Jezken Prototype Gearbox DH Bike - The Interview

Nov 6, 2010 at 21:39
by Mike Levy  

While there are some great production bikes out there, sometimes the most interesting machines are made on a small budget and by only a few people. Australians Jeremy Sherwill and Kendal Judd are a shining example of what happens when you mix together equal parts determination, vision, and know-how. The result is their Jezken gearbox DH bike.

Inside you can check out photos of the bike and read a great interview with Jeremy about the design.





Jezken Prototype Gearbox DH bike


The Jezken looking ready for action.
The Jezken looking ready for action.


The who's, what's and where's. How many people are behind Jezken and where are you guys based out of?

Initial inception of the idea was mine (Jeremy Sherwill) whilst I was studying Mechanical Engineering at university in Melbourne. One of my good buddies, Kendal Judd, came on board and we set about designing the bike for our final year project. Like a lot of companies do, we just used our names to come up with a brand - Jezken. We have a couple more people giving input to the project now, but it is definitely still my baby. We don't have a fixed location at the moment, but most of the work is done in a little town called Albury/Wodonga which lies on the New South Wales and Victorian state borders in Australia. I worked for an engineering company called Omega Technical Engineering which gave me access to some pretty expensive CNC machines to get the job done.


I'm not going to lie, I've not heard of Albury or Wodonga. Good riding nearby?

This area is pretty important to me, my parents live there and my Dad, who is also an engineer, has become more involved as the project has progressed. Our team riders are also nearby. There are quite a few good tracks around the area we test on. Most of the riding gets done up at Mt. Beauty, an Australian Nationals track that has a really good mix of terrain to ensure everything is working smoothly.


It sounds like somewhere I should escape to during our wet and gloomy B.C. Winters. Back on topic though, why design your own bike?

The initial idea came from having some time on my hands, I like to work on something in my spare time. I did a lot of reading and researching of what is out there and how it could be done better. I know that what we have, even as a prototype, is a whole lot better than a lot of bikes out there. We are both passionate about riding and being able to work on a project that you are really interested in makes it so much more rewarding. So far Jezken has been a side project to work and university, but we would love to make it a full time profitable venture. Luckily I had the opportunity at school and work to have access to a CNC machine and taught myself to use it. Apart from welding and heat treating, we designed and manufactured everything - from manufacturing jigs to the actual frames. We have learned a lot from the first few revisions and the time required to make new bikes should go down quite a bit.


The Jezken uses a low and centrally mounted gearbox that allows the bike to have as little unsprung mass as possible which lets the rear wheel respond quicker to the terrain. The bike sports 8
The Jezken uses a low and centrally mounted gearbox that allows the bike to have as little unsprung mass as possible which lets the rear wheel respond quicker to the terrain. The bike sports 8" of rear wheel travel from a standard 3" stroke shock and features geometry that allows head angle adjustments from 63 degrees to 65 degrees as the course demands.



I know that it's still the early days, but the bike looks great. What are the details?

We are up to the 3rd revision of the frame and the crucial details of the latest bike are:

• 8" of rear wheel travel
• An adjustable head angle from 63-65 degrees. The bottom bracket height is nice and low, but the actual specs for that are under wraps at the moment
• We decided on a linkage driven single pivot from the start as it allows a lot of adjustment of the leverage ratio to fine tune suspension performance and works well to incorporate a gearbox
• We are using a 3" stroke, 9.5" eye-to-eye damper. Providing an overall leverage ratio of 2.6, however the leverage ratio changes through the travel due to the linkage
• We have been developing the bike with Fox suspension, both the DHX 5.0 and RC4 dampers have been working really well - it's all in the shock setup
• You will notice that the chain actually runs through the swingarm, the design just ended up going this way purely for structural efficiency. It works well as the chain is tensioned and makes for a neat and unique looking rear end.




Gearbox bikes are known for generally being a bit weighty. How much does the Jezken weigh?

Internet forum weight weenies aside, performance is really what matters in the real world of racing. The overall package weighed 19.5kg (43lbs) the last time we checked.



But there is a lot more to a bike than just its total weight...

Low weight was definitely one of the objectives, but the biggest issue for performance is unsprung to sprung weight ratios and center of mass. This is where the Jezken really excels and anyone who has ridden the bike can really vouch for this. Without the weight of a cassette, freewheel and derailleur hanging off the rear wheel, the bike is able to track like nothing else. Our team riders have been amazed how well the bike works. Also, the majority of the weight is sitting in the gearbox which is central and low - this allows the bike to be moved around really easily.


The driveside view of the Jezken makes it look more MotoGP and motocross than mountain bike. Have a look at how the chain passes through the massive swingarm on its way to the rear hub. Although it looks like it would make a fair bit of noise, it is taut and doesn't slap the swingarm at all. The bike is said to be incredibly silent. Pivoting rear dropouts allow the chain to be tensioned by loosening the three bolts and rotating the entire unit back.
The driveside view of the Jezken makes it look more MotoGP and motocross than mountain bike. Have a look at how the chain passes through the massive swingarm on its way to the rear hub. Although it looks like it would make a fair bit of noise, it is taut and doesn't slap the swingarm at all. The bike is said to be incredibly silent. Pivoting rear dropouts allow the chain to be tensioned by loosening the three bolts and rotating the entire unit back.


How many prototypes have there been so far?

This season's race bikes are the 3rd revision, our first prototype was completed in August of last year, but due to an unfortunate accident (more on that below) we weren't able to test or race until the start of the following year. The main changes so far have been optimization of the swingarm and geometry. The first bike worked exactly how we expected so it was just a matter of building on that.



The Jezken is designed around a geabox. What advantages does this give the bike?

The main advantages as I mentioned early is low unsprung weight and centralized mass, but there are additional advantages that make gearbox bikes really unique. Low maintenance is another big plus, as well as no exposed drivetrain to get ripped off and spoil your day. Gear changes are instantaneous and silent, with or without pedaling.


And the disadvantages...

The main perceived disadvantage of gearboxes by the general mountain bike community is weight, however the bike's performance and race results so far tell quite a different story.




Using a gearbox usually means that your hands are tied when it comes to location of the main pivot, although chain growth is not an issue due to the pivot's location around the drive cog on the gearbox. Was this an issue at all during the design process?

We are actually quite happy with the bottom bracket/pivot relationship as it allowed for a slightly forward and reasonably high pivot which produces rearward axle path, but without the negative chain growth associated with most equivalent designs. As a lot of riders know, a rearward axle path allows for the wheel to move back and over square edged hits efficiently so the whole system works very well.


Which gearbox did you choose to use?
For the first few prototypes we have used a Universal Transmissions Gboxx2. From the beginning we have planned to make our own gearboxes, but it is a matter of time and money at the moment. We have dealt with Nicolai directly to order the gearboxes. As some people are aware, they have decided to stop making the Gboxx2, so that gives us plenty of motivation to get our own going. The gearboxes bolt to the frame with 8 bolts via male-female mounts (To understand this it's best to look at a picture of it). It has seven speeds and uses a twist shifter at this point in time.


Care to share some details of your own gearbox design?

Our own gearbox is really in the early stages with general layout and ideas are still being thrown around, there isn't a whole lot to talk about there.


You're a rock! Spill the beans for us...

Sorry! We have some pretty unique plans for the next revision of the swingarm as well, but can't let the cat out of the bag with that one either! You'll just have to wait...


It seems that gearbox bikes come and go without many gaining any traction with most riders. Why do you think this is?


That is a difficult question to put an exact answer to, but I think the bicycle industry is very ingrained with tradition and the derailleur has been around for quite a while now. An example of this would be carbon fiber frames in DH. As most engineers and technical minded people already know, carbon is an ideal material for DH, but it has taken one of the big players, Santa Cruz, to prove this to the masses. I think it is just a matter of time before gearboxes are common place in downhill racing. The advantages are so clear and we are definitely out to show how well these bikes can go!


The boys proudly showing off their hard work. It looks like someone spent their day at the polishing wheel! Take note of the dialed internal cable routing on this version as well.
The boys proudly showing off their hard work. It looks like someone spent their day at the polishing wheel! Take note of the dialed internal cable routing on this version as well.


I've heard that you have some fast Aussies on your bike...


Yeah, we certainly do! Liam and Joel Panozzo live in Mt. Beauty which is just up the road. I met Liam through riding and we were both pretty keen for him to race on a Jezken. He ended up winning the first race on the bike in the 09/10 Victorian State Series and went on to win the overall series title. He was pretty excited the first time he rode it. This season both Liam and Joel are riding Jezken and we are excited about how things will go.



Getting feedback from those two must be invaluable as well?


For sure. Joel has had nothing but good things to say about the bike and that means a lot coming from someone who has had a hand in developing a lot of successful bikes. Liam had quite a bit of input in refinements to this season's race bikes and it makes the process a whole lot easier. We are really stoked to keep working together, getting results, and making bikes.

The Jezken's swingarm in the early stages of life.
The Jezken's swingarm in the early stages of life.


You had a major setback that involved a kangaroo on the highway. What happened?


Yeah, old skippy thought it would be a good idea to jump out in front of us last year as we were driving back from the World Champs in Canberra... unfortunately we had the newly finished Jezken Mk1 on the back of the car. The bike's main frame was ripped in two, but amazingly we were able to still use the swingarm and some other components on the next prototype. However in the big scheme of things surviving a multi roll over at 110km/hr is a pretty sweet feeling. My buddies got out with a few cuts and I ended up with a broken arm and a pretty sore neck, as for the car... well, the pictures tell the story. At the time it was tough because all that work got destroyed without getting to enjoy it. That's all behind us now and now we don't swerve for critters!


This is the car that had the run-in with the Kangaroo. Hard to believe that anyone could survive this, let alone escape with mostly minor injuries.
This is the car that had the run-in with the Kangaroo. Hard to believe that anyone could survive this, let alone escape with mostly minor injuries.



Do you have plans to bring the bike to full production?


At the moment it is going to be a little while before going to production, it all comes down to money. I'd be lying if I said I wasn't keen to get something going. When we were drawing up concepts 2 years ago our goal was to make the bike out of carbon fiber, but time and money didn't allow us to do this straight away. This remains a big focus and I hope to get a small production run (20 or so bikes) for the next model. This would be for people I know, our race team, and still a controlled testing program. At this point I can't really comment on price for the bikes - that said, I think they will be good value for the performance you get!


Thanks for your time, Jeremy! Any shout outs to those who have given you a helping hand in seeing the Jezken come to life?


Of course! There have been many, but a short list would include my old boss John Hinrichs and Cheyne Forbes of Omega Technical Engineering, Rob Chaplin from RC Metalcraft, Geoff Sherwill for putting in plenty of hours to help make it happen, and Ken from Tekin Suspension. Thanks guys!


You can keep tabs on the Jezken bike by checking out their blog.
All photos courtesy of Jezken


The Jezken machine looks like a very sorted bike, simple and with the most weighty bits put where they make the most sense. Let's hear from all of the internet armchair engineers out there, what do you make of the bike?
Must Read This Week









187 Comments

  • + 11
 I really respect the people who are developing this bike, and the design seems very well thought out. We need people pushing the envelope like this.

To the kiddies who say "it looks like a...": There is a reason why most bicycles look the same. A triangle with room for the shock will look like this unless you mount the shock outside of the triangle or vertically. KHS, Giant, Da Bomb, Azonic, Turner, Canfield Bros, Specialized, Norco and many others have used this design or one very similar to it.

In regards to the ugly comments, why on earth would small scale designers use expensive hydroformed and manipulated tubes in the prototype stage? Once the angles are where they want them, they can use any of the offshore tubing suppliers to come up with whatever look they like. When they switch to carbon, they will have all the freedom they would like with esthetics.
  • + 6
 The voice of reason. All good points.. there are only so many ways to mount a shock, post, and fork.
  • - 1
 These guys ARENT pushing the envelope. They are using a gearbox with a bad rap which is about to be discontinued. How is that innovating?
  • + 4
 Cheers Willie1, jason21218 unfortunately you can't build a gearbox overnight - We started this in university a little over 2 years ago....and our focus was to get a bike running. Have you ridden a Gboxx? Do you know how it rides? Pretty sure 2 guys who ride at a world cup level know what's going on...
  • - 2
 The fact hat you're defensive about your shortcomings here says it all.
  • + 1
 Jason21218 your such a dick! Every prototype has shortcomings, its called development for a reason! The gboxx purpose is to utilise a similar setup to the proposed finished product so that it may be tested and improved upon. You have probably never ridden one, will never be able to and to be honest, the bike in the pictures... You will never ride it, you have not bought it so have not had to deal with its "shortcomings", so why get so angry about it? You need to settle down mate, derailleurs also have shortcomings.
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  • + 8
 If its article about "Jezken Prototype Gearbox DH Bike - The Interview" you shouldn't give on main page this photo of poor kagoo :/
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  • + 5
 nice to see all the armchair experts are still out there, similar negative reponses to when my ti gearbox bike was on here, i say good work, good to see something different and to all the detractors, spend less time on your computers and get off your arses and lets see you do better
  • + 2
 Cheers bud.
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  • + 7
 Just out of interest, how many gears has it got? (I've just read this top to bottom so sorry if I've missed it mentioned somewhere!)
  • + 5
 Just added it, thanks for the heads up. The bike has 7 speeds.
  • + 16
 please make a normal style shifter, thats the only thing i hate about gearboxes atm
  • - 10
 loving the use of sheet metal in the swing arm
  • + 0
 Aussie boys are making great bikes
  • + 1
 Looks very similar to the Millyard racing bike ..

www.pinkbike.com/photo/4888842
  • + 24
 looks like the kangaroo has broken swing arm
  • + 2
 does the bike get much chain slap, on the swing arm or is it taught enough not to touch it?

props looks sick
  • + 1
 3rd picture i think.. says the chains 'taunt' should say 'taught' but the answer is yes.. s'posed to be pretty silent Smile
  • + 4
 looks like a dhr with a heavy box on the back.
  • + 2
 looks like they took the kangaroo pic off, i guess it was to graphic
  • + 1
 PerryDH, I've been told that the bike is essentially silent when being ridden. The chain is tight enough, similar to a single speed bike, that it doesn't bang around on the swingarm.
  • + 1
 mtb1stdegree,

Generally hitting a roo head on writes off your car, but we are told not to swerve because you can fly off the rd, into on coming traffic, or do worse damage than just killing the roo.

Plus, hitting it at 100+ km's an hour (front on), there wouldn't be much of it to see.
  • - 3
 whats with the neg props knob heads? it is sheet metal... as seen in the 2nd photo from bottom where its just tacked together.
  • + 2
 the bike looks super similar to the older turner dhr
  • + 1
 idk if i like it it looks uneeck sryy for the spelling haha
  • + 1
 front triangle looks just like 2009 and earlier dhr's.
  • + 1
 Really well done... But, designing a frame is just one small part of the total package. Coming up with your own gearbox is going to require a lot more time and money.
  • + 0
 Reminds me alot of Hondas gearbox bike (Honda G cross, Honda rno1) but revised for the better.
I like it
  • + 1
 i dont thnk the bumper on the truck did much
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  • + 4
 I've been riding a G-Boxx equipped DH rig for 2 seasons now and I will never ride anything else. First because I'm deeply against the idea of a rear derailleur for DH use, 7 speeds is enough for me and I just LOVE not hearing that stupid rear derailler slapping just as if everything was to come apart. Their new twist shifter is way better than first generation and I got use to it very easily over the triggers, if you guys think you can't get use to it then you're at a very low level of riding. And besides you don't shift THAT much when going downhill, quick tip : just concentrate on trying to let off the brakes instead of shifting, you might end up going faster. And of course it's not for the broke arse guys. But, eh, whatever floats your boat. I think you gotta actually ride one and give it a chance for one complete day before saying there is no purpose for such a nice piece of german engineering.

I think the guys here on this article did a nice job on that frame guys and opposing myself to the mass here I think these welds aren't too bad, they're certainly not as consistent as a Taiwan made bike (like 97% of the guys on this website actually ride) but they're definately free of any major defects and i'm sure they're structurally sound. Nice work ! I know why you keep pushing the product, wishing you guys all the best !
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  • + 4
 Man, all you guys giving it shit need to shut your mouths. Why don't you don't you try designing and producing your own DH bike out of pocket with some new ideas that are trying to push the ordinary of whats standard in bikes today. Do that, then you can come back and have a little bitch on the interwebs about how gearboxes are shit, blah blah blah. I reckon Jeremey's done a sweet job with these frames, they look sick in person and are almost silent. If this bike can win events under the Panozzo's, then I don't see anything wrong with it.
  • + 1
 i would still never buy it because it looks like the type of bike that you wouldnt see on the world cup riden buy a podium rider- but i totaly understand were your coming from...
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  • + 7
 Do yourselves a favor and take the coffee away from the welder; he has the shakes!
  • + 1
 yea they dont look as good as they could be.
  • + 1
 That hole in the corner is what concerns me, it is an ideal place for a crack to start.
  • + 2
 Most of the pics in this article are from the first bike, we weren't happy with the welding on that bike and subsequently he was replaced by someone who could do a far better job! However as mentioned in the article the swing arm survived the car crash and was used for a season.
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  • + 3
 One Word "Prototype". I like how people are saying that it's "ugly" or that it needs smoother lines or that it needs graphics. It's a prototype!! They built it to test the technology and see what other improvements they can make. In my opinion I think it's awesome that technology has come this far to be able to put this kind of engineering and talent into a piece of art like this. The grip shift ideally would be a better alternative than just a standard shifter on the gear box. I also like the fact they eliminated the rear derailluer. To be honest when pushing the envelope you always have "trial and error". It's the same thing with music, your not going to just write a song and bam there you go. First you have to write guitar parts or get a melody then you write the rythm section (bass and drums), then you have to write lyrics. After all is said and done then you play once over or twice or three times or shit a million. If don't like a certain verse or bridge you have go back and make some changes. Same as a protoype frame. Great work I like the creativity and talent on this nice piece of machinery.
  • + 2
 Thanks mate, I think some people neglected to take notice of "prototype". Before this we had built zero bikes.
  • + 1
 Good work guys. Can't wait to see the final production of this bad boy!!!
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  • + 2
 Lovely bike, but I don't see how it addresses any of the problems that Nicolai and Diamondback UK have had with G-Boxx 2.

The complete bike is no lighter than the Sabbath was.
Using the G-Boxx means it's going to cost a bomb, which will make it a hard sell if it's going to cost a lot more than a V-10c or 88.
Still got the Dog awful pull-pull grip shifter on the bars.
Pluss the G-Boxx is hard to service.

It's a lovely looking bike, just like the Sabbath was/is an incredible piece of machinery. But with the G-Boxx it'll struggle to ever be a viable product. Why are you guys persevering with something that's already failed for multiple brands?
Surely your time and money would be better spent working out a way to adapt the derailleur in a box Honda came up with to use (more) standard parts. Road mech and a cassette doesn't need much space. Couple of hundred weight lighter too...
  • + 3
 I agree with all the criticisms but its companies like this that have brought us to the point of evolution we are at now. Without them we would still be using rim brakes. People felt this way about full suspension xc bikes and now they race world cups on them. I agree that this is currently not a viable option but at least someone is exploring the idea. Its innovation like this that pushes technology forward.
  • + 1
 I also don't see why MTB gear box's are so big and bulky , you look at the gear box on a super bike which handles over 180BHP and then compare it to the size of the ones we get to use with our 1/2 BHP maximum legs pushing power thru it , to me it makes no sense .

But yeah Gear box's are , in my opinion , are one of the only things left in MTB that are gonna make a big impact , I can't wait till they are more common place
  • + 3
 Granted, the Gboxx2 isn't the lightest or smallest thing around, but I like to think of the Jezken as more of a hint of what could come down the road. Picture the bike with much smaller/lighter gearbox, whether that is of their own design or someone else's. It's damn cool even in it's current form though.
  • + 1
 here here Mike!!
  • + 0
 check the brooklyn machine works race link frame............. www.brooklynmachineworks.com
  • + 3
 Good lord, Rectum, what the hell does that Brooklyn, which is admittedly very nice, have to do with the Jezken? You've posted that link all over this article, but the bike doesn't use a gearbox, just a conventional derailleur combined with the high jackshaft mounted pivot. It's nice, but has nothing to do with the discussion.
  • + 3
 We had to prove Geometry and function before going out and designing/building our own gearbox. It takes a lot of time to do a gearbox...I know we can do a bike that is a whole bunch lighter! This is our first one and it will definitely be evolved into something way more refined.
  • + 1
 Fair enough.

Dumb question, ever thought of using an Alfine hub as a sort-of-ghetto gearbox?
Mounted in the frame and using the centrelock mount to link a cog to the cranks. Like a Superco Silencer but with a fixed rear hub and the Alfine between the main pivot bearings. That's got to be at least worth a thought.
  • + 1
 Not really a dumb question. Yeah we did consider something like that. It is what GT did with the iT1. They found that the gear ratio spacing was quite high and not ideally suited to downhill. That said if you have seen the Zerode prototype bike they are using a modified hub type transmission.
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  • + 2
 As a prototype - very cool. Once you get the investment I can see you looking to replace box section with tubing etc, further lightening the bike and getting a bit less bulky.
As for running silent, I think I'm alone in the use of a roox roller coaster (remember them!), with the twin sprung sprockets on the return chain line my 'standard' DH bike is pretty much silent the entire time.
Carbon rear would make this a mad bit of kit...
  • + 2
 Cheers mate. Carbon is in the works.
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  • + 2
 I'd would love to see the proportion of people who have openly criticised this PROTOTYPE bike as ugly along side the proportion of posers on the trails who have pretty bikes, even prettier gear, and all the riding skill of my mum. (Anyone who has seen my mum tottering around or her hybrid with the woollen sheepskin seat cover and basket on the back will know that this is NOT a compliment).
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  • + 1
 My only question is, how much power is lost due to the gearbox? Obviously due to physics, the more parts separating your legs and the power output wheel, the more power is lost due to interia, drag and friction etc etc. Heck, cars lose over 15% of their power due to power lost from the drivetrain.

Sure, 15% might not mean alot to regular people, but that is huge if you're pinning for a podium spot where every millisecond counts. I can definitely see some advantages of a gearbox but it's not the most efficient way of delivering power with bicycles. Loss of pedaling power might not be much of an issue in DH, but I can definitely see power loss as a problem with XC riders.

Not saying a gearbox will be an instant fail. I'm actually intrigued by it, but I'm just wondering if it can compete with it's derailleur brothers in efficiency.
  • + 1
 Off the top of my head...

... it should not lose anything near 15%. A Rohloff IGH has 16 gears and loses 2-4%. People think that is a lot, but a traditional derailler loses 2-3% at the 'S' of the chain running through the jockey wheels.

If you are really interested, there are a few scientific papers on the subject - but would take me some time to find - the bottom line is the loss is only a tiny fraction more than a traditional derailler.
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  • + 1
 I think this is an awesome bike. This is also very good for a prototype coming from two guys working in their spare time, Well done. I think gear boxes are the future for sure, they are sealed and will require very little maintenance, over time they will get smaller and more efficient (and cost less). I just switched to a Hammerschmidt and I can tell you I'm never going back. I just have to get rid of the other derailer and I'll be set.
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  • + 1
 I have to agree with fix the spade. Even though the gearbox is a cool idea I could not see myself doing overhauls on one easily. So maintance/cost could be an issue for the everyday buyer. I would like to know how one of these bikes would hold up after a season of frequent garbanzo laps? The weilding looks kinda shotty...but not bad for a newb. I really like the idea of a gearbox, but until its cheaper, lighter, and more user friendly I cannot see them becoming a mainstream component on your everyday Dh bike.
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  • + 1
 Seems like the worked on it a lot, and it's not the worst looking bike out there. But one thing, i don't like is the chain route. It goes between a hole in the swing arm, which i don't like the look of... But it looks pretty nice other than that!
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  • + 1
 fantastic looking prototype, and huge props to the guys behind the bike!


you want to know "why" gearboxes have not come into the mainstream?

its really simple...

...think how much money SRAM and Shimano make from selling chain/derailleur based drivetrains that wear out as you use them in the dirt, and are vulnerable to crash damage, causing an expensive repair bill

the accountants at these companies know exactly much money they make from customers using an "open" drivetrain system that is vulnerable to crash damage, and introducing a sealed, crash resistant gearbox system would wipe out these massive sales!

conspiracy theory? not really...just common sense when you think about "how" SRAM and Shimano make their money after the initial OE business (which is not as profitable as the aftermarket parts replacement business)?

it will take someone with the might of SRAM or Shimano to introduce a refined, lightweight and industry standard affordable gearbox system, but its not in their interests to do this Wink
  • + 2
 If one of the small guys can make something that is within the price range of existing bike and is refined I think things are going to change. We'll keep at it as I'd love to see this happen.
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  • + 1
 i cant understand why people just dont stick with the old gearing??, like the sram gears you know. jus think about the hassel when it brakes, and the cost?. i recon soon we witt av to put tax MOT and ownership pappers for these bikes lmao XD, but anyway nice bike. l8as
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  • + 5
 i am sending you a bill for my laptop as i have just chunderd all over it
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  • + 1
 like i said earlier, theres plenty of people on here who talk the talk, but how many have actually tried to make something themselves, i decided against buying run of the mill dh frames years ago and made my own from t45, ran it in uk for two years had a dirt mag article then sold it to make another, made a titanium g-boxx bike too which got bagged out on here too,
as some people with brains on here have said, when you're making small volume or one off's you have to build with whats readily available, you can't buy shaped sections or hydroformed parts so tube is the best cost effective option, once you've built something and tried it, then you can start thinking about getting sections made, theres only so many ways you can design and build a bike frame so somewhere along the line you'll get similarities, thats no bad thing, as for why use a gearbox? if the honda was affordable people would have bought it, if the top riders were using gearboxs all you losers on here would be pissing your pants wanting for mummy and daddy to buy you one, things have to progress otherwise we'd all still be riding hardtails with rim mounted brakes, i loved my g-boxx, i just can't be bothered with dh anymore, too many poseurs

keep up the good work jezken
  • + 2
 Thanks Albert we would have loved to use hydro-formed tubes...I can guarantee the first production bike will look quite different from this.
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  • + 3
 i cant see my self riding an ugly bike even it performs 9/10 so in the words of dragons den(british tv programme) 'sorry but i'm out'
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  • + 1
 This an ol' article. I know that. I just found it & had to say this thing is sooooo pimpy. It's so clean & sensible & makes so much sense. I hope they get somewhere with the carbon version. I bet there's plenty of ways to lighten gearboxes too.
[Reply]
  • + 1
 from smudger5 hi guys just read your article on jezken bike i think its amazing. gearbox bikes are a bit of a holygrail in the biking world i remember some of the earlier versions that looked like some industrial scaffolding with wheels and still remember the honda gearbox bike and the development that giant company did only to pull out and crush the bikes once they finished.i realy hope you get the money to continue with your plans an inovate your bike
[Reply]
  • + 3
 Pretty sure Brooklyn Bikes doesn't have a gearbox as all of their models still have a rear derailleur. Also, Minnar raced on a Honda gearbox bike that was pretty sweet
  • + 0
 yeh, but it was what? a derailleur inside a box? lol ... I think all of these things aren't the real thing so far at least. Speaking of which, what about the HammerSchmidt, ain't that good enough for DH application? Kinda weird you don't see many brands use that on their high-end models, not to mention I haven't seen them on any of the WC bikes yet.
[Reply]
  • + 1
 One thing i don't understand is, if a gearbox eliminates the derailleur and cassette, why use a traditional cog and chain. Why not use a small belt drive instead. It would last longer than a chain and be less noisy when it rattles against the swing arm. Maybe thats a stupid idea, I don't know.
  • + 1
 g-boxx did have a belt drive as well
  • + 1
 There is no getting around the fact that chains are the most efficient way to deliver power to the wheel. That being said, there are good arguments for the belts as well, especially the lack of maintenance needed.
  • + 2
 In the current configuration it was impossible to include a belt (technical reason: too smaller belt wrap angle), it was definitely an idea we toyed around with a lot....it may be something we include on a bike further down the track.
[Reply]
  • + 5
 Yeah Jeremy!! RAD INTERVIEW!!!!
[Reply]
  • + 1
 Oh my god...
This thing is so damn ugly its insane!
The front end is JUST like the old Azonic Eliminator, and then adding some sheet metal, which will never hold with those crap welds (I know this, being as my dad is a Gaspipe-welder) and some random gearbox with a GRIPSHIFTER...
Get SRAM to make a good gearbox with something like X.0 shifters, then we're talking.
Brooklyn Machine Works and Nicolai are the only true companies who mastered the Gearboxes, along with Diamondback maybe...
  • + 1
 I think that at this rate everyone is a long ways from "mastering" gearboxes. As for the welding, keep in mind that it is a prototype and a very limited amount have been made. I'm sure the welds would be much nicer if the bike was in full production.

The gearbox is far from random as well... And it does only work with twist shifter.
  • + 2
 hahah glad you liked it! I'm glad I didn't take your advice about the swingarm, it lasted a multirollover car crash then a season of racing.
  • + 1
 urrr, it is a nicolai gearbox. did you even read the article? DERP
[Reply]
  • + 1
 I was a huge fan of the Honda NR-01, and this looks very familiar! Maybe you guys could look use their design for some ideas. I would love to see how it final product turns out, and i wish you guys the best of luck!
[Reply]
  • + 2
 I suppose someone would like to see what happened to the kangaroo? Warning, not for the faint-hearted: www.pinkbike.com/photo/5842322
  • + 2
 lunchtime! sorry not very tasteful...
  • + 1
 lol, I'm sorry it's just funnyy!
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  • + 2
 i get the impression that it is a solution to a problem that does not exist.
[Reply]
  • + 1
 very cool idea guys, keep up the good work, and keep us posted eh!!!! Just a thought on final drive, what about a gates belt drive instead of a chain?
[Reply]
  • + 1
 that will look nice when its painted and stickered up Smile

what happens if your wearing trousers and they get caught in the chain coz it looks like it will hurt on that :L
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  • + 2
 looks great, I think their on a good direction for slowly evolving the bike.
[Reply]
  • + 2
 Speaking of un-sprung weight, doesn't that huge swing arm kind of ad back the weight of the derailleur and cassette?
  • + 2
 Just because it's large in size doesn't mean that it is heavy. Picture a large diameter tube that can be thinner, but just as stiff and strong. Having said that, I have no idea if it's actually weighty or not =)
  • + 1
 That's true, idk the weight of it.It could be light, just looks beastly is all.
[Reply]
  • + 1
 hahah hell yeh!!! better to pin those bastards head on then dodge 1!! had 1 jump into the side of my car bout a month ago, if i wasnt speeding ide of hit him on the front Razz
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  • + 1
 I remember seeing this one of kendals mate's (oddly my room mate) facebooks and going whoa hangon!? Aussie?! good to see it's going well for them!
[Reply]
  • + 2
 Bugger the bike - I am more impressed that Jeremy got that fat prick Liam out racing for a whole season!
[Reply]
  • + 1
 Looks like the front end of a turner DHR with the back end of an orange 224, and the linkage looks very similar to the turner too.
  • + 1
 Yeah, I was about to say that they pretty much put a gearbox on a turner. Looks pretty sick though boys! Full support and props for Aussie bike manufacturers!
[Reply]
  • + 1
 honestly I would say unbrakeable too from the looks of it I like it alot,great work guys!
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  • + 1
 reminds me of Hardland bicycles from way back when --- slightly over engineered
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  • + 2
 looks like and old turner dhr
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  • + 1
 sick as fuck components but really, the frame urgh looks outstandingly ugly!
[Reply]
  • + 1
 wtf? there is no blood on the car and why is the truck on the back all screwed up too?
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  • + 1
 i dont like it i like the ahead gear box bike more that thing is absolute beast
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  • + 2
 That bike would look great 10 years ago! ...im sorry...
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  • + 2
 chain is TAUT-don't TAUNT me. :-)
[Reply]
  • + 1
 ok that thing might have a gearbox which is awesome but DAYUM that this is ugly as f***
[Reply]
  • + 1
 Rad interview and very sweet bike innovation Frown But you didn't have to post the dead kangaroo!
[Reply]
  • + 1
 Why hasn't some one simply built a beefy internal gear rear hub like a Shimano Alfine.
[Reply]
  • + 2
 seriously? a kangaroo did THAT???
  • + 2
 they swerved to miss the roo, obviously swerved to much to not roll and not enough to miss it.
  • + 0
 newbikesoon, your from canada havent you ever heard of people hitting dear? it absolutely destroys your car.
  • + 1
 The 'roo did damage for sure, but I'm betting that the multiple rollovers did most of what you see in the photo. It isn't all that uncommon for people to completely write off their car or truck by hitting a moose here in Canada. I guess they are a bit bigger than a kangaroo though... I know I've read about people dying from this.
  • + 1
 luigi's right though, even deer can do some gnarly damage, and they seem to be about the same size as a kangaroo
  • + 1
 @ mike

the kangaroos kill people either cause they over steer and roll (as above) or the roo comes through the windshield and kicks the people to death, brutal both ways
  • + 1
 with kangaroo, unless they are mid hop, most of the time they hit the front of the car - their centre of gravity is much lower than a deer. deer are up on stilts and they go through the windscreen. the other thing is that kangaroos are completely stupid. deer try to get out of the way - kangaroo can be bounding along beside the road scared of your car and then swerve into your path. on two occasions i've hit them riding my bike... actually one of them hit me - knocked me off my bike sideways. kangaroos taste better than deer too - and soooo cheap at the moment. very healthy meat.
  • + 1
 deer dont always try to get away they run in front of the truck or freeze on the road and some run away
  • + 1
 just to let you guys know this is from hitting a baby moose (just a tad larger than a full grown deer(not a buck)

www.car-accidents.com/2006-Auto-pics/8-6-06_nh.jpg
  • + 1
 kangaroo is delicious!!!!
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  • + 2
 Looks as the old 2005 giant faith!
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  • + 2
 prolly cause chains are 99.5% efficiant already.
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  • + 1
 whats the weight of this? didn't see it in there must of over looked it.
  • + 2
 43lbs is not that heavy at all... I think we're all getting a bit spoiled by all of these new mega light bikes coming out. I think a lot of us would be surprised to find out what a lot of those WC bikes actually weigh.
  • + 1
 not bad at all. my dh is like 56lbs.
  • + 2
 56lbs - DOUBLE ZOIKES!
  • + 1
 you can say that again, time to up grade.
  • + 2
 mine is 41 and im completely satisfied with it! 43 is awesome for a gearbox bike if you think about it
[Reply]
  • + 1
 I wonder how much it costs???
  • + 1
 It's not for sale, believe me i've tried Razz

I can vouch for the complete lack of noise this thing makes. It's eerie Eek
  • + 1
 Yep, gearbox bikes sound like someone rockin' their single speed hardtail down the DH track. Pretty sweet.
[Reply]
  • - 3
 I know just about everyone wants to say it but dosent want to offend the creator but the bottom line is...........this bike is ugly,pointless,and bulky.......... if anyone has a reason why this bike could replace the top of the line konas, norcos, giants, spelized ETC. please tell!
  • + 1
 Honestly, I don't think that it's goal is to replace any of the bikes that you've mentioned, but more of an exercise in what's possible with the current technology. There are advantages to this bike, there is no doubt about that. Ugly? I would disagree, but that is subjective. Pointless? Wow, don't even know where to start but I can see a lot of points. Bulky? It is lighter than many other bikes out there and if you read the article you'd know that the extra weight is placed where it has the least effect on the ride, and the lack of weight in other places in proven to be a benefit.
  • + 1
 This bike is far from pointless. We really need to get rid of the derailleur, imagine if you didnt have to pedal to shift gears. You could shift while jumping for example or while plowing over or through a rock garden.
  • - 1
 Ok if you dont think this bike is ugly your on crystal meth! and scottc i can shift in rock gardens and i can shift in mid air its called pedaling through rocks, and in mid air its called leg muscle or clip ins!
  • + 3
 hahaha pointless?? Are you on crack buddy? You actually change gears in the air whilst pedaling! Smile I love it.
  • + 1
 well iv seen a much better gear box bikes... and im preety sure he decided to try to smoke the coke thinking it was crack... just sayin...
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  • + 1
 The frame looks kinda grim.. like a Cannondale :S sounds good tho Big Grin
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  • + 1
 that top pic looks toy size for some reason
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  • + 1
 that bike is just 100% beef!
[Reply]
  • + 1
 DB already has a gear box out in the UK.
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  • + 1
 always good to see a new alternative to existing companies Smile
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  • + 1
 to be honest some of the welding looks abit bad :/
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  • + 1
 looks like a heavy pos to me. sorry but p o s.
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  • + 1
 looks like and awkward turner DHR
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  • + 1
 Reminds me of a Nicolai Ion G-boxx
[Reply]
  • + 0
 Nice forks and back shock but I'm not to keen on that frame...It's a bit plain..needs some graphics and colour.
  • + 3
 There have only been a few made and it's still very early in the prototype stage. Stickers may not be too high on the priority list at this point.
  • + 1
 ahh okay cool.
  • + 2
 Mike's on the money here, graphics definitely weren't a priority. However this seasons bikes have graphics, you'll see that in the next feature!
[Reply]
  • + 1
 some of those welds...are well ugly
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  • + 1
 that is the most retarded looking chainstay
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  • + 1
 Cool bike. GT brought carbon to DH before Santa Cruz, just to be clear.
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  • + 2
 ugly as hell,
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  • + 1
 nice bike nice crash as well
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  • + 0
 looks like a cannondale judge rip off Blank Stare
  • + 1
 What? You're going to have to explain that to me... I don't see it. At all.
  • + 1
 Sorry, I recalled the wrong frame, I meant to say it somewhat resembles the Canifield Jedi...at least when looking at the front triangle. Of course it's more beefy and all but still, when I look at it, I don't see original design nor innovative one. When you look at Lapierre, now those looks like some rather original designs and I don't have a Lapierre, just saying.
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  • + 0
 Oh man the rear end on that thing is so ugly!!!!!
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  • + 1
 looks like a chumba
  • + 1
 ya, the f5. but man does this thing look like a beast!!!!!!
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  • + 0
 omg, thats Sam Hill`s Kangaroo ...
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  • + 0
 thats so sick, and such good technology!
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  • + 0
 pretty sick how it works but fuck is it ugly
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  • - 1
 i prefure the car to that bike...
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  • - 1
 czemu kangur nie ma ręki?
[Reply]
  • - 2
 i hate the frame. its got a terrible design and geomtery! good luck selling it
  • + 3
 The geo is very similar/same to what is commonly found on current DH bikes, and this being a DH bike, that makes sense to me.
  • + 3
 Terrible geometry hahah It was benchmarked from over 10 successful current designs, but I guess you would know, also it's a prototype it won't be sold.
[Reply]
  • - 3
 flexalicious
  • + 3
 Interesting that you can tell by looking at the photos above...
  • + 1
 youre right. it more so the oldschool frame layout that tipped me off but youre right
  • + 1
 What is old school about the frame layout?
  • + 2
 the large spacing of material in the shock area (between the seatube and downtube), odd distribution of material throughout, funky angles
just gives that vibe
  • + 2
 At the ripe 'ol age of 16 you know alot about the feel of "oldschool" bikes. Smile
  • + 1
 right, because mountain bikes are sooooo old
  • + 2
 Photo analysis...In engineering we call this Visual FEA (Finite element analysis). It's crazy stiff.
  • + 1
 the swing arm looks f*ckin like a oranges thts how its oldscool mikelevy!
[Reply]
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