SRAM Automatix 2 speed hub.

[mornview]

The cog is concave, I flipped it to get a better chain line alignment on this bike, my other bike worked better the opposite way. Is the chain line is measured from the center of the hub to the cog, or from the dropout to the cog? I'll measure it and post up what is is once I find out.

Yep, measure from the center of the hub to the cog.

Alternatively, since I know the hub is spaced at 130mm, and half of 130 is 65mm, you could just measure from the dropout to the cog and subtract that from 65mm.

 

[Bicycle808]

Remember, these hubs ship with spacers to easily switch from 120mm to 130mm spacing, something to keep in mind while measuring.

I haven't measured myself but online searches suggest that chainline is @45mm with a flat cog; you can go up or down a few mm by using a dished cog.

HTH
Rob

 

[villageidiot]

so, im digging the concept of this hub.... it would allow me to keep the gearing i have on low, and then it would auto shift to a more brisk gear when i spin out the 44-20.............. with no cables.

no matter where i ride, theres hills, and with the 44-20 i can cruise up em sitting down without killing myself. but when i get on the flat the gearing is spun out and its got no speed, just cruise.

anyone put this hub in a worksman frame? i have a shimano coaster (12g spoked alloy weinmann) and if i knew it could fit, might shell out the dough for the get rad.

or is there another hub (no cables) that i should look at?

 

[mornview]

Remember, these hubs ship with spacers to easily switch from 120mm to 130mm spacing, something to keep in mind while measuring.

I haven't measured myself but online searches suggest that chainline is @45mm with a flat cog; you can go up or down a few mm by using a dished cog.

HTH
Rob

Ah, I did not know about the spacers. Thanks for the info; that opens up a few other projects I could put this on.

It sounds like 40-45mm is pretty much the standard chainline when it comes to coaster brake hubs, but I just measured my (single speed coaster brake) KT hub and got a chainline of 35mm (measured as accurately as I could). Hmm ...

 

[mornview]

so, im digging the concept of this hub.... it would allow me to keep the gearing i have on low, and then it would auto shift to a more brisk gear when i spin out the 44-20.............. with no cables.

no matter where i ride, theres hills, and with the 44-20 i can cruise up em sitting down without killing myself. but when i get on the flat the gearing is spun out and its got no speed, just cruise.

anyone put this hub in a worksman frame? i have a shimano coaster (12g spoked alloy weinmann) and if i knew it could fit, might shell out the dough for the get rad.

or is there another hub (no cables) that i should look at?

I'll let the other guys answer this with certainty, but just some speculation on my part:

1. I'm guessing that Worksman frame is spaced at 110mm (or maybe 116). So you'd have to spread your frame a little bit.

2. The flange diameter might be greater than your Shimano hub (often seems to be the case with 2 or 3 speeds).

Another option would be to track down an old Sachs Duomatic ... two speed kickback spaced at 112mm, so little (or no) frame spreading on your part. Of course, tracking one down is another matter ... I've been trying to do that for quite a while myself (although apparently other people here are just finding them in the trash ).

 

[Bicycle808]

Mornview is correct; i just wanted to point out that the INB is spaced at 110mm, and it can be made to accept a 120mm hub like the SRAM Automatix.

Another cable-less IGH to look at is the Sturmey-Archer s2c, which is a true kickback instead of an auto, and is typically spaced at 116. (Some variants ship at 120mm OLD, but they can be easily de-spaced to 116mm.) These have the advantage of allowing you to control the shift points, but they have the drawback of switching gears as you brake. Also, eaely hubs had some QC and reliability issues; later/current examples seem better.... but by all accounts, the SRAM Auto is bulletproof.

And yeah, like Mornview said, the Fichtel&Sachs Duomatic is a brilliant old hub, that easily fits in a Worksman frame.

 

[mornview]

I should probably just create a seperate thread for this, but I'll go ahead and ask it here anyways:

What is the difference between the S2C and the B2C? Both seem identical from all the information I can dig up.

 

[Bicycle808]

S2C has an aluminum hubshell, while the B2C has a steel hubshell. The B2C has a lower msrp, but if you shop around, you can usually find the S2C for the same price.

 

[Bicycle808]

The two hubs have identical innards....