Pick a bike with BIG FLAT REAR DROPOUTS

dogman dan

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You'll see us say this over and over and over.

When choosing a bike to use a rear hubmotor, pick one with BIG FLAT DROPOUT PLATES.

It just makes everything soooooooo much easier. Today I was converting my Giant OS3 commuter bike from a front hub street ride to a trail riding rear hub motor dirt ride.

1 File dropouts 2mm deeper as usual
2 Figure out which set of washers center the rim good
3 Drop in the motor, put two old school design torque arms on the axle,
4 Drill two holes and install two bolts.

Done! Damn, that was the easiest rear hub install yet. What could be simpler and more elegant?

I'm going to be really pleased with this build. I'm aiming for 15mph, 2812 motor. With the new bike I get to use a really fat rear tire that couldn't fit on the mongoose. I'll run it on only 48v, and build it to pedal getting great wh/mi with no battery box in the way like the mongoose. The mongoose is still around, but with a 72v controller and 2010 motor, it now zooms to 30 mph.
 
Yup, that's the way to go.
Been preaching this for years.

This is why i am such a fan of the old Trek 4300/4500 bikes. I went through about 3 different used bikes until i found these.

torqueplate4.jpg


torqueplate3.jpg
 
Just did this last week on my aldibike - was a bit worried but you've made me feel good.

Couldn't get a nut on the back of the bolt due to the cluster being close behind the dropout - managed to tap an m6 thread instead and use a nice looking capscrew.

I often wonder if the two piece torque arms are a good idea on high torque builds due to looseness at the joint between first and second link. :?:
 
The two piece design works best when you have two clamps on the second piece. Then the second piece can't rotate or slip. The second piece has to rotate to slip the bolt where the two pieces connect. Finding quality hose clamps has become an issue though.

Just got the bike out for a test spin. I'm going to love it. Much better suspension than the old mongoose blackcomb dirt beater. It has a pretty good marzocchi fork. Feels great riding over softball size rocks.

15 mph is fine now that I'm sick with chronic fatigue. I don't ride more than about two miles, to run the dog. So I lightened up, and carry just 5 ah of 14s, instead of 10 ah of 20s. The fatter 2.7 inch rear tire is great for deep sand which we have plenty of. But now it's very nice to pedal it too, with no battery boxes banging my knees. Battery so light, I just stuck it on a rear rack, and can't even tell it's there. :mrgreen:

The old mongoose is nice too, with a 9c 2810 on 72v. Still great for blasting down dirt roads at 30 mph. :twisted:
 
I ended up doing this on both sides.
 

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Very true!

I just edited the title of the first post, to clarify that this thread was showing what kind of dropouts work good for an easy rear motor conversion.

But since you brought up the subject, Schwinn and other brand beach cruisers and no suspension MTB's or comfort bikes make great front hub bikes. Front hub conversions are super easy, provided you don't complicate things with suspension forks, or carbon.

Stock torque arms are designed for the steel front fork, and work fine. C washers are recommended, or grind down the supplied tabbed washer so it fits the QR cup on the fork better.

But if you have a bike that needs a torque arm for a rear dropout that is funny shaped and hard to make work, there are alternatives.

Grin Cyclery has the new universal rear torque arm. http://www.ebikes.ca/store/store_connectors.php

And I just noticed yesterday a very nicely designed torque arm for the disk mount side of bikes that have disk mounts. See them here.

http://endless-sphere.com/forums/viewtopic.php?f=31&t=49635
 
I am doing dropouts right now. My Trek Session 10 has bolted on dropouts, so it is only a matter of doing a steel replica. Flat bolted on dropouts on my V 10 were quick and easy to do, I was hoping for the Session to be similar. Yet they are offset and shaped in a way that requires 1 1/8" thick steel to reproduce. With an angle grinder, hand drill and files, I am started for a long job of steel sculpture. Bolted on dropouts are ideal for a neat dropout job, but not always the easiest.
 
My claud has big dropouts.
images


1993 hardtail claud butler cbx aluminium. Oversized in most ways.
 
One more reason I prefer the old school 90s mtn bikes. Everything nowadays has some funky design to make it look special. Also a 90s FS bike is much more likely to have good triangle space. Not today's mtn bikes - with those sloping top tubes and trend of smaller frames.
 
Go look at the Surly Troll frame, big crmo drop out that allow horizontal removal of the wheel without removing the de failure. I have two of these frames and love how they Handel and they are in Cr mo and built to last.
 
Good advise! Where did you guys get those nice looking "old-school" torque arms? I like the ones in the pictures--digman's and neptronix. Please let me know where to find them.

Eric
 
veloman said:
One more reason I prefer the old school 90s mtn bikes. Everything nowadays has some funky design to make it look special. Also a 90s FS bike is much more likely to have good triangle space. Not today's mtn bikes - with those sloping top tubes and trend of smaller frames.
Funky?
May I remind you that 90s FS bikes were junk compared with modern designs. Weight, travel, strength, pedal-ability and geometry were all inferior.

Today's MTBs are not designed for mounting batteries and hub motors. They are designed to be ridden as MTBs.

Want a frame designed for e-bikes - buy a Stealth or opti or whatever else is there on the market.
 
full-throttle said:
Today's MTBs are not designed for mounting batteries and hub motors. They are designed to be ridden as MTBs.
.

True. I was explaining to a guy who makes carbon fibre frames the other day that us ebike guys are running around Kmart/Walmart with magnets looking for suitable donor bikes to cut/weld and shut. He thought the fact that we'd gone full-circle on materials and price remarkable/hilarious.
 
Hardcarve1 said:
Go look at the Surly Troll frame, big crmo drop out that allow horizontal removal of the wheel without removing the de failure. I have two of these frames and love how they Handel and they are in Cr mo and built to last.

The Surly Troll and Ogre (29" version) also have large M10x1.0 threads just above the dropout slots. These could be use to anchor torque arms, mount heavy duty battery racks, or both.

troll2.jpg
 
Chalo said:
The Surly Troll and Ogre (29" version) also have large M10x1.0 threads just above the dropout slots. These could be use to anchor torque arms, mount heavy duty battery racks, or both.
The mind boggles, what did they intend that needs an M10 bolt? Especially as they have two M5 right above it.
 
-dg said:
Chalo said:
The Surly Troll and Ogre (29" version) also have large M10x1.0 threads just above the dropout slots. These could be use to anchor torque arms, mount heavy duty battery racks, or both.
The mind boggles, what did they intend that needs an M10 bolt? Especially as they have two M5 right above it.

It's original purpose was for a trailer. Quoted from Surlybikes: "Like the fork, the rear end allows all-at-once rack, fender and disc compatibility. Spaced for 135mm hubs, the ‘dropouts’ are just like Troll’s…rear load horizontals with a derailleur hanger, slotted disc brake mounts, M10 x 1mm threaded holes for mounting Surly Bill & Ted trailer-connecting hardware (or B.O.B. Nutz), and a dedicated anchoring point for a Rohloff OEM2 axle plate. We designed a ton of versatility into these framesets because we want you to build up a Troll or Ogre the way it will best serve you."

I wish they'd use this rear dropout design in their fat bike lineup. :|
 
Beat me too it. Looks exactly perfect for my next contemplated modification to my frankenbike. A trailer hitch. I'm thiking in terms of a large steel hoop, that would allow attaching anything from a bob trailer, dolly, or even a garden wagon.


Those surly dropouts are real winners. No surprise, surly is the bomb. I keep waiting for them to build the worlds best full suspension longtail.
 
dogman said:
Those surly dropouts are real winners. No surprise, surly is the bomb. I keep waiting for them to build the worlds best full suspension longtail.

You may have a long wait, then. Surly first popped up with their original "Rat Ride" single speed MTB as an alternative to mainstream MTBs that had begun to go gadget crazy. I think we'll see Surly offer (mechanical) suspension about the same time that Trek commits itself to an all-steel, all-rigid, all single speed bike lineup. But they have been on the forefront of airbag suspension development for years now!

bikes_moonlander.jpg


I do wonder whether there might be a Surly "Big Fat Dummy" in our future. Some folks are already rolling their own.

3611958113_2647e0d65d.jpg
 
If you're handy with a welder, or you have an old crmo frame to experiment on, Surly do make and sell various dropouts.
Bottom RH of this page:
http://viewer.zmags.com/publication/a8e5bd2a#/a8e5bd2a/458

Paragon machine works sell them too FWIW.
 
Samd said:
If you're handy with a welder, or you have an old crmo frame to experiment on, Surly do make and sell various dropouts.

Paragon machine works sell them too FWIW.

And Henry James (whose website is brutalized at the moment), and Nova Cycles.
 
Yep, there are some nice components out there for those who weld, from a variety of sources. If you weld and have steel frames, pretty easy to just make a simple pinch dropout too.

Once thing I really liked about that surly one was that though it had fixie style horizontal dropouts, it still sported a derailur hanger. Thought that was a nice touch.

I think you are correct, Surly will never get into suspension stuff. But if they did, I'm 99% sure they would do it better than most. I think a good approach would be very old school, two shocks on either side like vintage motorcycles had. Lots of extra shock capacity for the heavy loads, and the cargo beam would be well supported. Not exactly new tech that would need expensive R&D.

If we see it happen, it might be more likely to be Kona that does it. But Surly would do it better if they did. The one who might do it is whoever works with Grin. It would be a snap for Paul Brodie to design a modification to the extracycle frame, converting it to a swing arm and two shocks just behind the motor mount. The Grin connection is why I thought surly could be thinking about it.
 
You can buy a frame that has removeable dropouts too and then make your own to bolt in.
For example, MacMahone CroMo 4130 frame
 

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that is why im very glad more and more ebike specific frames are coming, two of which coming from Europe:
- Greyborg
- Torque Raptor

and Phasor from USA..

biggest advantages being:
1. in frame dedicated battery box / space
2. steel bolted dropouts
3. 150mm or 165mm dropout width

I started with Kona Dawg, great bike but there is only limited amount of mods i can do in my garage without tools ect...

135mm motor range is limited, you get some with lower power just to realize after 2 weeks that you need more adrenaline and you are stuck...
 
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