Every bike conversion in one place — gearing, speed, tire sizes, and going electric.
Estimates for planning only — real numbers vary with rider weight, terrain, wind and tire pressure.
Free bike converters plus plain-English e-bike conversion guides. Calculate gear ratios, gear inches, cadence-to-speed, tire sizes and mph/km-h, then learn how to convert any bike to electric with the right motor kit, battery and the law on your side.
Read our guidesConverting a bike you already love into an electric one is one of the most satisfying projects a DIY cyclist can take on. For a fraction of the price of a factory e-bike, you can keep the frame and geometry that already fit you, learn how the whole system works, and end up with a machine tuned exact
Read more →Pick the wrong motor and you will spend the life of your e-bike fighting it: a screaming hub motor that overheats on every climb, or an expensive mid-drive that was overkill for your flat seaside commute. This guide compares the two head to head across the things that actually matter, then gives you
Read more →The battery is the heart of any conversion: it is usually the most expensive component, the heaviest, the one with the biggest impact on your range, and the only one that can genuinely catch fire if you buy badly. Get it right and your conversion is a joy; get it wrong and you are either stranded sh
Read more →If you have ever tried to compare two bikes, or work out whether a new cassette will give you an easier climbing gear, you will quickly bump into three overlapping ideas: gear ratio, gear inches, and development (sometimes called metres of development or roll-out). They all describe the same underly
Read more →Few corners of cycling are as confusing as wheel sizes. The same wheel might be called 700c by a road rider, 29er by a mountain biker and 622 by an engineer — and they would all be right. Meanwhile "26-inch", "27.5", "650b" and a tangle of French and inch markings on tyre sidewalls leave plenty of r
Read more →Your gear ratio is the single number that explains why one bike feels effortless on a climb and another feels like wading through treacle on the flat. It is also one of the easiest things to work out yourself: you need nothing more than the ability to count teeth and do a little division. Once you c
Read more →Whether you are reading a race report from a European tour, comparing notes with a riding buddy across the Atlantic, or simply trying to make sense of a speed limit sign while bikepacking abroad, sooner or later you will need to switch between miles per hour and kilometres per hour. The conversion i
Read more →Few things in cycling cause as much head-scratching as tyre sizing. Pick up three tyres from three different decades and you might find one labelled 700x28c, another 27 x 1 1/4, and a third simply 28-622 — and depending on which numbers you trust, you could end up with a tyre that physically will no
Read more →Fitting a hub motor conversion kit is one of the most satisfying jobs you can do on a bike: in an afternoon you can turn an ordinary machine into a capable electric one, using little more than the spanners already in your toolbox. Hub kits are popular precisely because they are forgiving. The motor
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