How fast should you safely go on 16" bikes?

[nukezero]

Dahon sells the 16" wheel folding bike Jifo and its only ~20lbs. I think this might be fun to convert to an electric.

I see that leafbike has a 1000W / 48V kit for their 16" bike. It goes 54.6KM/h 34MPH unloaded which is pretty fast. Loaded will probably still be pushing above 20mph for this 16 incher. I'm pretty anxious now to put together this direct drive kit and pair it with the Dahon Jifo. Since the Jifo is a single speed bike, it's going to be more of a scooter now. Since I want to maximize speed, the direct drive would make sense.

What do you guys think?

 

[zombiess]

Depends on the bike and the rider. Personally, I'd slap the highest speed wind motor I could find in it and run it on 50-125V as long as it felt somewhat stable.

For 20" wheels, a 9C 2806 or even better a 2805 would be awesome. Not sure if they can still be purchased though. A high speed geared motor could work very well in a 16" wheel and you could probably run it really hard compared to a 26" setup. 16" + high speed geared setup = light, can probably go 30mph with the right voltage battery and have great efficiency.... sounds fun, I think that's what I would do.

 

[nukezero]

Depends on the bike and the rider. Personally, I'd slap the highest speed wind motor I could find in it and run it on 50-125V as long as it felt somewhat stable.

For 20" wheels, a 9C 2806 or even better a 2805 would be awesome. Not sure if they can still be purchased though. A high speed geared motor could work very well in a 16" wheel and you could probably run it really hard compared to a 26" setup. 16" + high speed geared setup = light, can probably go 30mph with the right voltage battery and have great efficiency.... sounds fun, I think that's what I would do.

Thanks. Apparently, I haven't found another suitable 16" folder that is as clean as the Dahon Jifo. I only worry if this bike can handle such modifications as the whole bike itself is only 20 lbs!! The leafbike kit (magic pie) is itself 20lbs (without the battery) so I bet if I slap on a DD motor like that, it would be extremely tail heavy. I want to pick up a 48V 10Ah frog battery for this as I think that should be good enough.

So now I have to decide between the leafbike dd kit or the cute 100 rear motor kit. The only problem is there doesn't seem to be any shops, even online, that carries this bike. It's also going to be difficult for me to find out what the rear dropout size is.

 

[dogman dan]

I would think that the wheel size would not affect safety that much, other than big wheels handle deep potholes better.

What freaks me out when I get going fast on bicycles, is when the frame starts whipping around, and you know a tank slapper is a twitch of the frame away. The high speed wobble can happen at 15 mph, if the battery is carried poorly. If a lot of weight is carried in panniers, even strong frames can be seen flexing side to side with every pedal stroke.

Then you have the brakes issue. Typical cheap V brakes are good to 30 mph at least for sure. But I've seen thin looking caliper brakes on extra cheap bikes that aren't much good past 10 mph.

 

[MadRhino]

Yep, wheel size doesn't matter much in handling speed, providing the frame is stiff and surface good.
Tire width, construction and compound are making a much bigger difference, and choice of wheel size for street performance is often about tire availability.

Then, folders are generally not made for speed, and not stiff enough to ride aggressively.
Some may feel comfortable to ride very fast on them though, it is a matter of personal confidence and experience.

 

[chas58]

That bike has a lot of things that bend/fold/extend/telescope. All that means it is not going to be very stiff and solid. It is hard to tell just from looking at the picture, but 15-20mph maybe? IT looks to me that it has too many adjustable joints to be stiff and stable enough much beyond that point.

I know people who are comfortable riding bikefriday’s 20-30mph, but it really depends on the build quality and adjustments with something like that.

 

[2moto]

Maybe it's just me, but that looks to be a deathtrap at 30 MPH, even 25 MPH. It's not the speed that's the problem, as they say. It's the sudden stop at the end that's the problem. How will that work in an emergency stop?

 

[cwah]

I've been riding 16" brompton bike for a year at 25-28mph without problems with pad brakes. Pot holes are a real nightmare at from 20 mph at night because you don't really spot them fast enough.

I also tried to go over 30 mph on the little brompton and it gets dangerous beyond this speed. When I see a car I can't really brake or anything and add a small accident out of it from a car that didn't use its turn light.

 

[friendly1uk]

Doesn't D8veh have one of these?
I don't think I would want to put 20 unknown units of weight on the back of a bike weighing the same, then add a frog box to the back too. I think that little folder would be all over the place. Why not buy the bike and load it appropriately before thrashing it down a hill? Then you can be sure.

I reckon a cute at around 2kg and 18mph would be more suitable, and fit in with the folding bikes ideals. You could use a 10ah frog and still of added under 6kg.

 

[nukezero]

You guys are probably right. Anything greater than 22-23mph on this folder is going to be tough.

I'm thinking about pairing it with the Cute 100 motor along with the 4.5kg 10ah 48V frog battery.

20 lb bike + 6 lb (motor/controller/cables) + 10lb battery = 36 lb total. The max weight on this bike is recommended at 220lb. I weigh 155.

I will be perfectly happy at 20MPH with the Cute 100 motor @ 48V 12amps.

 

[gogo]

15 MPH is the most I'd recommend on my Currie ezgo 16" folder. I've given it 56V to go 35 and didn't like anything above the stock 15. The snappy acceleration was nice, but the inertial moment of the steering is small and makes the steering twitchy. Maybe the more experienced manufacturers of small wheel bikes have a way of mitigating the twitchiness.
Re: Better deal than electric bike?

 

[MattyCiii]

My mainstay e-bike is a Dahon 20" folder that does 30mph frequently. I've had it up to 37mph (scary!). It has (marginal) suspension. I must have over 4k miles on it as a high speed, high acceleration e-bike. That said, I plan to build another bike (a DIY folder built to handle the punishment) and shelve this bike, before the fatigue of hard riding results in a crash.

 

[swbluto]

I have a bike with a 16" wheel. If the road is perfectly flat (No potholes, no grooves, etc.), then you can safely go at least 25mph. However, with potholes and grooves, I'd highly suggest keeping the bike below 15 mph. If you hit the right sized hole at 20 mph and the front goes out of commission, the fall is going to hurt like a bitch. Trust me, I know - I've done it.

20" and higher wheels are HIGHLY preferable for higher speed riding.

 

[nukezero]

Here is a video of the folding bike in action. They claim 7 seconds folding. That's probably not including the pedal installation. But overall, I like its extreme compactness, super lightweight, looks, color, and it's capability to do 20mph, hopefully on 36V Cute 100 motor.

http://www.youtube.com/watch?v=QkHUaWoa0MA

I'm starting to like this bike a lot. I wonder if anyone of you could guess what the dropout size is for the 16" bike, both front and rear. 135mm is about 5.2 inches and it seems like the rear dropout COULD be 5 inches wide but I'm not so sure. It's really hard to tell.

I know other Dahon 20" folders are around 130mm ish right? So would it make any sense that the 16" wheels would have a smaller dropout if the hubs are all the same? I mean, the hubs should all be the same width regardless of the size of the wheel right?

 

[MattyCiii]

My Dahin Jetstream might be 130mm dropout REAR, but I fit 135mm hubs into its Al rear swingarm just fine. The front is somewhere near 80mm (either 80mm or 74mm, I don't care which) making replacement front hub a SOB to source.

 

[nukezero]

My Dahin Jetstream might be 130mm dropout REAR, but I fit 135mm hubs into its Al rear swingarm just fine. The front is somewhere near 80mm (either 80mm or 74mm, I don't care which) making replacement front hub a SOB to source.

Thanks, it looks like my dreams of working with the Dahon Jifo is killed. I found the specs for the rear hub on the Dahon Jifo:

REAR HUB Dahon technology, mini, 1-speed, OLD: 76 mm, 20H, bearing structure, freewheel in one-piece, 10T, aluminum alloy hub

They are using 76mm over-locking distance. That is no way in hell stretchable to 135mm :lol: :lol:

I guess I'll have to do with the Jetstream P8, that was my next choice. How do you like it by the way? How is the suspension ride?

 

[d8veh]

I have a Dahon Jetstream 20" wheels with a Q100 in the back. It does about 22mph at 48v. The handling is generally OK, but small wheels quicken the steering and have less gyroscopic effect to keep you stable, The main problem is on bumpy bends, where it's difficult to hold the bike steady compared with bigger wheels. 16" wheels will be even worse. There's no problem in a straight line.

 

[richdeloup]

I'm now getting my Dahon up to around 55mph with upgraded fox suspension, 2 torque arms and disk brake upgrade, I wouldnt say that it feels safe but not too much difference than a scooter.
http://endless-sphere.com/forums/viewtopic.php?f=6&t=51360
(small wheeled bikes at the bottom of link pages)

 

[richdeloup]

Back on topic though, my 16" will go 40mph but is pretty scary with no suspension. potholes come up fast and can throw you off balance, where as they are soaked up with the suspension on my Dahons. Big fat tyres help.

 

[richdeloup]

I see that leafbike has a 1000W / 48V kit for their 16" bike

I bought a few black-lightning motors from Peter at leafbike and they have been great, a bit noisy but fast. He also sells the motors separately if you want to purchase an upgraded controller.

 

[nukezero]

Can anyone read Japanese??? Does that say 130mm rear dropout in the diagram? I think I may have found my 16" funny bike to electrify from Dahon.

 

[d8veh]

I can't read Japanese, but it looks pretty clear to me next to the picture of the rear drop-outs: 130mm.

 

[richdeloup]

Nukezero, Are you still planning to go for the cast 16" wheel from Leaf, as a few things to think about if you are?

Firstly, the side wall pattern isnt flat for rim brake pads so you really need to find a bike with disc brake lugs or a different motor. I use mine with rim brakes but they dont work! and pads wear out and get a groove cut in them within 30miles use. If you want to use a disc on the motor you will need to use a screw on adapter in order to fit the disc to the motor.

Secondly, without rear suspension, the wheel takes all sorts of abuse from pot holes and being cast is prone to cracking. as mine has!
Thirdly, you will need to find an inner tube with a 90 degree bent valve as otherwise cant access a pump to inflate it. These are almost impossible to source now. Halfords (UK) sells a bent valve adapter which works but is a bit of a pain to use.http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_771011_langId_-1_categoryId_165661

You shouldn't have too much problem fitting to the 130mm dropouts.These are just my experiences and you may be planning something different or they may have changed the motor, but looks identical if this is the one you are going for?
http://www.leafbike.com/products/diy-bike-conversion-kit/16-inch-electric-hub-motor-kit/16-inch-48v-1000w-electric-bike-kit-rear-wheel-654.html

My 16"er is good for a fun 10 min ride but if i was you and wanted a more capable bike, I would go for the Jetstream. You could even fit 16" wheels to it. Rear for sure as the P8 comes with disc mounts, front may be a bit harder as standard forks dont come with mounts, although you could prob get a disc brake adapter for the forks.
Upgrade the 150mm shock to a better 160mm one and it would push up the bottom bracket height so the ride height would be more like a 20" but with the fun and torque of 16" wheels.
Just thinking, its your project!

 

[richdeloup]

Me again, sorry for taking over your thread, keep thinking about other considerations that I came across on my builds!!

If you have your heart set one of these Dahons, I would go for the Presto over the Jifo (youve prob decided that all ready) for two reasons.
The first being that it has horizontal dropouts, meaning that you could get away without using a chain tensioner as you can move the wheel back or forwards to adjust the tension. This is also safer than vertical ones as your wheel isnt likely to 'drop' out of the frame, although If i was you i'd fit some torque arms anyhow.
Secondly, the bars on the Jifo look scary to me! the extra extension join/locking bracket are generally pretty flexi. I bent the originals on my bike and changed over to an adjustable riser stem and bmx bars. This isnt possible however on the Dahons as they use their own size aheadset style fitting father than a quill stem.

The Presto bar system looks the same as on the Jetstream and holds up to all sorts of abuse (for now).