Dekra D-Drive bike trades the chain for direct-drive

Anyone who's ever gotten clothing caught in their bicycle gears and been sent tumbling to the ground with a shredded pant leg will surely appreciate a new bike that ditches the derailleur in favor of a safer, cleaner, lower-maintenance direct-drive system. Just introduced Stateside by importer Dynacraft, the Dekra D-Drive bike uses a drive shaft to transfer power from your pedal-pumping legs to the back wheel, and includes a fully enclosed bevel gear system from Shimano to ease your load on those uphill climbs. Of course, with only three gears (changeable through a twist of the handlebar), this model will never be seen cruising victoriously down the cobbled surface of the Champs-Elysées at the end of a Tour de France, but at $300 it seems like a reasonably-priced way to roll around town hassle-free.

[Via Gizmag]

[John @ Jun 21st 2006 9:10AM]

glad to see this tech coming stateside, although the price is something of an aversion - a brand new bike using new tech for $300 can't be too high in the quality department.

let's see some conversion kits.

[Zamosa @ Jun 21st 2006 9:11AM]

Direct drive bicycles hvae been around for ages. I'm not talking last year, I'm talking decades ago. I wonder how this manufacturer got so much press for coming out with a new product that isn't new?

[Blue @ Jun 21st 2006 9:16AM]

Direct drive is not a new technology. It was used almost 100 years ago and abandoned.

NO bike shops will work on them, and finding parts for the drivetrain is impossible.

300$ for a 3 speed piece of poop with non-standard, unservicable parts??? No thanks.

You can get a 24 speed hybrid from Giant or Trek for that same kinda money. And those bikes will last alot longer.

[Lloyd Hobden @ Jun 21st 2006 9:20AM]

Heard of a bash guard? Stops the your trousers getting caught up (as well as primarily protecting your chain rings!).

Not going to be of much use with full-sussers yet because thins thing's not going to allow for any chain growth.

Hopefully one day it will become a good solution for 'proper' bikes but I guess the casual rider can benefit from not getting greasy trousers until then!

[Dan @ Jun 21st 2006 9:34AM]

Does anybody make an electrical power transmission. So the pedals turn a generator and that generator powers a motor at the rear (or front) wheel

[James @ Jun 21st 2006 9:36AM]

Blue, you sound a lot like the guys in the VOIP comments who work for a Telcom co. Do you work in a bike shop?

LCD? What's wrong with my CRT?

[chris @ Jun 21st 2006 9:37AM]

has something new happened in shaft drive tech? last i knew there was some serious energy loss in the multiple gearboxes

[chris @ Jun 21st 2006 9:45AM]

Dan: there's a HUGE loss in power in electrical generation. not to mention you'd have to add about 15-20 lbs is stuff to even make it work at all, that's more than some bike weight to start with!

[daaper @ Jun 21st 2006 9:51AM]

jeep debuted an AWD bike a loooong time ago that used a drive shaft for the front wheel. they said it's the "first of its kind". I'm assuming they meant about the AWD part, not the drive shaft -even then, i'm not sure it's the first. but anyways...

http://www.i4u.com/article443.html

http://www.amazon.com/gp/product/B0007W2FOU/ref=nosim/002-0650482-5969667?n=3375251

[Paul @ Jun 21st 2006 9:58AM]

http://www.vcasa.net/bike/

[blah @ Jun 21st 2006 10:37AM]

Hm... Granted, it's not the greatest bike in the world.

Still, I may get one each for my spouse and I. If you replaced the seat/seat post, stem/handlebars, forks, rims/tires, and get rid of the rack, it might make a decent crusier. Certainly better than taking-out my $3000 mountainbike every time to ride.

[binaryvisions @ Jun 21st 2006 10:50AM]

Um, I want to see some numbers to back up the claims of "higher efficiency".

A chain based drivetrain like we run now is VERY, VERY efficient. As efficient as any mechanical system around.

I'm not an engineer, but isn't one of the main power losses in any drive system from changing the direction of the power? Which is why a rotary engine is so efficient? With a chain based drivetrain, you have a directly driven rear wheel in the same direction as the power being generated. This has to change the power's direction twice.

This is fine, and there have been other AWD bikes on the market that have used drive shafts, but I don't see the chain based drivetrain being replaced anytime soon. It's just too damn efficient.

[tr @ Jun 21st 2006 11:05AM]

the biomega copenhagen, which uses a shaft drive, has been around for some time now. okay, it's not $300 like the dekra. i guess it is good to see the tech trickling down to less expensive bikes.

http://www.biomega.dk/biomega.aspx

[delta5 @ Jun 21st 2006 11:08AM]

uhm, slacker?

"...they are very much unserviceable but provide the benefit of higher efficiency, less wear (system is completely enclosed from elements), and slightly faster response when pedaling..."

Not true. The most mechanically efficient power transfer is via chain-drive. The shaft drive will have crown/pinion gears which have high friction. Well maintained chain and cogs give nearly 0 friction.

If shaft really was more efficient, you'd have to ask yourself why Lance Armstrong's $6800+ Trek TTX is chain driven. Nearly all race bikes, road and mountain, are chain-drive. Jeep's and Christini attempted shaft and rotational cable drive, and Jericho used/uses a belt drive system. Neither have taken off.

http://www.christini.com/
http://www.mtbr.com/tradeshow/interbike2001/jericho/
(Jericho Bicycles currently does not have a site)

[delta5 @ Jun 21st 2006 11:10AM]

damn, binary, you beat me to it...

[starpause @ Jun 21st 2006 11:27AM]

having everything enclosed would be great for winter riders. i haven't been through a winter where i DIDN'T have to replace my chain along the way.

on the other hand, i love my fixed gear, and i'm not giving it up just to avoid buying a 10$ chain :)

[ian @ Jun 21st 2006 11:35AM]

I remember when I was a bike messenger that I used to hang out in bike shops on slow days, and one day someone came in with a shaft driven bike. It's a good gimmick, but completely pointless. A roller chain can, under ideal conditions, have an efficiency of up to 98% (http://www.hw.ac.uk/mecWWW/research/mdk/res.htm).

For the record, Jeep's bikes are crap. Christini makes decent 2WD bikes, but I can only really see them being useful if I was riding across the Sahara or the Arctic. When mountain biking, most of your weight is on the rear wheel during pedaling. And yes, I mountain bike a lot.

[matt @ Jun 21st 2006 11:47AM]

aside from the efficiency loss, I'd be concerned about the max torque that can be transmitted through the shaft... the gearbox on either end doesn't look large enough to me, especially knowing that I've put enough torque through my chains to break several of them on different occassions...

[Robert @ Jun 21st 2006 1:18PM]

True, while this may never see light in a normal stage race in any pro-peloton, technology like this could be benificial in Time-trials. While weight may be a considerable trade, fully-enclosed is the trend with the highest-tech TT bikes so getting rid of chainrings and chains could be quite a plus.

[Kevin @ Jun 21st 2006 1:53PM]

Ian, Christini bikes are the same as Jeep bikes, just re-branded, as far as I know.

Yes as all the rest have said, old news, and in my opinion shaft drive blows. If you want true biking advancement look at the Nicolai G-Boxx and similar technology; they enclose 7 or so gears inside a closed unit, like a car's transmission. 21 or 24 gears or whatever is highly unnessesary as 5 or 6 of them are either geared too high or too low, another 5 or 6 of them being to close of ratios to be a difference, and another few being the same ratios.

[asurroca @ Jun 21st 2006 1:57PM]

Wow, this is the best thing ever. I HATE it when my chain gets stuck like once in a blue moon! (rolleyes)

[neale @ Jun 21st 2006 3:18PM]

tuck the inside of your trouser leg into your sock. problem solved

[aiden @ Jun 21st 2006 3:34PM]

dynamic bicycles offers shaft-drive 9-gear bikes and offroad bikes for $500.

http://www.dynamicbicycles.com

[delta5 @ Jun 21st 2006 4:46PM]

kevin, I believe the Nicolai G-Boxx bikes are based around the Rohloff SpeedHub, which is 14 speeds:
http://www.rohloffusa.com/frame.htm

Still, lower efficiency with all the gears. Same idea as the G-Boxx concept, but more efficient is the Honda Downhill bike. MTB Action magazine did an article about it a while back, it's just the standard bike gear cluster, but inside a carbon fiber box instead of at the back wheel. (I wish i could find the pic, but I'm at work)

[KWillets @ Jun 21st 2006 5:30PM]

IIRC Major Taylor rode a shaft-driven bike.

[Julie Chadwick @ Jun 25th 2006 9:46PM]

I don't care whether you guys think this is old or new--my car had had a similar drive for years. All I know is that if they can make this thing with some super-light metals, it would be a sweet substitute for the old (ball and) chain.

[Mark @ Jun 26th 2006 2:58PM]

Chainless bikes are fun to have. This one is offered at a great price.

[Megan @ Jun 28th 2006 2:39PM]

Dan, if any bike had any sort of motor, even if it was powered through a generator you'd have to have a license for it.

Otherwise with this bike making things easier, I wouldn't go for it. A standard bike gives me exercise, and going up hills is where you get most of your exercise from bikes.

To solve the pant leg problem, I just wear shorts.

[albert @ Mar 3rd 2007 8:52AM]

What a bunch of professors together.... But has any of them actually ever been on a bike with shaft drive? Also I don't understand why somebody would want to make a comparison between shaft drive bikes and Lance Armstrong's bike, it's totally pointless. I own a Biomega Copenhagen myself. Yes, I know it is heavier than a chaindrive bike, and yes I know it is less efficient than a chaindrive bike. This doesn't mean that I move along like a slug however, the only times I'm being overtaken is by a guy on a racebike in full race clothing. For me the Copenhagen looks brilliant and drives excellent. I've been driving it to work all winter (15 km. a day)and didn't have to service it once. Now with spring coming I only need to hose it down and check the brakes and that's it. And I know I shouldn't take it offroad, that's not the purpose of a bike like this. But for what I need it for it is brilliant!

[rhodabike @ Apr 1st 2007 9:18PM]

I agree, Albert. I have a lightweight road bike, a touring bike, and even a track bike (not used much any more, admittedly), but I'd consider a shaft drive bike for city commuting. I could pedal down to the pool to swim laps at lunch time without having to change out of my office clothes. (And I'm sorry, but tucking a pant leg into a sock is so... geeky.) Chain drive is efficient - if the chain is nice and clean and well-oiled. Not being a complete gearhead, I'm just not interested in spending hours each week cleaning a mucky chain.

[Grunchy @ Dec 9th 2007 7:27PM]

The G-Boxx looks interesting, like a super-duty alternative to the Shimano Nexus. For ordinary cycling I'd choose the Nexus. If I was into downhill racing I might have the G-Boxx.
I looked into the Copenhagen, Awesome!!! Performance penalty (apparently) is about 5% higher friction, but that is relative to a well-maintained chain. I maintain my chain about once a year, if that, so I suspect the D-drive is actually more efficient. My drive train on my road bike is toast, the chain is all stretched out and my pinecone is pooched (after several thousand km), same as on the Merlin. So much for that idea. See, the trouble is the chain is a greasy gritty piece of grub that I don't even want to look at. You think Lance deals with his chain? He has mechanics who put gloves on and that tune his ride to the nth degree before each and every ride. His bike is a sewing machine, mine is like a trusty dusty rusty Chevy. For example, I put Greentyres on it because I don't want to deal with flats. Sure the ride is a little bit harsh (pfft! like riding a cloud compared to Lance's bike) and the rolling friction a bit higher, but I can head out to the mountains without a spare tube & pump. That's the appeal of the D-drive. It's not for everyone, it's not for racing particularly, but then guess what I'm not a racer!!
One thing about the Copenhagen, it has two chain stays plus the shaft drive tube, it looks a little awkward. The Dekra D-Drive eliminates one chain stay and puts the shaft drive in its place. Ahhh... so much better. I hear changing a flat is much harder on a shafty, oh rats looks like I'll have to spring for another set of Greentyres. Oh well!

[Morpheous @ Jan 3rd 2008 2:00PM]

Dan, SRAM makes one, the "SPARC", a rear hub that stores power and delivers power assist for hills and other inclines. It wieghts a bit, but will do what you are asking.

[richardb @ Apr 19th 2008 1:09AM]

I have had two shaft drive bikes for hte past 6-7 years, and combined I have covered ~10,000miles on them.
They are no match for my race bike in terms of efficiency or weight, but for a bike I can hop on and ride any time of the day/night or year it's hard to beat. (they are fitted with decent mud guards and dynamo lights also).