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the gearbox thread

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
all gearboxes, all the time. is the derailleur doomed to extinction? planetary gears, ivt's & mystery boxes - are there designs that will eventually rise to the top & become standardized (read: affordable & commonplace), or will gearboxes always be limited to exotic applications? here's a forum for random discourse.
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
here's a couple random pics to start: the b1 petespeed internal deraileur:

gt's (nexus?) gearbox:

nicolai's rohloff-based g-boxx:


three interpretations. disuss.
 

dw

Wiffle Ball ninja
Sep 10, 2001
2,944
0
MV
Not to derail your thread, but there are not too many engineers on this board, and as an aside, I dont think many of the engineers on this board have really thouroughly researched the application and its idiosyncrasies that surround each system. I think at this point, I am the only person in the world who has actually attempted to build any sort of gearbox standard and then successfully implement it on more than one bike. (The conglomeration between myself and Karl Nicolai of last year that brought forth G-Boxx)

What im saying is that you are probably not likely to come up with much more than random people saying "thats cool". Nothing wrong with that, just saying I dont think that your questions can be accurately answered on this forum.

Not to mention this has been discussed to all holy hell on this very site. Id suggest you start with the search feature.

dw
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
true. i think an all-encompasing forum for armchair speculation & the latest developments might be a good thing. there can never be enough redundant debate & morbid horse flogging!
 

Wingnut

Turbo Monkey
Nov 12, 2003
1,410
89
Sorry, I'm Canadian ..sorry...
I like the PeteSpeed design. Honda's is definately over-engeneered in my opinion, it's basically a four cylinder engine powered by the riders legs, but why turn perfectly good rotation into linear motion and back to rotation, is it only to acheive the near-infinate gear ratio's? Is the GT's similar to the Rohloff?

I think the derailleur will stick around for a long, long time.
 

EVRAC

Monkey
Jun 21, 2004
757
15
Port Coquitlam, B.C., Canada
I'm a gearbox freak. I basically can't get excited about any '05 bikes, cause they all still have rear d's.

Let's start a list:

Honda
GT
Nicolai
Evil
B1
Lahar
BCD

Anyone else?
I heard rumors about a Rocky Mountain version. No pics or anything. A friend saw some drawings. Keep your fingers crossed.
The more players in this game, the better.

Steve
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
yay. a kindred soul. hey - you live down the street! cheers! does rm have an adequately sophisticated r&d dept. to develop something like a gearbox??
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
damn, you build some neat machines, bcd. is that second one rohloff-based?

here's some vintage gearbox (circa 1997): paul brodie's 99'er:


i raced with a guy who had one of these back in the day. pretty nuts for the time.
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
0
amarillo
xy9ine said:
damn, you build some neat machines, bcd. is that second one rohloff-based?

here's some vintage gearbox (circa 1997): paul brodie's 99'er:


i raced with a guy who had one of these back in the day. pretty nuts for the time.

paul actually called me one day to " pick my brain"!

i had alway looked up to his bikes, then he called me.

it was cool. :)
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
paul is a cool guy. he's now restoring/remanufacturing vintage road race motorcycles. apparently his work is highly regarded in those circles.
 

buildyourown

Turbo Monkey
Feb 9, 2004
4,837
0
South Seattle
bcd,
I notice your version with the der simply mounted inboard uses the same sliding sprocket that we saw in those eurobike pics. How did you accomplish this? Just wondering what you ended up using for a bearing. Considering the current offerings of hubs, I think this would be the best design. Good protection for the der but you still have parts that are easy to find should something break. Me likes!
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
0
amarillo
buildyourown said:
bcd,
I notice your version with the der simply mounted inboard uses the same sliding sprocket that we saw in those eurobike pics. How did you accomplish this? Just wondering what you ended up using for a bearing. Considering the current offerings of hubs, I think this would be the best design. Good protection for the der but you still have parts that are easy to find should something break. Me likes!
well no, mine was fixxed to the bb and had chain line problems.
this design also asi have said b/f makes the bike shift reeeeally slow.
no quick shift b/c the ring at the crank is small.

not the best design.

i think a variable trans ratio is the best. one at the bb and one at the high pivot. they would work in congunction and cuthte space needed for ratios on half.

i have been doing some drawlings on mine.
 

Toshi

Harbinger of Doom
Oct 23, 2001
28,188
2,513
dw said:
What im saying is that you are probably not likely to come up with much more than random people saying "thats cool".
gearboxes are pretty cool in my book
 

EVRAC

Monkey
Jun 21, 2004
757
15
Port Coquitlam, B.C., Canada
does rm have an adequately sophisticated r&d dept. to develop something like a gearbox??
Probably not.

Alex, thanks for those pics. Nice to have a closer look. I read on your site that you're waiting for a Rolhoff 7spd. I wrote to Rolhoff about this, suggesting they make a dh version (for normal bikes). I figured a 7 speed would be lighter and a through axle would be sweet. They said no. The axle is the main part of their design, and it would cost too much to change. Other than that, why don't you like the 14? Seems to me more speeds = better. The Nicolai TST is a dh bike with 14 speeds. Sweet.
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
0
amarillo
EVRAC said:
Probably not.

Alex, thanks for those pics. Nice to have a closer look. I read on your site that you're waiting for a Rolhoff 7spd. I wrote to Rolhoff about this, suggesting they make a dh version (for normal bikes). I figured a 7 speed would be lighter and a through axle would be sweet. They said no. The axle is the main part of their design, and it would cost too much to change. Other than that, why don't you like the 14? Seems to me more speeds = better. The Nicolai TST is a dh bike with 14 speeds. Sweet.
i talked to rohlof and there unit runs a high low two speed with the 7s to make 14. the bikes i design are for racing, where max amout of gears you need IMO is 7. i have a 4speed i am going to use at mammoth. i like not to have to DB click my shifter up and down to get gears.

yes, it is true it would be too much to change there axle. it has to remain fixed and the gears drive off it. they could make a 7s only to be frame mounted. it would be narrrower and have no spoke flanges. they told me it could be done but i think the Gbox thing moved them in a different direction.

the Vite will never make it off a LCD

BCD, love the old school double barrel cranks there.

man,! i wish carumba would have made it. i would still run them if they were a isis. a bike shop purchaced everything they ahde and were soposed to come back with a isis. never did though :dead:
 

EVRAC

Monkey
Jun 21, 2004
757
15
Port Coquitlam, B.C., Canada
How about using the new Nexus Inter-8 "Sport"?
Got this info from the Shimano Europe site, search for nexus:

Shimano SG-8R25 (NEW!)
Internally Geared hub (Premium)

Gear Change Support Mechanism

Shimano’s gear change support mechanism uses pedaling power to aid down-shifting. The result is fast and accurate down-shifting with an exceptionnal light touch. Mechanical shifting resistance is notably reduced so shifting is not affected under high loads.

Smooth Gear Change

The smaller idling angle realizes shockless, smoother shifting for stressless comfortable shifting.

Smoother Rotation

Shimano’s precise manufacturing abilities construct an internal hub that rotates with significantly less drag than previous models.

Close Ratio Wider Range

The new Inter-8 hub has increased its gear ratio to 307%, compared to 244% of the current Inter- 7 hub. The new Inter-8 hub also incorporates a closer gear ratio allowing a more efficient and comfortable pedaling cadence. A truly “all conditions” internal hub has arrived.

Better Sealing

The new Inter-8 hub has adopted a labyrinth seal system that shuts out water, and dirt to extend the service life and maintain smooth in all environments. Optionally a waterproof dust cap can be installed on the non-drive side before shipment, in case you wish to use the hub for combination with separate brake systems as V-brakes.

Robust Construction

Durable planetary and step-up gear sets assure long trouble-free service.

Premium Version

Due to needle bearings and better internal mechanics even more durable.

Speed 8 speed
Silent Clutch Yes
Shifting Power Modulator Yes
Shifting Lever ST-8S20 / SB-8S20
Corrosion Resist Coating Yes
Gear Ratio Total 307%
Gear Ratio 1 0.527
Gear Ratio 2 0.644
Gear Ratio 3 0.748
Gear Ratio 4 0.851
Gear Ratio 5 1
Gear Ratio 6 1.223
Gear Ratio 7 1.419
Gear Ratio 8 1.615
Axle length 184mm
Over Lock-nut Dimension 132mm
Spoke Hole 36H
Spoke Size #13, #14
Sprocket Teeth 16, 17, 18, 19, 20, 21, 22, 23T
Weight 1550g
 

Tom DH

Monkey
Apr 24, 2003
144
0
UK
I think gear boxes have got a future in MTB I don’t know if they will ever make it into the XC market but there is defiant potential for it in DH.

The only problem I have with it is that it’s nothing new every one is just concentrating on using a rear gear hub and putting it into the frame. I am not saying that it’s a bad place for it to go but its just using an old idea.

All the hype at the moment is about the gearbox but the so called gearbox is just a rear hub that has been in production for a long time. At work this week I was sorting out a room and I came across an old BSA bike. This bike just had something special about it and I couldn’t throw it away, so I thought I would tack it a part. It had a gear hub on it and I thought it was just a Sturmey archer one but it was a BSA now this hub had to be about 65 – 75 years old and was still going strong.
Now my point is that this was an old hub, which uses the same technology as this “new” gearbox idea.

What I am getting at is that we need to concentrate more on an actual gearbox not a rear hub and then work on the frame design.

Then you have got the B1 that looks like just a cassette above the BB so not much going on there.

Then you have got the Honda, which I don’t know anything about, but it’s the one that I think has had some thought about completely designing gearbox.

It’s a good thing that all these companies are getting involved with this idea but I think that Honda are going the right way about it.

And then you have got the compatibility problem, which I think will always be a problem. The g-box idea is good to try and make a standard but if gearboxes are going to be used then they are going to have to be part of the frames structure. So I don’t think that a standard could ever be made that all companies could use. They should concentrate on there own designs and the one with the best will make the most money.

Having said all this I am very exited about this and the next DH frame I get I want it to have some sort of gearbox .
 

ioscope

Turbo Monkey
Jul 3, 2004
2,004
0
Vashon, WA
MBA says it's a crankset attached to a tranny-ish gear which clicks an adjustable angle rockerarm which ratchets another wheel which is directly attaached to a chain whick goes to a patented freewheel which can roll backwards, something about protecting the gearbox.
 

prophet6

Chimp
Mar 25, 2002
96
0
North Easton, MA
bcd:

Vintage!

I could however see a hydrolic version of that... use something like a gripshift w/ a master cylinder to push hydrolic fluid. That'd run down a line and drive the spanners on those wheels either in or out.

pretty neat.



p6
 

Kntr

Turbo Monkey
Jan 25, 2003
7,536
20
Montana
The new Nicolai seems to be one of the best set-ups I've seen. I need a new trail bike in the 6" range and it looks promising but I still have to see the price.:(
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,860
252
vancouver eastside
EVRAC said:
hmmmmmm... dw mentioned he had been exploring alternative gearbox applications. i suppose it could be something other than the (rohloff-based) g-boxx. (though it could just as likely be a hoax to throw e-speculators into a frenzy).
 

ioscope

Turbo Monkey
Jul 3, 2004
2,004
0
Vashon, WA
Has anyone actually torn off a derailleur, or broken one?
I know it can happen, but I have only barely bent one, and it still works.