Two speed Staton

[appye]

do you know if I can order the staton kit with anything bigger than a 16 tooth freewheel on the hub? I would like to go bigger because if I am going to go with a super low gear ratio, I want to be running on as big of sprockets as possible as the chain will probably last longer this way.

 

[kerf]

The only left hand freewheel in existence, to my knowledge, is the ACS 16 tooth. I don't think anything more is necessary as the gearbox gives 18.75 / 1 reduction. If you go with a 415H or 41 chain, Staton can supply down to a 8 tooth output sprocket, resulting in a 37.5 / 1 reduction. To put that in perspective, an 8 tooth with 7000 RPM engine speed results in only 14.6 MPH. It should climb a wall with that. You will break the bike frame before the drive train fails.

 

[appye]

Heh ... well you answered my question anyway. The reason I was asking was that I figured that the chain would last longer if I were to achieve the same ratios using larger sprockets, for example, a 20t driving a 25t would achieve a 23.4375 ratio. I read somewhere that chains wear sooner if they are running around small sprockets.

I will still grab this kit, as I am pretty much set on it now anyway, I just want to cover all my bases. Thanks for your patience. How do you calculate the actual speeds at xRPM anyway? 7000rpm is way below what this engine will run happily all day long at right? What RPM would you max this engine out at for a long cruise? Maybe that will better help me decide on ratios.

 

[kerf]

Chain is cheap enough not to worry about wear too much. I run mine below 7k most of the time but thats just me. I put together a spread sheet, using my actual wheel diameter (26 1/3"), engine rpm, and sprocket size. Once I plug in the sprocket size & RPM, it gives me speed.

=(((A7/(18.75/($B$4/16))*($A$4*3.1459)/1056))

A7 = Engine RPM
B4 = Output Sprocket
A4 = Wheel Dia.

 

[appye]

uh ... ? So this is excel type cell formulation? Works so long as i use the same cells you have in there. Perhaps you can just send me the spreadsheet? appye@yahoo.com

 

[duivendyk]

I have never quite understood why Staton uses such a small (16t) rear drive freewheel,possibly it's the largest one available with lefthanded thread.Using a larger one decreases the tension on the chain and also the down force on the supports in direct proportion to its size,a 32t sprocket would have 1/2 the tension,not only that, the flex angle of the chain links on the sprockets, that determine chain wear would go down by two to one also,for a 4 to 1 decrease in chain wear !.The same applies to the input sprocket, another 4 to 1 factor.Chains are fairly cheap though,but a worn chain can mess up your sprockets,then replacing the chain does not help much anymore and you will need to replace both chain & sprockets.Of course the wider chains like #41 are much less subject to wear than the typical narrow 3/32 derailleur chain on the pedal side.

 

[kerf]

You know far more than I about chains and sprockets. I only know this system works and it works well.

 

[appye]

yeah, I figure that I will have to replace my chain once a year or so just to make sure nothing goes wrong. Of course, the only thing I would really worry about would be the chain getting into the spokes when I am going at speed. I was thinking about setting up some kind of enclosure for the chain to prevent this.

 

[kerf]

May get into the spokes, don't know. I had a master link failure (don't use them anymore), my chain fell into the street. Only reason I knew it was gone, bike lost its go.

 

[duivendyk]

Master links & deraillers are incompatible,I'm pretty sceptical that you can do much really ,to protect your wheel if the chain ends up in the wrong place.