i see the bb spindle but don't understand why there is a out put chain ring there?
G-BOXX Planetary, first pics
- Thread starter Wilhelm
- Start date
i could read, i see now. its a bb pivot with 3 chains.
most people liking high pivots could use this by laying it horizontal with a reg bb below it to drive
the unit. omit the bb splin on out put shaft.
i like the 3 chains for a diab. you have to spin it fast for good shifting, then run a 1-1 or less
to the rear wheel.
I agree with your ideal of omitting the concentric output to achieve a high output. Simplifies it as well and uses a normal bb.
Couple problems with this design (both as presented or as bcd suggests)
1- Using a cassette as the driving chainwheel would create huge loads on an 11 tooth cog. Enough that it would skip over the teeth. Imagine the torque. Even a 14 or 15 tooth would probably still not work. I suppose the planetary speed reducer would halve the loads, so maybe....
2- The cassette would have to have all the ramps, pins, and steps to aid in shifting, cut backwards. (small cog on the left, large on the right) Not saying it couldn't be done, but it would mean a custom cassette.
Couple problems with this design (both as presented or as bcd suggests)
1- Using a cassette as the driving chainwheel would create huge loads on an 11 tooth cog. Enough that it would skip over the teeth. Imagine the torque. Even a 14 or 15 tooth would probably still not work. I suppose the planetary speed reducer would halve the loads, so maybe....
2- The cassette would have to have all the ramps, pins, and steps to aid in shifting, cut backwards. (small cog on the left, large on the right) Not saying it couldn't be done, but it would mean a custom cassette.
O.k. would this be a Good/bad idea,
Two shifter for the rohloff hub thumb on left and right side, thinking paddle shift idea here? Never need to use a brake finger to shift then.
Maybe I am just crazy.
Two shifter for the rohloff hub thumb on left and right side, thinking paddle shift idea here? Never need to use a brake finger to shift then.
Maybe I am just crazy.
Lahar designer had the same thought. It was mentioned on here about a year ago. Nicolai are doing it on their new bike I think(non Rohlof but gearbox).It's the perfect idea for DH,but hard to design for a Rohlof as the cable goes limp on the one not being used,so you'd need a big spring or perhaps a rotating device(like the shifter)where the cables split,and have it as close to both shifters as possible. So the cables are very short.
Yeah I thought about the dual shifter thing. I was thinking the shifters would have to have:
-have no indexing in them
-have enough throw for 7 gears
I don't think there would be a problem with one of the cables going limp. As you crank one shifter it would pull the cable, that's attached to it, out. While the other cable would be pulled in and wrap around the little spindle-type thing attached to the hub.
I wouldn't mind trying it, I just need to find the right type of shifter and I don't know what that would be.
-have no indexing in them
-have enough throw for 7 gears
I don't think there would be a problem with one of the cables going limp. As you crank one shifter it would pull the cable, that's attached to it, out. While the other cable would be pulled in and wrap around the little spindle-type thing attached to the hub.
I wouldn't mind trying it, I just need to find the right type of shifter and I don't know what that would be.
I've been working on a paddle shifter design, but it's way more tricky than you'd first guess. Each paddle needs a one-way ratchet or clutch that disengages at the beginning of it's stroke or when the other paddle is pushed. Also as was said, the other cable would go limp. If you pulled on the housing it would all pull apart. You're not going to find something that's already made that would work.
Ok, I now know what you mean about the cable going limp.... I had something else in mind. Actually, scrap my idea, I just realized something else that wouldn't work. Twist shifter has to stay!
I am not thinking of using any current shifter ideas but build a new shifter pair that would have to have a "jumper" cable between the shifters to release one when pressing the other. First problem for me is dropping the money on the hub so I can get an idea of how much cable I have to move and if I would want to re-invent someone else's wheel.
If you are eagerly awaiting news about the G-Boxx 2 and counting down the last 5 days till December 24th (http://www.ridemonkey.com/forums/showpost.php?p=2771242&postcount=440) to "... see the BOXX mystery on the video premiere Dec. 24. 2007" on http://www.g-boxx.com, you can have a first look to a G-Boxx 2 related amazing news even today:
First CAD screenshots of the all-new NICOLAI "Ion GB II":
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=3,
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=1,
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=2.
Found in NICOLAI Factory News No.4 2007 (unfortunately in German only): http://nicolai.dbap.de/customGates/scripts/newsletter.php.
Enjoy
First CAD screenshots of the all-new NICOLAI "Ion GB II":
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=3,
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=1,
http://nicolai.dbap.de/SID=sied1f503dda10c2c9536e09a24983fe/index.php?screen=mi.gallery&pid=666&sno=2.
Found in NICOLAI Factory News No.4 2007 (unfortunately in German only): http://nicolai.dbap.de/customGates/scripts/newsletter.php.
Enjoy
Attachments
Wouldn´t Dave WEAGLE´s "Split Pivot©" (Concentric Dropout Pivot http://www.split-pivot.com, http://www.sicklines.com/2007/06/08/...vot/#more-1487, http://www.ridemonkey.com/forums/sho...ht=split+pivot) or TREK´s "ABP©" (Active Breaking Pivot http://trekmountain.typepad.com/king...explained.html, http://trekmountain.typepad.com/king/fuel_ex/index.html, http://www.cyclingnews.com/tech.php?...es/trekworld07, http://thisjustin.bicycling.com/2007...k_fuel_ex.html) be appropriate "remedies" to improve the performance of gearbox bike rear suspension, even because of this constructions allow to keep the chain length unchanged? What do you think about?
The split pivot looks like a vary viable option and it appears as if it could be built in a manner that would make that pivot very laterally stiff.
I can't see any bennefit,and may make chainline harder.
Yes I think it would work well, with a concentric pivot of course. I think this was probably in the back of DW's mind when it was developed. It would be an efficient way to create a stiff structure with independent braking.
I´m so impressed because of DW´s "Split Pivot©" looks so simple and clean. So, I hope that many manufactureres of gearbox frames will make use of it and get an licence of his patent.
Besides, the secret of the G-Boxx 2 is visible now ... 7 parallel chains, so far (http://www.g-boxx.com).
Besides, the secret of the G-Boxx 2 is visible now ... 7 parallel chains, so far (http://www.g-boxx.com).
You would still need some way of adjusting the chain length, which might be a little more difficult with concentric pivots at both ends.
Also, despite the visible chains in some of the background shots, I believe the new g-boxx uses 7 parallel toothed rubber belts. They weigh a tonne less.
I absolutely agree with you in both points.
I think that adjusting of the chain/belt length could be done for instance by means of some type of excenter mounting of the bearings, like TR!CKSTUFF´s "Exzentriker" bottom bracket mount (http://www.trickstuff.de/index.php?p=d110de1).
Sometimes around the Eurobike 2007, there was told in the gearbox thread of the NICOLAI support forum (http://www.mtb-news.de/forum/showthread.php?t=107737&page=5, #188) that they indeed will test a belt driven gearbox version in the spring of 2008. Besides the lower weight, the GATES® Poly Chain® GT® Carbon™ polyurethan belts (http://www.gatesprograms.com/carbon/) don´t need any lubrication (and consecutively save this part of regular service), should hold up a very long time, and were not so much prone to stretching like a conventional roller chain.
no spriken ze deutch
What can I do for you?
Recently, Falco MILLE of NICOLAI stated that the 7 speed G-Boxx 2 will be available for OEMs exclusively, not for the aftermarket (http://www.mtb-news.de/forum/showpost.php?p=4362854&postcount=316).
I agree with EVRAC. So far as I would like to interpret the video (http://g-boxx.com/videos/G-Boxx-2-general_function.wmv) it seems to me that all the seven parallel "pairs of sprockets and chain" appear to spin simultaneously all the time the crank arms are moved. The position of the magnetic slider inside the hollow driveshaft makes moving only one particular triplet of pawls which then gets engaged with the driven shaft (like a freewheel mechanism) and so determines the gear ratio. Otherwise it would make no sense to me.
Of course. The chain drive configuration level of the "G-Boxx 2" is the only one that is available now as well is shown on their website (http://g-boxx.com/e-background.html, http://g-boxx.com/e-g-service.html).
Actually, that's pretty simple and elegant. If I had to make one I'd do a lot of things similarly. Now all they have to do is make a case that doesn't use 5 pounds of fasteners and they'll be in business.
With a list of all components(forks,wheels,brakes etc)and their weights + the weight of the gearbox,how much weight is left to make the actual frame?
I'm interested.
I'm interested.
You bet.
Sounds promising. Please upload some pics from Sea Otter Classic for all of us who can´t come to Monterey/CA.
About 8lbs of frame weight (no shock), with a conservative build. Definitely reasonable considering the box is a stressed member. Could be another lb or 2 lighter (than 40) with a light build. Ill post some teaser cad pics once I get some FEA done...
Any news about the project? We would like to see some CAD pics.
However: Some news on the g-boxx.com website: http://www.g-boxx.com/pdf/GATES-Carbondrive08.pdf.
So 8lbs without the heavy gearbox or shock? The gearbox as a stressed member should help them to be made lighter than a conventional frame.
No way you'll get that below 40 with a reliable DH build. sorry but NO WAY.
Frame is at 7lbs without gearbox or shock. With the low leverage ratio and fairly linear actuation curve, we can run an air shock in rear and still get good reliable performance (no blowing up DHXes). I will be running tubeless setup to drop a bit more weight. 40 is definitely an achievable number at this point. Ive got a couple of other tricks up my sleeve that will help realize the overall weight. Rear end is done and parts are being machined now (4130 steel) and the front triangle has been designed and the material is now here. All I have to do is put out the part drawings and get the front end started.
Two gearboxes should arrive from G-boxx at the beginning of april. Just for clarification, the 4+kg weight is of the box with chains, they dont have the belted version ready yet, but this will likely drop at least a pound if not more from the assembly.
I havent had time to upload pics because of work and proposal stuff blowing up right now. Ive got some screenshots that I will post though when I have a free hour or so.
Two gearboxes should arrive from G-boxx at the beginning of april. Just for clarification, the 4+kg weight is of the box with chains, they dont have the belted version ready yet, but this will likely drop at least a pound if not more from the assembly.
I havent had time to upload pics because of work and proposal stuff blowing up right now. Ive got some screenshots that I will post though when I have a free hour or so.
This might be the first steel g-boxx bike.
Nice.
Nice.
Rear end is steel for volumetric efficiency over AL. Front end is 7005 AL for stiffness (larger diameter tubing) and weight. Best of both worlds in my book. Im starting to get really really excited now that things are coming together. My final specs are: 13.75" BB, 65.5HA, 45.3WB (at full droop), 22.5 effective top tube, and shock placement as low as you can get with a gboxx. 12X150mm rear hub. The COG for the bike is literally going to be at the front of the Gboxx case, a little higher than the output gear.
Rear triangle should be just over 3 lbs and the front triangle about 3.5 lbs.
Rear triangle should be just over 3 lbs and the front triangle about 3.5 lbs.
Some pics of a nice gearbox bike by Frank REUBER (company located in Dortmund/GER, http://www.fingercolt.de), the "BoxxHorn G7": http://www.reuber-die-marke.de/boxxhorn.html.
Too bad that the non-german-speaking majority won't get it...
quite a bit like HaveFaith's rig. Not bad at all. Someone's got to do this with a split-pivot rear dropout.
