Review: Gepida Rodanus 1000 Yamaha tandem (mid 2012)
It's the first electric tandem we've ever tested, and one of a very few on the UK market. So how does the Gepida Rodanus 1000, with its Yamaha power assist system, match the demands of two-up riding? Read the review in full.
Posted by Peter Eland on Thursday 6 Sep 2012
This review appeared in Electric Bike magazine Issue 5. You can download it as a high resolution PDF. Or click the viewer below to read the review with the original print layout - or scroll down for the full text and images online!
Gepida Rodanus 1000 Yamaha tandem
It's the first electric tandem we've ever tested, and one of a very few on the UK market. So how does the Gepida Rodanus 1000, with its Yamaha power assist system, match the demands of two-up riding?
Tandems are a relatively specialist area of cycling, with the numbers sold small in comparison to solo bikes. Yet it is a niche with enduring appeal, offering a uniquely sociable riding experience to couples, friends and families. It's also a great way for riders with visual impairment or balance problems to enjoy the benefits of cycling, and for pairs of riders of even very differing strength to tour together.
On the downside, tandems by their nature are awkward to transport and bulky to store. Failing a van or a motor-home large enough to fit the bike inside, a car roof rack is the usual solution: on the best ones you can attach the tandem at ground level then swing it up via a spring or hydraulic mechanism. Just do a web search for 'tandem roof rack' to explore the options.
Tandems do also tend to be expensive, partly because of the lower numbers in which they're made and partly also because they have to be made robustly to cope with the weight and strength of two people. This puts demands on frame and wheels in particular, while the brakes must also be designed to handle the weight of two riders on descents.
Electric assist is a fairly new concept to tandems, presumably because it's such a niche market. The only other electric tandem on sale in the UK is I believe the £2100 Pedego Tandem, which is very much a cruiser-type machine, rather than a tourer like the Rodanus. There's also a Panasonic-powered tandem from Flyer in Switzerland, but it's not sold in the UK as far as I'm aware. Some users have fitted kits to existing tandems too, of course.
This Gepida Rodanus retails at £2199 via importers E-bikesdirect, who have bases in London and East Sussex. Gepida themselves are a well established e-bike maker from Hungary; we reviewed their 'Reptila 1000' in Electric Bike Issue 1. This machine was the first sample of the bike which E-bikesdirect have received, and they say they'll request a number of changes to future machines in response to some of the comments I've made in this review. Gepida also offer the machine with the Bosch electric assist system (at a rather higher price), and E-bikedirect can obtain that too.
There's a two year warranty on the whole bike including battery (that it retains 70% of capacity after that time), and spares currently cost £449. The Yamaha system is well established worldwide so future availability should not be a problem.
If you register on the Gepida website the frame has a lifetime warranty, too.
» ON THE BIKE
The Rodanus is an imposing machine, with its oversized aluminium frame looking well up to the task. A single frame size is available, measuring around 54 cm at the front and 45 cm at the rear (bottom bracket centres to top of seat tubes). It's good to see mounting points for three bottle cages on the frame, plus a neat set of mudguards ready-fitted. There's also a Pletscher rear rack: not a super heavy duty touring model, but fine for general use. At the front is a midrange Suntour suspension fork, with a lockout function and relatively short travel (around 50 mm), so very much for on-road comfort rather than any serious off-roading.
The key feature is of course the Yamaha power assist system, which in typical crank motor fashion is built into the frame at the front rider's bottom bracket.
The Yamaha crank drive system.
It's a torque sensing system, which responds by multiplying your pedal input with assistance from the motor. But unlike the version we tried back in Issue 1, the Rodanus's system also has a speed sensor, which in this case comes in the form of a sensor attached to the hub of the front wheel. As we'll see when riding, this has the welcome effect of freeing the system from the need to cut out at a particular pedalling cadence (rotations per minute) to comply with legal speed limits - one of our complaints last time.
The battery pack clicks out of the bike in an instant once unlocked; the charger supplied is a 'dock' type into which the battery slots, so you do have to remove the pack for charging. The pack itself is rated at 26V, 8.2Ah, giving a capacity of 212 Wh.
A simple handlebar control gives a display of battery status and allows you to select the power assist level.
The wheels are 700c (28") sized, built with heavy box section rims with 36 spokes, and with the standard 135 mm axle width at the back. Some tandems use more spokes and wider spacing, but 36 and 135 should be fine for normal use - and will make spares availability easier.
The front hub is actually a Shimano hub dynamo, providing power to the LED lights front and rear. The Yamaha speed sensor disk was a very tight fit here - it would just squeeze up against the dynamo connector, squeaking at low speed until I gave it a drop of oil to ease the contact between the two surfaces. This will likely be fixed in future bikes.
A hub dynamo in the front wheel, with the Yamaha speed sensor on the right.
At the back is the SRAM DualDrive hub, which combines a 9-speed derailleur cassette with a three-speed internal hub gear. This is a tidy and well-proven system which has been around for many years now, and it makes a lot of sense on the Rodanus.
A basic steel carrier rack is fitted, complete with spring clip, light and pump.
Tandems do tend to need a wide range of gears; they're fast on the flat (with around half the wind resistance, but twice the power) but are typically slow on hills (perhaps because the two riders can never perfectly coordinate their efforts).
So normally a triple chainring is used along with the rear cassette, with the connecting chain to the front rider running on the left hand side of the frame. Here, the connecting chain from the Yamaha runs on the right, so there's not really space for multiple chainrings, but the hub gear gives back the extra range.
The transmission runs down the right hand side of the bike.
The range is set a little high overall for my taste, but then again the electric assist should remove some of the need for really low gears.
Both wheels are also equipped with 'Stroker Ryde' hydraulic disk brakes from Hayes, with 160 mm rotors front and rear. Generally tandems tend to use the largest disk brake rotors available, typically 203 mm, for extra heat dissipation on long descents. But if you avoid extreme descents the stock disks should be just fine. If you do want more braking, upgrading to the larger rotors would be fairly straightforward for a dealer.
It's definitely a good idea for any tandem to have three brakes, and here a further backup V-brake working on the rim of the rear wheel, and operated by the rear rider, is provided as backup.
The brake levers are rather impressively designed, and along with the polished metal levers of the gear shifters, the electric assist control and the adjustable stem it all gives the front handlebars a very high tech look. The front rider also has super-comfortable Ergon grips with great palm support and built-in mini bar ends, for a comfortable hand position gripping the ends of the bars.
The front handlebars have a hightech look, with the Hayes brake levers and Ergon grips.
On our bike, the rear rider isn't so lucky: their grips are round and hard. It was also tricky to raise the handlebars high enough for a comfortably upright riding position: a telescopic type stem would help here. Both of these improvements (telescopic stem and ergonomic grips) will be in place for future bikes, say E-bikesdirect.
Also, although both saddles are wide and squishy, it was surprising on a 'comfort touring' tandem of this quality not to see a suspension seatpost at the back. Because the rear rider can't see and anticipate bumps, and is right over the rear wheel, riding at the back of a tandem is known to be 'harsh', so suspension seatposts are pretty much standard. Again, E-bikesdirect confirm suspension will be fitted on future bikes.
Finally on the niggles, I'd liked to have seen a more substantial clamp on the front rider's seatpost. With the rear rider's handlebars also attached to it there can a lot of leverage twisting it around, and it moved several times during the review, mostly while pushing the bike. A solid Allen key clamp might be better than the quick release one supplied. E-bikesdirect are looking into changing this, too.
The weight of the machine, at around 31 kg, is very reasonable for a machine of this type.
» ON THE ROAD
The Rodanus feels commendably rigid on the road, and the front rider gets plenty of control through those wide front bars. It felt solid and stable up to any speed we could manage, even downhill. The brakes were good if not stunning, but being brand new they were still wearing in. They're certainly smooth and give good fine control. The gears also performed well.
So how does the electric assist fit into tandem riding? Well, it immediately throws up an interesting state of affairs. Because there's a freewheel built into the Yamaha drive, the two riders' cranksets are not linked firmly together as they are on a traditional tandem. The front rider can freewheel at any time, leaving the person at the back to pedal on alone. Not that I would, of course.
This also means front and rear pedals aren't 'in synch' automatically, and each rider needs to move their own pedals round into position before setting off (usually the rear rider can do that for both). It's just a minor adjustment to standard tandem technique and we were quickly used to it. Equally, the extra freewheel didn't seem to affect the 'communication' between front and rear riders - after a while the back rider learns to start, stop and ease off during gear changes instinctively, sensing the front rider's intention through the drivetrain.
A simple control console operates the Yamaha electric assist system.
Anyway, from the first instant of pedalling the electric assist kicks in, giving a welcome boost to get you up to speed. It's smooth and intuitive, and the system cuts in and out fast enough to make easing off for gear changes simple, too. As I mentioned it's great that there's no cadence related cut-out: you can pedal as fast as you like and the motor will keep helping, up to the 15 mph legal limit.
I did find, though, that the fairly muted noise of the motor became harsher and louder as we pedalled faster, and this tended to encourage a relaxed pedalling rate under power.
On the flat the tandem would roll past the 15 mph power assist limit quite easily, and we'd then be riding unassisted. It goes well for a tourer, and then as the speed drops on any sort of gradient or into a headwind, the electrics provide some very welcome relief.
The Rodanus seems made for holiday and leisure riding use, where speed isn't the object but riding without strain is. In this role it works very well; the electrics taking care of any 'peaks' of effort while not adding undue weight. Unless you're in the saddle all day in the hills you're unlikely to exhaust the fairly modestly sized battery; it took us on a 30-odd mile ride with plenty of capacity remaining, but we were pedalling a fair bit.
The Yamaha drive system is much improved by the speed sensor, and responds well, offering an intuitive feel to the power assist. Working through the gears, it can help you up most hills, and it really does take the hard work out of ascents or headwinds, especially if one or both of you is flagging a bit towards the end of a ride.
The battery is looking a tad small by today's standards, perhaps, but the efficient nature of the torque-sensing drive means range should be adequate for most - it only tops up your own efforts rather than replace them. Also, on the flat at least, the extra speed of a tandem means you'll be above 'assist speed' much of the time.
The Rodanus's bicycle specification is fine for what it is, a leisure/ touring tandem. Tandem nerds like me will certainly find areas to upgrade, but for leisure riding it should easily suffice.
The few slightly puzzling design decisions around rear rider comfort will all be fixed by the importers E-bikesdirect, so they won't be an issue for future bikes. The front rider, meanwhile, is treated to a very nice set of handlebar controls for brakes and gears.
At £2199 the Rodanus is a substantial investment, but as quality tandems go - let alone electrical ones - that price is not out of order at all. The warranty also ticks all of my boxes, with a well defined battery guarantee, and the lifetime frame warranty as a bonus.
As with any tandem, it's a machine you really should test ride as a couple before deciding whether it'll suit you both, but if it does it could bring a unique togetherness, and effortlessness, to your cycling.
SpecificationWeight overall (inc batteries): 31.2 kg
Battery weight: 1.89 kg
Bike only weight: 29.30 kg
Charger weight: 1.00 kg (inc. mains cable).
Battery type: Li-Ion.
Battery capacity: 212 Watt hours (8.2Ah 26V).
Gearing: 9-speed derailleur gear plus 3 range hub. 48T ring, 12-32T sprockets. Ratios 30-147".
Brakes: Hayes Stroker Ryde 160mm hydraulic disks front and rear.
Lighting: front LED, rear LED.
Other accessories fitted: mudguards, carrier rack, stand, bell.
Price as tested: £2199.
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