BO15 Cyrus the Virus

[Psychographic]

I had a lot of catchup to do on this thread. Great progress. Especially the sexy speed holes.

Have you thought about trying to find a wheelchair mag as a front wheel?

Or may this 20" mag for a front wheel. ($100 shipped on ebay)

View attachment 123895

I have that very wheel saved on my ebay watchlist. The problem is, it doesn't match my rear hubs (maybe I'm being too picky, especially for my pocketbook), although I haven't completely ruled it out yet as it's a beautiful wheel.

I have been trying to do something with what would normally be the seat post tube. I found a chrome 1" lowrider seat post with a twisted cage. I'm thinking of cutting a section out and welding in a section of the lowrider seat post. If I can make it long enough, I can weld it in leaving the chrome on the cage and masking it off when I paint the frame. I think the twisted cage somewhat resembles the spokes on this wheel and could tie it in.

As for wheelchair mags, I've only ever seen plastic ones, and I need to mount a rotor to it. So that rules them out.

 

[Psychographic]

The tap for the derailleur mount arrived today. It was straight to the basement to tap and tack weld it in place. It wasn't easy to get it lined up, I'm just the slightest bit off. Once I finish welding it secure, I'll put a crescent wrench on it and try to give it just the slightest twist to get it lined up a bit better. I have to hope this derailleur works as the other one I have, will mount lower and has a longer cage (the part with the jockey wheels). I might have to add a tensioner to the bottom of the chain, it's pretty close to the chain stay.

Now that I look, there is not enough room for the lowrider seat post idea.

I'm toying with the idea of another "filler" piece on the seat stays. I think it needs to be much smaller though.

 

[OddJob]

Have you tried shifting through the gears yet to see if that derailleur you have on there will work with the Mega Range freewheel, all the way into 1st ?

 

[Psychographic]

Have you tried shifting through the gears yet to see if that derailleur you have on there will work with the Mega Range freewheel, all the way into 1st ?

Not yet, the vendor I got it from said it should work. I finished welding the bracket and have it fairly close. There are is a lot of alignment that I'm sure will drive me crazy and test what little patience I have for stuff like this.

With a little luck, I'll know tomorrow if it works.

 

[OddJob]

Not yet, the vendor I got it from said it should work. I finished welding the bracket and have it fairly close. There are is a lot of alignment that I'm sure will drive me crazy and test what little patience I have for stuff like this.

With a little luck, I'll know tomorrow if it works.

The derailleur itself has some built in adjustments, as well as your cable tension, cable ease of pull through the housing and stops, and ergonimics of the shifter position.

 

[Psychographic]

The derailleur itself has some built in adjustments, as well as your cable tension, cable ease of pull through the housing and stops, and ergonimics of the shifter position.

I have the limits adjusted for the position of the freewheel right now. I have to get the freewheel adapter where it needs to be on the axle (I think it needs to go more to the right from where it is now), then make sure the derailleur cage is aligned both vertically and horizontally. Hopefully I can steal the shifter off the Trek bike I have to get started, it has the same freewheel as the trike. It's a lot of aligning to do with just two hands and very little knowledge of what I'm doing!

What would be the biggest help for me to get started how long I should make the chain. I'm pretty sure it's too long right now. Do you have any pointers on how to figure the length?

 

[OddJob]

I have the limits adjusted for the position of the freewheel right now. I have to get the freewheel adapter where it needs to be on the axle (I think it needs to go more to the right from where it is now), then make sure the derailleur cage is aligned both vertically and horizontally. Hopefully I can steal the shifter off the Trek bike I have to get started, it has the same freewheel as the trike. It's a lot of aligning to do with just two hands and very little knowledge of what I'm doing!

What would be the biggest help for me to get started how long I should make the chain. I'm pretty sure it's too long right now. Do you have any pointers on how to figure the length?

The one thing I can't see is what your mount looks like for the derailleur on your frame. When properly mounted, the B-screw has to butt up against the mounting surface to offer resistence and tension on the main spring which will position the upper pulley in the best position. This is especially crucial on the Mega Range cog. It is the only thing that will keep the chain from rubbing on both the cog and the upper pulley, causing it to run rough or not engage properly.

Here are a couple photos that will help with chain length, the adjusting points on the rear der, and the B - screw.

On a typical bike build, I usually turn the B-screw in about 3-4 1/4 turns (just one twist of the wrist, not a 360 degree turn). This helps the der have more response in general. On your Cyrus, I'm not sure because of all the other 'factors' involved.

 

[Psychographic]

Again OJ to my rescue with advice!

With what little tinkering I've done, I'm either going to have to try the longer derailleur, or get a different freewheel. Again my lack of knowledge slows my build. Looking at your pic, it seems maybe the longer cage (is it called a cage, I hate to keep using the wrong terminology for the part that holds the jockey wheels) won't be a problem as it doesn't appear it will hang straight down, unless it moves a lot in high gear.

BTW, this derailleur doesn't have a B screw, unless they've hidden it real good.

What I probably should do for now is get the axle finished so it's at least rideable, then I will know how hard it will be to pedal. Maybe I won't need the granny gear seeing as I have such small diameter rear tires.

 

[OddJob]

You are correct, sir! The 'cage' is the term for the retainer part of the two jockey wheels.
And as you've said, there should always be tension on the der so that it never hangs straight down.
It will be interesting to see how your Cyrus is geared, and what gears you will actually use when riding. You won't have as much leverage as a normal upright bike, so you may want to leave that Mega Range freewheel on and try the longer der with the larger lower pulley wheel.

Looking forward to seeing this thing rolling!

 

[Psychographic]

The saga and frustration continues!

I stole the derailleur off the Trek to test,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Nothing on this darn drivetrain is easily accessed. The rear axle housing is in the way of everything on the derailleur. I can only get about a 1/4 turn on the derailleur mounting bolt (a ball driver would be very useful right now), and that is while trying to hold the derailleur open and lined up with one hand, while aligning the bolt! Then when it's time to access the limiting screws, guess what's in the way, yup, it's that pesky axle tube! Add to that a slippery greasy chain (I absolutely hate having greasy hands!), and an old guy with very little patience for mechanical work, I've got a recipe for disaster. I'm surprised tools and parts aren't flying across the basement! I will admit to cursing every part used on the bike and their mothers!

So now I have a new dilemma, guess where the lower loop of the chain goes? Yup, right into the chainstay.

Build a cool trike I said, it'll be fun! I need to stop listening to myself.

Questions will be coming on how to overcome the corner I've painted myself into.

Will Psycho get this figured out, will the evil Cyrus win the battle? Stay tuned, same ..... time, same ..... channel!!!!!!!!!!!!!!

 

[handyandy1100]

Sent from my SM-G986U using Tapatalk

 

[OddJob]

One word. Single. Speed.

 

[Psychographic]

One word. Single. Speed.

Even though I get frustrated, I do enjoy the challenge. Plus I'm old, and live in the northeast, where nothing is flat. I NEED gears.

 

[Verrt]

One word. Single. Speed.

Or nexus 8 speed

 

[OddJob]

Or nexus 8 speed

Yes! Or even a 3 spd would give you some range, with only one chain line to worry about.

 

[OddJob]

What gear(s) were you in when the chain was rubbing ? I'm wondering if you are mainly going to use gears 1 - 4 (lowest and next 3) if in those positions, with the chain at a greater angle to the chain ring, if that will clear your frame?

 

[Psychographic]

Who knew you had to pay attention to what you are doing?

I stole the matching shifter to the derailleur, used the hook on my chain breaker to take up some slack and started testing. Pedal till the hook reaches the derailleur while shifting one gear at a time, then back pedal to the chainring, and do it again (I don't want to shorten the chain before I know how much to take out of it).

So I'm making progress! Not every gear is working perfect, but I've made no cable adjustments yet. I get to 1st gear, no go. I look at the cage and it's not lined up. I KNOW I adjusted the limits and it lined up before. After a few minutes it dawns on me, I didn't put the lock collars on the axle, so it's moving side to side as I'm shifting. Not only that, but I never tightened the crank . So now I'm making progress, it goes into 1st gear!

The chain now clears the stay, but will hit if it bounces around, which I'm sure it will. So I will need a tensioner, or guide.

The new question is, how close to the derailleur can I put it before it interferes with the operation of the derailleur?

 

[Psychographic]

What gear(s) were you in when the chain was rubbing ? I'm wondering if you are mainly going to use gears 1 - 4 (lowest and next 3) if in those positions, with the chain at a greater angle to the chain ring, if that will clear your frame?

I forgot already, it was either 1st or 7th. Call me stupid, but if it's got 7 speeds, I want them all to work.

 

[OddJob]

Who knew you had to pay attention to what you are doing?

I stole the matching shifter to the derailleur, used the hook on my chain breaker to take up some slack and started testing. Pedal till the hook reaches the derailleur while shifting one gear at a time, then back pedal to the chainring, and do it again (I don't want to shorten the chain before I know how much to take out of it).

So I'm making progress! Not every gear is working perfect, but I've made no cable adjustments yet. I get to 1st gear, no go. I look at the cage and it's not lined up. I KNOW I adjusted the limits and it lined up before. After a few minutes it dawns on me, I didn't put the lock collars on the axle, so it's moving side to side as I'm shifting. Not only that, but I never tightened the crank . So now I'm making progress, it goes into 1st gear!

The chain now clears the stay, but will hit if it bounces around, which I'm sure it will. So I will need a tensioner, or guide.

The new question is, how close to the derailleur can I put it before it interferes with the operation of the derailleur?

Great news! And you can fine tune those adjustments as well. And yes, shifters are matched to der's. So that was prob the half of it.
Don't mount the chain tensioner too close to the der. You want the chain to move fluidly through the pulleys. Closer to the crank is better than closer to the der.

You don't want to constrict the chain line, so you may need to play with that some. Maybe a piece of PVC pipe might be good, smooth, easy to mount with a hose clamp / change angle, etc.

Otherwise, you could just pad the part of the frame that is getting slapped with the chain.

 

[Psychographic]

Great news! And you can fine tune those adjustments as well. And yes, shifters are matched to der's. So that was prob the half of it.
Don't mount the chain tensioner too close to the der. You want the chain to move fluidly through the pulleys. Closer to the crank is better than closer to the der.
View attachment 124091

You don't want to constrict the chain line, so you may need to play with that some. Maybe a piece of PVC pipe might be good, smooth, easy to mount with a hose clamp / change angle, etc.

Otherwise, you could just pad the part of the frame that is getting slapped with the chain.

That pic helps a lot.

I will most likely use a jockey wheel for the guide/tensioner, or one like I used on Top Fool. BTW, it's 1st gear that hits the chainstay. I've experimented with how much to shorten the chain. Using my previous mentioned method of shifting gears, I shortened the chain about 7-8 links. With it too short, it would not go into 1st gear. I added a link until it went in smoothly. I need to shorten it 5 links.

Too short in first gear,

This works, it's in 6th gear and I have about 2" of ground clearance. Not a lot, but I don't plan to do much off-roading. I'm hoping to put the tensioner somewhere between the yellow lines. I think I'm going to need to put one on the upper loop of the chain also as it might hit the seat stay.

I think I'm now down to adjustments. With it set where it is, 3rd gear is hard to get, and I need to readjust the limit to get into 7th.

Making progress