Autobike - need some help

[KD5ZXG]

Lets talk derailleur for a moment...

The CSA derailleur in my hand is a dead ringer for the Sunrace RDM10 (available and cheap). Granted, CSA added an oversized guitar pick of furniture slider material. The torsion spring that presses outward has been removed and replaced with a linear pull from corner to corner that pulls inward instead. Very little actually changed.

RDM2T has what looks like the CSA linear pull spring, only change which corners (pins) of the box it grabs. A little concerned this one claims to be "indexed" but no evidence any such mechanism lives in the derailleur, maybe in the shift lever which doesn't affect us. RDM15 same same.

 

[us56456712]

I had a Schwinn with a similar set up. I have been told they are notorious for wearing out.

 

[KD5ZXG]

What's to wear? No moving parts back there except gear teeth, and those look fine. Bearings and cones that support the freewheel are overtight and don't move except in pantleg emergency.

Bearings and cones that support rolling weight behave normally, and will get fresh grease. Only the sliding guitar pick shows obvious and significant wear. I'll have to make a new pick. Mostly worn where chain was unexpectedly rubbing, not on the autoshifter business face you might expect.

The original CSA front freewheel (lets assume Sunrace?) was complete trash by word of the previous owner. But I am not using anything like that. I've got TSDZ2 motor with sprag instead of pawls. Complete different animal, not saying better.

Now I am concerned my heavy sprag might drag (and wear) while coasting, but shouldn't be a problem when pedals / motor / chainring are in torque sensor synchronized motion.

500W could easily be too much power while autoshifting cannot be suppressed. Only testing to destruction will tell. I am a long way from finished. Sturmey RXL-RD5 is my backup plan.

 

[KD5ZXG]

CSA with worn and broken pick. Spring pulls inward.

Sunrace RDM10 looks the dead ringer, but wrong spring type.

Sunrace RDM2T. Right spring hooked over wrong two posts, maybe the easier fix.

 

[KD5ZXG]

Sunrace MFM05 6DS claims to be a "friction" type. Not sure if that means what I want it to mean. Inner splines for freewheel removal might be Park FR-1.3? Front two dimples for cone removal or adjustment Park SPA-2. A normal freewheel with low pressure grease could simply be over-tightened to make friction. Only my theory, not yet proven.

Why does this modern friction freewheel lack the original indentation of the gear faces? Teeth all look the same too. No lockring. Prolly gone cheap I suspect...

 

[KD5ZXG]

These sliders aren't thick enough to make a new pick of nothing else. But did let me repair the old CSA pick by holding broken pieces together while JBWeld cured. Its good the new face doesn't add much thickness. Wouldn't shift correctly if too thick.

Autoshifting pick face (the face designed to rub) wasn't even noticeably worn, only the chain facing side was. So the new face is somewhat pointless, other than for gluing convenience. Something obviously wrong with the alignment of a prior chain, I'll have to watch for that.

Local surplus shop has a bunch of large chunks of Teflon and Delrin. Either might make a better blank for a new pick. Teflon doesn't hold its shape very well. Old blocks once square, now curled and warped from just sitting around. Maybe laminated onto a spatula blade for stiffness? Could Teflon even be glued to metal? Delrin best matches the appearance and feel of the old pick, but not exactly.

Even the largest guitar picks aren't quite big enough. Giant PVC novelty picks won't last. The obvious shortcut of starting with a pick to make a pick seems a non-starter.

 

[deorman]

Note to self: Don't buy a broken autobike.

 

[RustySprockets]

Did you get the front freewheel spider squared away? A continuously moving chain is essential for this design to shift as intended.

 

[Dizzle Problems]

I had/have one of these bikes. Had, because it is now a single speed swing bike. I do still have the entire functioning drivetrain though, and would like to sell it.

The difference in the derailuer it came with and the mircoshift one pictured above is the auto shift is 'low normal' meaning it rests in the low gear as opposed to the high like most derailuers. There are mountain derailuers that are low normal as well. I believe the shimano deore from the early '00s is low normal. but they are intended for a 9 speed set up.

The freewheel pictured is friction because it is intended for a friction drivetrain and shifters, as opposed to index shifters. That is why the is no ramping (indentations) on the cogs.

theres a pic in this old for sale thread of mine of the rear wheel and drivetrain-

http://ratrodbikes.com/forum/index....cannondale-girls-higgins.102208/#post-1031602

 

[KD5ZXG]

Did you get the front freewheel spider squared away? A continuously moving chain is essential for this design to shift as intended.

Yes, both sprags of my TSDZ2 motor allow forward chain motion, though intent was entirely different. Pedals, motor, or both together can advance the chainring. Motor can't spin the pedals and hit you in the ankles because the pedal sprag would slip. Pedals won't drag an unpowered motor because the motor sprag would slip. By complete coincidence, if a sprocket wants to advance the chain, both sprags slip.

Two sprags slipping mid-motor is certainly more drag than an FFS with pawls. Fortunately still less than the rear fricwheel. Chainring also seems to turn within this derailleur's ability to pull. I think it might work, not yet sure how well.

Error when I said freewheel cone was overtight. For purpose of free vs friction, the cone does not adjust. Freewheel *RACE* adjusts via SPA-2 dimples, and purposely overtight to make friction. Probably simple greased with no high pressure additives. Not cones and races that carry rolling weight, just parts of the CSA friction freewheel.

I see no necessity for destroying mine. But here's how the dimpled race turns, and what's inside:


CSA's derailleur is bent too. Couldn't tell before test fit on the bike, but it is. Need to decide how to safely bend it back. Or just get a straight new Sunrace, earlier identified as dead ringers. Inside vs outside can be simple as move the spring to alternate corners of the parallelogram. If Dizzle still wants to sell his complete original set, I am interested.

My neighbor just gave me a parts bike with front disk brake that half solves how mine might stop.

 

[KD5ZXG]

Half the spokes were thoroughly trapped behind the autoshifter, and I had no safe place to grip the hub to unscrew the freewheel. So, I re-laced them in a pattern for maximum torque in one direction only. Had to put three in the other side as well, else too wobbly. With some difficulty and a BFWrench it unscrewed to reveal a pretty normal hub beneath all that.

Arr, this be "UNNICORN" (how they spell it) in raised plastic letters on the backside. Holeee Belleviles Bikeman! Not what I thought at all. Friction comes from a cone spring washer. What?!?

Totally normal freewheel. Wasn't overtight at all. I suspect that way of making friction could have worked too, but not what they did. A raised ring of metal on the back of the castle compresses the Belleville. That ring might be a normal Sunrace feature or not, I don't have another for compare.

How cone spring meets castle to create friction. Same Belleville from the other photo, not two of the same.

For lack of knowing the proper word, I'm calling the non-standard two-tiered casette a castle. I should take the sprockets off and show you. That will have to be later, cause I got another chore to run.

 

[KD5ZXG]

My original black spokes (sized for 3i) are too short, or at least half of them seem to be. And not knowing anything about how to lace a wheel, I scratched a few trying to make the impossible fit. Not wanting to use all silver for the long side, only those with sliding weights. May have to buy extra spokes tomorrow.

 

[KD5ZXG]

Around the three minute mark, RJ flips his Shimano freewheel. We can see the same raised ridge, another dead ringer. And does not appear to be anything special exclusive to FFS. We might assume this was common feature of Shimano freewheels of the time, not just CSA, not just Sunrace. How did Shimano FFS make friction? Did they use the same sort of spring washer?

 

[KD5ZXG]

CSA appears to use a normal 13-28T 6 speed Sunrace freewheel, probable clone of Shimano. Other clones appear to have the same friction compatible feature on back (by visual only, not verified fit).

Wonder how well it might handle an 11-28T 7 speed freewheel? I see freewheels up to 10 speeds, but the construction on the back varies. For example, DNP Epoch is not quite the same. Also the matter of the autoshifter pushring. Can't easily get around more than 28T. Also the question how far from center the pushring can travel? And just how wide are those crazy 8+ freewheels?

Seven in a clone looks do-able, and the extra sprocket 11T is on the small end where it don't get in the way. Sunrace don't make this range. Shimano used to but quit. DNP isn't compatible on the backside. But I find generic China (drilled to look like DNP sprockets, but still Sunrace-like on the back) for $9.99 that look the perfect fit.

There's a Sunrace 9 speed, that more than covers 11-28T. Plus a useless 9th sprocket that too big but could maybe be removed with an angle grinder. Here again the question how wide is that sucker? Washers behind the pushring could deal with offset caused by the missing sprocket. But thats still range of 8 sprockets, can it push that far?

Need to find some 3D nutter willing to print a 10 speed sized pusher. Then need to find a 10 speed freewheel with old friction compatible backside, not too sure that exists yet. 9 speed 11-32T exists. Again no-name China drilled to look DNP, but at least they gave a picture of the back. Maybe that's sticking out too far past the threaded area, could a shim ring correct this?

Still on track to get the original CSA parts working. Got plausible length spokes now.

 

[KD5ZXG]

Original CSA 6 speed: 1 1/8 inch stack. CSA pushring travel: 1 1/8 inch
9 speed I was looking at was 40mm, not gonna work.
My axle isn't even long enough.

My old spokes too short even for the short side, catching only a few threads.
New spokes too long even for the long side, need to cut more thread and nip the ends.
Back to the drawing board...

 

[KD5ZXG]

So, I returned to the clown who measured, calculated, and sold me the wrong spokes. Nothing he's got to correct it in black, but maybe has a set in silver. To fix my overlong he wants +$2 apiece to roll extra threads. Peeved to have stretched my non-existent budget $50 for same day spokes the wrong length after the bike store measured the original problem and acted like they had the perfect solution. Could have ordered 36 of any length off the slow boat for $10, but wanted results while still on vacation.

Cruise down to Harbor Freight, and guess I was lucky not to find dies small enough. Cause I had no clue the rolling process was not removal, but to cold forge threads up from pressed grooves. Getting my head around this online, cheapest machine to roll them right (Cyclo or Hozan?) is not less than $150. Forget it.

At least the set I bought was too long. Maybe some other way to take up slack. Washers at the J bend, or under the nipples? Perhaps twist spokes where they would normally cross? Rumoured to eat about 2mm per half twist. Whatever I do mustn't interfere with the autoshifter. Can't fit more than one thin washer at the J. Can't lace any pattern that doesn't closely resemble the original. Could maybe twist a little further out than a natural crossing, and would make the relevant parallel spoke sections even more parallel. Need to make sure that plan wouldn't bind in some other way.

If 2mm rule of thumb holds, I might need a half twist on the long side and a full twist on the short side. Probably ought to make a jig to pre-bend at least the 1st half twist at the same place on every spoke. Drill a hole in a ruler or something.

 

[RustyGold]

Probably just order the slow boat spokes for $10...your other solutions, aside from re-threading, seem like potentials for problems.

Jason

 

[KD5ZXG]

Well, I have a new bucket of similar looking parts from China, none quite exactly fit...

Did not realize that freewheel threads of the CSA hub extend further from the spoke flange than usual. This appears to give room for the unnicorn mechanism behind the freewheel. Normal freewheel hubs will not clear it. So I am stuck figuring how to attach disk to the original hub with no threads or brake flange on left side. Has enough barrel sticking out that something ought to be attachable, or threads cut on a lathe.

I have no access to such a lathe. Could maybe weld a flange? But would trap the three lobed plate in the way of getting spokes in or out. Maybe I could drill one access hole or slot through that plate, and rotate to each spoke position. Then I'm gonna need a spacer (maybe a wider axle too) to keep the disk from hitting the frame. One of the el-cheapo universal freewheel hubs I bought might donate its solid axle to the cause, cause no other parts seem adaptable.

My new $5 derailleur is almost a dead ringer for the Sunrace, but has longer cage than expected. Not sure it pulls with enough force to overcome the front sprag. The parallelogram spring is of the corner variety, and not easily relocated. I would have to drill out two swaged corner pins and replace with bolts. Could temporarily work as standard rear freewheeling derailleur till I figure how to fit the unnicorn. Original CSA/Sunrace jockey wheels seem to have bearings that spun freely, new ones are just plastic on axles and drag somewhat. New metal is noticeably thinner too. Light is not an advantage if it folds...

203mm disk brake isn't big enough to clear the unnicorn either. Why did I assume it would without measuring first? Now trying to get hold of a 10" or 255mm tandem brake with holes in the right places to pass the unnicorn's three protruding bellcranks. Anyone know how to cut a hardened 10" saw blade without warping it? Would be great if disk and lobed plate could be unified, but clearance for bellcranks is priority. If lobed plate causes too many problems, it could be replaced with bailing wire in a pinch. Just there to provide centripetal force, and keep unnicorn from being drawn and thirded by centrifugal weight.

Shimano MT200/M315 hydraulic calipers I ordered on the cheap are technically awesome, but the hoses aren't nearly long enough and replacement hoses cost more than new calipers. With my apehangers, I had to use rear caliper for the front. For $35 spent, one working isn't horrible. Useless short hose caliper can maybe go on front of some 24" bike with low flat bar, or trade for ???.

203mm caliper bracket did not fit my Sunlite deluxe double springer properly. Wants outside edge shaved to keep from scraping disk face, and a stack of washers to clear the disk edge. Else it only clears 195mm, not 203. All on there now and working. I also own a normal 180mm disk and bracket that fit better. But want front diameter at least equal to rear, and the rear might now need to be 10", so go figure...

 

[KD5ZXG]

Shimano FFS doesn't have same cone spring washer behind it. Front looks unusual, maybe there.


Even overtightened race, FFS, or other friction solution without cone: I think unnicorn may be too thick to fit any replacement hub not clearanced for it. So instead of cutting threads on the brake side of my CSA hub, or wishing for nonexistant extended threads on freewheel side of a standard disk brake hub, maybe I could thicken the inside face of the spoke flange and shave it back? Assuming the new hub might be aluminum and could be thickened with a zamak brazing stick and some half moon scraps. Drill holes before shaving away the reference.