New Build Question Sturmey Archer/Jackshaft

[rustycase]

Of course you are right, 5.7, Many ways to skin a cat, and that's part of the fun of it.

Certainly do not need the 6.5hp. But for $75 I could not pass it up.
I figgered if it's got that much in it's powerband, it should do well for normal MAB use when at lower rpms.
...I was real pleased to see the general reviews on the engine have been quite good, almost everywhere I've looked.
With a CVT, I think it would be optimal for reliability, and response.

5.7, I looked for a sprint record but couldn't find one, so far.
I think it would be a fun race!
Your low cog would probably zip out real fast, right?
I was hoping to find a 100yd sprint time for a bicycle racer, but no luck.
I did find a 83mph record for undrafted on level ground, though. There's a bunch of crazy records in the wikipedia... like downhill off a volcano at over 100mph ! LoL

Best
rc

 

[5-7HEAVEN]

LOL, I know what you mean.

I bought a new 6 hp Robin engine on ebay for $100. I just couldn't pass it up, and it'll be one of my projects in the future.

I'm swapping the 63t chainring to a 72t sprocket, as we speak. That'll lower first gear from 32.46:1 to 37.09:1

 

[rustycase]

Wow! 37:1 !

That's gonna pull tree stumps, 5.7 !

Actually I know very little about proper ratios for a specific effect. Must read through all the threads on that topic, soon.
One thing I considered is that it's probably possible to rip the spokes right out of a rim, or hub.
I did read the thread where a fellow named CAM fastened his driven sheave to the rim itself using a bunch of bent-up brackets he fabricated and screwed directly to the rim. He's built a replica BTR with belt drive.

Anyhow, since I've got these Sturmey-Archer SA hubs, I'm considering if I should weld ears directly onto the hub to fasten the sprocket to. I'll need to take them apart for inspection, anyway, before making any decision about actually running them... I could weld on them when they are cleaned out.

Does anyone know where to get that cute little chain that is used to shift the gears??? I could use a foot of it.

Best
rc

 

[Deleted Member 4613]

5-7, I studied your response on gear ratios and what I get from it is, although the SA 3 speed can work, it doesn't have enough gear ratios, so I would buy an SA 5 speed or eight. I'm more bothered by using a 2 stroke engine, which I have read nothing good about, too many problems, very finicky whereas my 4 stroke HS 142F is perfectly solid, reliable. So what is the solution here? A four stroke with the jackshaft and SA? Appreciate and comments. Let's find the best power system.

 

[rustycase]

Which of the selectable hubs is the most robust? I think that's the main question...
I recall skipping in and out of a gear when I was a pedaling kid!
We didn't like 'em then, for that reason.
Now that I've seen the fix, in repair threads, maybe that's OK, but I'm concerned they will get damaged too easily when under power.

I've got to read through the jackshaft threads to find out which is best way to go.
Seems it could mediate the need for a chain tensioner by shortening the final drive run.
If the jackshaft is a Sturmey-Archer hub, that's good, too!

Anyone have comments on that application?

Best
rc

 

[5-7HEAVEN]

That's gonna pull tree stumps, 5.7 !

Actually I know very little about proper ratios for a specific effect. Must read through all the threads on that topic, soon.
One thing I considered is that it's probably possible to rip the spokes right out of a rim, or hub.
I did read the thread where a fellow named CAM fastened his driven sheave to the rim itself using a bunch of bent-up brackets he fabricated and screwed directly to the rim. He's built a replica BTR with belt drive.

Anyhow, since I've got these Sturmey-Archer SA hubs, I'm considering if I should weld ears directly onto the hub to fasten the sprocket to. I'll need to take them apart for inspection, anyway, before making any decision about actually running them... I could weld on them when they are cleaned out.

Does anyone know where to get that cute little chain that is used to shift the gears??? I could use a foot of it.

Best
rc

The low gear is on the bike. I'll know how well it works soon, when I ride to town today.

I have absolutely no problems with my wheelset, which I inspect after every ride. They are aftermarket aluminum rims w/32-spoke, 14g stainless steel, still true, aluminum rims, which I've used for a year. No signs of wear and tear.

Three-speed hubs will work, theoretically. However, the gear spread will be wide.

It's like installing a three-speed transmission, compared to a one-speed tran or an 8-speed transmission.

 

[5-7HEAVEN]

5-7, I studied your response on gear ratios and what I get from it is, although the SA 3 speed can work, it doesn't have enough gear ratios, so I would buy an SA 5 speed or eight. I'm more bothered by using a 2 stroke engine, which I have read nothing good about, too many problems, very finicky whereas my 4 stroke HS 142F is perfectly solid, reliable. So what is the solution here? A four stroke with the jackshaft and SA? Appreciate and comments. Let's find the best power system.

Unsure how strong SA 3-speed hubs are. However, it's like having a 3-speed transmission versus a 1-speed sprocket versus an 8-speed transmission. The SA will have a wide gear spread. If you have a very low first gear, you will also have a comparatively low third gear too. With an 8-speed internal hub or cassette, you can have a stump-pulling first gear and a freeway-flying overdrive 8th gear. Heck, you might not even need to use several high gears. On my present setup, I only use the first 5 gears.

If I were me, I'd set up for a shift kit and an 8-speed cassette.

Mike, since you have the HS 142F, use what you have. If you have the SA, go for it. If you have a cassette, use it, whether 5/7/8/9 speed. I really enjoy the 8-speed. It is cheap, durable and dependable. If you feel you have too much power, be gentle with your drivetrain and find the engine's "sweetspot". You want it to work in its power range. My engines like to twist and whine. Your 4-stroke might be a workhorse with power down low. Keep the revs where they should be.

You don't need a tach. Your engine will tell you where it wants to be working. Listen and be in tune with it.

 

[Deleted Member 4613]

5-7, I like your comments, but the HS 142F is already on my first bike. So I am weighing another 4 stroke or a 2 stroke, and leaning towards another 4 stroke. So the final configuration might be a 4 stroke with a jackshaft and an 8 speed SA hub with brake.

 

[5-7HEAVEN]

Thanks for compliments, Mike.

Good luck, sir. I am unfamiliar with 8-speed hub's reliability. I like the fact that you can shift gears at a stop, with internal hubs. With the cassette, you need to be in the correct gear BEFORE coming to a complete stop.

Mental note: shift to first gear before coming to a complete stop! If centrifugal clutch is disengaged, blip throttle to ensure gear change.

 

[pbeggs]

5-7, I like your comments, but the HS 142F is already on my first bike. So I am weighing another 4 stroke or a 2 stroke, and leaning towards another 4 stroke. So the final configuration might be a 4 stroke with a jackshaft and an 8 speed SA hub with brake.

im running a 2 stroke 80 cc (66,.. whatever) i have the jackshaft geared for hill climb (30 tooth input instead of 17 as sick bike parts kit) i have waaaay huge amounts of torque (ripped the dropouts out of my frame) but the 8 speed s/a with drum brake is still working (i dont shift under power and tend to take it easy on my drive train (im out in the country,. no traffic to try to zip through, no need to speed shift)

gear train is as follows

motor output 11
jackshaft input 30
jackshaft output 10
large sproket crankset 48
small sproket crankset 30
hub sproket 25
26" wheels

tops out in 8th at about 30

havent found a hill i cant ride up

i have this geared about as low as possible much higher speeds would be possible with more standard gearing

i would suggest the matching drum brake front hub,..