Advice on building a custom off road bike.

harryS

Well-Known Member
#21
I did the 2WD for the fun of it, but it turned out not to be much fun riding a fatbike in snow w/o a snowmobile suit, and without a partner, there was alway the chance I would have a mishap and freeze to death in the woods, just 1/2 mile from McDonalds. I still have the motor with snow tire on a fatbike rim, but the fatbike is now rwd with summer tires.
 
#24
Would you say that 2wd is actually dangerous, or does it just take some getting used to? I did see those harnesses. But, I am not sure if I would use a harness, just splice the wires, or maybe enen control the front and rear with 2 separate throttles.
 
#25
Would you say that 2wd is actually dangerous, or does it just take some getting used to? I did see those harnesses. But, I am not sure if I would use a harness, just splice the wires, or maybe enen control the front and rear with 2 separate throttles.
I can't imagine bothering with two throttles. Sounds doable but in practice, I thought it sucked. Not enough hands to manage effectively. Splicing isn't always as simple or effective as it sounds.
 
#27
I didn't see the 2wd wiring post. But, if you could send me a link, it would save me the headache of trying to figure it out myself. The other option would be 1 throttle. But, also have a button to push when I need a 2wd boost, like on the straight sections.

I haven't actually bought a bike yet. I was going to pick up a used one from Craigslist. What should I look for in a bike?
 
#28
I didn't see the 2wd wiring post. But, if you could send me a link, it would save me the headache of trying to figure it out myself. The other option would be 1 throttle. But, also have a button to push when I need a 2wd boost, like on the straight sections.

I haven't actually bought a bike yet. I was going to pick up a used one from Craigslist. What should I look for in a bike?
For 2WD be certain to find a bike with a STEEL not suspension fork. The diagram is in another 2wd post here.
What is you intended purpose in building a 2wd? I and others will make better suggestions with more information.
 
#30
Long story short, I need a bike that can climb a very specific hill near my house, to enable me to get to my garden. I dont care about range or speed. I want use the Dewalt 20v batteries that I already own. I have a ton of them. 2 of the 20v (18v under load) batteries in series limits me to a 36 volt system. The biggest reasonably priced 36v geared hubs that I can find are only rated for 500 watts. If one of the 500 watt geared hubs on the rear can get me up the hill with little or no pedaling, I will leave it as is. If not, I would add a 2nd motor to the front for extra power getting up the hill.

Thanks for the link. I will study the diagram if / when that phase of the project comes along.
 
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harryS

Well-Known Member
#31
I want to use battery docks like this one: https://www.ebay.com/itm/1x-battery-adapter-for-DeWALT-20v-Max-18v-dock-power-connector-12-gauge-robotics/142979592702?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 This will enable me to use the Dewalt chargers that I already own, and also be able to continue to use the Dewalt batteries on my power tools, when I'm not riding the bike. Wiring these 20v max (18v under load) batteries in series, I will have the option to go 18v, 36v, 54v... Since, nothing in the bike world seems to operate on 54v, 36v seems the way to go. I am confident that the larger dewalt batteries put out well over 20A.
I think you will need 4 of those adapters. Two to get a nominal 36V and two more to parallel up your packs. The ebikeling controller will draw 22A.

The current controller will run on either 36V or 48V. A nominal 48V battery is 54.6V peak. Three of your Dewalt packs in series will be 63V peak. That is the max ratings of the 63V capacitors inside the controller, and I would not try it. Not sure the LED display can handle it either.
 
#32
I’ll be using the Dewalt flex volt 6ah batteries in 20 volt mode. In 20 volt mode, they have 3 sets of cells paralleled internally. I would think that these batteries could output 22+ amps without even breaking a sweat. That is unless they have an internal breaker or electronic current limiter that I don’t know about. I will contact the battery dock manufacturer to see what he knows about it. If I have to, I will go with a 4 battery/dock setup. But, I am hoping to not have to go that route.
 
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#34
I put the kit on well enough to take it for a test ride, and I am really impressed with the power of this bike. It is a lot of fun. I haven’t been able to try it on the trail that I am ultimately gonna ride it on though. But, I have ridden it on a similar sized hill, and it went up the hill with just a little pedaling. It felt like I was pedaling on level ground when going up this hill. Where can I get disc brakes for this rear hub?
 

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harryS

Well-Known Member
#35
Glad to see you did the conversion and that you like it!

You cannot easily get disk brakes for that bike. I don't see any caliper lugs on your frame.

1) You can buy a new fork with the disk lugs for the front. That's a costly adventure. Probably have to replace the headset and definitely buy a new wheel, and it changes the rake/trail.

2) You can buy this gizmo for the rear. It holds a disk caliper and clamps to the old v-brake bosses. RJ the bike guy on youtube has a howto video,
https://www.ebay.com/itm/New-MTB-Bi...P:sc:USPSPriorityFlatRateEnvelope!60565!US!-1

3) Switch to this kind of brake. I have them on half the bikes I converted. In fact, the first ebike I converted wouldn't stop and it had 20 year old center pull brakes like yours. I was losing a lot of friction in the cable because of rust so I changed that too. Least expensive solution. and worth a try. It also has the same ebikeling motor and stops very well with these style of brakes. I also changed the fork, but never saw the need to put on a front disk. This pic is of a later bike.

vbrake.jpg
 
#36
I put the kit on well enough to take it for a test ride, and I am really impressed with the power of this bike. It is a lot of fun. I haven’t been able to try it on the trail that I am ultimately gonna ride it on though. But, I have ridden it on a similar sized hill, and it went up the hill with just a little pedaling. It felt like I was pedaling on level ground when going up this hill. Where can I get disc brakes for this rear hub?
California eBikes, I support their motors, sells a tektro set. We get orders from EU and AU. Not common here but price to quality is very good. I’m told. I make no $ nor do I support them. I’m fastidious about my rim brakes. 26” discs with KoolStop grey eBike pads. Good to 25mph. Funky discs have longer stop distance, especially over 20mph. Everyone should grab a friend and do panic stop drills, and KNOW how the brakes function.
 
#37
Glad to see you did the conversion and that you like it!

You cannot easily get disk brakes for that bike. I don't see any caliper lugs on your frame.

1) You can buy a new fork with the disk lugs for the front. That's a costly adventure. Probably have to replace the headset and definitely buy a new wheel, and it changes the rake/trail.

2) You can buy this gizmo for the rear. It holds a disk caliper and clamps to the old v-brake bosses. RJ the bike guy on youtube has a howto video,
https://www.ebay.com/itm/New-MTB-Bi...P:sc:USPSPriorityFlatRateEnvelope!60565!US!-1

3) Switch to this kind of brake. I have them on half the bikes I converted. In fact, the first ebike I converted wouldn't stop and it had 20 year old center pull brakes like yours. I was losing a lot of friction in the cable because of rust so I changed that too. Least expensive solution. and worth a try. It also has the same ebikeling motor and stops very well with these style of brakes. I also changed the fork, but never saw the need to put on a front disk. This pic is of a later bike.

View attachment 32302
As always peerless advise. Finding replacement forks can be an adventure but I’ve found several very nice forks with both brake options. My aborted 2wd Mac fork was steel and set up for rim and disc. As well as sturdy fender tabs for dual torque arms. The struggle was finding a fork that wouldn’t trash the intended geometry. I think when discussing brakes it’s helpful to understand the build and it’s overall specs. My BBS01’s 2013 stop on a dime with KoolStop MTB orange pads. My BBSHD needed BB7 mechanical discs at minimum.
 
#38
The more that I think about it, I am gonna hold off on the brake upgrade until I get a better bike. The day that the conversion kit came in the mail, I bought the first steel framed, non suspension, used bike that I could get my hands on for under $50. Once I ride it for a while, I can determine what I really want in a bike and possibly pick up another used bike that is better quality.

I was able to try this bike today on the trail that I bought the bike for, and I was able to climb the hill that I was worried about with just a little pedaling. I could live with it as is, if I had to. But, I Have decided to order a front wheel kit and go for 2wd. I will post pics throughout the project.