HonCheung

Hello friends, i am a Industrial Designer and my current project is to design a FOLDING BICYCLE FOR URBAN CITY riding.
DOES ANYONE have any suggetions on current folding bicycle issues, and what could make a better folding bicycle**********

Hon(",)

spambait11

For urban city:
- it better be portable and easy to carry, hopefully not bulky (or as one design had it, turn into its own backpack)
- must be light
- must take 10 seconds or less to fold
- wheels shouldn't be smaller than ETRTO 349 (my bias)
- must have good luggage system or carrying options
- no part of the frame or chainring should hit the ground when folded
- must have good cable routing, or eliminate cables altogether
- must be ridable in all kinds of attire: suits, skirts, etc.
- should fit a wide range of rider heights
- should accomodate a wide range of rider weights
- should use standard-sized parts (or not use many unique parts)
- might need fenders, lights, bell, etc.
- must look good

Happy designing!

invisiblehand

Certainly, here in the US, the low weight limits are a problem. Related to the weight restriction is that many of the bikes flex under any serious load. So if you decide to have long handlebar posts and seatposts, expect to deal with > 90kg men.

The problem with the 349 -- i.e., the ~16" wheel -- is that the selection of tires is much smaller than the more common 305. For instance, the the Schwalbe Big Apple tires are available in 305 but not 349. So if you went with 349, you will have to include some sort of shock absorbtion system which makes the bike heavy and more complicated.

A nice perk is the ability to push the bike on wheels while folded. The Brompton/Merc with the skate wheels has this function. Many of the Dahons have this functionality as well (just keep the seat post extended). This makes a heavier bike more acceptable. Here is an example https://www.gaerlan.com/bikes/dahonfold/dahonfold.htm

Even though you restrict the design for city/urban riding, any well designed folding bike is useful for a lot of of purposes. Using standard parts and sizes will allow your design to be applied to many purposes. For an example, look at Dahon's Speed series -- Speed 8, Speed Pro, Speed TT -- and similar designs in its lineup. Dahon, unfortunately, has many proprietary parts. So what would I want to see? If the rear hub-spacing is 132.5mm, then an owner has a lot of options for gearing. Furthermore, if the seat tube has a diameter of 34.9mm then a front derailer can be installed at some point.

Good luck!

yellowjacket

Nobody's mentioned price! Urbanites who want these probably have smaller budgets than yacht-owners who want these.

Might seem obvious, but the thing should latch together securely when folded so you can lift it one-handed. Not with a little velcro strap that will get lost, either.

Platy

As others have said, a high weight limit for U.S. models.

spambait11

Ooooh, price is a good one!

349s are a good balance between size and speed - not too big, but pretty quick. 349s are to 305s what 451s are to 406s. Tires for 349s are meant to be skinnier since they are designed primarily for the go-faster crowd. If you want to add to your bike design, you can make it so that the customer has the option of swapping 349s and 305s - just make sure to design brakes arms that can accomodate both rim sizes.

james Haury

In my humble opinion 20 inch (406 mm)wheels are much better than 16 inch. They roll better ,there is a larger selection to choose from and they give a better ride. I love my 20 inch folders but mostly ride my ss and fixed 20 inchers.I like to take the ss out to new areas and nose around on weekends or use the fixie as a cure for cabin fever in winter. Fat 406 mm high pressure capable tires offer good shock absorption and and can be pumped up to roll fast on smooth roads. P.s Which Newcastle One somewhere in the U.S or Newcastle Upon Tyne?

james_swift

Typical folders default to a cramped, upright riding position. Not only does this make extended rides uncomfortable (most of the rider weight over the bum and lower back), but the uneven weight distribution over the bike makes for very poor aerodynamics and handling, and an unweighted front-wheel that washes-out easily. I have drop bars and a pretty good roadie-style stretch on my Swift.The bike handles and cuts through the wind beautifully. My Dahon, on the otherhand, has the typical Dahon-ish cramped, upright riding position. Not only does my upper body catch the wind like a sail, but the unweighted front wheel has repeatedly washed-out from under me several times, causing me to crash (embarassingly) once. I also get a sore bum and lower back on rides longer than 6 miles. It also handles like crap.

invisiblehand

I agree that 20" wheels result in a better ride. They also result in a bigger fold and probably a heavier bike. For an urban/city bike, I would think that the smaller fold and less weight would trump the better ride.

As long as the components are standard, then price should be flexible. If you begin with a good design--consider the Trek frame used for their touring bike and hybrids--then one can simply select the appropriate components.

HonCheung

Hello everyone, THANK YOU ALL FOR RESPONDING TO MY QUESTION SO FAST AND I HOPE I CAN KEEP YOU ALL UP TO DATE WITH THE BICYCLE DESIGN,
First of all i really think that there has been great advice been given to me!! and i will for sure take them up!!!!

Thank you all friends!!! Happy riding

Hon(",)

HonCheung

Hello James nice to meet you! thank you for the advice i do thicker and bigger wheel is soft on the road giving a better ride, and i do think this is a big issue of my bicycle design, to select the right size, or give the rider the oppion of both.

Ps Im from Newcastle England

hon(",)

geo8rge

small dia wheels do not deal with potholes well.

rolls instead of being carried like strida.com

anti theft devices. pitlock type skewers

generator hub

drum brakes like strida.com

low maintenance hubs: Phil wood, internally geared.

alternative to folding
sandsmachine.com

Chains stain clothing
condsider a belt drive: strida.com
shaft drive
enclosed chain
wax instead of oil

dannyg1 

I've come to the conclusion that aluminum is not a good build material for a folding bike with small wheels. The Swift/Xootr is the only aluminum bike I've seen that doesn't have gobs of reinforcement in the BB area, where the forces generated by the long top tube act as a flex lever and along with the forces generated by pedaling, necessitate great strength. The Birdy, in particular has a massively overbuilt top tube and four weld/contact points at the bottom bracket; since it doesn't fold, it feels as though it may last (at least in the main frame. The front and rear suspension assembles both are suspect for me now).

Someone mentioned standardizing the seatpost tube size and I'm sure you'll find that you must shim a very large tube here, again because the forces generated are far higher than on an ordinarily sized frame. Steel and titanium are the options most likely to work and, given the strength requirements, steel might be a weight competitive choice. Check oyut the Bike Friday line for a good selection of lighter weight steel frames.

On a note of personal choice, I like to fold my bike in half, on the horizontal plane (like the Dahons and rather dislike the gymnastic effort required to fold bikes that have the rear wheel swing under. I refuse to actually fold my Birdy simply because it's such a messy folding design.

A refinement of the handlepost would be welcome and don't forget to study a little history. There've been som very interesting designs put out in the past, like the Panasonic/Soma ti journey.

Good luck,
DG1

EvilV

Ha ha ha - so am I. I assume you mean Newcastle upon Tyne. Maybe you're at the University doing Mechanical Engineering. One of my sons is there doing that course.

MichaelW

Most folders are very adjustable but come in one-size-fits all.
You need at least S/M /L frames with the L having longer frame and rear triangle + stronger, stiffer construction + more room for large cranks.
The S one needs shorter frame, lighter construction.

A lightweight 8 spd hub for narrow dropouts.
Use of carbon fibre for unusual moulded shapes eg enclosed rear traingle transmission system.

LittlePixel

Hi Hon - I grew up in Teesside; nice to hear of another northeasterner.
My 2¢ worth:
Hub gears may seem heavier but they are so much less hassle - especially on a folding bike.
I think the area that needs most work in folding bikes is the handlebars and stem - getting a good position is hard and sometimes the stem is really flexible. I'd look at recent ideas at handlebars used by brompton.

Dahon are using a new dynamo hub this year that allows things like mobile phones/iPods/GPS systems to be recharged when riding. I think this would be a nice feature on a design project like yours if only for the "wow" factor (I've been throught the design college mill myself so I have a clue as to what they'll be looking for). Check out their 2006 catalogue - I think it's in the 'accessories' section at the back.

Consider the idea of fixed gear also - it's still a niche but growing in popularity amongst commuters, and though not for everyone - you can't really get a lighter or more maintenence free drivetrain. Fixed or freewheel - either makes for a simple bike, though not for hillier climes.

I'd also look at Pantour suspension hubs as a good front component - again - a lot lighter than a full suspension fork setup and weight is THE issue with a bike you carry as well as ride.

Also - the ability to 'wheel' the bike like wheeled luggage is a good feature - bromptons are great for this (though a handle of some sort so it can be towed like a case would be cool.)

Finally - Regulars here will be going 'oh no not again' about this one because I'm always mentioning them - but there's this really cool bike made in Japan by Kuwahara called the Gaap (sadly not available in Europe or the US) that has a pretty original take on folding and a smart rollerblade-wheeled rolling mode.

here:
https://www.rintendo.com/Products/Sma...ap-folding.htm
(be sure to look at all the Gaap links on the left nav)

Hope that's some help; You have to promise to share your final designs with us when you finish the project!

Best
Huw

spambait11

If you do the one gear thing, I'd suggest just a single-speed as fixies can be dangerous: get a pant cuff or shoelace caught and you and your bike might be riding under a car. Plus, fixies are dangerous drive trains to maintain *if* you have to adjust one. The tip of my right index finger was almost torn off because I wasn't paying enough attention while turning the cranks and cleaning the chain. Sure - call me stupid; I don't care. I'm just thankful to have the tip of my finger back.

james Haury

I love my fixies and for what I use them for(Riding on ice and snow in winter )they are far safer than a single speed that coasts.You just have to be mindful of what you are riding . As for getting a shoelace caught and ending up under a car? Use a chaingaurd .You can run brakes on a fixie if you want extra braking.Once you get used to braking by ******ing the pedals you may find you barely use them.I plan on having the best of both. I have a single speed that coasts and an extra rear wheel dished for a 6 speed freewheel. I shall remove the freewheel add a fixed cog I recieved today , and secure it with loctite red or blue( i want to try blue and see how it works ,red is very permanent unless you heat it to 260 degrees Fahrenheit)When winter comes i will simply have the wheels switched out. The bike was originally a 6 speed but it has horizontal dropouts.Mr Cheung may want to design his bike as a ss but with the rear triangle spaced so that a flip flop hub can later be fitted.In this fashion the bike can be run as fixed or freewheel.Twenty inch wheels make doing so easier as gearing options are more readily available and less expensive.

spambait11

Might be riding under a car.

A chainguard should be light and good looking (i.e. none of that Dahon plastic stuff), and not affect the fold. Hm. Maybe a chainring guard would be sufficient.

Whatever the wheel size, might as well make it compatible with what's already out there: if 20" wheels, use Dahon's, Swift's, or Bike Friday's front and rear dropout spacing; makes buying wheelsets much easier. If using ETRTO 349s, use Brompton's spacing, then buy Merc wheelsets.

meb

Much of the emphasis in objectives discussed thus far relate to commuting folders. There will be distinctly different objectives for a travelling touring folder.

A travelling folder needn't break down quickly, but there is more emphasis on compactness to fit in airline dimensions. It needs be a better performing bike as it will be the high end bike at the distant location. Depending on terrain, there may be a need for suspensioin-somethimes the suspension can be incorporated as part of the folding.

There is also a significant need for folder improvements in the recumbent area.

More thoughts for the commuting type folders-grease free features such as a full encircle chainguard or belt drive.