Two speed Staton

[appye]

Kerf, I have been thinking about doing something similar to your idea. I don't think I will be going with a deralleur just yet, as I think that I will mostly use the cruise unless I want to do some mountain riding. For now, i don't mind backing up and moving the chain manually.

I do have some questions about your tensioner though. It looks like you are using some kind of (EDIT: polyurethane) skateboard wheel sort of thing for your tensioner rollers. Why not put sprockets there? Also, what is the tensioner pivoting on? Does the pivot use a bearing of some sort? I have been using a GEBE system and the tensioner really does not actuate all that well because it is rotating directly on the bolt threads...

I looked through the thread, but I apologize if you already answered these questions. I also have not yet ordered my Staton kit, so if you have any pointers, that would be great!

 

[kerf]

I just got home, the rollers are motorcycle chain rollers from Cycle World. They allow the chain to move when derailed. I used a plastic flange bushing with a bronze bushing inside to allow the idler to pivot on the 1/4" stud.

 

[appye]

I see. These aren't really noisy? The engine would probably overpower any chain noise though. I guess that makes sense to have a roller there instead of a sprocket, like you say, the chain needs to move laterally when going from one gear to another. Would you expect these to last for years and years?

With your bushing setup, the tensioner moves freely? Meaning, say the chain was attached to a poorly centered GEBE drive ring. As the bike was running, would the tensioner move back and forth to accomodate this?

 

[kerf]

I've got about 500 miles on the rollers with no wear and yes it pivots freely.

 

[appye]

Cool. I just thought of another question about your drive ratio. Do you do any mountain riding? On the low end, is 23:1 good enough for you to get up pretty much anything without pedaling? I was thinking about maybe going with a 12 tooth gear, but I wanted to hear your opinion on that.

Thanks.

 

[kerf]

The R460 reaches max torque at 8k which puts my bike at 27.2 mph, probably a little fast for off road use. A 12 would be better I would think but still pretty fast at 7 or 8k.

 

[appye]

Okay, so the torque peak is at 27.2 mph, but do you still feel safe doing 35-40mph on this thing? I was thinking that if I can do 30mph without feeling like I am going to blow the engine, I would be happy, but I want to go as low as possible otherwise.

 

[kerf]

I only use that gear for hills where I can run up in a short burst. I generally cruise at 6700 - 7200 / 28 - 30 mph on the 16 tooth. At that RPM range the 13 will give you 22 - 24 MPH.

 

[appye]

Well, I guess the only way for me to know for sure what cog I would want would be for me to try them out myself. They are not too terribly expensive, so I should just pick up a few and try them out! I definitely want more than short burst uphill. I do exercise on my bike, but there is a 10,000 foot mountain range real close to me and I want to be comfortable tearing around out there without worrying about having to pedal to the point where my heart is going 180bpm, and I don't want to get off of the bike and push uphill. I don't want to be intimidated by ANY hill or mountain!

EDIT: I am not too terribly worried about keeping the engine always operating at peak efficiency when going uphill, so much as I am worried about it being able to take me up any mountain at 25mph (hopefully).

 

[kerf]

I've found the R460 doesn't take well to indecision, like getting on the throttle when you're starting up hill at low RPM. It likes to be pulled into the torque curve (7-8K) before loading up. When that's done, it does a good job of fighting to maintain it's speed.