New build with stretch cruiser

[dpearson2011]

Hello all, I have enjoyed this forum for some time (months) and I am now ready to start putting together my list of parts needed for my first e-bike.

I want to build a stretch beach cruiser with a rear hub capable of ~30mph top speed and about mid 20's cruising speed. I originally wanted the fastest of the fast (as most noobs do) and a mid-drive motor but decided that this was to complex for my first build. I decided to go with a hub motor and was thinking about something like this:

Motor: Crystalyte HS3540 rear hub from ebikes.ca (heard about their rep and seem to have positive feedback all around)
Controller: 25A Infineon (thought about 35A but per there simulator, it doesn't seem worth it to upgrade)
Battery: 48V 20Ah LiFePO4 from Ping

Total so far: 1303 without tax and shipping.

Bike: Still haven't made a final decision. There are not very many geared stretch cruisers available and they seem to be a pain to install a 6 speed cassette. The front runner right now is a 3 speed micargi that you can view at the following link:
http://www.bennysbikestore.com/product/mustang-gts-nx3.aspx

I have a few questions about this setup and was hoping that ya'll could provide some answers for me.
How can I know for sure that the rear hub crystalyte will fit this bike without taking it to a machine shop?
Will this be ok with a coaster brake or will I have to install a rear disk? Would it even be possible to install a rear disk brake on this bike?
Does the PING battery come with a BMS? I have very little knowledge of batteries and will need a fairly complete system shipped to me.
Any other suggestions on a different type of stretch cruiser? I would like to keep the entire setup less than $2K and with the above setup it is $1670 without shipping which I am sure will be pricey.

Thanks in advance for any advice and I have really enjoyed this forum so far.
-D

 

[gogo]

I have a Kustom Kruiser Roadster stretched cruiser. I love the easy foot-down when stopping, but because you can't put your feet underneath yourself to deal with big bumps, its just not suitable for anything but slow cruising speeds. It would need a good rear suspension for anything above 15 - 20 MPH.

I've often thought that a set of pegs positioned so you could stand on them might solve the issue, but even that may not be quick enough to be sufficient. See if you can get a ride on one and then make your own assessment.

Unless you use a coaster hub as a mid-jackshaft in the pedal driveline and mount a solid sprocket on your rear hubmotor, you won't have the option for coaster brakes.

If the rear stays are steel you can probably bend them apart for the proper clearance.

Yes, Ping batteries have a BMS. 48V 20AH might be best split and put on either side of the rear wheel in saddlebags, or panniers.

 

[dpearson2011]

I would prefer to get rid of the rear coaster brake and use a disk instead. I am now sure how easily this can be accomplished with this bike and I am certainly open to suggestions for other types of cruisers. I don't plan on doing 30mph routinely but rather cruise in the low 20s. I live in Denver and they have excellent bike trails and roads. I was hoping that with the springer fork in front and springs on the seat, the ride would be comfortable at these speeds.
The description of the bike frame is steel so I assume that includes the rear. I am sure that this would also need torque arms for this motor setup.
Thanks for the opinion. Anyone else know how easy it would be to get rid of the coaster brakes, add a disk brake and whether or not the rear hub motor would fit the frame?
Thanks,
D.

 

[Willow]

...very similar setup planned to my bike. I would however ditch the ping for a decent high discharge battery pack - sony cells for example (36 - 48V range) (not LIPO).... and get a bigger controller. My mini 50amp Kelly will do 100amps+ which makes for some easy hill climbing, and burst of power when you need it. Motor and controller never get hot - and the Kelly is far smoother than the Infineon.

I did have to get 10mm machined off the shoulder of the axle of the motor for it to fit - no dramas though. The torque plates I designed (simple - 10mm thick clamping type) have mounting holes for the disk brake - as the original bike did not have disk brakes. Good luck with your build.

 

[FeralDog]

I haven't built a stretched cruiser .... yet.
They do very look interesting.
If I were to start on one, maybe a front hub Direct Drive http://ebikes.ca/store/store_nc.php with either front disk brakes, or a V-pull type?

ICE Motor bike guys (years ago) had some luck with Micargi Mustang and somehow adapting a front brake ----> http://i272.photobucket.com/albums/jj176/redb66/newred1.jpg

For hilly area, I would like to check out a 7-speed rear version of the Mustang http://micargibicycles.com/index.ph...ategory_id=27&option=com_virtuemart&Itemid=53
-- Firmstrong also makes an interesting stretch (but I know I would personally need some more gears) http://www.bikebuyers.com/FS-URBANDELUX.htm
---- I currently use Schwalbe Fat Franks http://www.schwalbetires.com/node/1330on a modified big box store bike. Run them on about 45-50psi and use an extra sprung seat and they get comfy in town on bike trail use (for occasional bumps).
-----Tough decision is to buy a ready built stretch cruiser, or piece one together from the frame-up to suit you? Money ... money....money
Parts example only, NOT a recomendation , just for general referance---> http://ep.yimg.com/ca/I/yhst-10337746512064_2266_38383179 and http://www.bicycledesigner.com/cruiser_bicycles.html

Please keep us posted on your build. Best of luck to ya!!!


Edit to fix kinks in links

 

[Drunkskunk]

That is a nice bike. Its going to have some technical chalanges.

With a 3 speed rear, the stacing for the back axle should be 120mm. the Crystalyte HS3540 needs 135mm. Since the frame is steel, you can spread the frame to make it fit. its something you can do at home with a 2x4, or a car jack, or a realy long bolt and a bunch of nuts, but it takes some care to do it.

Disc brakes can be added. But since this will be your only brake on a vehicle capable of motorcycle/scooter speeds, it needs to be done right. you'll need to weld the mounts on. Bolt on conversions would never be safe enough for a primary and only brake.

That motor should work. Its over kill, and the next motor down, a 500W 9C 2806 could also be considered overkill for most people, but if you have many steep hills to climb, Overkill can be a good thing. However, the Ping battery wouldn't support anything a motor that huge. At a minimum, you need a battery that can support 40 amps continous real-world output, with much higher bursts. And with that, you won't be pushing the motor to even half of it's potential. Anything less is either a waste of motor, or a killer of batteries.

 

[dpearson2011]

Thanks for suggesting the 9C motor, it looks like it would do the trick also. Do ya'll think that a better option would be the 9C 2806 motor with a 25A controller and a 48V 20Ah PING battery? This gets me close to 30mph but may be a better motor/battery combo. Would there be any major tech issues with this and the front springer fork? Also, how difficult is it going to be to get rid of the coaster brake and install a rear disk. Taking it to a machine shop to secure the disk brake would certainly be an option.
-D

 

[dpearson2011]

Drunkskunk and willow have sick rides.

Bump.....issues above

th

 

[dogman dan]

A 9c motor, or any of the nearly identical motor brands would do what you are wanting from the bike. The 2806 is a fast winding best suited to smaller wheels. The typical 2807 or 9x7 winding will do 27 mph on a low amps controller with 48v. But nothing wrong with the idea of the clyte motor either, and Grin is a great dealer to do business with. Top of the list for customer service for example.

Unless you need really long range, you don't want a 20 ah ping. Just too big and heavy to carry comfortably. Get a 15 ah, and carry it in the front of the frame rather than in the back. Or, other good batteries are gaining popularity, as said above. Limn, and limns.

However, if you want more amps in the controller, then you'd have to get the 20 ah ping, or even larger if you went really big on the controller. You might have to find a battery with a higher continuous discharge rate.

The bike itself. I know you want a stretch, but you might want to consider a cheaper starter bike. You can get decent beach cruisers with 7 speeds and two good v brakes for a very small price in any walmart. This bike would be a snap to convert to a rear motor. It's got the same gears in the back, and good brakes. Cruisers are slightly long, so they track and corner beautifully. If you insist on a stretch, then there simply has to be a model out there that similarly has two v brakes and a 7 speed rear gears. Anything else will be a royal pain to make into what you want.

Anyway, a regular cruiser to start with will get you going immediately, will cost less, and hitting those bumps at 25 mph won't hurt so much.

 

[dpearson2011]

I may change the bike to a Micargi Mustang NX7, motor to 9C 2807 (or 2806 whichever would be better suited to the bike) and battery to a 48V 15Ah (or 10Ah).
Would it be reasonable to keep the rear coaster brake in place if I can get a front disk installed?
Would the springer fork allow a front disk brake with this hub motor in place?
Also, any suggestions for battery dealers/website to get the 48V 15Ah?
thanks in advance.

 

[dogman dan]

You can't keep the rear coaster brake if you use a rear motor. Seriously, find a bike that has a rear disk brake mount or rear v brake mount.

I was just saying this on the other cruiser thread, find a frame that has 7 speed rear and two v brakes, and it's easy to fit a rear motor. The dropouts will be the right width, and you keep your brakes.

Front brakes only I would really hate. Part of that is years of riding a crappy motorcycle that had rear brakes only. But if you really need to stop, lock that front wheel and you are screwed. It's just plain dangerous to ride with only a front brake unless you only go 10 mph.

Front hub would work, but not as nice to ride as rear on a cruiser IMO. For front hub you want a stout fork, stouter than many of the springers out there.

 

[FeralDog]

Ready-made "stretch cruisers" are made to look good, and ride on nice asphalt paths that aren't too hilly.
IMHO, anticipated max cruising speed should be closer to 20-25mph for the Average Joe on that builds geometry.

Most store-bought stretch cruisers look like they need a beefier front fork (SEE my prior post for the Monarch II springer link) or a rigid fork with disk brakes (again: see my prior links).
Limit your speed a bit down to 25mph, front DD hub (maybe regen braking?) , beefed-up front fork with disk or v-pull brakes, and the rear coaster and gear set should be as practical as you can get?
Or am I being redundant?

dogman is likely correct in steering you towards a regular "beach cruiser" for your first build, but those darn streeeeeeeeetch versions sure do look good!

Remember, the build sucks if it doesn't have brakes.

 

[dpearson2011]

The 9C 2806 and 2807 are front hubs. Therefore I would have a rear coaster brake and was wondering about installing a front disk brake. Of course I realize that I need two brakes.
I really want to make a stretch cruiser work but I guess I would reluctantly consider a full suspension. Very reluctant...
Anyway, would this motor put to much stress on the springer fork?
-D

 

[FeralDog]

dpearson2011
I think you are seeing the difficulty of trying to build a bike a paragraph at a time.
I've ridden many of the bicycle trails around Denver /Golden/Boulder . IF I were to try a stretch build, I personally would like a back-up of 7 speed gears to assist the motor.
I would like a fatter tire on the rear for bumps, and a rear coaster brake with front V-Pull should be A-OK and the front brake lever / motor cut-off circuit would be nice. .... IF ... IF I would not expect 30 mph speeds on those trails. Disk would be nice simply because many aftermarket forks oft come with disk brake mounts.
Like you , I wonder about the robustness of the stock Micargi front springer fork, especially the stock un-reinforced dropouts !!!. They are an unknown factor. Thus:
See the example of front fork aftermarket selections " just in case" ? Chopper tubes and Rigid forks can be a cheaper alternative replacement on the Micargi stretch. http://www.bicycledesigner.com/bike-parts/bicycle-forks/
That Monarch II Springer is rumored to be pretty tough (but expensive) see pic --->

Wish I could help you more but your dreaming of building in somewhat virgin territory.
I do think a stretch can be done , just not a fast .... and safe one .... that's not expensive $$$$.
I think the only way you can find out is to commit to the build, or change course and go standard Townie or Beach Cruiser style build.
Best of Luck in your endeavors !

 

[jimw1960]

Front motor builds can be a lot easier, but it's a bad idea to have a front motor with the springer fork--too much flex under the motor torque. If you want to stick with the front motor approach, swap the springer for a rigid steel triple-tree front fork with disc mount. Something like this that you can cut to size: http://www.ebay.com/itm/TRIPLE-TREE-32-CHOPPER-BIKE-BICYCLE-Chrome-FORK-1-w-Disc-Tab-Black-/330774141736?pt=Cycling_Parts_Accessories&hash=item4d03acdb28

That shouldn't be too expensive. Is the Micargi a threaded headset? If so, you might have to look around for a fork that has disck mounts. For speeds under 25 mph, a rigid frame and fork are OK, especially when you have the big fat tires that your cruiser will have. I have ridden a front motor for years and it handles just fine. But you definitely want to have two brakes, especially if your rear brake is just the crappy coaster brake that comes on the Micargi. An upgrade that you could do later is to swap out the rear Micargi hub with a good Sturmey-Archer internally geared hub with roller brake.

Stick with the stretch; follow your dream and don't listen to these guys telling you to start with a 7-speed wallmart beach cruiser. You are going to have a bad azz bike with just a few upgrades to the Micargi.

Update: here is a fork powdercoated in black for even cheaper than the chrome. That would look killer on the black stretch Micargi.
http://www.ebay.com/itm/Fito-TRIPLE-TREE-CHOPPER-FORK-23-BLACK-for-26-Beach-Cruiser-Bike-Bicycle/131048249750?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D18059%26meid%3D2727126416652356083%26pid%3D100005%26prg%3D8304%26rk%3D3%26rkt%3D4%26sd%3D330774141736%26

 

[jimw1960]

I was looking at some pictures of the Micargi Mustang model. It looks like it comes with a threaded headset, which could make it harder to find a rigid fork with a disc mount. Have you checked out the Micargi Royal? From the pictures, it looks like treadless headset, which would open up your choice of forks a lot more.

http://www.bikebuyers.com/royal-photos.htm

The Bronco model also looks good and has a lower stance than the Royal if you want more of a low-rider:
http://micargi-bicycles.com/bronco30-photos.htm

 

[gogo]

Front motor builds can be a lot easier, but it's a bad idea to have a front motor with the springer fork--too much flex under the motor torque.

The 'rigid' forks you link to would, in comparison to the springers in question, be more accurately termed flexies. Not that they would be unsuitable, but they are many times weaker than the dimensional, multi-element construction of the springer. Springers are basically the same thing as a rigid, but with dimensional reinforcing (think triangle). Springers are very strong, and much stronger than any single-plane 'rigid' or suspension fork.