Primary Belt drive by Bob Newby

johnmead

Well Known and Active Forum User
Non-VOC Member
However the pictures are too small to see any of the details. Even clicking on them to make them bigger, you still only get a @ 2inch x 3 inch picture. Do you have larger copies of those pictures?
 

vincenttwin

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VOC Member
Trev
Yes but what about the cover T5/3 ,the belt kit I have the belt is 30mm.
Screen Shot 2013-03-27 at 8.27.37 AM.jpg
this is a photo from Bob Newbys web site ,
I am still looking for some one who has put one of these kits on to a road going bike and used the Vincent cover.
 

Spqreddie

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VOC Member
And Waht about the reduction ratio of the kit?
I'm planning as well to put one of those on my '48 rapide, and i remeber that when i spoke with Bob Newby he told me that he produces two versions 1: 1,8 and 1: 1,6, i guess the difference will be in the front pully number of theets and the clutch drum remains the same in both versions.
Wich would be closer to the original ratio?

I also remember that he was not sure about the cleareance of the original cover,
With the double thoothed belt, the main problem remains the generator pulley width.

Thanks,
Edmondo
 

nkt267

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VOC Member
Divide the number of teeth on the clutch by the number of teeth on the crankshaft pulley and that will give you the ratio..John
 

vincenttwin

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VOC Member
I am thinking that there is at least 2mm you could take off the back of the gen pulley and maybe up to 10mm you could take off the front of the gen pulley and maybe another few mm off the case ,
yes I think you will have to pull the primary cover to get to the gen pulley as it will never come out of the small gen pulley cover...
Also you will have to machine away where the current clutch oil seal sits and maybe some around where the belt will run.
I went with his 36/68 and gen pulley of 32 which should give it 1:8 and spin the alton a little faster than the nice plastic gear.
Peter

But so far no one has fitted one that I have to a std road bike and Patrick Godet over in France was not over enthused about the double sided belt.
 
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Spqreddie

Well Known and Active Forum User
VOC Member
Divide the number of teeth on the clutch by the number of teeth on the crankshaft pulley and that will give you the ratio..John

Thanks John,
i know, but i'm away and i have not the possibility of counting the theet and i was wandering if somebody could share the ratio of the original sproket/clutch set up to see how close it is to the Newby set up.
thanks,
Edmondo
 
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