A-DamW
1 kW
Pretty sure this one will fit a my1020(219 chain):
Comment, criticize my build. But be nice I’m new!
- Thread starter Drubieg
- Start date
A-DamW
1 kW
Here is some good info on "Chordal Action":
That whole site has great info for all things chain.
Drubieg
1 W
Thanks!
Close, but no. MY1020 uses a 8x10mm shaft, that's for a 8x12 shaft.Pretty sure this one will fit a my1020(219 chain):
Do you have the chain to tire clearance to offset your rear sprocket towards the spokes a bit instead of adding an idler?
Hummina Shadeeba
10 MW
An idler on the tensioned side of the chain needs to be mounted very securely as it’ll have a lot of tension on it. What idler and on what tube would u mount it so it’s running parallel with the chain? You said the chain would hit the rear brake so I guess you’d mount it to the seat stay, but that tube isn’t aligned and sounds awkward to do.
If the idler is to avoid the chain hitting the frame, I’d maybe even dent the frame if not much needed, which would be hard to do but surely could take it. If the idler is just to avoid the brake I’d take it off and do a regen rear brake and they can be plenty powerful at all speeds down to like 2mph and you’ll have a front brake too. I’d take the rear brake off and do the regen rear regardless.
I don’t think you NEED an idler to get more teeth engaged
I like how ur doing a giant chainring on the back.
If the idler is to avoid the chain hitting the frame, I’d maybe even dent the frame if not much needed, which would be hard to do but surely could take it. If the idler is just to avoid the brake I’d take it off and do a regen rear brake and they can be plenty powerful at all speeds down to like 2mph and you’ll have a front brake too. I’d take the rear brake off and do the regen rear regardless.
I don’t think you NEED an idler to get more teeth engaged
I like how ur doing a giant chainring on the back.
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Drubieg
1 W
I have it mounted on the slack side. If I put the sprocket closer to the spokes then the chain hits the tire, they are pretty wide tires
Drubieg
1 W
I had some 3/16 inch steel I used to mount the idler sprocket with a u bolt. I also was able to space it out to get it in line with the other sprockets. I also used washers on the rear axle as spacers to widen the rear dropout. I also did end up just taking off the rear brake. I'll try to figure out Regen braking. Got more batteries and another box so now I have saddle bag style battery mounting that I can easily remove with wing nuts
Looks peachy 
, especially the hard case panniers.
Re: U-bolts - If you have some spare tubing, tuck a 2" or so length under the U-bolts to discourage crushing/dimpling frame tubes. Just halve the 2" addition length-wise - particularly the vulnerable down tube.
, especially the hard case panniers.Re: U-bolts - If you have some spare tubing, tuck a 2" or so length under the U-bolts to discourage crushing/dimpling frame tubes. Just halve the 2" addition length-wise - particularly the vulnerable down tube.
Another possible option:
They make these things, probably conduit or pipe hangers, which come with plastic support rings...you can either use the actual support rings (if you can find one), or more likely 3D print (or have printed) something like this, that spreads the load from the U-bolt over more surface area (same idea as the pipe halves above). I found one, once, somewhere, and found it was exactly the right shape and size for fitting over a common bottom bracket shell, and was going to use it for my first 'bent build way back when as a bushing to test the pivot idea (before making something permanent), but I could never find another one (no place of any kind that I could contact had ever seen one or had any idea what it was for, and at the time no internet searches could find it either).
The only concern would be if the pressure on the ring was great enough to cause the plastic to split or deform.
This is the way I would have used it (and which you could, too, though you'd have to cut the ring open to get it over your frame)
This is the actual part and bracket it came with:
They make these things, probably conduit or pipe hangers, which come with plastic support rings...you can either use the actual support rings (if you can find one), or more likely 3D print (or have printed) something like this, that spreads the load from the U-bolt over more surface area (same idea as the pipe halves above). I found one, once, somewhere, and found it was exactly the right shape and size for fitting over a common bottom bracket shell, and was going to use it for my first 'bent build way back when as a bushing to test the pivot idea (before making something permanent), but I could never find another one (no place of any kind that I could contact had ever seen one or had any idea what it was for, and at the time no internet searches could find it either).
The only concern would be if the pressure on the ring was great enough to cause the plastic to split or deform.
This is the way I would have used it (and which you could, too, though you'd have to cut the ring open to get it over your frame)
This is the actual part and bracket it came with:
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For the price of your pipe hanger, Amber, you can buy a 12" stick of 1-1/2" x .058" wall 4130 from
www.aircraftspruce.com/catalog/mepages/4130tubing_un1.php for a smidgen over 5 bucks +sh.
Not difficult to spread and wrap larger frame tubes after halving. Chromoly is much stiffer and ideally suited for such applications.
www.aircraftspruce.com/catalog/mepages/4130tubing_un1.php for a smidgen over 5 bucks +sh.
Not difficult to spread and wrap larger frame tubes after halving. Chromoly is much stiffer and ideally suited for such applications.
Drubieg
1 W
Is crushing the frame with the u bolt really a large concern? It's a stout steel frame and I try not to overtighten stuff
Drubieg
1 W
That's a good point
PaPaSteve
10 kW
The idler is likely to loosen the "U" bolt over time in some way.
Secondary attach the idler bracket to the uni-strut in some way for piece of mind.
Weld, or small piece of angle with bolts ?
Battery box location looks better.
Only on the internet. That frame is probably straight gauge 4130. I'm guessing this is already a heavy bike, I wouldn't want to add any unnecessary weight. I can't tell from the pictures, is your idler bracket attached to/ part of the motor mount plate somehow? If not, it probably should be.
I have that same rack you're using for your batteries. If I were carrying that kind of weight with it I'd figure out a way to replace the adjustable vertical braces with 1 piece bars to avoid bending your seat post, or worse. The clamping set screws slip down slightly any time I carry weight on mine.
If your gearing is still too tall now you could try a smaller (24") rear wheel, since you've already sacrificed the rear brake and pedals. You might like what that does to the frame geometry for high speed handling.
Drubieg
1 W
I'll see what I can do. I figured stuff would get loose overtime. I tried to put lock nuts/washers or loctite where I could
PaPaSteve
10 kW
Center of the idler bolt is cantilevered from the center of the seat tube by 2" or so.
Just a gut feeling based on experience, ~ Torque of the drive chain multiplied by the lever length will cause bending or twisting of some nature.
Drubieg
1 W
Yes I'll have to see by how much, I thought it might. I also have the bracket butted tight up against the other motor mount strut and against the heat sink and was hoping that would help it stay rigid. But I'll give it a test and see
Hummina Shadeeba
10 MW
This is 26” wheels and a 29” fork with an excessive 180mm travel I think it was. I went to the extreme with picking this fork and it’s way too long and tilts the frame to a 60.9 degree headtube angle which is slacker than downhill bikes have.
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