rear sprocket tooth count

hey guys...

so i have a very custom build on the go...custom hard tail frame that will gladly accept a 16" wheel......wondering if anyone else has experimented with a smaller size rear and has any confirmed working rear sprocket sizes.....stock front sprocket (850 commando)..............

I'm going to fit a fat squatty 16" rear someday so will be calling TC to find out what he suggests as that's what TC runs on his 850 Interstate he takes to rallys while they bring his 3 enigne wonder in an ole chevy van. Most 16" tires are rather taller side walls that our 19 & 18" sizes so not that much difference in road speed gearing but more mass to spin if geared up much. I think TC mainly runs the 16" for the extra mileage.

You know if he runs it with a 42 tooth sprocket tho?

a mark III rear wheel?

TC has 16" rim mounted to regular 850 hub-drum sprocket but I thought the drum has 43T not 42, hm. I've done 3 different sprocket teeth count/ratios on my SuVee and learned there's reasons to avoid some teeth count ratio's d/t the cyclic repeat wear patterns to avoid or put up with wear wise. I've tried 3 different ratio's on past Peel to find 21T final ratio her best but Peel had accidental power combo that could still lift front at end of 1st two gears and pull hard in 4th to way over the ton. On my wimpy factory Combat I like 20T best but don't try to spank sports bikes on a factory Combat just barely keep up with them up to 115, even though Trixie could pull over 120 but then its straining crank rpm jump rope for so little extra thrill i refuse to do it. 125 is about the fastest anyone but the very rare racer or insane squids will pull to in Ozark Mt roads. I rarely go over 90 mph on Trixie, even though that is point she gets her second 2S cam wind eager to pull higher, so I'm proud of my discipline not too but no such qualms on next Peel with changable sprockets on hub.

42 teeth is all you can use with the stock hub unless you do a weld on and than it will have more teeth. you will need 1 tooth more on the front with the 16" rear wheel to be close to the same ratio as the 19" wheel. the other option is to adapt another rear hub so you can have a choice of rear sprockets. I also don't like to go big on the front sprocket as you add more stress to an already over stressed gearbox.

ianfotheringham said:

You know if he runs it with a 42 tooth sprocket tho?

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right. would like not to have to change the front sprocket - and finding norton wheels isnt as easy as one might like...sorted out the front with a '70 sl350 drum brake wheel...so only one to tackle now - thinking of going with a 16" cb750 wheel....any thoughts on a non o-ring 530 chain working with a stock commando front sprocket?

the 530 NON o ring is what was standard on the Norton. I prefer to convert to the 520 o ring for a rider. the 530 o ring will most likely have clearance issues. as to gearing what do you plan to use on the front? with a std primary ratio and a 19" rear I like the 21-42 for an all round rider and like stated with a 16" rear you would need a 22-42 to be close to the same.

ianfotheringham said:

thinking of going with a 16" cb750 wheel....any thoughts on a non o-ring 530 chain working with a stock commando front sprocket?

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well, stock on the motor happens to be 20 and a stock cb750 rear is 48....we'll see how it goes......

I am 100% sure it will WAY under geared as with that combo it would be like having a 17 tooth front sprocket.I hope you don't plan to ride it farther then 1/8 of a mile at a time. if you want to run that wheel tire combo you will need a 36 tooth rear sprocket to ride at any reasonable cruse speed/distance.

ianfotheringham said:

well, stock on the motor happens to be 20 and a stock cb750 rear is 48....we'll see how it goes......

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