain has a roller width of 1/4" (.250) therefore the sprocket cannot be the same as it would then be an interference fit, which in turn would put unnecessary loadings on the g/box as well as sapping horsepower!

Are you measuring the thickness at where the chain rolls over the sprocket or somewhere else on the sprocket?

exrm193 · Post by **exrm193** » Tue May 15, 2012 8:13 pm

right down the centre of one of the teeth

How do I measure the pitch of a sprocket???

How do I measure the pitch of a sprocket???

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Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???

Re: How do I measure the pitch of a sprocket???