If I knew then what I know now, and bought a new folding bike today…

When I bought the Dahon Vitesse, like many folding bike riders, it was a “first bike,” and I went into it knowing considerably less about bicycles than what I know now. Since then, you’ve seen how much it’s changed over the three years I’ve had it at this writing.

It also has to be said that as far as platforms go, with the Vitesse D7, I started at the bottom of the pile. The process of making the bike keep up with my developing abilities as a cyclist was costlier and more involved than I’d like, but it did help me understand the mechanical nitty-gritty of bicycles more.

That got me thinking. Given my current knowledge, if I was in the market for a folding bike now, or if I was advising someone I knew who was eyeing one…what would I be looking at?

AT LEAST EIGHT COGS ON THE BACK WHEEL

A Shimano Tiagra 10-speed cassette sliding onto a splined freehub body on a rear wheel. The same freehub body should work with 8- and 9-speed cassettes too.

This is priority number one. Make sure whatever folding bike you consider possesses at least an eight-speed drivetrain. This means that its stock wheelset has a rear hub ready to accept 8, 9 or 10-speed cassettes on its splined freehub body, considerably reducing on your expense, since you won’t need to switch out hubs or wheelsets.

Bikes with 6- or 7-speed drivetrains are based around freewheels, screwing onto a threaded rear hub. They’re fine to start with, but as far as drivetrain development and upgrade options go, they’re dead ends.

The rear hub is the foundation of most bicycle drivetrains; if you want the bike to grow with you, it is imperative you buy a bike with the correct one. Fortunately that just means that, at the minimum, an eight-speed bike is your best bet.

A REAR DERAILLEUR HANGER

My Vitesse came with a non-replaceable rear derailleur hanger and a screw-on freewheel.

This is easily second priority. I was lucky with the Vitesse, as it came with a rear derailleur hanger, albeit one fixed to the frame and non-replaceable.

Many of Dahon and Tern’s bikes come with Neos rear derailleurs. This used to be Dahon-speak (or Tern-speak) for “no rear derailleur hanger,” because these mount directly to the chainstay. This greatly limits your upgrade options for rear derailleurs. Fortunately this seems to have changed, and Tern at least offers aftermarket dropouts that can mount rear derailleurs – and makes bikes that can use them.

A Neos rear derailleur. The dropout looks like it can be swapped with one containing a rear derailleur hanger.

Sure, you can upgrade the rear shifter alone, as the rear derailleur is just a slave to it anyway. The moment you introduce drastically different cassettes into the picture, however, you might end up regretting being stuck with a Neos unit.

A DOUBLE CHAINRING CRANKSET

It’s not up there in terms of priority items…if we were back in 2013. These days, it’s hard to ignore the breadth of inexpensive folding bike options that come with a road double crankset as stock equipment.

Many folding bikes have a large single chainwheel of around 52T attached to their cranks. The intention is to give the bike’s drivetrain the gearing to emulate a full-size bike, reducing the need to spin the pedals at a crazy high cadence. This works most of the time…on the flats. Introduce a mild uphill gradient, however, and it’s tough negotiating it with such a large chainring, even mashing away with a 30T cog at the back.

A Dahon Vitesse P18. Note the brazed-on tab for the front derailleur, absent on single-chainwheel versions. Also note the large 55/44T chainrings, specifically made for small-wheeled bikes.

It becomes very handy, then, to have a smaller second chainring as a bail-out gear. Yes, bikes that have double cranksets (and relevant shifting hardware) are usually a little more expensive, but I feel it’s money well spent. Otherwise, the bike’s frame usually doesn’t have any provision to mount a front derailleur, which means resorting to front derailleur adapters…that can be expensive and hit-or-miss in effectivity.

Luckily, LitePro specialized itself around Dahon’s and Tern’s bikes, and other bikes with a seat tube outer diameter of 40 mm. Some bike brands however aren’t so lucky, such as Doppelganger.

My Vitesse D7 needed a LitePro SP8 front derailleur adapter, which mimics the braze-on tab on the Vitesse P18.

DISC BRAKES…?

A Dahon Formula S18 from 2013, sporting a double crankset and Avid mechanical disc brakes. Perhaps the ultimate iteration of the KA-series frame in flat-handlebar form.

Riding my TCX for two years now, I am totally sold on disc brakes. Sorry, rim brake fans, but they’re simply inferior. In my amateur motorsport days, I spent four years beating more powerful cars lapping around a racetrack simply because I had better braking as my primary weapon.

That said, my only concern with disc brakes on folding bikes is bimodal commuting. In a crowded train or bus, a rotor can get bent out of shape, have undesired liquids spilled on it, have somebody else’s finger or leg cut on it…or some other mishap.

And by the way, disc brakes are a feature of the frame itself; the frame tubes are strengthened to cope with the forces generated by these brakes. Attempting to retrofit disc brakes on a rim brake frame is a very bad idea.

WHEEL SIZE: 406 MM VS 451 MM

A modified Tern Verge X10, fitted with a deep-section 451 mm wheelset.

Due to the influence of both road bikes and mini velos, the 451 mm wheel size (the “fractional” 20″ size, e.g. 20″ x 1-3/8″) has gained popularity. The larger wheel size boasts many benefits, such as improved speed and decreased rolling resistance. Aesthetically it certainly looks nicer, and bulks up the frame of a folding bike quite nicely.

The 406 mm size (the “decimal” 20″ size, e.g. 20″ x 1.5″) is a folding bike mainstay for one big reason, however: BMX. Unless BMX dies out or becomes out of fashion, the supply of 406 mm wheels, tires and inner tubes isn’t going away.

Bino rolls on a 406 mm wheelset. Next to 451s, these look slightly dinky, but they do the job.

Besides consumables availability, there are other downsides to a 451 mm wheelset. You can’t get a 451 mm tire wider than 35 mm, and fenders this size can be harder to find. Technically, you can make a folding bike frame equipped with 406 mm wheels work with a 451 mm wheelset, but it will require relocation of the V-brakes.

451 mm wheels are tempting, but I can’t recommend them. Not yet, at least.

FRAME MATERIAL

Aluminum alloys, such as 6061 and 7006, are the norm for many folding bikes.

The default choice for many is aluminum: affordable, relatively light, and can be made pretty strong. Not the best reputation for ride quality, though, which is why you rarely ever see forks made out of the stuff. Combine that with the inherent disadvantage in ride quality on smaller wheels, and you’ll see why comfort isn’t a strong suit for most folding bikes.

Too many people underestimate steel, thinking that it’s heavy and cheap, but 4130 chromoly steel largely addresses those negatives while providing the material’s legendary ride quality. Indeed, my Vitesse came with a chromoly steel fork.

The whole business of folding these bikes introduces the risk of water ingress and rust, however, so I’d give the nod slightly toward aluminum. Stainless steel or titanium would be great options but cost too much.

SUMMARY

Look, it’s perfectly fine to get a 6- or 7-speed folding bike with rim brakes. Given proper maintenance it should give you years of enjoyment as is.

Unfortunately, it’s also a lousy platform for upgrading to better componentry. Depending on what bike you buy, it’s completely possible to spend more than its purchase price in upgrade costs alone.

At the very least, budget permitting, I’d recommend a 2×8 folding bike with 406 mm wheels and disc brakes. It will be more expensive at the outset, but it’s better equipped to grow alongside you as a cyclist, and should offer better bang for your buck overall.

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I hope you found this interesting, informative or educational. Let me know what else you want to see featured on the blog by leaving a comment. Happy riding.