Offset chain sprockets
Posted: Mon Jun 29, 2009 4:35 pm
I have been in touch with www.sprockets.stenor.com regarding them making sets of offset front and rear sprockets so that a 180/60-16 tyre can be used without problems. I have asked them for price quotations for 1, 20 and 50 sprocket sets. If the price is reasonable I would hope to supply forum members either myself at cost price or to set up some kind of group buy direct with Stenor. The costs indicated ( I suppose for a 1off sprocket) on their web site are:
Below are the estimated costs of special sprockets (prices include VAT but not Postage)
Manufacture of gearbox & engine sprockets £50+
Manufacture of gearbox sprockets with offsets £60+
Manufacture of small to medium sized basic flat rear sprockets £45+
Manufacture of medium sized basic flat rear sprockets £60+
Manufacture of larger sized basic flat rear sprockets £80+
Manufacture of dished and offset rear sprockets £75+
Retoothing gearbox & engine sprockets £50+
Retoothing drum sprockets and other larger sprockets £65+
If the same sprockets can be used for both 750 and 906 (and others) it would clearly be an advantage in terms of numbers. From suppliers of aftermarket sprockets I have found that the same 38-tooth rear sprocket appears to be used on both 750 and 906, but the 16-tooth gearbox sprockets appear to be slightly different. The 750 is 12mm wide and the 906 is 16mm wide. (As a new member of the forum I'm not yet sure how to include jpg images of the sprockets with a message - can someone help?).
Questions:
a) Is there any interest in a group buy of these offset sprockets at a discount? I was thinking of getting them made in batches of 10 or 20 sets at a time. If there is no interest I'll order a set just for myself and others can do the same if they want to.
b) Is a 16-tooth front and 38-tooth rear correct or is there a demand for other sizes?
c) What should be the offset? 8mm? Please only answer if you have direct experience of fitting a 180/60-16 tyre.
d) Is there a difference between the 750 and 906 front sprockets or would the same one work for both?
e) I notice from the Avon web site that on a 5-inch wide rim the Avon Cobra 180/60 tyre is 182mm wide x 630mm diameter and the Avon Venom-R 180/60 tyre is 180mm wide x 625mm diameter. Does anyone have similar dimensions for other makes of tyre? Avon says that the actual tyre width can vary by up to 2mm due to the nature of the rubber.
GT-UK
Below are the estimated costs of special sprockets (prices include VAT but not Postage)
Manufacture of gearbox & engine sprockets £50+
Manufacture of gearbox sprockets with offsets £60+
Manufacture of small to medium sized basic flat rear sprockets £45+
Manufacture of medium sized basic flat rear sprockets £60+
Manufacture of larger sized basic flat rear sprockets £80+
Manufacture of dished and offset rear sprockets £75+
Retoothing gearbox & engine sprockets £50+
Retoothing drum sprockets and other larger sprockets £65+
If the same sprockets can be used for both 750 and 906 (and others) it would clearly be an advantage in terms of numbers. From suppliers of aftermarket sprockets I have found that the same 38-tooth rear sprocket appears to be used on both 750 and 906, but the 16-tooth gearbox sprockets appear to be slightly different. The 750 is 12mm wide and the 906 is 16mm wide. (As a new member of the forum I'm not yet sure how to include jpg images of the sprockets with a message - can someone help?).
Questions:
a) Is there any interest in a group buy of these offset sprockets at a discount? I was thinking of getting them made in batches of 10 or 20 sets at a time. If there is no interest I'll order a set just for myself and others can do the same if they want to.
b) Is a 16-tooth front and 38-tooth rear correct or is there a demand for other sizes?
c) What should be the offset? 8mm? Please only answer if you have direct experience of fitting a 180/60-16 tyre.
d) Is there a difference between the 750 and 906 front sprockets or would the same one work for both?
e) I notice from the Avon web site that on a 5-inch wide rim the Avon Cobra 180/60 tyre is 182mm wide x 630mm diameter and the Avon Venom-R 180/60 tyre is 180mm wide x 625mm diameter. Does anyone have similar dimensions for other makes of tyre? Avon says that the actual tyre width can vary by up to 2mm due to the nature of the rubber.
GT-UK
