mud's RC motor reduction unit/MTB bike build

[AussieJester]

thanks guys

this is very much like what
Grinhil is attempting to do isn't it?

I guess it is, I somehow missed that thread. now that I've seem it I really like the idea of mounting the motor under the rack for weather protection and putting the battery on top which is easier than putting it in the triangle. nice design grinhill

I will most likely put a plastic cover of some sort over the drive unit and mount the battery in the triangle. I would have put the battery on the rack, but I've tried putting 10lbs on a rear rack and didn't like the way the bike handled. hopefully the battery in the triangle will balance it out enough.

Should work out well Mud your using lipos aren't you? The Astro and your reduction drive don't weigh f*ck all
prolly hardly notice them there?

KiM

 

[mud2005]

Should work out well Mud your using lipos aren't you? The Astro and your reduction drive don't weigh f*ck all
prolly hardly notice them there?

The astro and drive weigh a few pounds, but I doubt it will be noticeable once I put the battery in the frame. I'm thinking the battery weight being low will balance out the motor weight being high. If not I'll just redesgin the whole thing
no Lipos yet, I'm using a 24V 10AH Lifepo4 pack I bought a year ago. I may upgrade the battery at some point though, but for now I'm just going to cruise around between 18-22mph and use this bike mostly for riding to work.
In my mind though I'm building a twin motored Lipo shredder. damn you Matt and your PK ripper! ever since I saw that thing I've wanted one
As soon as I get this bike finished I'll start on another one, what else would I do??

 

[AussieJester]

no Lipos yet, I'm using a 24V 10AH Lifepo4 pack I bought a year ago.

Thats a problem pleeeease tell me its not a ping lifepo4 so we can remain friends...
If it is, I'm almost positive DoGman will trip over himself buying it if you take a couple bucks of the retail price :?
Seriously man, the astro on 24v c'moooon...

KiM

 

[dequinox]

Mud if you want to use my chain breaker you're more than welcome...but you should be able to find one in town. It's best to just have the tool around anyways. Also when you get around to doing the plastic cover let me know. If you want to use the vacuum former I made you are also welcome to that. I did a nice guard out of some polystyrene and it works pretty good. Very stiff and light.

 

[mud2005]

Thats a problem pleeeease tell me its not a ping lifepo4 so we can remain friends...
If it is, I'm almost positive DoGman will trip over himself buying it if you take a couple bucks of the retail price :?
Seriously man, the astro on 24v c'moooon...

hehe, you got me AJ I wimped out when buying a battery and don't hate me, but it is a ping. whats wrong with a ping anyway it was cheap, came with a bms and charger, has 3C discharge rate, and only weighs 5lbs.
I want to upgrade to higher volts, but I'm going to need some advice as I'm not much of a battery expert that's why I got a ping - easy as can be.
so help me pick out my next battery eh smart guy I would get me some Lipo but I will be bringing my bike to work and taking it through the airport then through the restaurant to the back of the kitchen where I work. If by some unfortunate circumstance I get a Lipo fire I will never be allowed to bring my bike to work again which would suck.
so what are my options then? cell man pouches? and then I have to get a bms and charger and figure out how to wire it all and not over charge it? how much is that going to cost? you see my dilemna, I have no clue basically.
I would like a 48 volt high C rate Lifepo4, charger and bms w/o spending a fortune. is that possible? school me mate

Mud if you want to use my chain breaker you're more than welcome...but you should be able to find one in town. It's best to just have the tool around anyways. Also when you get around to doing the plastic cover let me know. If you want to use the vacuum former I made you are also welcome to that. I did a nice guard out of some polystyrene and it works pretty good. Very stiff and light.

TOO cool deuinox 8) I am definitely going to want to talk to you about that vacuum former. I would like to make a lightweight cover for the motor and also for the battery and charger.
Thanks for the offer on the chain breaker, but I really need to buy one. If you know where to get one locally let me know I was using a punch and a hammer to remove links, but its a huge PITA and now I can't even find my punch.

One more question for y'all. I'm wondering if it would work to make the motor mount adjustable to tighten the chain and eliminate the need for a spring tensioner? It seems like the tensioner would be better for preventing the chain from coming off.
My prevoius builds had the motor down near the dropout so the chain was short and needed nothing but a little adjusting to make it run perfect and I never had a chain come off.
This build on the other hand has a long chain and it seems like others in this position use a spring loaded tensioner. opinions? experiences?

 

[dequinox]

TOO cool deuinox 8) I am definitely going to want to talk to you about that vacuum former. I would like to make a lightweight cover for the motor and also for the battery and charger.
Thanks for the offer on the chain breaker, but I really need to buy one. If you know where to get one locally let me know I was using a punch and a hammer to remove links, but its a huge PITA and now I can't even find my punch.

One more question for y'all. I'm wondering if it would work to make the motor mount adjustable to tighten the chain and eliminate the need for a spring tensioner? It seems like the tensioner would be better for preventing the chain from coming off.
My prevoius builds had the motor down near the dropout so the chain was short and needed nothing but a little adjusting to make it run perfect and I never had a chain come off.
This build on the other hand has a long chain and it seems like others in this position use a spring loaded tensioner. opinions? experiences?

I know you can get one from McGuire Bearing, but other than that I am not sure ...maybe Eugene Fastener...they have an assortment of weird tools. Oh, another place to look would be Fastenal. They are located on the same end of town that E.F. is. Yeah you're welcome to the vacuum former anytime...its limited to about 20-something inches on a side, and is bigger than your conventional oven but I was able to complete a form by shoving it in there diagonally. I didn't think about the oven size before I built the darn thing

For a long chain you probably ought to just make it a motor-tightening type. I don't think you'll want to deal with making a roller or drag tensioner...and the ability to move your motor back and forth should take care of that. With aluminum be aware that some flexing will happen and be sure to test that out before running down the road with it. A wrapped chain can do some damage to your spokes...trust me.

 

[AussieJester]

hehe, you got me AJ I wimped out when buying a battery and don't hate me, but it is a ping. whats wrong with a ping anyway it was cheap, came with a bms and charger, has 3C discharge rate, and only weighs 5lbs.

With that battery a Unite 300watt motor would be pushing its limits you will be tragically disappointed with performance
can't stress that enough. Pings have a cutoff in their bms dont they? that will be tripping every single time you accelerate
i regularly run over 100amp with my turnigy can/could cruise along pulling 15 amp on the flat but the motor would get hot quick these motors love revs Cell_Man a123s are your safest option or lipos i wouldnt be to concerned about them my latest failure with them saw 5v on cells and there wasn't even a rupture in the cells let alone fire, i believe the newer lipos to be a far bit safer than they were 2-3 years ago after witnessing this.
Still...wouldnt leave them unattended while charging. LiL over 200dollars will get you 4 turnigy packs 44 10ah weight is a couple of kilos 20c discharge

KiM

 

[mud2005]

I ended up going with adjustable motor mount and tensioner. I tried just the adjustable motor mount first, but when I spun the chain around there were some spots where it was tight and others where it was loose. So I threw together a simple tensioner, just have to add a spring and it's done.

Pings have a cutoff in their bms dont they? that will be tripping every single time you accelerate

my v2 ping would trip on accel, but I added some solder to the shunt and it fixed it.
my v3 hasn't tripped once yet.

i regularly run over 100amp with my turnigy can/could cruise along pulling 15 amp on the flat but the motor would get hot quick these motors love revs

hmmm, my previous builds were 24v and I cruised around at 15-20 amps most of the time and the motor never got hot at all, but that was at full throttle.

I am going to read up on Lipo and those a123 packs. hopefully this bike runs well and I can just swap in another battery without any major changes

 

[AussieJester]

You have the chain tensioner on the wrong side buddy
its meant to go on the 'slack' side of the chain not the
side you have it on. When you apply power that side is
taught the other side is loose.

KiM

 

[mud2005]

You have the chain tensioner on the wrong side buddy
its meant to go on the 'slack' side of the chain not the
side you have it on. When you apply power that side is
taught the other side is loose.

d'oh! thanks KiM I'll move it tomorrow

 

[amberwolf]

I was using a punch and a hammer to remove links, but its a huge PITA and now I can't even find my punch.

I've got a breaker for bike chain, but for the little (#25?) chains off the exercycle and scooter I used a small torx bit, as I didn't have a punch that small.

One more question for y'all. I'm wondering if it would work to make the motor mount adjustable to tighten the chain and eliminate the need for a spring tensioner? It seems like the tensioner would be better for preventing the chain from coming off.
My prevoius builds had the motor down near the dropout so the chain was short and needed nothing but a little adjusting to make it run perfect and I never had a chain come off.
This build on the other hand has a long chain and it seems like others in this position use a spring loaded tensioner. opinions? experiences?

Tensioners add a bit more noise and take a little tiny bit of energy out of the system. If you have a perfectly aligned chain that is just a bit too long, it's better to make an adjustable motor mount for tightening it, especially if there is a lot of torque.

I tried both on CrazyBike2's system, and it was way better with no tensioner, though I still have issues with getting stuff aligned right (or it's not staying aligned under torque, still not entirely certain).

If you are having troubles with the chain coming off, it means you have alignment issues, and need to stiffen (triangulate, perhaps) the motor mounts/rack, as the tensioner probably won't help as much with that as fixing the issues. Especially under vibration and whatnot.

 

[recumpence]

You don't need a chain breaker. Just grind the end of the pins off a link and pop the end plate off. I have never used a chain breaker.

Matt

 

[dequinox]

d'oh! thanks KiM I'll move it tomorrow

Lol I did that the first time around too on the reduction side of my build! Something I just didn't think about. You're not alone!

Yeah I am hoping to move up to 36v myself if I get a decent summer job. Being a poor-@$$ student sucks. Anyways, at some point I will spring for an astroflight, an HD freewheel, and a nice battery. That's all that is missing so far...

Dylan

 

[katou]

But how do you put the pin back in, if the head is ground off?

I've used a chain breaker with bike chain, but I only had to do it once or twice.

Katou

 

[12p3phPMDC]

You need a master link to replace the permanent link you just ground off.

There may be a permanent link that you could reinstall, anybody used such a thing?

 

[amberwolf]

I've had no problems with using a chain breaker to remove and reinstall a link, as long as I do not reuse that same link as the breakpoint again (just mark it with something; a scratch, etc).

In some cases I have been able to redo the same link a couple of times, but it could come out under high torque loads so I would never do that to one driven by a motor. There's usually no reason to, anyway, as there are typically enough links in a chain that if you have to take it off enough times to redo any of the links a second time the whole chain's probably worn out anyway.

 

[12p3phPMDC]

Do you re-peen the pin after you re-install it? probably don't want to overdo it in increase the chain friction on that link.

Here's a good little article, there's all sorts of ways to deal with chain...

http://www.parktool.com/repair/readhowto.asp?id=25

 

[amberwolf]

I don't. I just use the breaker in reverse. Doesn't mean it'll work for everyone, or every chain.

 

[dequinox]

Yeah I had some major problems getting my chain to go back together and stay together. I don't know how many times I would hear KACHUNK.....KACHUNK.... as a stiff link went round the chainwheel Lol

And MUD! Hows the build coming along bud?

 

[amberwolf]

The stiff link is actually easy to fix. When you are using the chain tool to reinsert the pin, then just before you are done with the last twist on the screw, maybe a half turn, loosen it back up, then back off the holding screw all the way, so that the chain is going to be pushed differently.

When you now retighten the insertion screw, it will push the *other* plate against the alignment brace the chain rests on, and slightly push the far plate away via the pin, unstiffening the link. It only takes at most a half turn to do this usually.

 

[mud2005]

to fix a stiff link I just put some pressure on the stiff link by "bending" the chain. I don't really bend it, but I'm not sure how else to describe it.
Here's a pic to that I hope shows what I mean.

I put pressure or "bend" the chain in both directions until the link moves like it should.

And MUD! Hows the build coming along bud?

well I took too long as usual thinking about how I wanted to build a battery box. I finally decided on a simple design and the aluminium is going to arrive in the mail tomorrow
I'm getting some .08 thick 6061 for the box and I'm going to use some angle and rivets to hold it together.
I'm going to make some frame brackets from 1" x 2" x 2" pieces.
nothing fancy just want it to be strong, waterproof, and last a long time.

 

[amberwolf]

If it were me, I'd add one more mounting bracket on that box:

 

[mud2005]

If it were me, I'd add one more mounting bracket on that box:

thanks amberwolf, yeah I will most likely add a bracket there also. Once I get the box made it will be easier to work out the mounting brackets

 

[amberwolf]

first time I put SLAs in the triangle of the original DGA, I thought I could clamp one above and one below the tube and they'd balance. Worked great till I turned leaning hard and one of them tipped into the cranks.

Went with a seattube clamp (ziptie, at the time) too, real quick.

 

[dequinox]

Looks good mud. You order aluminum in the mail? How much is that and whereabouts do you get it? I've been using Coyote steel here in town and they have a lot of good stuff...some 2nd material as well. You can freely peruse the bins and pay by the pound for some of it.

Also I solved the stiff chain problem the same way as you...but sometimes the pins didn't hold because I didn't screw them in far enough...