fun calc

garyboy · Post by **garyboy** » Tue Oct 30, 2018 4:01 pm

here's a fun ? puzzle which has a surprisingly simple method of calculation.

I am awaiting delivery of my new jt 45 tooth rear sprocket.
it is for a std 520 chain.

will it get through my 8.75 inch wide letterbox?

(assume a half inch tooth length.)

Cone · Post by **Cone** » Tue Oct 30, 2018 4:06 pm

Depends on the delivery agent

If it’s yodel or dpd they’ll just leave it on your doorstep and put something through you letterbox saying it’s in your designated safe place

garyboy · Post by **garyboy** » Tue Oct 30, 2018 4:21 pm

But my neighbours are thieving bazaars and there are not places safe from them .. and I can't get to the nearest depot and I need it today and must go shopping for cake urgently

steve the grease · Post by **steve the grease** » Tue Oct 30, 2018 4:42 pm

garyboy wrote: ↑Tue Oct 30, 2018 4:01 pm here's a fun ? puzzle which has a surprisingly simple method of calculation.

I am awaiting delivery of my new jt 45 tooth rear sprocket.
it is for a std 520 chain.

will it get through my 8.75 inch wide letterbox?

(assume a half inch tooth length.)

45x1/2" =22 1/2" If C=Pi D then D=C / pi so 22.5 / 3.14= 7.165 or 7 5/32 if you like.
However the diamenter is based on half an inch at the point where the links sit not the crest of the teeth, so the diameter will be somewhere nearer 8 inches I would guess , So if your sprocket is in a Poly bag probably YES and if its a cardboard box Probably NO. *

* Did I get a maths O level?

daveuprite · Post by **daveuprite** » Tue Oct 30, 2018 4:44 pm

The main thing is that you have your cake. If you have cake a stolen chain doesn't matter so much.

chunky butt · Post by **chunky butt** » Tue Oct 30, 2018 4:49 pm

Yep, sod the chain, defo go for the cake

garyboy · Post by **garyboy** » Tue Oct 30, 2018 4:54 pm

Steve .. I think the pitch of a 520 chain is 5/8 inch. . ?
Method correct though

http://www.moto-chains.com/site/898528/page/578189

garyboy · Post by **garyboy** » Tue Oct 30, 2018 4:56 pm

Since this brexit debarcle I can't have my cake and eat it

and I like cherries too

so I must wait for postie

zimtim · Post by **zimtim** » Tue Oct 30, 2018 6:27 pm

The size, pitch length, link thickness is all irrelevant as it will depend on the packaging of the chain, and the packaging of the packaging.

It will of course fit if you impact the chain then feed it through the letter link by link

What cake ???
And did you get enough for everyone

pinball1008 · Post by **pinball1008** » Tue Oct 30, 2018 7:41 pm

Yes. Box should be around 120x30x300 mm
Just measured the one I have in a box ready to go on

fun calc

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