Choice of folding bikes to covert?

[dermot]

I'd like my next bike to be a 20" wheel folder, with a Puma in the front and internal hubgears at the back.

I'm thinking of the Dahon Vitesse D5:

http://www.foldingbikes.co.uk/dahon_vitesse_d5.htm

Any thoughts on this?

It has a lightweight Alu frame, but steel forks - which seems a good plan bearing in mind Knoxie's comments about torque on a Puma. I'm planning to run at 48V and hoping to do a custom pack that would fit on top of the forward half of the hinge on main tube of the frame.

This would leave the rear carrier free for luggage and also distribute a bit more weight on the front wheel - again a good plan, perhaps, from Knoxie's videos.


So, good idea / bad idea - other options??

 

[jondoh]

I've converted a Dahon Speed D7. I can recommend this bike.

I've got a 406 hub motor on the back wheel.

I have to say having the hub on the back makes the bike feel better. I've had no problems with the drop outs spreading on the rear. I've had dropouts spread on two front forks from two different bikes (26" with 408 hub motor).

The AL frame bikes may be light but the Chromo frame on the Speed and mariner are also pretty light. I think it would be safer to stick with steel. Plus you can spread the frame easier (i had to with my bike) with steel than with AL.

 

[Ypedal]

I 2nd the rear motor idea.

I had a Downtube FS with a rear 405, was a good bike..

Keeping the motor on the rear keeps the wires in the back of the frame, makes folding the bike easier as the only wires acros the hinge are the throttle and cycle analyst !

 

[dermot]

I really wanted to have an internal geared hub at the rear, hence choice of a front hub motor - I don't expect to be doing anything terribly extreme, so hope the handling will not be an issue.

If I keep the battery pack on the forward section of the tube, I shouldn't need to add any wires crossing the hinge.

How did you guys mount your batteries?

 

[jondoh]

I have battery on a rack in the back and the controller mounted on the underside of the rack (beneath the batteries) so with the rear motor, the only thing that crosses the hinge is the throttle wire. The throttle wire is very thin so folding doesn't bother it.

I'm not sure what the objection is to rear hub. The puma does come in a rear hub version.

I worry about the front drive version because the puma has a lot of torque-- much more than the crystalytes. I chose the crystalyte because it was cheaper and while it doesn't have nearly as much torque, the crystalyte has more speed (28 vs 25 mph) in a 20" wheel.

 

[Ypedal]

Before: ( Looking for after picture... i have one hell of a collection to sort thru ! lol )

 

[Ypedal]

Found it!

 

[jondoh]

I really wanted to have an internal geared hub at the rear, hence choice of a front hub

oh i get it now!

you know, i never change gears. you really don't need gears on a motorized bike-- seriously. Save that internal geared hub for a nicer, non motorized bike!

 

[Ypedal]

I agree. A single speed BMX style is usually the ticket. Build a dependable system and enjoy the bike.. you get exercise at 20 km/h or motor on to 30+ depending on choice of front chainring.

Even in a tall gear, with 500w pushing you along you can zip up hills at a good clip. only the reaLLy big hills slow you down if you don't have a big enough battery to sustain 20 amps.

The folding bike with 36v 20ah Lithium pack was amazingly fun to ride !!

Only time you would ever need a large cluster in the rear is if you had to start from a standing stop, up a large hill, and need to get moving quickly...

Hit any hill while on the move, and at a certain point you slow down to where the pedals start to come into play, you simply push as hard as you are willing to pedal, and at a certain speed you syncronize with the motor, reduce throttle until you can start to feel the motor drop off keep this position on the juice lever.. ( sidenote: when you have a meter on the bars you really see what speed vs power amounts to.. very interesting to watch.. dangerous when riding in busy traffic !! )

single speed works just fine for me.

ok.. rant over !

 

[Dalecv]

Here is a folding bike set up in a similar fashion as you are thinking about. I don't find any problems with the handling and have ridden it on dirt/gravel roads. I did use the lower gears when climbing some steep hills and without the electric assist I would have been walking the bike up the hill.

The SLA batteries are too heavy and when I can afford it I will upgrade this bike to a 405 or 406 and lighter better batteries.

I think the Dahon would make a good choice for something similar. It sure is a lot cheaper than a Bike Friday.

 

[dermot]

Gentlemen - thanks for the info and feedback!

I currently have a Trek 6045 (700c wheels) with a Heinzmann 221rpm front hub on 36V with 13AH of NiMH which I've used daily for going on 5 years.

Range is fine (although the whole kit is rather heavy). It does not have as much torque as I'd like and where I live has some pretty steep hills (and I've suffered from back trouble for many years), which is why I was thinking of keeping the hub gears - my Trek has 7, but in practice, I use only top, middle and bottom.

I have 90 A123 cells so can make up a ~ 50V at 13.8AH pack or other combination. Top speed is less of an issue compared to hill-climbing (oh yes, I'm a bit of a heavyweight, too) , but would be nice to improve a bit on the current top speed of 18mph.

When I'm on longer rides (and there are plenty of fine country pubs around) I like to get as much exercise as possible - commensurate with not aggravating my back trouble - which was another reason for prefering gears. Some days, however, I need to rely almost exclusively on motor drive.

I guess I could use a single-speed with a rear Puma and one of these: http://www.kinetics.org.uk/html/mountain_drive.shtml

But it is a bit expensive and non-trivial to fit - might see if a local bike shop has the tool and skills.

If, on the other hand, a rear Puma at 50V with a single gear will get my 250+ lbs up steep hills without stress, then I guess I could just go the simple route.

Maybe I should drop in on Knoxie again next time I'm in Banbury to see how the new Puma performs in a 20" wheel - I was pretty impressed with the older model in a 26" wheel on 37V.

 

[GGoodrum]

Hello all. I just found this wonderful forum. I've been into RC electric helicopters for several years, and have been into a123-based setups since the first DeWalt packs hit the market a couple of years ago. I have a website (http://www.tppacks.com) that caters to to this area. Recently, I've caught the ebike "bug", and have done several conversions. I started with a Bionix setup on a lightweight mountain bike. I found it grossly underpowered, even with an a123-based "booster pack", so I went looking for more powerful setups, and found the Crystalyte models.

My 2nd conversion was a Townie Electra, with a C-lyte Phoenix Cruiser (5304?), which ran on a 16s a123 setup. Power was a ton better, but I still had problems with some of the hills in my area.

Getting back on topic, I've recently converted a couple of folding bikes, as my next projects. The first is a Dahon 20" Mariner, which now has a Phoenix Racer (5303?), the 4840 controller and an 18s6p a123 pack setup (60V/13.8 Ah...). I like the Mariner because it is light, but still strong. To get the big motor to fit, however, I had to spread the front forks slightly. I choose to use the front hub version, mainly for balance, as I like to have the packs in the rear. Power with this setup is very strong, hitting peaks of 2300-2400W, which is enough to get my 250 pounds over pretty much anything.

I just finished doing a 2nd folding bike conversion, this one a West Marine Port Runner. This is a great conversion candidate, as it has a beefy/wide front fork, and is also fairly light. This also got a Racer and one of the new finned 4840 controllers. Since this one is for my wife, I can get away with a lot fewer a123 cells. It uses a 16s4p configuration but with her on it the range is about the same as my 18s6p setup in the Mariner (15-18 miles...). I saw peaks around 2000W.

Here's some pics:

With th RC Heli stuff, we started out carefully charging and balancing packs, with every charge, like we would do with the high-end LiPos. After quite a lot of testing, we now know that a123s will do a lot of self-balancing, if you fully charge the pack, and if the pack is initially constructed using closely matched cells. There are lots of ways we make packs, from simply pulling the 10 cells out of the DeWalt pack, and shrinkwrapping it, to using a solderless kit that uses G10 plates between 4-cell locks. The latter method is what I used to make the packs shown above. Here's what one of those look like, without the shrinkwrap:

Finally, I also just completed a makeover for the Townie, switching to the 7240 controller, so that I can run two DeWalt packs in series. I had some special mounts made, from G-10, that each hold 4 DeWalt packs. These mounts are designed to slide into the channel on a Topeck MTX rack. Here's what it looks like:

Anyway, sorry this is so long, but since I'm new, I can't start my own threads yet.

-- Gary

 

[xyster]

Hey Gary,
Welcome. There's some other folks that joined us from the RC community too. You just have to join the !Public group in order to start threads:
http://endless-sphere.com/forums/groupcp.php
It's an unfortunately necessary anti-spam measure.

My 2nd conversion was a Townie Electra, with a C-lyte Phoenix Cruiser (5304?)

Yes, the 5304 is aka the Cruiser. I use a rear 5304 in a 20" wheel with 20s li-ion and love it. An impressive stable of bikes you got and nice work on the packs, you really need to get torque arms on those front 5304s. If you don't, two really bad events are likely to occur, especially at voltages 48v or more, but can occur at 36v too, even if the dropouts look strong enough:
1) The torque on the axle will spread the dropouts
or
2) The motor will hop out of the dropouts without spreading them

In either case, as the forks dive into the ground and the rider performs an endo over the handlebars, the wheel goes spinning down the street without the bike, the wires ripped from its insides and wrapped around the axle.
This has happened to more than one person here, as a consequence of both scenarios.
Even though it's a rear hubmotor, I use DIY torque arms I cut from stainless steel on both sides of the axle.
There are commercial solutions available. Here's one:
http://www.poweridestore.com/Hub-Motor-Acces/Torque-Arm/Hub-Motor-Torque-Arm
It doesn't fit all bikes without some tinkering.

Another weak point is the seatpost rack with what looks to be about 20lbs of batteries on it. A few of us, myself included, have busted seatpost racks as the metal fatigued over time. Using a rear hubmotor with most of the battery weight up front is another option for balancing the weight while enjoying the benefits of a rear hubmotor such as stronger dropouts and a more motorcycle-like ride. Whether better on front or rear is a perennial debate around here.

 

[Ypedal]

GG DUDE !!!! Excellent work !!!! beautiful craftsmanship there !!! Bravo !

The folder with DW packs looks the best, welcome to the forum !

Xy is right about the torque arms.. keep a close eye on those dropouts.. and as soon as you get the chance make some arms..!!


but wow.. i love the look !! and i know the ride !!!

 

[GGoodrum]

Thanks for the tips and the welcome.

Actually, I have these torque arms on all three bikes. They come with the motor. On the red Port Runner, it is mounted on the left, or "port" side. On the other two, they are mounted on the other side, incorrectly, I suppose, but all I did was flip the reverse switch on the controllers and it seems to work fine.

Having the packs in back is mainly a "peace of mind" issue for me, just in case something goes wrong with the pack. In that case, the "flames" will always be behind me. Working with tempermental high-power LiPo cells has made me extremely cautious (I've personally had several spectacular explosions/fires in some of our helicopter setups...) and although I've never seen, or heard about, a single a123-based incident, I have seen a pack catch fire from shorts. The a123 cells are inherently safe, and extremely robust ( I once had a heli lose a blade link, which caused the blade to droop down and slice the helicopter into pieces. It hit a 10-cell a123 pack that was mounted up front, launching it like a low line drive. It ended up 200 yards away, planted in the weeds. Other than a dent in one of the cells, and a tear in the shrink wrap the pack is fine. I just picked out the weeds, and re-did the shrink wrap. That pack is still going strong, and it has over 500 cycles on it. ), so I don't worry about individual cells blowing up. It takes quite a bit to kill one of these. All that I've ever seen happen is that seal on the positive end pops, and the cell vents a bit. No fire, just a "pfft". This is usually caused by apply to much heat to them, while soldering. BTW, since the cans are aluminum, and a bitch to solder to, we leave the tabs on, and solder to them. The exception is with the solderless plate setups, which are bolted together.

The 18s6p setup on the Mariner does weigh a shade over 20-pounds but it has a standard bolted-on type of rack, which distributes the load pretty well, I think. Each of the 16s2p packs on the Port Runner weigh about 5-1/2 pounds, which doesn't seem like a problem for the post mount, as it is supposed to be good for 20 pounds, I think, but I will keep my eye on it. On the Townie, the 8 DeWalt packs and the mounts do weigh a total of about 20 pounds so the post mount will be temporary. I have a standard rack for it now, which I will install this weekend.

-- Gary

 

[fechter]

Anyway, sorry this is so long, but since I'm new, I can't start my own threads yet.

-- Gary

That's been taken care of...

Great pics, and welcome aboard.

 

[dermot]

I finally managed to get a bit of time over the weekend and go look at some folders.

One of our local bike shops had a good range of folders, I looked at the Dahon speed 5.

Problem is that the front forks are only 75mm wide, which pretty much precludes everything except the lowest power motors, unless I try and spread the forks by a large margin - not recommended, I'm told.

There is a very similar model with a standard cassette at the rear, rather than an internal hub, looks like wider forks.

Looking at some of the photos posted in this thread (and a big thank you to all who have responded - very helpful) it looks as if I should be able to fit a decent motor in the rear - the Puma is 135mm, is that similar to the X5 series?

Since I'm really going to use this bike mostly as a local runabout, I'm reassured by the comments about rear hub and only needing a single gear ratio.

Thinking about it, even with my current 700c wheel, I rarely drop below top gear on the Trek6045 (and I'd already put in a smaller cog at the rear as the original ratio was too low).

Given a 20" wheel and a Puma on 48V, it looks like I should be OK for hill climbing, even with my intermittent back trouble.

Everything I've read implies that a Puma/20" wheel/48V should give me better hill climbing than a Heinzmann500W(221rpm model) /700c wheel / 36V - and a better top speed too, I currently get around 18mph on the flat, that should go up to the mid-20s or so.

All being well, I hope to get the bike as soon as I get a Puma - the shop say they can respoke the wheel for me at the same time.

Then I just(!) have to make up my pack of 90 A123 cells from the pile of DeWalt batteries on my shelf.

 

[JDELUNA]

I too am thinking of putting a PUMA on the REAR of my 2007 DAHON Speed P8 and running it at 56volts with Milwaukee emoli packs. Where in the USA are the NEW Puma's available from ?? Thanks for any info. God Bless

 

[jondoh]

The P8, does that have an AL frame? I think I have to repeat that I had my frame (Speed D7) stretched to accomadate the 406. I think it was around 5 ~ 10 mm that it had to be stretched out. That's kind of a LOT of stretching. Chuck (my LBS guy that did the stretching) said he wasn't sure if this would be possible with an AL bike. Double check your spacing!

My performance predictions for a 20" puma is 32 mph * 20/26 = 24.5 mph this is with 56v emoli. It should have fantastic torque. My 406 does 26~28 mph but i don't have hills to deal with.

 

[JDELUNA]

The P8, does that have an AL frame? I think I have to repeat that I had my frame (Speed D7) stretched to accomadate the 406. I think it was around 5 ~ 10 mm that it had to be stretched out. That's kind of a LOT of stretching. Chuck (my LBS guy that did the stretching) said he wasn't sure if this would be possible with an AL bike. Double check your spacing!

My performance predictions for a 20" puma is 32 mph * 20/26 = 24.5 mph this is with 56v emoli. It should have fantastic torque. My 406 does 26~28 mph but i don't have hills to deal with.

Actually the P8 that I have has the 4130 Chromoly frame at least that is what the sticker says on the frame. If the Puma can do 32mph with the 56volts, that is plenty fine for me. So where can I purchase the new PUMA in the USA ?? God Bless

 

[jondoh]

I believe the main distributor for the puma kits is Texaselectricbikes.com

If they don't have them, I know thesuperkids.com also sells them (though they have to get them through Texaselectricbikes.com)

Hopefully you'll be able to find the version of the motor with the higher wire gauge. Maytag got his with smaller wires and then upgraded them himself.

http://endless-sphere.com/forums/viewtopic.php?t=541

I've ridden his ride-- great bike! Not only does it have tons more torque than crystalyte, it weighs about half as much! To bad it's not geared for higher speeds for 20" wheels.

Dahon.com does not show a P8 bike. They have several models with a P8 suffix and all have 20" wheels. The 32mph is for 26" wheels only.

 

[JDELUNA]

I believe the main distributor for the puma kits is Texaselectricbikes.com

If they don't have them, I know thesuperkids.com also sells them (though they have to get them through Texaselectricbikes.com)

Hopefully you'll be able to find the version of the motor with the higher wire gauge. Maytag got his with smaller wires and then upgraded them himself.

http://endless-sphere.com/forums/viewtopic.php?t=541

I've ridden his ride-- great bike! Not only does it have tons more torque than crystalyte, it weighs about half as much! To bad it's not geared for higher speeds for 20" wheels.

Dahon.com does not show a P8 bike. They have several models with a P8 suffix and all have 20" wheels. The 32mph is for 26" wheels only.

jondoh,



Thanks for the info on Texaselectricbikes.com, I will contact them and see if they have any of the new PUMA's with the larger wire gauge wires. As for my P8 I actually bought it from here:


http://www.gaerlan.com/bikes/speed/speed.htm



I had "G" rebuild the rear wheel for me with straight 14 guage spokes since I weigh close to 220 pounds which is what DAHON posts is close to the limit of 235 pounds. He does excellent work, the wheel has remained true, ever since I bought it back in June 2007. I would highly recommend buying a DAHON from him as he actually opens the box he gets from DAHON and checks and tightens all the screws and bolts, and does a test ride to make sure everything is working correctly, most dealers will just have the bike dropped shipped to you from the factory. He actually gave me an nice "PINOY" deal, since I was a fellow islander . God Bless

 

[GGoodrum]

I have done two folding bikes now, one a Dahon 20" Mariner, and the other a 20" Port Runner from West Marine. Both have front-mounted C-lyte 5303 "Racer" hubmotors. The Mariner required spreading the forks slightly, to get the motor to fit, but the Port Runner has forks that are plenty wide already.

Although I'm very happy with both setups, if I had it to do over again, I would use the rear-mount version. The reason is simply because with the motor up front, it makes it a bit harder to fold the bike.

-- Gary

 

[The7]

I prefer the front mounted hub on your foldable because the rear mounted hub will make the rear very heavy with the rear mounted battery.

 

[GGoodrum]

I agree, having the weight distributed like this makes everything much more balanced, which is even more important with the smaller-wheeled bikes, I think, but it makes it just slightly more difficult to fold the bikes, that's all.