Wolfshoes
Member
Two spokes broke at the knuckle on the rear wheel of my 3 year old Schwinn beach cruiser. The bike apparently was shipped flat when the box specified it was to be upright. With stress of weight on the side of the wheel, it apparently failed years later. To replace the wheel, I had a custom wheel builder lace a SRAM hub in a strong alloy rim as wide as the original rim. With a new tire and tube this set me back about $200 at this point. The hub adapter I custom made from hardwood; drilled and attached the flat 36 tooth sprocket using common steel lag bolts. The SRAM hub requires a larger adapter center hole of 2 1/8 inches. The 9 hole bolt pattern was also larger at 3 1/2 inches diameter.
The SRAM model appears to have been made mainly for use by a original equipment manufacturer since in order to achieve the desired benefit the size of the front pedal sprocket would need to reduced in size by one third. This would make for easier push offs of the bike from a stop and provide a lower gear for hills. Therefore the front sprocket was changed from 44 teeth to 32 teeth. This cost $15 including freight.
At push off, a native tire speed is achieved based on the pedal sprocket sizes used. At about 10 mph the tire speed increases by about one third due to gearing in the hub. With the smaller front sprocket, the usual bike speed using pedals is achieved after the second speed kicks in. Before that, the bike pedals easier.
The higher gear kicks in under load; as the bike slows down, the lower gear will not kick in under load. You have to be going less than 10 mph and stop pedaling for the lower gear to kick in. With a 32 tooth front sprocket, it is possible to pedal assist the motor on a uphill grade at about 14 mph.
The built in coaster brake has been working well with better stopping power, in my opinion.
The SRAM model appears to be better built than the usual coaster brake hubs. The extra gear is achieved without the need of a shifting cable. The rear axle appears to be made of a better steel than the stock hub and it is not hollow like a common three speed. The gearing is shielded (not sealed) keeping out the grit.
So far the unit has been trouble free, but not many hours are on it. The SRAM two-speed fitted to stainless steel spokes and a strong rim looks like a worth while upgrade to the common beach cruiser build; in particular if there is more than usual weight on the rear axle of if the rider is unhappy with the common coaster brake hub and is willing to spend some money.
Any impure thoughts of adding a shift kit and making a auto two speed cruiser would need to cope with the reality of the 10 mph shift speed. An auto shift would need to be more like 25 mph. This hub may have some applications behind a centrifugal clutch since it would reduce the restart load after a dead stop. I could add some pictures, but at this time there is a problem uploading pictures. There does appear to be some posts showing interest in this hub but to date I am not aware of a post where it has been installed on a motorized bicycle. A seller website mentions thousands being sold. If it is worthwhile on a pedal cruiser, the device is more than worthwhile after a motor is added to the bike.
The SRAM model appears to have been made mainly for use by a original equipment manufacturer since in order to achieve the desired benefit the size of the front pedal sprocket would need to reduced in size by one third. This would make for easier push offs of the bike from a stop and provide a lower gear for hills. Therefore the front sprocket was changed from 44 teeth to 32 teeth. This cost $15 including freight.
At push off, a native tire speed is achieved based on the pedal sprocket sizes used. At about 10 mph the tire speed increases by about one third due to gearing in the hub. With the smaller front sprocket, the usual bike speed using pedals is achieved after the second speed kicks in. Before that, the bike pedals easier.
The higher gear kicks in under load; as the bike slows down, the lower gear will not kick in under load. You have to be going less than 10 mph and stop pedaling for the lower gear to kick in. With a 32 tooth front sprocket, it is possible to pedal assist the motor on a uphill grade at about 14 mph.
The built in coaster brake has been working well with better stopping power, in my opinion.
The SRAM model appears to be better built than the usual coaster brake hubs. The extra gear is achieved without the need of a shifting cable. The rear axle appears to be made of a better steel than the stock hub and it is not hollow like a common three speed. The gearing is shielded (not sealed) keeping out the grit.
So far the unit has been trouble free, but not many hours are on it. The SRAM two-speed fitted to stainless steel spokes and a strong rim looks like a worth while upgrade to the common beach cruiser build; in particular if there is more than usual weight on the rear axle of if the rider is unhappy with the common coaster brake hub and is willing to spend some money.
Any impure thoughts of adding a shift kit and making a auto two speed cruiser would need to cope with the reality of the 10 mph shift speed. An auto shift would need to be more like 25 mph. This hub may have some applications behind a centrifugal clutch since it would reduce the restart load after a dead stop. I could add some pictures, but at this time there is a problem uploading pictures. There does appear to be some posts showing interest in this hub but to date I am not aware of a post where it has been installed on a motorized bicycle. A seller website mentions thousands being sold. If it is worthwhile on a pedal cruiser, the device is more than worthwhile after a motor is added to the bike.
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