Not surprisingly, there are two general groups of people I've met when it comes to selecting folding bikes, and they are:
- the total first-timers, and
- the non-first-timers (coming off a background of mountain, road, triathlon, BMX etc)
Disclaimer: I have absolutely no financial kickbacks for any of the writing below (unless otherwise stated), however you are encouraged to add a pinch, or a pitcher full of salt to my words. However, do not overdose and get high blood pressure... *grin*
There are some considerations even before coming to talk about the different number of teeth on the chainring or the cassette to pick for your bike. That primarily, would be your purpose for a bike. What would YOU want to do with your bike?
October 2013 - On tour in Hua-lien County, Taiwan
- Cycle touring;
- Exploring Singapore (or where you reside);
- Group rides;
- Commuting to/from work;
- Grocery shopping;
- Supplementing to save money by parking a car at a low-cost carpark;
- Exercising (and perhaps a little cardio workout);
- Weight loss;
- Getting toned legs...
The possibilities are endless, and thus you need to know at least one major purpose for the bike, and have a secondary purpose for it. This way you know you are not into it for an impulse buy.
Shifting - SRAM or Shimano?
L-R - SRAM x7 shifter, Shimano XT shifter
It doesn't make too much a difference. It's like the often asked question about Canon or Nikon - just use whichever you're more accustomed to. Either way, I don't have an endorsement package from either of them - just use what you're happy with. I'm using SRAM on my mountain bike and folding bike - solely because of their older trigger style release paddles. More on this another time...
Tires
This is a short topic - I'd happily settle for a 1.75" tire for a 20" wheeled bike, however these days I'm much more comfortable talking in ETRTO terms (coincidentally same as ISO specifications). Hence I use 44-406 to 47-406 tires as they are fat enough to contain enough air volume to allow excursions onto rough terrain, but not amounting to real cross-country mountain biking.
There is also some unexplained desire by new riders especially to go for thinner tires, or lighter tires - such as those 1.25" in diameter. My 1.75" tires weigh more but it's assuring to know that it's less likely (but not immune) to skid out upon hitting a sandy patch on the road. And the bonus - the ride is a lot more comfortable and less jarring! And the speed difference between the two tires' weights can be mitigated by the gearing ratios - so no one will be left behind.
Just to share a little tidbit - it's easy to hit speeds when your tires are inflated properly. Soggy, under-inflated tires will never pick up any speed at all.
Road or Mountain Componentry?
Just to answer this quickly and keep things simple for now - let's just stick to road bike componentry. I will cater for a mini-Frankenstein drivetrain eventually, but not those exotic stuff that JTek Engineering's Shiftmate (link) can do. I have been mixing a light amount of mountain bike components into my folding bike - however I will share with you the technical considerations for doing so.
Folding Designs
Note that a Brompton swings its rear wheel downwards - the rear of the bike is upside down after the folding. I'll call this a "wheel-tucker" - most Terns and Dahons are "side-folders"
- those that fold up by tucking the rear wheel by swinging it under the main body - I call these "wheel-tuckers", such as Brompton, Birdy, Bike Friday, Anemos and;
- those that fold sideways which includes most Dahons, Terns, plus almost every other generic makes - these I would call "side-folders";
- and those that fold and fit into your pocket (requires your name to be Doraemon, though)
Some of the frames come in 126mm, 130mm and 135mm OLD (over-locknut distance) so you will need to take note. Typically, those using disc brakes are 135mm OLD, but you still need to be very sure, as this may make it or break it for you when it comes to upgrading for the future. How much hair you have left after ripping out clumps of it just because you bought the wrong bike with the wrong frame dimensions depends on this... you get the idea.
Wheels, Wheel Size and the Fold
Ah - this is "simple"! There are some weighing of pros and cons for this - general rule of thumb goes that the smaller the wheel diameter - the smaller the entire bike will fold down to. Brompton folds incredibly beautifully - it's a 30+ year old masterpiece that doesn't seem outdone by anyone else. It's on 16" wheels - or ETRTO 349 (349mm for the BSD - beat seat diameter). It's perhaps best if you could take the time to join the rides that LoveCycling SG (Facebook link) organizes and ask owners of various bikes if they could show you how it's folded... and unfolded!
If you're wondering, 16", 18" and 20" are the most commonly used folding bike wheel diameters - with 20" being the most common. The case to highlight this is especially when you might end up touring in another country - imagine the horrors if you have a puncture and you can't find either a tube or tire because it's not commonly found!
Carriage Racks
If you're thinking of using a heavy duty touring rack such as the Tubus LOCC (link) like me - you need not look at the wheel-tuckers - reason being, once the bike is folded, you will not be able to push the folded bike around at all - as the rack that would usually be above the rear wheel, will be on the bottom! On the contrary, the side-folders have both the front and the rear wheel side-by-side, which means your rack will not be scraping the ground... That's what I figured out early in my search for a folding bike - even before I bought the bike!
The proprietary rear racks for the Birdy (US$ 175, link) and Bike Fridays (US$ 205, link) are very nice - however do note the arbitrarily high prices! The Tubus LOCC is just US$ 85 for those outside of the EU! (Bike24 link - prices correct as February 2014)
Another consideration for the Tubus LOCC - it is the only rear rack that I know of, that uses Rixen-and-Kaul's KLICKfix system (link) to hold an ABUS U-lock. You will know what I mean should you buy a U-lock, but hate to use it because it's troublesome to take it off your bike, and then keep it. KLICKfix makes it easy! Come to think of it, it seems that German companies bandy up together to make things work - ABUS, Ortlieb, Rixen-and-Kaul and Tubus making things happen for riders!
Materials-wise, please go for chromoly - avoid aluminum if you can. I know there are people who say aluminum lasts forever, and I would be lying if I said chromoly racks will last forever too - but in terms of material, I'd suppose chromoly will be much hardier on the whole. Period.
Jokes aside, Surly really has a rack called the Nice Rack. Seems that they changed the name to be something less offensive... Don't believe me? (link)
Panniers
L-R Panniers by Arkel and Ortlieb
I'm not going to write a lot about this yet - however as petite Bromptons can fold down to, they cannot allow regular Ortlieb Front Roller panniers to be used at all - not unless you make some level of modification. I've been using Ortlieb Front Rollers and Back Rollers for some years now, depending on the amount of gear I want to carry. These are the type of panniers where it's considered "one big black hole" where everything goes right into - so there are others with pockets such as Arkel (link), Vaude (link) and Lone Peak (link). Wayne at TheTouringStore.com (link) has amazing advice on his site as well, although communication is limited to email unless you're from USA.Brakedancing...
Fine, so that was really pun-ny! There are three major classes of brakes used by folding bikes:
- caliper brakes, those used by road bikes;
- V-brakes, usually utilized by cheaper mountain bikes;
- mechanical disc brakes that use a wound steel cable to inside a form of Bowden cable housing, and;
- hydraulic disc brakes that use some form of fluid to compress the brake pads;
- and finally the rare hydraulic rim brakes.
If you planned for a bike with disc brakes - congratulations! However you'd have a dilemma over mechanical, or hydraulic disc brakes. I chose the latter - and for what I deemed a good compromise. More to come soon!
Wheel, wheel, wheel...
The first immediate first upgrade I would suggest would be to fix up a custom set of wheels. Why would I suggest a custom pair of wheels, and what other considerations would I suggest here?
First of all, the wheels are your first point of contact to the road, aside from the tires. How smooth they roll, will either add or subtract from how enjoyable your riding will be. I'm not a fan of fancy spoke patterns at all. The larger spread of a rim that is between two spokes, will usually indicate either the wheel is overbuilt, or has very strong rims. For any price points, I will avoid anything like paired spokes. I'm not versed in wheelbuilding, but I would reckon getting spoke lengths correct might be a challenge.
I customized my new wheels upon Hope's Pro II Evo disc hubs - because of my desire of using disc brakes along with positive engagement while pedalling - plus having a near-all-black-stealth look.
Mechanical Advantage (M.A.)
For this topic, we need to understand the concept of mechanical advantage (link) - just to keep things simple, divide the chainring count by the cassette cog count. If you get lesser than 1, you get a high M.A., if you get more than 1, it's a low M.A. To keep it simple, "divide front by back".
For example, a 44T chainring with a 11T cassette cog gives 4.0. That's a low M.A.
That's what you would want to use to go fast... on level ground or downslope.
For example, a 22T chainring with a 34T cassette cog gives 0.65. That's a high M.A.
That's what you would want to use to go at all... on severe upslopes.
Chainrings & Cranks
An in-depth discussion is here (link)
Vintage Shimano Dura-Ace 7700 crankarms with Rotor Q-Rings, 130mm BCD
For climbing purposes, it is imperative that there are at least two chainrings. The larger one will be used for cruising speed (what speed that really is, is up to your own comfort), and the smaller one will be used for climbing (you'll never know when you'll need it!).
There is an interesting interview with the creator of Osymetric chainrings at Cyclingtips.com.au (link), and here's a review of the Rotor Q-Rings I wrote in 2006 for Togoparts.com (link). I do not know of anyone using the Ridea PoweRing setup, hence I cannot comment much about them. Whichever way you go, round rings are passe. For those with knee injuries (I had a knee meniscus wear-and-tear situation years ago), a good non-circular chainring can make a world of difference to your knees' health - I swear by Rotor Q-Rings now! Warning: Stay far, far away from Shimano's seriously flawed Biopace crankset/chainrings - they are designed counterintuitively and screws up big-time - they're one of Shimano's biggest booboos ever!
And in case you didn't notice, Shimano has been revising their crankarms to look swell with their proprietary chainrings, to give an industrial-polished look - but personally I think it's just a ploy to prevent people from changing to non-Shimano aftermarket chainrings as those I mentioned - because it'd look butt-ugly because the 3D look of the crankarm will just pop right out abruptly. I see it as a ploy that Shimano is employing to make sure riders will faithfully stick to their round chainrings...
My current Rotor 3D crankset, bought off eBay in great condition
175mm, conventional 24mm axle, 110mm BCD with 50/34 chainrings
However all that being said, there are the mountain bike cranks (most typically with a 104/64mm BCD for triple, and 110/74mm BCD for double). However, as a rule of thumb (yes, my thumb) you can forget about using mountain bike cranks because the largest chainring 4-arm spider doesn't seem to be a hair over 48T. You'll gain massive climbing powers akin to Spiderman, but you'd be eating a lot of dust. This is due to the double whammy of a folding bike (which usually denotes a 20" wheel or smaller) PLUS the low-gearing of mountain bike cranks. An easy way to tell if a crankset is meant for road bikes - the BCD (bolt centre diameter) is 110mm (only), 130mm or 135mm. That's about it for modern bikes. Anything from the 1950s... sorry, I'm not competent in those...
Speaking from personal experience, I prefer the single-bolt system that Rotor uses in the 3D crankset - it uses a "tight-normal" clamping system - meaning that when the single bolt is loosened, the left crankarm is already gripping the crank axle fairly firmly. In fact, you'd have to "force-loosen" the bolt to expand the left crankarm, so that it can fit into the axle! All it takes to secure the left Rotor crank is very little torque, to know it is securely in place.
Conversely, Shimano's Hollowtech II method usually engages two bolts, but when both bolts are loose - the left crankarm is loose too! Because of my inexperience (and not having a torque wrench, yeah, I know...) I managed to strip the threads in one of the two threads. I'm sure there's more than just me alone who have managed to score this feat. You have been warned! Torque wrench coming right up!
Cassettes
An in-depth discussion is here (link)
A SRAM XX1 11-speed mountain bike cassette,
with a Shimano Dura-Ace 11 speed cassette
with a Shimano Dura-Ace 11 speed cassette
My first folding bike came with a 52/39 chainring combination, along with a 11-28 (not sure, I didn't bother to check) 8-speed cassette. One of the first things I decided to do was to swap out the cassette to a used 11-34 9-speed that I previously used for my mountain bike. You may ask, why didn't I get a new 10-speed cassette since I'm doing an upgrade for this bike anyway?
I would assume at best you'd end up with a 11-28 like on a Tern Verge X20. That bike will cost you a pretty penny! I hope you noticed that there is are two chainrings for this model. However if you're thinking of touring - regardless of how much weight you think you'd be carrying, it's always good to have spare capacity to climb up that darned slope instead of getting off the bike and push.
The late Sheldon Brown has a fantastic gear calculator on his website. For starters, I would use a 11-34 or even a 11-36 for my cassette - it's prudent to have a bailout gearing. The lowest of Tern's chain driven, 20" bikes seem to have a lowest gearing of 26 gear-inches - where my customized foldie with 20" wheels has hit as low as 22.0 gear-inches and even then it was still hard to feel anything when trying to cycle up Wuling Pass. However because I opted for a 9 speed drivetrain, I am limited to a maximum to 11-34 for a cassette.
7, 8, 9, 10 or 11 speed?
First things first, if you were looking for a cheap beater folding bike that you want to reserve the option to upgrade to something incredible (by conventional means) I will advise you to get at least a 8-speed foldie - whether it's a 1x8, or 2x8 setup (one chainring with 8-speed cassette, and double chainrings with 8-speed cassette respectively) - that would suffice. Key reason being, a bike frame with a 8-speed wheel has a very good chance to be upgraded to 9- or 10-speed due to the dropout rear width of 130/135mm. The significantly cheaper 7-speed bikes have it at 126/130mm typically, and will end your upgrade options, noting that the 7-speed cassette may or may not use a cassette lockring that 8, 9 and 10 speed cassettes use.
For my personal experience, I went for a cheap folding bike frame with a 135mm OLD (over-locknut-distance) spacing so that I could immediately retrofit a new set of wheels built upon the Hope Pro II Evo hubs - because I'm a proponent of disc brakes for tough riding around.
Bottom Bracket
Different bottom brackets, clockwise from top left -
External bearing type (SRAM/Truvativ GXP shown),
Shimano Octalink V1, Shimano Octalink V2, Square Taper (Shimano shown)
The bottom bracket is affixed within the bottom bracket shell of a bicycle frame - and to the bottom bracket (hereafter, "BB") the crankarms are fixed. The BB provides the alignment of the chainline which is the distance between the centreline of the bike frame and the chain in the neutral, "central" gear combinations when rested on the middle chainring (or halfway between the two chainrings) as well as the middle of the 8/9/10/11 cassette cog.
There are four main standards (actually, much more!) - Shimano has its discontinued Octalink, an industry-open ISIS Drive, Hollowtech II style, and of course the classic square taper (which I don't have much experience in myself). Personally I find Hollowtech II styled external BB solutions to be the most versatile - although the quality of the tap and threading of the bottom bracket shell on the bicycle frame to be pure hit or miss precision. For this reason, both my bicycles at this moment are using Rotor's SABB (Self-Aligning Bottom Bracket) which allows for imperfections in the shell - yet allowing the cranks to work flawlessly smooth by means of a cup-and-socket system.
Strange Bedfellows...
That caught your eye, didn't it? *wink*
I'll add some limited experience I've had about mix-and-match drivetrains and such... such as how I'm using a set of shifters by SRAM, with a rear derailleur by Shimano... although not many have heard of Shimagnolo or Campagano or Sragnolo... I'm sure some hybrid monster exists out there. I'm not advocating it, but there are such monsters out there... Nessie, please show up and tell the truth!
My Own Folding Bike...
...is a mongrel.
"YOU WHAT?!"
No, really. It is a mongrel bike. This was how it started out in April 2013...
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and this is how it pretty much looks like these days...
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Pimped up? You bet.
Essentially the trick was this - I had gone through the considerations that I listed above and then some, and I concluded I wanted a bike that would meet the following criteria:
- side-folder, so that I could mount a Tubus LOCC rack to carry my U-lock;
- disc brake capable (because I love the power it provides);
- able to be upgraded to a pimpin' Hope Pro II Evo wheelset;
- capable of being transported to other countries for a potter-around tour;
- cheap enough to be a BATA (buy-and-throw-away) frame that can be easily replaced;
- have gear ratios that allow me to pedal away with a touring load;
- front suspension capable so I can ride dirt paths in comfort.
If you're an old hand at it, you'd notice the frame is a spitting image of Dahon's Formula/Speed/Vitesse frames... (NYCEwheels link) which if done correctly, can be a fast bike (not exceedingly, of course) that suits my bill! And the price for this bike? It was just S$ 295 on Taobao (link) - of course that was before adding shipping fees to Singapore. But more importantly - there wasn't another bike of any similar price (under S$ 500) that had the option of using disc brakes. Coupled with the fact that there isn't an official agent for this "brand", so I'm not going against my other friends and acquaintances who are selling bicycles for a living. Note also that I changed my bike from "Landrover" to "LAN Drover" as an insider joke... (link 1, link 2) With all shipping and customs tax included, this didn't cross S$ 450 for the whole bike!
On my first order, I bought THREE of this bike - a gamble, you might call it. However the quality was surprisingly good - and months later I bought another TWO more of it, plus another 2x9 speed version of it (albeit with a differently shaped frame). And today, it is really one of its kind on Earth. *grin*
How I pulled off this feat - I was lucky, I suppose. I was almost seduced to get a 1x7 folding bike, but thanks to some experience I noticed that the dropouts (where you hold the wheels to the bike frame) were unusually thin - which means it's a steel frame. Aluminum is less strong than steel so usually it's beefed up to give structural strength. The folding stem/handlepost (oh! whatever it's called!) shown in the photos were also of good quality - along with the main body joint/hinge (see how much I hate technical terms?) that also seemed study - and not made of steel. As long as it has an area big enough, aluminum can be stronger than steel.
Budget
Before you asked me about your budget - let me ask you - who doesn't have a budget? This is a metal steed (about to blurt, "steel steed" but mine is aluminum-based, sorry!) that is used for various purposes (you read that opening of mine and did your homework, didn't you?) so it doesn't make a heck lot of sense to buy and continually upgrade. That would be like buying a 286 computer this year (2014) and trying to get it up to par with the quad-core our handphones have today! It's a crazy, futile experience and that's a lot to be spent.
I cannot say that I know everything (I'm sure Sulaiman of The Rebound Centre knows EVERYTHING) but I do know what I am looking for in my bike. Hence the Taobao idea...
I cannot say for sure the most expensive stuff is indeed the best - and so long as you keep away from exotic rubbish like carbon fiber on a bike, you'd save A LOT of money. I enjoyed looking at the broken stuff on BustedCarbon.com (link) where all sorts of stuff carbon fiber, just break up while "just riding along". You have been warned!
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