80 tooth 8mm chain sprockets (freewheel mounting)

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80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Thu Jun 30, 2011 3:01 pm

80 tooth 8mm chain sprocket, drilled ready to bolt onto a 16 tooth freewheel.
I wanted one to replace the 100 tooth on my bike & the laser cutters made 9 - NINE!!! so I have a lot of spares.
Also the old 100 tooth is spare now ;^)
here's one installed
Image
I'll post to UK for £12
overseas I'll have to price it up as and when.
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Mon Jul 11, 2011 5:46 am

I've cleaned & bevelled the teeth on these - still have 7 left ;^)
it goes on a
http://www.chainreactioncycles.com/Mode ... elID=54209
(as seen on the picture above - 8x 6mm bolts)
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby Kin » Sun Jul 17, 2011 4:57 am

So, uh, is this by any chance possible to use to increase the top speed of a 20" bike? I realize now you use it on the other side of peddle chain to connect to a high rpm motor, but is there any chance that I could use this to switch out with my forward chainring? Or, if it "depends," how would I figure that out? Thanks
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby JoramsWeapon » Sun Jul 17, 2011 11:52 am

What is the diameter of the sprocket?
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Sun Jul 17, 2011 12:13 pm

Kin - it's just an 80 tooth sprocket, made to bolt onto a standard freewheel. It's 8mmj pitch chain to keep the size down. On the pic abave it's on a left hand thread freewheel, but there's no reason not to put it on a RH thread freewheel on the other side.
Mr weapon, about 8" - 80*8 is 640mm circumfrence, divide by pi & 25.4 to get inches...
The 100 tooth sprocket has now gone.
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby Kin » Sun Jul 17, 2011 11:41 pm

(See below, accidental double-post)
Last edited by Kin on Mon Jul 18, 2011 3:04 am, edited 1 time in total.
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.

My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby Kin » Sun Jul 17, 2011 11:43 pm

Sorry, I tried (failed) to read online to understand the difference between chainring mounting and freewheel mounting, and I also don't have my bike or any bike with me for the next half month to visually check it out. I'm looking to mount the big ring in the front of my bike (the ring connected to the peddle), which I think is called the chainring (in replacement of the existing ~54t ring). I have a 7-speed in the back but the front is just one ring. So, just to clarify- do you think this would be possible? If so, that's awesome. And, could you clarify what the price is +shipping to the US east coast [U.S shipping just if you have an idea]?
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.

My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby mwkeefer » Sun Jul 17, 2011 11:44 pm

How much do you want for these bob?

I may be interested depending on the price, also what is the weight?

Thanks in advance,
Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby spinningmagnets » Sun Jul 17, 2011 11:50 pm

Kin, be aware that when swapping in a very large chainring to the Bottom-Bracket (BB, pedal-axle), sometimes the ring will hit the front of the chainstay. A 52T chainring is a popular upgrade for E-bikers who travel near 30-MPH, and also want to add pedaling to reduce amp-draw. someframes a 52T will fit, and some frames it will not.

Make a cardboard copy of the 80T diameter, and see if it will fit before ordering.

BobC, Thanks for making these available! Will they only bolt onto the 16T freewheel? Its not a problem, I just want to clarify what freewheel sizes it will bolt to...
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Mon Jul 18, 2011 4:58 am

Kin - I'm afraid I suspect this is not what you want - it's made for small 8mm chain, not 1/2" bike chain. You couldn't use it in combination with any other standard bike transmission parts (deraillieurs, cassettes etc.). If you just want a big chainring, look at bike pats suppliers.
Mwkeefer - I am looking for £10(is that about $14 ?) + posting . I'll try to find out postage costs after I've weighed one..... I suspect it weights somewhat less than a pound (300g) - i'll weigh one tonight.
Magnets - it's made to bolt on a 16tooth freewheel - 8 bolt holes lining up with every second sprocket notch (you can probably see it in the photo above)
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby Kin » Mon Jul 18, 2011 5:05 am

Oi, I see what you mean now.
Thanks though :)
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.

My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Wed Jul 20, 2011 2:20 am

Sprocket weighs 270grams (that's under 10oz). Weight of freewheel clamp plate & bolts.... no idea
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby mwkeefer » Thu Aug 11, 2011 10:50 pm

still have any available? PM me if you do, I will take one - just factor fast shipping with tracking into cost and let me know the total... in USD if possible.
Thanks in advance,
mwkeefer
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Wed Aug 17, 2011 11:33 am

mwkeefer - costs to the states were just a bit exorbitant - are you sure you wouldn't perfer me to publish the dxf file & get it made locally - regardless of cost I have bad experience shipping stuff stateside - (delays & disappearance)
And I'm on holiday so I can't post til next week.....
Yeah I have 5 or so left ;*)
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby mwkeefer » Fri Aug 19, 2011 11:29 am

I can work with Gerbers and DHF if needed, locally i have a shop which will cut them for me on their CNC but... I and a few others here in the states are interested, where would you be shipping from? Perhaps I can bulk a few of them from you at once and then distribute them here in the states? PM me and we could work out the details :)

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w
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Re: 80 tooth 8mm chain sprockets (freewheel mounting)

Postby bobc » Thu Mar 15, 2012 4:58 pm

All gone now. This is the dxf file if you want to take it to your local laser cutting place and get one made ;^)
sprockclamp is the ring that goes on the other side of the freewheel teeth. Make both out of 3mm mild or stainless steel.
Cheers
Bob
Attachments
sprock80x8.dxf
(463.01 KiB) Downloaded 47 times
sprockclamp.dxf
(40.07 KiB) Downloaded 30 times
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