World’s fastest Schwinn cruiser

[Tony01]

Hub motor Qs205 50h v3
Controller Asi bac8000
Battery 74v 60ah- 4.4kwh
Max power around 24kw
Max phase amps 510
Max speed: yep
Max acceleration: beats Harleys, loses to Tesla Model S
Forks: Suzuki k10, modded. Stronger springs and fabbed spring perches.
frame: 50% 1980 schwinn cruiser; 50% 2019 American mild steel.
Front hub: 1969 Yamaha 110mm
Rims: 17x1.4 36h aluminum
Tires: front Michelin pilot street blackwall 80/90, rear IRC 90/90

Previous build: 212cc ‘69 Yamaha
Next build: Tube frame ebike build

**********************************************
Original post:

Here’s a build I’ve been working on for a little over a year, riding several months. Haven’t had much time and quite frankly losing interest to finish it, so I thought I might make a thread before I do.

So I’ve been wanting to do a full suspension Chicago cruiser for a while. I almost did so with my 212 schwinn but my buddy talked me out of it at the time, and I ended up doing an 8” chainstay stretch on that one which worked out great.

Here’s the current state of the bike. Not much left of the cruiser frame. This is actually the same frame that I used in my 212er before it got a catastrophic frame crack after thousands of miles which led to me building the 212 Yamaha bike. Needing a rough frame to cut up I did not hesitate to modify the crap out of it.

Not to mention, I lost a 3/8” extension in the seat tube a few years ago, so had a reason to start cutting.







I’ll go piece by piece of course.

The specs are as follows:

80s Schwinn cruiser
19x1.6” rims, 3.25/100-19 tires
Qs205 50h hub motor
ASI 4000 controller
77.7v 24ah 600 amp discharge battery
Suzuki k10 fork, DNM DV22 rear shock

Here’s how it started:


It came out to just over 81.5” long, so just an inch out of the bike size limit for local trains and a quarter inch shorter than my solid drawing.

 

[Tony01]

I did some work on the frame. Too much work maybe. But see, I had this vision 5 years ago of a FS cruiser, so I have to build it of course. Those ebike frames while cheap and easy, all look the same to me. It has to be a cruiser.







I got some clamping torque arm dropouts made, and sold a few sets to cover mine and make a small profit. The guy who made them was not the owner of the shop where they were made. cheap tho. All warped, a bit thinner in the middle due to bowing the material from clamping pressure, and cinch bolt holes twenty thousandths off center. I could cut Teflon tighter than this guy does steel. But good enough for this.








Did some fiberglass work. I dread finishing it. Even talking about it is painful!! Polyester resin is cheap but eats white foam. After I made my foam plugs I had to cover them in aluminum foil to keep the foam intact. After that I glassed up several layers of 1.5oz mat and biaxial cloth. I have a big can of bondo sittin here...

Fiberglass sandwich



Built up some wheels. 19x1.6 with 8g spokes, a 5” drum in the front and an 8” core hub motor in the back. Rear wheel with tire weighs a whopping 43lbs!

The front wheel was some work. I restored the hub. Installed new bearings, cleaned, painted all the small parts, etc.

 

[Tony01]

Built my own battery. I found these cheap cells on eBay (search for spim08hp). I bought 60 cells to start on eBay for $340 for a 20s3p pack so that gave me 1776wh. Some were found to be no good so had to replace for $30. So the price at this point was $210/kWh.




They are 25c/5c discharge/charge so we are talking 600/120a in my pack. I do not exceed 300 amps however. Although during heavy braking it is possible the battery will see ~100 amps coming back for a second or two. Yes it generates damn near 10kw during regen braking.

They were made in two blocks of 14s3p and 6s3p in series to fit in the front triangle.










To put these cells together I made some battery bars. At first I looked into copper stock but soon realized it would be expensive, heavy, and gummy as **** to work with and cut up with or without real tools. I decided to go with 6101 aluminum for its decent conductivity, light weight, low price, and easy workability. As long as tools cutting aluminum are fed well there is no reason why they shouldn’t last.



So the best deal I could find was around $45 for a few bars of 1x.25 and .75x.125 full round edge bar. From each battery bar length of material i would get two bars. I made an easy manual working process with drill jigs for each width of material. I would drill 4 holes and scribe a line for length, on both ends of the bar, then switch on a cheap craigslist table saw to make lengthwise and part off cuts to get 4 bars. On the 3/4 inch bar the round edge is only 1/16” radius but on the bigger bar it’s double and needs to get cut off as well. So the 3/4” bar took one cut about 3 inches long down the middle, and the 1” got left edge, right edge, and down the middle. I felt before buying the saw that it would do the job, and it did.

Drill jigs are welded up with material on the sides to align the bar in the jig, have the four holes, with the bar locating on a pin pressed in at the end of the jig with a sight hole to make sure the bar is seated up against the pin before drilling. The other side of the jig is used for scribing overall length line. No pic of the drill jigs, but here are some 1/4” thick bars full of burrs with a scrapped test length of material on the left.



Later I had a buddy come and help deburr the parts. They needed a chamfer on both sides and about 10 seconds each to clean the burrs on a mounted angle grinder. I cut all the material I got, and ended up making around 150 pieces.

I then used stainless 10-32 button head bolts and low profile locknuts to keep the thickness of the bars and bolt well under the thickness of 3 cells or 6 cells as needed.




6 gauge power cables, 20 gauge balance wires, all crimps (2x in the middle of the pack)

 

[Tony01]

A couple pics of the battery bar production setup. They aren’t very pretty but they do the job. This is the 1/8”h x 3/4”w bar jig still attached to the clamp.

The saw I used was a crappy table saw with a 7” blade with HSS teeth about an inch apart. So a wood blade. I used a drop indicator to straighten all the teeth to where I could get a cut width only a few thousandths bigger than the width of the teeth. Surface finish isn’t perfect but I don’t really give a damn for something that is always hidden. These things just have to hold the battery securely together and provide a good flow of electricity.







IIRC I cut around 20ft total.

Got started on the bondo work. First time. I think I caked it on there way too heavy. Doing the time with a rasp is slow but mildly rewarding.

 

[Tony01]

At some point in time I was without a working charger, and I was about a mile from my house when my volts started dropping down too fast. These cells are rated for a 2.5v low. Well I took the 20s pack down to about 56v going about 10mph to try and not push it too hard. I guess the pack may have been unbalanced but I smoked 3s. They were probably the lowest 3p’s of the pack. That is 9 cells all just acting like a piece of wire 0v each.

I opened it up and they were in different places. These cells did not catch fire or explode or even all rupture. The bad ones just puffed up. I got one or two that did probably with smoke that came out at the time. Reconfigured the pack as two blocks of 14s3p and 3s3p to buy new cells and add them to the smaller block, or ground.





Out of nine cells only ONE ruptured.

I rode on 17s for about two weeks. Top speed 74mph with 17s at about a half charge. On a full charge with 8 more volts this probably coulda been nearly 80. Not bad for an only 63v system.

The controller is good to 22s but the popular setup is 20s. Well for symmetry in my 2-block battery I opted to go 21s, adding 12 cells in a 4s3p to the ground, so now the thickness of both blocks would be the same.



The 74v on battery is actually a 77.7v now. Needless to say it got a LOT faster. A huge step from 17s.

 

[Tony01]

A funny feature I built into the battery is some power taps at different points. so I can stick weld with it if I have to. I just have to setup some banana plugs for the leads or something. Still figuring it out. Gonna give it a shot welding one of these days. With how many frame cracks I’ve had so far away from home, it would be nice if the bike was its own welder.

So after some riding and even crash testing it (and finding that the bike is mostly tough) there are a number of quirks. Fortunately I have a lot of time to work on it as I heal up. Probably be ready to let it try to kill me again in the spring. All the regular stuff broke. As it is right now I have a bent fork, cracked headset lower cup, and a badly dented rear wheel with 7 broken spokes. I have already replaced the handlebar stuff, put a new pedal crank as one broke in half, replaced the mirror. A new hall throttle took a few minutes of wiring. I did away with the mode switch so now just have a simple on/off with the control mechanically stuck in street mode that I have set at a measly 3000 watts. It does slowly get up to about 35-40 which is just above the magic speed to make the rear wheel dent tolerable, but is pretty much unrideable except at pedal bike speeds due to my injuries.

The bike is currently running a 19” rim or about 25” OD, setup for an estimated ....mph. (in race mode). This is about ...mph faster than I really want to go. Since both wheels are going to change with the fork change, I feel it is a good time to go to 17” rims with some smaller tires. Hoping to reduce rim and tire weight by about 5lb each. Replacing the K10 fork with a relatively modern dual crown bicycle fork will help with another 10lb easily. Current weight is around 165 and trying to get it down under 145lb. A smaller 22.5”od tire will reduce gear ratio by about 10%, hopefully reducing top speed to around ...mph.

 

[indian22]

Tony I like and though I've somewhat mellowed in my old age I still like speed and your bike displays admirable quantities of go fast currently amped, volted and charged!

Interesting and fun build to follow.

Rick C.

 

[Tony01]

Rick, thanks! I’ve mellowed some too. I wanted a worthy upgrade from a 212 and got way more than I bargained for. If not just performance, the best things are the zero maintenance and absolute quiet. Back in my 212 days I was adjusting a chain, changing oil, brakes, whatever, tightening something back up, damn near once a week putting some 700mi a month. This one just gets plugged in! Racked up a thousand miles real fast on the ebike. Never wait for it to warm up. Nobody sees you at all. Easy to hit a pedestrian in driveways and parking garages. Soon the bike will have paint and then it will truly be invisible in the night.

 

[indian22]

Rick, thanks! I’ve mellowed some too. I wanted a worthy upgrade from a 212 and got way more than I bargained for. If not just performance, the best things are the zero maintenance and absolute quiet. Back in my 212 days I was adjusting a chain, changing oil, brakes, whatever, tightening something back up, damn near once a week putting some 700mi a month. This one just gets plugged in! Racked up a thousand miles real fast on the ebike. Never wait for it to warm up. Nobody sees you at all. Easy to hit a pedestrian in driveways and parking garages. Soon the bike will have paint and then it will truly be invisible in the night.

Tony though I'm a gearhead and will continue building and riding gas bikes, I totally concur with your comments about the positive aspects of e-bikes. Personally my three e-bikes (including my hybrid) have really impacted my biking experience. I ride every day, year round with the exception being really extreme weather events, so I appreciate the exceptional low maintenance & zero public and police hassles. Each of my e-bikes have distinct personality's, but each is great. Full suspension MB, Fat tire and hybrid. The MB with three 36v. packs has 100 mile pedal assisted, moderately, range. It's a 7 speed, seldom use more than 3 or 4 of these. The fat bike is, well, fat, comfortable, single speed, fun and dang fast for it's heft? I've got a plan in mind for a classic 1915 electric bike as my next e-bike build to suit my classic vintage passion. Electrics aren't coming they're here & battery tech will soon blow past all the current concerns involving battery weight, price, safety, charging times, speed and range! Convenience, fun and minimal maintenance are available now.

Rick C.

 

[waynesdata]

Did you have to solve many problems to get the Suzuki k10 fork to work? Was the steerer tube a strange size?

 

[Tony01]

Did you have to solve many problems to get the Suzuki k10 fork to work? Was the steerer tube a strange size?

Not really. Steerer tube is 1” threaded. I had enough bearing cups and races to make it work.

I do not recommend this fork unless you and your bike are somewhat normal weight (I am an average build guy, but my bike is 165lb right now) For me it is heavy duty but the springs are far too light and it bottoms out regularly. It might work for you of course. Iirc my bikes weight distribution was 45/55 so about 75lb on the front without a rider. If you get down to that number with you on it it may work for you.

I recommend going with a suntour xcm if you need the 1” or some other modern single crown. K10 fork is a repro from the 60s!

 

[Tony01]

17” rims are in. The nice people at Treatland thought it would be funny to wrap the box in Victoria’s Secret tape!!

Time to decide what will go on the front. Bicycle fork for sure ($150+)

Option 1: run the drum. Cheapest option and the strongest brake. Mod it down to 110mm wide (currently 125w), use 20x12 bushings and run in a 20x110 DH fork. Fab up a brake plate stop.

Option 2: get a 9x100 fork and run a 203mm disc

Option 3: get a 9x100 fork and run a 1000w front hub with 203mm disc. +150 hub +250 controller. Front brake will now be 95% regen.

Probably going with option 2/3. Have an aluminum disc hubbed wheel here with cup/cone bearings. I just opened it up and the cups appear to be removable, bore measures approx 30mm with a ruler. Have to check with a caliper hoping to find it’s a 29.97mm or so.

These rims are 1.4”w inside and about 1.9”w outside. I think the biggest tire I can fit is about an 80mm wide. Probably gonna go with 70fr 80rr. Pictured compared to 19x1.6 steel rim.

 

[waynesdata]

What makes your bike so much faster than other Electric bikes? Are you running 2 hub motor? Better controller or battery?

 

[Tony01]

Well, took out the cup/cone bearings from the disc hub'd wheel, the one in the pile pictured above. Sadly the bores measure about 15 thousandths smaller than 30mm. Too bad, have a sealed bearing axle with two bearings brand new 30mm OD just waitin'. Could take it to a shop... it wouldn't be cheap.. or just buy a hub... ugh, hate this part. Going on ebay, aliexpress, searching, see what's out there, blah blah blah.

 

[Tony01]

What makes your bike so much faster than other Electric bikes? Are you running 2 hub motor? Better controller or battery?

It's all up there. A battery that can dump high amps without breaking a sweat, a controller with advanced functions (field weakening) and a motor with a lot of copper mass, with an aluminum core for wicking away the heat more effectively. Heat sinks coming soon so I can push high power, more often.

 

[zean]

Excuse me Tony01. There must be a bearing store in San Francisco and even in San Jose both. I believe that they should have any bearing that you are looking for. Am I right about this?

 

[indian22]

Well, took out the cup/cone bearings from the disc hub'd wheel, the one in the pile pictured above. Sadly the bores measure about 15 thousandths smaller than 30mm. Too bad, have a sealed bearing axle with two bearings brand new 30mm OD just waitin'. Could take it to a shop... it wouldn't be cheap.. or just buy a hub... ugh, hate this part. Going on ebay, aliexpress, searching, see what's out there, blah blah blah.

Tony it's a great feeling when things measure up to fit, but then there's the search which I look at as a treasure hunt, some work it's true; but also quite rewarding.

Better bikes through great persistence.

Rick C.

 

[Tony01]

Excuse me Tony01. There must be a bearing store in San Francisco and even in San Jose both. I believe that they should have any bearing that you are looking for. Am I right about this?

The store you’re talking about is grainger. However, that’s not quite the way it works. Bearing bores are machined for the bearing; not the other way around. A cartridge ball bearing bore will typically be a press fit of a standard tolerance of approx a thou per inch diameter. So in a 30mm/1.1811” I am looking for a bore of about .0012”/.03mm smaller or approx 1.1799”/29.97mm. This one measures 1.168”. Even if it was .005" I could probably fit it with enough heat and a big enough vise. but still have to spend too much money on the front end with a disc caliper, bicycle fork, etc, and then brake pads at $20 per set, for some crappy braking relative to the 5" drum I have now.

I'm trying to steer away from bicycle parts. They tend to be very expensive to save ounces on bicycles, when motorbikers are simply looking to save pounds over motorcycle brakes.

After doing some research I think I am going to stay with the strong drum and pick up a hydraulic EBR fork from treatland. It’ll be sized correctly, have the tab for the drum brake, aluminum clamps and lowers, direct mount handlebar, and have a 25-26mm threaded steerer. Hopefully about 5lb lighter than the k10 and more responsive. Ordering spokes now.

 

[zean]

Excuse me Tony01, I appreciate the explanation on how a cartridge bearing has to be one onethousanth of one inch greater per inch diameter of the hub's bearing bore to be press fit appropriately. Yes bicycle parts are very expensive, like tires. Moped tires are much less expensive, much stronger and DOT speed rated. And yes moped forks and hubs are also more appropriate for motorized bicycles. The forks are much stronger and the solid aluminum hubs are very solid and stable. Grainger has an eclectic mix of various maintenance parts for manufacturing, industry and hobbies. Bearing stores like Adam-Hill in South San Francisco and Bearing Engineering in San Jose and others around the area have mostly bearings with some chain, shafts and sprockets. Some say if they don't have your bearing, they can find it. Maybe you're right. Bearing Stores are for the big guys working on factory machines as big as a house, not for bicycle bearings in bicycle hubs. I appreciate all of your insightful information that you share after spending a lot of your time doing research. Thank you. The frame you built with the rear suspension is very nice.

 

[Tony01]

Sourcing parts is tough. I’ve gone through all the forks from treats and pretty much it comes down to this: options are limited for drum hub wheels if you want a modern (larger) fork tube size AND hydraulic dampers.

Disc forks are easy. But to go that route I have to buy a spoke hub with a compatible disc, caliper etc. Which I’d have to do with a bicycle fork; in which case I’d prefer the bicycle fork. Sadly I would not be able to resist adding another hub and probably 25% more power, which is a recipe for an early death if this bike isn’t one already.

All of these have aluminum trees and lowers.

hydraulic fork with skinny little 28mm tubes. $370

30mm tube non-hydraulic, $200

31.8mm tube hydraulic, $150. Probably rounded up from inch and a quarter. Legs only for $80. But this one comes with a 20mm OD steerer and no fender/stabilizer mount. Well $hit.

If there is a dual crown rigid fat tire MB fork for 1.25” legs it would work, but probably not have a direct mount top crown. Problems every which way.

Probably gonna go with the 30mm non hydro because I’m sick of all this part hunting.