Warren's 350 MAC mid-drive (finally) recumbent

[Warren]

Well, I thought I would rename this thread, as my questions have all been answered, and now it's just rolling on the miles. We were out of town for the three nicest days all month. Its been cold and rainy since we got back. It was 46 degrees today, but at least the it was sunny, and calm. So I did a short 36 mile ride to get the odometer to roll over to 1001 miles!!

Its been pretty uneventful. No cooked Hall sensors, magnets, or cells. No tires ripped off the rim. But I've gotten lots of exercise, and seen deer, hawks, even a baby copperhead. And I get to laugh at dogs now.

[dumbass]

First stage: motor to left side Bottom Bracket cog
Second Stage: right side cog to rear cluster

Where are the freewheels in this config? Does that mean the pedals have to move under motor power?

How ever you build it be sure you have a good freewhee between the motor and your peddles. Never have the peddles turn from the motor. You can really get hurt that way.

I use a jack shaft setup between my motor and the rear wheel. This give a good oppertunity for gear reduction plus a great place to mount a freewheel. You can also replace the peddle shaft with a longer one and install a freewhell directly on the peddle shaft.

Bob

[Warren]

Bob,

"Never have the pedals turn from the motor. You can really get hurt that way."

Stokemonkey has been doing this for 8 years with no problems. There could only be a problem if your motor is geared higher than you can pedal comfortably. Are you imagining the throttle hanging wide open? So what? I ride with mine wide open at all times. The pedals turn about 80 rpm. I can clip in and out of my pedals, as they go around, at that speed.

Warren

[dumbass]

Bob,

"Never have the pedals turn from the motor. You can really get hurt that way."

Stokemonkey has been doing this for 8 years with no problems. There could only be a problem if your motor is geared higher than you can pedal comfortably. Are you imagining the throttle hanging wide open? So what? I ride with mine wide open at all times. The pedals turn about 80 rpm. I can clip in and out of my pedals, as they go around, at that speed.

Warren

Warren,

I would certainly never tell anyone how to equipt their bike. But sorry I don't think that having the motor powering the peddle chain without a freewheel to protect you is not safe. But if your comfy with it that's cool.

Bob

[Warren]

Made a Y cable to run my two 5 amp chargers in parallel. The setup works great. Reduces a full 936 Wh charge, into my 1170 Wh pack to two and a half hours! And the BMS stays cool the whole time.

This will allow me to do some really long rides now. No more of these wimpy 80 mile days. I can hammer out 75 miles in three and a half hours, then charge, and ride another 75.

1197 miles, so far.

Dang! It was cold this afternoon...in the 40's. 1259 miles now.

[dbaker]

Great to see that Linear racking up those miles. You posted 2 sprocket options for the motor. Which one did you end up using?

[Warren]

dbaker,

"You posted 2 sprocket options for the motor. Which one did you end up using?'

The 15T on the motor, to a 53t on the crank is perfect with my "36 volt", 30 Ah pack. Typically, people who bicycle a lot average about 80 rpm, racers average more like 90+. Non-bikers are more comfortable at 0-60 rpm.

I'm up to 1448 miles today. I got my Zzipper experimenter bubble the other day, so I am anxious to get that on. It should be good for about 5% more speed, or range. But most important, it should keep me, and the battery, a little warmer, once we get some real winter weather. So far, climate change has meant pleasant riding this fall.

Warren

[dbaker]

Was the 15t a sprocket that bolted to the disc brake rotor mount and if so where did you get it

[torker]

Awesome build. I have a Sun EZRider that I want to do a hubbie midrive or crank drive setup. Do you have any more pics /info on how you managed the dual crank setup? That looks like a simple setup. Also, Other than driving the crank on the left- Is the original right side bike drivetrain stock? Close ups would be awesome.

[Warren]

So, I finally got the bike as I had originally envisioned it. I ended up modifying the front right cover. I had my local machine shop turn down the two steps on the cover. They turned down the smaller shoulder, slightly, to allow this cog to slide on.

http://www.velosolo.co.uk/disccog15.html

They turned the larger shoulder down to 35 mm diameter, to allow me to install a 5 mm thick aluminum ring, 35 mm ID, 64 mm OD. The ring has 12 holes drilled and tapped to match the 44 mm disc brake BCD, for the cog. The cover has six countersunk holes through from the inside, to bolt the ring to the outside of the cover. The cog bolts to the remaining six holes in the ring. Basically, I duplicated the disc brake mount from the left side to the right side. But the one on the right side is 5 mm thick, instead of 7 mm thick. The sprocket sits right in the middle of the gap between the cover, and the motor mount plate. There is about 2 mm on either side of the chain, which acts as a chain guide, so the chain can't derail when it swings. It works perfectly! I saved one and a quarter pounds of weight, a chainring, 116 links of chain, two chain guides, and two power robbing idlers. And I have a better chain line, so I no longer get grease on my right calf.

One 116 link chain runs from the 53 tooth chainring to the 15 tooth cog on the left side of the motor. One and a half chains, about 175 links, goes from the 15 tooth cog on the right side to the 12-34, 8 speed cassette in the rear.

Got that EV grin!

[GITech]

Hi Warren,

Nice! Got new pics?

BTW: Nice legs!

Jay

[Warren]

Jay,

Sorry to take so long. Hope this works.

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Warren

[ddk]

very nice job Warren

[Warren]

ddk,

Thanks. Hit 2,063 miles today. Sunny, 60, low wind, 83.5 miles, 20.2 mph average, 10.7 Wh/mile. I love this bike.

Warren

[Warren]

Batteries like it warm.

When I got this bike running, back in the fall, I took my first real ride October 17th. That was the last really warm day, that I got to ride any distance. I spent the winter trying to match the Wh/mi, and speed of that ride. If I maintained the same or better average speed, the Wh/mi was up 10-15%...until yesterday.

We matched the record high for the date, set in 1990, 86 degrees F. That was nine degrees warmer than my ride back in October. The average wind speed was the same at 4 mph, but maximum back in October was 9 mph, gusting to 18 mph. Yesterday's max was 21, gusting to 30.

10/17/11
80.2 mi 20.9mph ave. 10.2 Wh/mi

3/15/12
80.7 mi 21.1 ave. 10.1 Wh/mi

[www.recumbents.com]

Looks great on the Linear! That's a good recumbent platform for an ebike, nice long wheelbase, big wheels. Very nice.

- Other Warren.

[Warren]

other Warren,

Thanks for the compliments. Yours was one of the bikes I checked out, before building this thing. You have been at this e-bike thing a lot longer than me. I wish I could commute to work on this bike. Maddening. I could ride an e-bike 20 miles to town, but there is a death zone all around the perimeter, a two mile stretch that would require an actual electric motorcycle. I could build a 50 mph e-bike, but I would get arrested with days.

So I just satisfy myself with long rides on my days off. Bill Bushnell is my all-time hero.

http://mrbill.homeip.net/hybridBike.php

[Warren]

Rolled over 2,441 miles today. Blue skies, low humidity, 68-71 degrees, light wind. Only had time for a quick ride before work.

32.6 miles, 22.6 average, 41.0 max, 12.3 Wh/mi.

I figure I will need to replace my chain, and tires at 3,000 miles, to avoid any roadside repairs. No flats yet. No overheating. No flying solder, or puffed cells. It will be interesting to see how long this motor will last actually running at the wattage it was designed for.

[Warren]

Tuesday noon, 65 degrees, clear, calm, dry. Headed out to Culpeper for lunch. Back home at 5:30, 77 degrees, partly cloudy, very little wind. Took the long way home, through Green Springs area, shooting for 100 miles...almost.

98.78 mi, 4:41.51, 21.0 ave, 37.4 max Used 23.64 amp hours of 24 amp hours available. Could have made 100 easy.

2,680 miles, so far.

[Seon]

Warren, your 350 MAC mid-drive seems a simple, elegant and achievable solution for a recumbent. It solves so many problems at once and also fits the pattern of use I have in mind.

I would like to copy it for my home made SWB 26" x 20". It's made from square section steel and it would be very easy to bolt a mid-drive mount onto it.

For this bike I won't need your range and speed. I'm using a Sturmey Archer three speed gear hub. But I would want to try and build a folding 26" x 26" LWB later on with an 8 speed or NuVinci hub.

But for now I'll stick with what I've got.

Before I go ahead, I wonder if you wouldn't mind giving me some advice about which MAC 350 to use. I have two questions.

1. I don't understand gearing very well but I read somewhere that the MAC 350 for rear wheel is set up to provide more torque for hill climbing. But maybe that's not an advantage given that it will be run through a gear hub in any case?

2. I wonder if using the rear wheel version would allow use of a cog that might screw on to the case where the freewheel would normally go. It would be a bonus if I didn't have to drill the case to take a cog fitting. Would using a rear hub motor allow your setup to be followed without having to drill or modify the casing in any way?

Best regards,

Seon

[Warren]

Seon,

I don't know where you plan to purchase your MAC 350. But if you are getting it from Paul, at Emissions-Free, the rear motor has the same winding as the front motor. If you are using that rear motor, you will be fine. As long as you are running 12 cells, you can use a 15 tooth cog from VeloSolo on the disc mount, and a 15 tooth, track cog on the right. You will need to Loctite the track cog on. Or you could weld a bolt lug on the flange of the track cog, then split the lug and sprocket to the cog's center hole with a saw, or thin abrasive wheel. Drill a small hole on the opposite side of the center hole in the cog. This would turn the cog into a split clamp,

http://www.daytonsuperiorproducts.com/i ... readed.png

allowing it to be locked to the hub.

What I like about the front motor is that the axle is 35 mm narrower, and it is a little lighter. The 100 millimeter axle width allowed me to use standard 4" aluminum channel for the mount.

I should mention that I am 165 pounds, and put out about 100-150 watts all the time. if you weigh much more, or don't plan to work as hard, I would suggest going with the 500 watt rear motor. That has quite a few wind options. The 10 turn would work fine with 12 cells, and the 12 turn could be geared for 12 or 16 cells.

Hope this helps.

Warren

[Seon]

Many thanks for replying Warren. That's great advice. I was sure there must be some way to mount a cog. Thanks for the info on the Mac 500. Aye, I was thinking of getting one from Paul at emissions free.

I'm now thinking of two (or more) bikes. One, inspired by Spinningmagnet's full suspension longtail, with a MAC 500 rear wheel motor wound for torque, that could take a heavy load of messages. And another, very much lighter bike, following the lines of your Linear, with maybe a Cute front wheel motor as a mid-drive. I like to stay off the main roads and that means something I can lift over fences. I see BMS are selling the Q128 as a 'Forward and Reverse' front hub motor. If that means that they really can be driven normally in either direction, then I'm thinking that the disc brake mount might accept some simply fabricated plate and shaft onto which I could attach a track cog and a single freewheel. Not as symmetrically elegant as your solution but something I could do myself without removing the casing.

http://www.bmsbattery.com/front-driving ... motor.html

I have since read on Sheldon Brown that there are a number of ways to spike a freewheel. And that some bottom bracket retaining rings will fit on a freewheel thread. It's all looking very doable now.

But your set-up really looks exactly what I could use here. I like where you have the cranks mounted. Did you do that yourself? I've been looking at the Linear models on their website but I don't see your one. Is it a folder? That would be the icing on the cake. There don't seem to be any Linears here in Scotland so I'll have to try and make something up using square steel tubing. I miss my LWB Bacchetta. I had a 200w front hub on it and that was all I ever needed. Just for when things got a bit difficult.

I'd love to try a low weight RCM set-u like this http://www.recumbents.com/mars/tetz/E-Assist.htm

But I don't know enough about gearing.

Many thanks again for the info. That's steered me in the right direction.

Best regards,

Seon

[kevo]

Warren,
Great information and a very clean build. Nice to see folks w/ electric who are still doing serious pedaling!

[Warren]

Seon,

The BMS Battery front hub seems to have no freewheel. This is not ideal for my type of riding.

Warren

[Warren]

Kevo,

Yeah. For my type of riding, more than the 350 watt MAC is pointless. I like long, quiet rides in the country. To do my typical lunch ride at 30 mph, instead of 20 mph, would require double the motor, and pack size, fatter tires, etc. Now we are up over 100 pounds, and no way I am going to pedal that home, if something fails.

Went for a 31 mile ride before work yesterday. Temps in the 70's, howling wind, flying plastic trash cans! All I could do to maintain 20 mph average on the way out. Averaged 25 mph on the way back. Overall average 22.5 mph, 12.75 Wh/mi. Great fun.

2815 miles so far.

Warren