Cycling Tech of the Month: E-Bike Battery Safety, Everyday SPD Shoes and a Steel Gravel Classic

Introduction

Every month we pull together the gear and technology worth paying attention to, and September’s list covers three very different parts of cycling: battery safety, footwear, and a steel gravel bike that has just been brought up to date. Two of those topics come back to the same question, which is what you actually get for your money. A cheap e-bike and a cheap pair of shoes both look like bargains right up until the point they stop doing the job you bought them for.

The battery conversation has moved from an occasional warning to a genuine industry concern, and it deserves a proper explanation rather than a scare headline. The shoe conversation is stranger, because several brands have decided that traditional cycling footwear is not what most riders want any more. And the bike of the month is a reminder that steel still has a place in gravel, provided the details are right.

What We Looked At This Month

We look for a few things. Does the product solve a problem that riders actually have? Is the design coherent, or is it a feature list with no purpose behind it? How does it compare with the obvious alternatives, including the cheap ones? And finally, does it make sense for the person it is aimed at, rather than for absolutely everyone?

That last question matters more than it sounds. A product can be beautifully made and still be a poor choice, and a product can be inexpensive and still be the right answer. This month’s list includes examples of both.

E-Bike Battery Safety: Why It Keeps Coming Up

The short version is that e-bikes and e-scooters run on multi-cell lithium-ion battery packs, and those packs can suffer from something called thermal runaway. A single cell overheats, often through a short circuit or through being charged at too high a voltage. That starts an exothermic reaction which breaks down the cell structure. In one cell it might be contained, but with so many cells packed together the reaction can spread to neighbouring cells and turn into a rapid, irreversible runaway, releasing highly flammable gases and producing exactly the kind of fire and explosion that has made this issue so visible.

It is worth being clear that this is not what happens to every e-bike, and quite the opposite applies to machines bought from a bike shop. The difference is largely in battery technology and in how the whole system is managed. Reputable manufacturers are going beyond the fairly minimal legal requirements, including cell isolation technology that shuts a cell down in the event of a short circuit or the beginnings of an overheat, which can stop the chain reaction before it starts.

That is the thinking behind the Electric Bike Alliance, formed by Cycling UK, the Bicycle Association, the Association of Cycle Traders and Bosch eBike Systems. The group launched an initiative called Ebike Positive, which aims to educate the public about the benefits of e-bikes and about buying bikes and batteries properly. Some brands go further still. Specialized, which developed its e-bikes in Switzerland, says it voluntarily complies with additional standards covering the motor, the battery and the charger as one system. That matters, because a third-party charger simply will not be accepted by the battery control module on a properly managed system.

The stakes are not theoretical. The London Fire Brigade recorded 155 e-bike and e-scooter battery fires in the capital in a single year, describing it as the fastest-growing fire trend in the UK, with three deaths and more than 60 injuries. Some transport operators in London will not carry e-scooters at all. The practical advice is straightforward: buy from a reputable manufacturer, ideally through a bike shop, and be sceptical of very cheap bikes and conversion kits. There is also a reasonable argument that trading standards need tightening, because awareness campaigns only reach the people who read them, while a £400 e-bike reaches everyone.

Bosch Performance Line CX

Bosch’s Performance Line CX is one of the systems named as an example of what a reputable drive system looks like, and it is a useful reference point for anyone shopping. It represents the category of e-bike motor where the manufacturer is investing in battery management rather than simply meeting the minimum bar, including the kind of cell isolation that can prevent a small fault from becoming a serious one.

The wider point is about buying a complete, coherent system. When the motor, battery and charger are designed to work together, the electronics can refuse a charger that does not belong. That is a less exciting selling point than torque figures, but it is the one that protects your home.

Pedaled Odyssey

The Pedaled Odyssey is the odd one out in this month’s footwear group, because it is not a cycling shoe at all. It is not SPD compatible. It is designed for bike packers, for the moment when the riding is done, the bike shoes are off, camp is set up, and you want something light and comfortable to let your feet breathe.

The problem is the value proposition. Yes, the Odyssey is light and packs down small, but bikepackers and hikers generally strap shoes to the outside of a bag rather than packing them inside it, so the folding trick solves a problem most people do not have. Comparable camp shoes from established camping brands, including insulated options from names like Exped and RAB, typically cost somewhere between £30 and £45, and a basic pair of sliders costs about £10. Against that, the Odyssey looks like a very expensive pair of camping slippers.

If you want warm, insulated feet at camp in British conditions, an insulated camp shoe is likely to be the better buy. If you simply want something to wear around a campsite in summer, sliders will do the job.

Adidas Velosamba

The Adidas Velosamba is not new, and it has become the reference point that every other casual SPD shoe gets compared against. It takes the Samba as a base and adds a plastic insole plate to which the cleat is fixed.

The result is genuinely stiff, which is exactly what you want when you are pedalling and noticeably less comfortable when you are walking. Because the cleat recess sits quite low, walking around produces a tapping sound, so it is best thought of as an everyday shoe with a cleat rather than something you would spend all day on your feet in. The upside is the look. It is an iconic silhouette, and it is popular for good reason.

Chapter 3 Transit

The Chapter 3 Transit is the closest rival to the Velosamba, but it approaches the job from the opposite direction. Instead of retrofitting cleat compatibility onto an existing shoe, it was designed from the ground up around it, following about two years of development, with the goal of creating something you can wear every day, walk in, run in, and still clip into a commuting bike.

In practice it works. The silhouette is reminiscent of a chunky low-top trainer, and it is comfortable to walk in. It ships with a base plate, so it can be set up as a flat shoe, and there is plenty of room in the recess for an SPD pedal. The important difference next to the Velosamba is the amount of flex, which is what turns the Transit into a genuine all-day shoe rather than a bike shoe you tolerate off the bike. Worn as a normal shoe, it does not ask to be thought about.

That makes it a strong option for commuters and anyone who wants one pair of shoes for the office and the ride in. It is not cheap, and it is priced above the Velosamba, which is a real consideration. In fashion terms, though, the asking price for a good-looking shoe of this kind is not unusual, and the Transit is asking to be judged on both counts.

Genesis Croix de Fer

The Genesis Croix de Fer is one of the original gravel bikes, having been around since the late 2000s, and this is its first update in roughly four years. It remains a steel frame, and the changes are mostly about bringing it in line with what riders now expect.

Cable routing is now internal, although only through the down tube, so the outer cable still runs the whole way through the frame, which keeps things straightforward for mechanics. Tyre clearance is up to a claimed 47mm, and there is apparently room to squeeze in a 50mm tyre depending on the tyre itself. A 45mm tyre will fit with full-length mudguards, which leaves useful mud clearance. Bigger tyres pushed the design team into geometry changes, because toe overlap is governed by an ISO standard and the leading edge of a larger tyre moves closer to your foot. Reach is now fairly consistent across frame sizes, with fit handled through stem length and saddle setback.

Elsewhere, the seat stays are dropped, partly for comfort and partly for a more modern look, and the top tube is oversized, which is claimed to improve both stiffness and comfort. There is a wide spread of frame sets: a chrome steel version, a 725 steel version, a 931 stainless steel version and a titanium version. Only the chrome steel frame is currently available as a complete bike, but the others can be bought as frame sets for custom builds. The 931 stainless steel frame set is £2,499 and the titanium frame set is £2,699.

Genesis Croix de Fer 20

The Croix de Fer 20 is the complete build you can buy now. It pairs the steel frame with a 2x10 GRX cable-pull drivetrain and TRP disc brakes, and it is not the cheapest bike in its class.

On the road it makes its case through behaviour rather than weight. A four-hour ride in Wales, mixing fire roads with more technical singletrack, left the impression of a bike that felt solid, comfortable and happy to keep going all day. It will not rival a carbon frame on the scales, and the geometry is slightly more aggressive than a race gravel bike or something close to cyclocross geometry, but it stays well short of extreme. The overall feel is planted and dependable, the sort of bike that flatters rough surfaces and encourages you to ride whatever is in front of you.

There is also a practical point about how Genesis sells. The brand works with local dealers rather than going direct to consumer. That may be part of why the price is higher, but it means the warranty and any problems are handled by a shop that knows you, which is worth something when something goes wrong.

Buying Advice

Start with the job the product has to do, not with the specification. If you are buying an e-bike, the single most useful decision you can make is to buy a complete system from a reputable manufacturer through a bike shop, rather than a very cheap bike or a conversion kit. The battery is the part you cannot easily inspect, and it is the part that matters most.

With shoes, ask whether you want a shoe for riding or a shoe for the day. The Velosamba is stiff and iconic and best kept for the bike and short walks. The Transit is softer, more flexible and designed to be worn all day, which is why it costs more. The Odyssey is a camp shoe rather than a cycling shoe, and it is competing with insulated camping footwear that costs a fraction of the price.

With the Croix de Fer, the choice is between a complete bike and a frame set. The Croix de Fer 20 gives you a ready-to-ride steel gravel bike with a sensible parts spec. The 725, 931 and titanium frame sets are for riders who already know what they want to bolt onto a frame and are happy to build it themselves.

Conclusion

September’s list is a good reminder that the interesting questions in cycling gear are rarely about headline numbers. Battery safety comes down to whether a manufacturer has designed a system rather than assembled parts. Casual cycling shoes come down to how much flex you are willing to give up. And a steel gravel bike comes down to whether you want a machine that is light or one that feels planted all day. None of those answers are universal, but they are all worth asking before you spend.