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the gearbox thread

buckoW

Turbo Monkey
Mar 1, 2007
3,788
4,737
Champery, Switzerland
That Mountain Cycle one looks cool. Is that the only hard tail with a gear box? Did the Evil one ever get made?

Have you guys seen this one?


It is Transcend's photo but I talked to the designer at Eurobike and it is pretty trick. They even made a system to seal the cables going to the hub with stiff copper housing. I like how you can take the wheel off and the chain stays on the bike.
 

Wilhelm

Monkey
Aug 10, 2003
444
19
That Mountain Cycle one looks cool. Is that the only hard tail with a gear box? Did the Evil one ever get made?

Have you guys seen this one?


It is Transcend's photo but I talked to the designer at Eurobike and it is pretty trick. They even made a system to seal the cables going to the hub with stiff copper housing. I like how you can take the wheel off and the chain stays on the bike.
It is not a gearbox bike at all. It is a very innovative fullsusser with a modified ROHLOFF Speedhub, an elevated pivot point to eliminate pedal kickback as most as possible, an encapsulated self tensioning chain drivetrain and many other solutions to get a low maintenance ride.

Further reading, more pics:
http://www.katz-bikes.com/sites/de/home.html
http://www.flowzone.ch/index.php?c=news&id=416&css=green
http://picasaweb.google.de/TFJ777/Eurobike07Part2.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
It is not a gearbox bike at all. It is a very innovative fullsusser with a modified ROHLOFF Speedhub, an elevated pivot point to eliminate pedal kickback as most as possible, an encapsulated self tensioning chain drivetrain and many other solutions to get a low maintenance ride.
How do you define a gearbox? This bikes gears are in a box,it does not have a derailer or exposed gear system. Where the gears are located is irelevant,isn't it?
Lots of gearboxed bikes have used Rohloffs,how are they different to those that use any of the G-Boxxs or a deraileur in a box type system(Honda)? Is it because the gearbox is rotating in the hub?Does a gearbox have to be seperated from the rear hub to class as a gearbox?
The definition is trivial,the bennefits,pros and cons are all that should matter,labels suck.
This bike will have all the great benefits of a Rohloff and those of an enclosed drivetrain,it will have a heavy rear end and more docile suspension due to the Rohloffs weight being on the swingarm.
I'd like to see inside the chain box,it'd be a great solution to my tandems low ground clearance for off road riding,by having the chain line higher.
I might try and replicate it with rollers and some plastic conduit(pipe).
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM

Wilhelm

Monkey
Aug 10, 2003
444
19
How do you define a gearbox? This bikes gears are in a box,it does not have a derailer or exposed gear system. Where the gears are located is irelevant,isn't it?
Lots of gearboxed bikes have used Rohloffs,how are they different to those that use any of the G-Boxxs or a deraileur in a box type system(Honda)? Is it because the gearbox is rotating in the hub?Does a gearbox have to be seperated from the rear hub to class as a gearbox?
The definition is trivial,the bennefits,pros and cons are all that should matter,labels suck.
This bike will have all the great benefits of a Rohloff and those of an enclosed drivetrain,it will have a heavy rear end and more docile suspension due to the Rohloffs weight being on the swingarm.
I'd like to see inside the chain box,it'd be a great solution to my tandems low ground clearance for off road riding,by having the chain line higher.
I might try and replicate it with rollers and some plastic conduit(pipe).

One practicable definition (http://www.g-boxx.org/index.html):

"Gearboxx-Bikes" or also called "Internal Transmission-Bikes" on the other hand contain a transmission mounted inside the main frame - the classic bottom bracket housing is replaced by an integrated transmission. Similar to previously described gear change mechanisms, a chain or belt drive system is used to provide power to the rear wheel. In this case, the chain (or belt drive) does not have any shifting duties.
 

EVRAC

Monkey
Jun 21, 2004
757
19
Port Coquitlam, B.C., Canada
One practicable definition (http://www.g-boxx.org/index.html):

"Gearboxx-Bikes" or also called "Internal Transmission-Bikes" on the other hand contain a transmission mounted inside the main frame - the classic bottom bracket housing is replaced by an integrated transmission. Similar to previously described gear change mechanisms, a chain or belt drive system is used to provide power to the rear wheel. In this case, the chain (or belt drive) does not have any shifting duties.
I agree. Nice bike, but not a gearbox. If it was, any gearhub bike would be. Not to say I wouldn't ride it....
 

Wilhelm

Monkey
Aug 10, 2003
444
19
if that versus went on a diet it'd be pretty sick....i like it alot.....high center of mass but nice, nonetheless.....'

is that a gboxx setup.? can you use a regular shifter with it?
The impressive VERSUS proto indeed has a G-Boxx setup. It was shown on the VERSUS booth at Interbike 2006 (http://content.mtbr.com/TRD_13_255crx.aspx). The gearbox "G-Boxx Planetary" was made by Karlheinz NICOLAI´s UNIVERSAL TRANSMISSIONS GmbH as a prototype in 2006, with a modified ROHLOFF Speedhub inside and the original ROHLOFF twist shifter, which never went into series production (http://www.ridemonkey.com/forums/showthread.php?t=164697&highlight=g-boxx). The "G-Boxx Planetary" was shown on a few gearbox proto bikes (among them ALUTECH "Pudel", DIAMOND BACK "Sabbath", NICOLAI "AMX", ORANGE "Strange", ROTEC) at the big bike shows in 2006 (http://www.descent-world.co.uk/index.php?option=com_content&task=view&id=425&Itemid=82, http://www.singletrackworld.com/article.php?sid=2125&PHPSESSID=e87672d534b85f8b58c7cfe7346d12d6, http://www.soulbiker.com/de/photos/album/gallery/eurobike-orange-2007/).
 

bikemonkey

Chimp
Feb 1, 2008
68
0
Santiago, Chile
The GBoxx is great but it limits the bike design to having the swing arm pivot point in the same place for all of the bikes that are using it. is this a good thing? I am in for a single high pivot, concentric to the chain ring design, but the pivot placement is crucial and not unique for all bikes and their different applications. Isn't it better to have a hub type box independent from the bottom bracket, something like the Lahar, the gt or so many others. this Independent Gearbox could be modular and have universal mountings on it. just like the gboxx.
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,940
353
vancouver eastside
^ i tend to agree, yes. the proprietary bb & cranks, and fixed bb to output distance of the gboxx are disadvantages in a 'universal' gearbox solution, imo. the lahar config is dead simple: freedom to use standard cranks / bb, allows placement of the gearbox & pivot in a multitude of locations, and it's (relatively) light - no large case with 62 bolts.

 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,115
6,055
borcester rhymes
me too...the big clunky box limits design creativity. Honestly, who's going to buy a bike identical to every other one if it costs more than all the rest??? Isn't that how morewood outsells Orange? It's the same bike, but cheaper....

seriously though, if you took all the bolts away, what would nicolai have left? Bolts and holes are what they know, it's what they do.
 

dhmtbj

Monkey
Jan 30, 2002
467
1
Boston
The GBoxx is great but it limits the bike design to having the swing arm pivot point in the same place for all of the bikes that are using it. is this a good thing? I am in for a single high pivot, concentric to the chain ring design, but the pivot placement is crucial and not unique for all bikes and their different applications. Isn't it better to have a hub type box independent from the bottom bracket, something like the Lahar, the gt or so many others. this Independent Gearbox could be modular and have universal mountings on it. just like the gboxx.
If you read further into the g-con 2.0 standard you'll see that the single pivot design is simply the most developed setup. A major aspect of the standard is that you can adapt it to any suspension design. They even have a crappy little video showing all the different suspension styles.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
If you read further into the g-con 2.0 standard you'll see that the single pivot design is simply the most developed setup. A major aspect of the standard is that you can adapt it to any suspension design. They even have a crappy little video showing all the different suspension styles.
They all have the same pivot location and a solid swingarm to the back wheel(99% of them).doesn't make much difference how the shock is driven. The bikes will ride nearlly identically.
Also the weight is heaps more than a Rohloff or any other hub type gearbox.
 

SuspectDevice

Turbo Monkey
Aug 23, 2002
4,174
383
Roanoke, VA
They all have the same pivot location and a solid swingarm to the back wheel(99% of them).doesn't make much difference how the shock is driven. The bikes will ride nearlly identically.
Also the weight is heaps more than a Rohloff or any other hub type gearbox.
Please re-read Jay's statement. The Gconn2 standard allows plenty of room for non-concentric pivot suspension. Just about any type of multi-pivot arrangement is possible with the use of a tensioner to regulate chain length.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
Please re-read Jay's statement. The Gconn2 standard allows plenty of room for non-concentric pivot suspension. Just about any type of multi-pivot arrangement is possible with the use of a tensioner to regulate chain length.
I admit to not finding any pics he mentioned of design possibilities,but, I can safely say,with the wheel path pivoting around the output sprocket,be it with multi pivots or single,they will all ride very similar and have the same flaws and characteristics. I was just commenting as it appeared he may have not realized this.Sorry for presuming he'd overlooked this,but it is the internet and a bike forum.
Can anyone link me to the site where it shows the options please. Is a high pivot possible? Either way,it still weighs way too much.
 

Wilhelm

Monkey
Aug 10, 2003
444
19
Please re-read Jay's statement. The Gconn2 standard allows plenty of room for non-concentric pivot suspension. Just about any type of multi-pivot arrangement is possible with the use of a tensioner to regulate chain length.
You all know the G-Boxx based year 2006 protos with Mert LAWWILL suspension as two examples to show possibilities in gearbox bicycle frame design beyond the simple single pivot:

ROTEC at Interbike 2006 (according to the G-Con 1 standard with G-Boxx Planetary):
http://www.ridemonkey.com/forums/showthread.php?t=97295&highlight=Rotec&page=18
http://www.ridemonkey.com/forums/showthread.php?t=97295&highlight=Rotec&page=20

CENTURION at Eurobike 2006 (G-Boxx 1 yet):
http://www.dual-slalom.de/gbikes/press.html, http://www.slogdesign.de/dia_bikestudien.html,
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288722
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288726
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288723
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288726
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288727
http://fotos-alt.mtb-news.de/fotos/showphoto.php/photo/288728
http://www.ridemonkey.com/forums/showthread.php?p=2271316#post2271316.


The GBoxx is great but it limits the bike design to having the swing arm pivot point in the same place for all of the bikes that are using it. is this a good thing? I am in for a single high pivot, concentric to the chain ring design, but the pivot placement is crucial and not unique for all bikes and their different applications. Isn't it better to have a hub type box independent from the bottom bracket, something like the Lahar, the gt or so many others. this Independent Gearbox could be modular and have universal mountings on it. just like the gboxx.
Very interesting to read:
http://forums.mtbr.com/showthread.php?t=378845
http://forums.mtbr.com/showthread.php?t=373852.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
The Rotec may have had a slightly different axle path to a single pivot mounted at the drive output,but not the centurion,no chain tensioner means it has the same axle path as a single pivot mounted at the drive blah blah. This was my humble point.
You could possibly over come all this using an idler to achieve a higher pivot or a variable axle path with idler or tensioner,but you'd be probably adding even more weight to an already overweight design.
 

bikemonkey

Chimp
Feb 1, 2008
68
0
Santiago, Chile
Exactly, you can work round it, but is hard. non the less the gboxx is a brilliant idea and the g-con standard is even brighter.

The Rotec may have had a slightly different axle path to a single pivot mounted at the drive output,but not the centurion,no chain tensioner means it has the same axle path as a single pivot mounted at the drive blah blah. This was my humble point.
You could possibly over come all this using an idler to achieve a higher pivot or a variable axle path with idler or tensioner,but you'd be probably adding even more weight to an already overweight design.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
Exactly, you can work round it, but is hard. non the less the gboxx is a brilliant idea and the g-con standard is even brighter.
Why would you bother? Look at this simplicity

That's the Lahars gearbox and it's simple four mounts,it can go anywhere,and offers a lot more opportuntiy for design. It has too many gears,but big deal,if it's lighter,then the gears are only a Token benefit. I think Rohloff must be hard to deal with,because I really can't understand why Nicolai etc stopped using them. This doesn't really matter,as both Shimanno and Sachs have decent hubs for gearbox use now.The Shimannos shifter cables are on the opposit side to the Rohloff making it a touch trickier,but as GT proved,very possible. I wish GT would just fix up that bike with decent Geo and stronger chassis.
 

bikemonkey

Chimp
Feb 1, 2008
68
0
Santiago, Chile
Jajajaja, when I say "Exactly" it is because I am agreeing with you. I very much like and embrace the gboxx, I think it is a step in the right direction but it is not the final answer to gear box bicycles. a more modular and compact system is required. specially from the builders and designers point of view.

Exactly, you can work round it, but is hard. non the less the gboxx is a brilliant idea and the g-con standard is even brighter.
 

djamgils

Monkey
Aug 31, 2007
349
0
Holland
haven't read the entire thread but from what I have seen of the G-boxx I think it is way too complicated and creates more problems then it is solving.
what are they thinking, 7 gears, 4.4kg, complicated design. the rohloff is about 1kg? and has 14 gears so it is apparently possible to design something usefull.
I would rather see someone developing a 5 to 7 speed hub that is suitable for dh. That way there is more variety possible in frame design only disadvantage is unsprung weight.
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM
here is my machined alfine i am working on.
made some room for the spline
adapter to tomi cog for rear chain line.

took off the spoke flanges.

lots of stuff going on in there huh? rollerclutches work great on large O.D.!






















 

UncaJohn

Chimp
Dec 27, 2007
34
0
Athens
Hmmm Alex,
How much narrower does the Alfine get with all this machining?
Are you planning to use the hub's axle as the rear suspension arm's axle?

Thanks,
John
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
Hmmm Alex,
How much narrower does the Alfine get with all this machining?
Are you planning to use the hub's axle as the rear suspension arm's axle?

Thanks,
John
I doubt he will(I may well be wrong),the Shimano hubs weakness for normal use is their axle,so using it as a stressed member wouldn't be advised,however the stress wouldn't be over the whole span like when used as a wheel,so maybe he is. I'm curious also now. Will you spill the beans on this Alex?
 

UncaJohn

Chimp
Dec 27, 2007
34
0
Athens
Well, yes i do agree, but the axle of that hub can just be the screw that will press in a pair of sleeve that will function as an axle.
I am looking foreward for those Alex's beans.....

John
 

bikemonkey

Chimp
Feb 1, 2008
68
0
Santiago, Chile
Nice work with the alfine, I can't wait to see the end result.
will you keep the chain on the left hand side and use a modified hub, or will go have it in a jackshaft style rerouting thingy to have the chain on the right?
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM
i am cutting the axles with 10mm left on each side.
the alfine will be 150mm wide total, that is about all i can do.
i will mount the hub in clamps very tight.

in my nexus project i only clamped one side and broke the axle.
i also was off on my concentric rear so the chain would go slightly
tight when compressed thus over stressing the axle.

the outside of the alum clamp that are basiclly a split seatube
gone to flats will have a large od bearing shoulder.
 

EVRAC

Monkey
Jun 21, 2004
757
19
Port Coquitlam, B.C., Canada
The Lahr gets closer:

http://lahrcycles.com/2008_02_01_archive.html

The bike went on its first shuttle ride complete with three runs down Brush Mtn. THe ride is TERRIFIC; back end is so light it feels glued to the ground. Cant wait to get a transmission in there.



http://lahrcycles.com/2008_03_01_archive.html

The transmission has been partially assembled for the first time, such that it can actually be spun. The best part was that it worked. Even with just 2 outta the 4 followers. Shifter seems to behave as designed as well. Looking to make a few design changes to make assembly and operation better though.

 

EVRAC

Monkey
Jun 21, 2004
757
19
Port Coquitlam, B.C., Canada
i am cutting the axles with 10mm left on each side.
the alfine will be 150mm wide total, that is about all i can do.
i will mount the hub in clamps very tight.

in my nexus project i only clamped one side and broke the axle.
i also was off on my concentric rear so the chain would go slightly
tight when compressed thus over stressing the axle.

the outside of the alum clamp that are basiclly a split seatube
gone to flats will have a large od bearing shoulder.
I found this on "Hubstripping" website. It might let you reduce the OLD (Overlocknut dimension) a bit.

I’m interested in the Alfine 8sp, but I want to run it with a rim brake and spaced down to 120mm OLD. Is it possible to replace spacers to get it down to something close to 120? I know the Nexus8 can go to 123mm. Any thoughts?
# Marco

November 16, 2007 at 10:31 pm

Hi Andrew,

I just stripped a Alfine and can give you the following advice.

http://hubstripping.wordpress.com/2007/11/14/shimano-alfine-hub-strips/

http://www.hubstripping.com/shimano-alfine/shimano-alfine-explosion-hub-SG-S500.pdf

Replace part 25 in the explosion drawing with another part 20 (You have to order this seperate! It´s a generall hub part! A good bicycle dealer has this on stock.).

After this replacement you have reduced the OLD by 5,4mm. There are no other possibilities in my eyes.

Gruß Marco
 

HaveFaith

Monkey
Mar 11, 2006
338
0
My design is getting there, still shooting for a debut at Sea Otter. Keeping it pretty simple, but expect a few small twists thrown in the mix. Looking like sub 40lbs is definitely a good possibility. G-boxxes have been ordered and they are on their way over the atlantic soon! I will post up a preview when I have the chance.
 

UncaJohn

Chimp
Dec 27, 2007
34
0
Athens
Now you hit something that i am looking for too. I am also trying to find ways to fit a speedhub within a limited space, so I guess that it would be really helpfull for lots of designers (and dreamers) to have an idea on how much they can nerrow those hubs. And i mean, not only the Alfine, but the Shram & Rolhoff too!

So, if anyone has this kind of information (yep i know the hubstripping web pages), and even better, accompanied with some diagrams or pictures, it would be really nice of him/her to publish it here (or into a tech-specific-thread).

Thank you all.

UncaJohn
 

UncaJohn

Chimp
Dec 27, 2007
34
0
Athens
Err, nope. It can be done, as far as you'll choose to replace 2 parts (one from each side) by intergrating them into your frame structure, or suspension linkage element in my case.
These are the part no 61 (the steel plate that keep the speedhub from rotating) and the part no. 6 (the threaded cup tthat holds the spocket and it's spacers).
My problem is that i cannot find how wide these parts are!

UncaJohn

And.
An additional problem that i'm having is that i cannot find the actuall Q-Factor dimentional data i need. By the term Q-Factor i mean the actuall free space between the inside of the crankarms. Some manufactures responded, some.... not and some did not understood the question, despite the sample image i was sending.
 

zspecial

Chimp
Jul 2, 2004
34
0
By the term Q-Factor i mean the actuall free space between the inside of the crankarms. Some manufactures responded, some.... not and some did not understood the question, despite the sample image i was sending.
I had the same issue as you. May not be the nicest way to do it but I went into my local bike shop with a ruler and a notepad and noted down the BB width, crank type, width at the widest part of the crank and where the widest part of the crank started. I may be able to dig these notes up ( probably quicker for you to do the same thing though ).

From memory a 73mm BB had 76mm from crank to middle of seat tube, 83mm BB had 81mm. Can't remember the crank types.
 

UncaJohn

Chimp
Dec 27, 2007
34
0
Athens
Yep, If i remember right, with a Shimano Octaling 73mm shell, 128mm axle i may have a full 160mm of "internal space". This with the XT octaling cranks.
An other option is to use those steel cranks, like Deity's and machine an axle of my own (damn those home made parts are always increasing)

UncaJohn