This week we've been in Lille at the headquarters of sports giant Decathlon, to take a look at their new range of electric bikes. And we've come away impressed: there's some well specced bikes that offer a good ride experience over a range of prices. There should be one to suit your pocket.

Decathlon have been making e-bikes for a while but the 2017 range is a bit of a reboot: the bike models in the city range have been designed from the ground up to work as either standard, non-assisted bikes or as electric bikes. There are three new e-bikes for this year. At the budget end is the elops 500e, which is a steel-framed city machine with a 24V hub motor system for just £599. The next bike up is the elops 900e (£949), which gets an alloy frame, cable discs, 36V hub motor system, LCD control and a suspension fork. The top-of-the range elops 940e (£1,699) has the Shimano STEPS mid motor system, a 10-speed Shimano Deore drivetrain and hydraulic discs. We took to the slightly damp a drizzly streets of Lille to give the bikes the once over.

B'Twin elops 500e £599

Six hundred quid is about as low a price as you'll find for a fully specced e-bike, short of pledging some cash to a crowdfunded start-up, which tend to offer serious discounts as an incentive to get the production ball rolling. 

All of the three new bikes in the B'Twin e-bike range are available either as a step-through or a diamond frame. To save money in production the elops 500 uses steel instead of alloy for the frame and fork, and is available in one size only. One thing that the three bikes share is an integrated light built into the head tube of the frame, with a rear light integrated into the rear mudguard.

The lights on all three bikes are powered from the battery (on the non-powered versions of the bikes they're dynamo-powered), and in the case of the elops 500 the 24V motor system is controlled by an LED controller that's the same in design and layout as the TranzX unit we saw on the £799 Pulse ZL-2. That's no bad thing as it works pretty well, although the way that it cycles through the modes is a bit of a niggle. Pressing the mode button cycles from eco up to sport and then back down again, rather than starting again at eco. That means if you're in normal mode you're never quite sure what pressing the mode button will do. It's hardly a deal-breaker, mind.

The battery sits in a custom steel rack that's part of the frame structure rather than being bolted on. At 210Wh the battery isn't huge, but you wouldn't expect it to be on a bike as cheap as this, and you'll still get a useful range out of the elops 500, especially if you're judicious with the use of the higher power modes when you don't need them. B'Twin suggest 30-45km is achievable, which it probably is on the flat. You'll need to be a bit more on the ball with your charging strategy than with a higher-capacity bike but it should be fine for most people's commuting or shopping trips.

Is it an enjoyable bike to ride? Yes, it's simple and pretty effective. The steel frame and lower-spec equipment make it fairly heavy but the rear hub motor is eager, especially in sport mode, and there's not too much lag from the pedal sensor before the power kicks in. The position is good for city riding and there's plenty of distinction between the modes. On the elops 500 and elops 900 only the highest power mode assists you up to the 25km/h legal maximum (and a bit beyond, if we're honest, with B'Twin making maximum use of the 10% wriggle room in the rules). The lower power modes cut out at a lower speed. That may or may not suit you: if you're doing slow, short runs around town then it'll work out fine, but if you've got a longer trip to do and you want to conserve the battery it's a bit restricting. The elops 500 has a comfortable saddle and grips, and we happily rode around for a couple of hours on the bikes without anyone complaining, so it's not restricted to short hops.

For £599 you're getting a decent spec: The Shimano Tourney 6-speed derailleur gears and alloy V-brakes work fine, and you're getting everthying you need for city riding as part of the package: chainguard, mudguards, integrated lights and a kickstand are all included. If you're after a cheap city bike that'll give you a bit of help on the hills, there's not many cheaper than this, and it's impressive considering what it costs.

B'Twin elops 900e £949

The next step up is the elops 900e, which is a very similar-looking bike but different in pretty much every respect. The steel frame is replaced with an alloy one, and you get a suspension fork to smooth the ride at the front. The V-brakes are swapped for mechanical discs, and there's an extra gear available from the Shimano Altus 7-speed drivetrain. Even the light, which looks the same, is brighter.

The change that makes up most of the cost difference between the two bikes, though, is the motor system. It's a 36V motor that's more powerful (30Nm of torque compared to 26Nm), and it's mated to a battery with almost twice the capacity: 418Wh. That should be good for a week or so of an average commute, with B'Twin suggesting 40-70km as the range on a single charge. The display is much improved too: you get a LCD bar unit that gives you a speedometer, detailed battery information and easy access to the three assistance modes. There's a walk mode available, as there is on all three bikes.

Again, the elops 900 is an easy bike to ride, sharing a very similar ride position to the cheaper elops 500 and the same comfy grips and saddle. The suspension fork is pretty basic but took a bit of sting out of the Lille cobbles and wasn't too susceptible to flex under braking. The motor is punchy, especially in power mode, happily firing you up to the assistance limit. The lower modes are well separated with the eco mode offering only the gentlest push and cutting out at about 18km/h.

Riding the step-through version of the bike after the diamond frame revealed just how much work that top tube is doing in keeping the bike stiff: step-through frames tend to be a bit susceptible to side-to-side flex and this elops 900 is no exception, although for the kind of riding you're likely to be doing on a bike like this it won't be a problem.

B'Twin elops 940e £1,699

The top bike in the B'Twin range, the elops 940e is the first bike that the company has made with a mid motor and they've chosen to go down the Shimano STEPS route. The bike is very well considered and the overall look is understated and classy, putting me in mind of the Koga E-Nova that I've reviewed in the past. The elops 940e has an alloy frame with integrated rack, and shares the same suspension fork as the cheaper elops 900e. B'Twin use 700c wheels for all three bikes, which this model getting uprated Schwalbe Energiser tyres.

All of the components on the bike should be reliable and give a long lifespan. Shimano's Deore 10-speed transmission is excellent, with plenty of gear range if you live somewhere hilly. The Tektro hydraulic disc brakes offer reliable stopping in all conditions. Again, you get integrated lights that are plumbed into the Shimano system's 400Wh rack-mounted battery.

The STEPS mid motor is a well-established unit now. It puts out 50Nm of torque and the more intelligent torque-sensing system means you can eke more range out of the battery which is the same size as the cheaper elops 900e. B'Twin state the range as 50-90km which, given what we've had from Shimano STEPS bikes in the past, is realistic.

The elops 940e felt very composed on the Lille streets. The better weight distribution that you get from having the motor in the middle of the frame was apparent, making the bike feel less back-heavy and more stable. The cheaper hub-motor bikes are by no means bad in that regard, but this bike was the best in terms of the feel of the ride. Both the elops 940e bikes we were riding had Selle Royal saddles but pretty much everyone agreed that the cheaper own-brand saddle on the other two models was actually more comfortable, so production bikes may come with that.

The most noticeable difference between the hub motors and the STEPS mid motor is that there's no lag at all: push away from the lights and the bike's immediately helping you. The application of power is smoother across the range of speeds, with the STEPS system offering assistance up to 25km/h in all three modes, which I prefer.

£1,699 is a keen price for a STEPS mid motor bike, and there are no compromises in the build, with a solid transmission, brakes and finishing kit. You get the addition of a frame lock on the elops 940e as well as the mudguards, rack, chainguard, integrated lights and kickstand. So the bike is ready for city action straight out of the shop.

Overall I was very impressed with the three bikes, which are offering good performance across a wide range of budgets. B'Twin warranty all their metal frames for life; the motor systems come with a two-year warranty and B'Twin also commit to keep batteries for their e-bikes in stock for at least seven years from the release date, so if your battery eventually dies you'll still be able to pick up a new one.