Folding bikes are extremely versatile, but they’re not quite as capable as their full-size counterparts. Most of them just aren’t made for rough terrain or aggressive riding.
But in terms of speed and climbing ability, they absolutely hold their own on smoother surfaces. That might come as a surprise, but there’s a simple physical explanation for why climbing is generally not a problem.
So, in brief, can folding bikes go uphill?
Yes, folding bikes climb hills as easily as a regular bike with similar gearing. However, many folding bikes are sold with narrow gear ranges, which often lack the extra-low gears that most standard bikes have. Naturally, your fitness is also a major factor.
In other words, climbing is not uniquely hard on folding bikes. Any limitation would be because of specs (which are usually upgradeable), not because of their diminutive size. In this article, we’ll take a closer look at why that is, and how to find a folder that suits your local ascents.
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How gearing makes or breaks climbing
The right gearing isn’t as simple as “use 2nd” or “buy an 8-speed bike.” Those are nice, intuitive numbers…but they’re completely relative. If we want to describe an objectively good gear for climbing, then we need an absolute number that applies to all bikes.
And that number is gear inches. The formula is simple: gear ratio (front teeth divided by rear teeth) times rear tire diameter. That gives a number in inches. The lower it is, the more torque and therefore easier climbing you can expect.
For modest, rolling hills, I recommend a folding bike whose lowest gear is about 40″ or less. Most folding bikes with 6+ speeds will have this, but use a gear inches calculator to confirm.
For very long or steep hills, look for 30″ or lower. In my experience, that lets most riders climb most steep, paved hills without too much difficulty. Stock gearing doesn’t typically go that low on folding bikes, but it’s an easy upgrade. It’s also an optional spec with some brands/models, like the 6-speed Brompton.
You’ll need to aim even lower on steep off-road trails. Then again, most folding bikes aren’t meant for that sort of riding in the first place.
If you find a model that’s perfect in every respect except gearing, then it’s probably still worth buying. You can’t easily widen the gear range, but you can “slide” the whole range lower by installing a slightly smaller chainring.
How much smaller? It depends on the current gearing, so use the gear inches calculator as your guide. In my experience, dropping about 5″ (perhaps 4-6 fewer teeth up front) can turn some hills from “nope” to “that wasn’t too bad!”
The simple math behind gear inches
I always use this calculator for exact numbers, but here are two tips for a quick estimate:
• The lowest gear is the number of teeth on the smallest front gear (if more than one) and the largest rear gear.
• For 20″ wheels with average city tires, use 21″ for diameter. For 16″ wheels with average city tires, use 17″ for diameter. The exact number depends on tire specs, but we’re only looking for an estimate.
Here are a couple simple examples to clarify.
First, let’s say you’re considering a 20″ folding bike with 40/52t chainrings and an 11-28t cassette. You’d use 40 / 28 * 21″ = 30″, which means it should climb like a mountain goat.
Second, pretend you’re looking at a 16″ folding bike with a single 54t chainring and a 10-26t cassette. You’d use 54 / 26 * 17″ ≈ 35″. That’ll work just fine around town, but may feel a bit stiff for big, sustained climbs.
A special note about hub gears
With an internally-geared hub, you need to account for the external gear ratio and the hub’s internal gear ratios. Here’s another great calculator that has presets for common IGHs. You can usually find that info in the manufacturer’s manual, too.
The six-speed Brompton is a more unique case. It uses two external gears with a three-speed hub. There are also three chainring size options from the manufacturer, each of which moves the whole gear range up or down.
How many folding bikes gears for climbing?
If you have a sufficiently low gear (see above), the overall number of gears doesn’t matter much for climbing. Anything with 6+ speeds will probably suffice for hills, but again, check the actual gear inches to be sure.
It’s easy to conflate gear count and gear range, but that can be a costly mistake that leads to more gears than you need! That’s because more gears doesn’t only mean wider range. It also means narrower steps within the overall range. And this gets truer as the gear count increases.
For instance, going from 3 to 6 speeds won’t double your gear range, but it might increase it by 60%, with somewhat narrower steps between gears. But from 9 to 18 speeds? Range may only increase by 30%, while creating much closer (often overlapping) steps in between.
Can you stand on a folding bike?
It’s easy to stand up on a folding bike to get more power for sprints and climbs. Surprisingly, they may feel more stable since small wheels also lower your center of gravity. However, some folding bikes have extra-narrow handlebars that might feel different (though not worse) compared to standard bikes.
If you find yourself standing frequently, then invest in a pair of small bar ends. These gives better leverage when standing, not to mention a couple of additional, ergonomic hand positions. I’m highly partial to this Ergon pair, which have unobtrusive bar ends built into supremely comfortable, rain-friendly grips. (Just realize that certain bar ends, at certain angles, may interfere with the fold of certain bikes. You might need to experiment a bit.)