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the gearbox thread

L

LMC

Monkey
Dec 10, 2006
683
1
thats what i initially thought when i watched the video, but i couldnt work out how he would get the correct ratio, the cam would nudge the cam followers 2x for every one full rotation of the input, looking at how much the output moves when he manually moves the cam follower, theres no way he could get a harder gear using that setup.

what i think he has done is attached the input to the output via another sprag so the default gear ratio is 1:1, when the cam followers move they 'nudge' the output forward to whatever degree
 
MobileChernobyl

MobileChernobyl

Monkey
Apr 16, 2006
392
0
Golden, CO
Yea, now I remember seeing that inversion in action. Makes sense how it would work with negative input. I will just use another sprag clutch with my design since I can't invert it like that.

Onto another topic -

Does anyone have a graph of the average power output of the average competitive cyclist for one rotation? I'm imagining a somewhat sinusoidal output from our legs. Theres gotta be something out there, they had to have one to design the biopace rings. I can't find any however on google
 
Wilhelm

Wilhelm

Monkey
Aug 10, 2003
444
19
EVRAC said:
Found some pics of the latest from Rotec. Didn't spot the TAG wheels before. Must say, looks hot. Go Sully!
Click to expand...
Hot looking with John riding the rig. So the super bend top tube doesn´t look too ugly. Seems this is one of the first gearbox bikes with Hopey´s steering damper.
 
ire

ire

Turbo Monkey
Aug 6, 2007
6,196
4
I like the bike, I don't really care for the wheels. Anyone know the travel?
 
John Sullivan`

John Sullivan`

Monkey
Sep 10, 2001
162
0
Seattle,WA
2nd gen proto will have a slightly higher tt so the shock can be flipped back into the correct ( in my eyes) resi up and forward postion. Still have't decided yet if it will be a straight tube as some have suggested though. Kinda like the curved tt look.

And yes the design does lend itself to be a great SP design! Hint,Hint!

8.25 inches travel but this may change slightly.
 
ire

ire

Turbo Monkey
Aug 6, 2007
6,196
4
Are there plans for eventual production? If so, any rough dates? Maybe '10?
 
Secret Squirrel

Secret Squirrel

There is no Justice!
Dec 21, 2004
8,150
1
Up sh*t creek, without a paddle
John Sullivan` said:
2nd gen proto will have a slightly higher tt so the shock can be flipped back into the correct ( in my eyes) resi up and forward postion. Still have't decided yet if it will be a straight tube as some have suggested though. Kinda like the curved tt look.

And yes the design does lend itself to be a great SP design! Hint,Hint!

8.25 inches travel but this may change slightly.
Click to expand...
When you put a large frame together, let me know. I will buy it. I will ride it. I will love it. You want another daughter? You can have mine for that bike. I can handle a pissed off wife.... :busted:

:banana::banana::banana::banana::banana::banana: :happydance:
 
John Sullivan`

John Sullivan`

Monkey
Sep 10, 2001
162
0
Seattle,WA
nsm, you don't want to know. Lets just say its 1st article effort and the next ones will be worthy of weight disclosures.

Its really wasn't important to me, the weight that is on these two frames.

In the end, it's very important that this design does meet what we deem, an acceptable expectation for weight and that's what we're working towards.
 
wuchi

wuchi

Chimp
Jun 7, 2008
17
0
Åre (sweden)
here is a design i've been working on.
this is just the renders of the first version.

Spec:
Travel: 8,5in
Shock: 9x3"
Chainstay: 420mm
Effective toptube length: 580mm
Seattube angle: 73
Headtube: 1,5"
Headtube angle: 66,5
Headtube height: 120mm
Headtube-to-axle: 570mm
Wheelbase: 1140mm




version2(which i'm working on right now) will have some changes in geo:

:: 20mm higher BB
:: support stay between the seatstays (close to the shocklink)
:: 10mm longer chainstays than version1
:: small reinforcement between seattube and toptube


the first prototype will be in good old 4130steel but after some real testing on the mountain there will be a reynolds853 version to save some weight.


please post comments and tips.

/rickard
 
Wilhelm

Wilhelm

Monkey
Aug 10, 2003
444
19
wuchi said:
here is a design i've been working on.
this is just the renders of the first version.

Spec:
Travel: 8,5in
Shock: 9x3"
Chainstay: 420mm
Effective toptube length: 580mm
Seattube angle: 73
Headtube: 1,5"
Headtube angle: 66,5
Headtube height: 120mm
Headtube-to-axle: 570mm
Wheelbase: 1140mm




version2(which i'm working on right now) will have some changes in geo:

:: 20mm higher BB
:: support stay between the seatstays (close to the shocklink)
:: 10mm longer chainstays than version1
:: small reinforcement between seattube and toptube


the first prototype will be in good old 4130steel but after some real testing on the mountain there will be a reynolds853 version to save some weight.


please post comments and tips.

/rickard
Click to expand...
Seems promising. Maybe a "Split-Pivot" rear dropout could be a further improvement (see further http://www.ridemonkey.com/forums/showpost.php?p=2965973&postcount=217).
 
joelsman

joelsman

Turbo Monkey
Feb 1, 2002
1,369
0
B'ham
you should mount the front of the shock on the top tube instead of the down tube, less stress going along the tube instead of pushing in the middle and you could fit the 9.5x3 shock easily

otherwise I think it looks great.
 
MrPlow

MrPlow

Monkey
Sep 9, 2004
628
0
Toowoomba Queensland
joelsman said:
you should mount the front of the shock on the top tube instead of the down tube, less stress going along the tube instead of pushing in the middle and you could fit the 9.5x3 shock easily

otherwise I think it looks great.
Click to expand...
At the expense of the correct suspension rate? I dont think it would be a problem.
 
wuchi

wuchi

Chimp
Jun 7, 2008
17
0
Åre (sweden)
of course it will have a discmount in the rear, I was just lazy when i put the assembly together late last night so i just mirrored the driveside dropout plate for now. i'll fix it for the next render.

and i think I will change the rearshock size to standard 9,5"x3" but with the same linkage rate etc. we will see, just a first proto. I made it 9x3 in the first place because i have an old shock in that size just laying and collecting dust at the time.


by the way, here in Sweden I already have 2 potential buyers, so i might just as well make 3 frame. and finance my own frame that way :)


ill post renders of the new version in the middle of the next week.

please comment and give me more tips along the way :)
/rickard
 
Last edited:
wuchi

wuchi

Chimp
Jun 7, 2008
17
0
Åre (sweden)
Wilhelm. the geometry is exactly what I want from a dh-frame.(when i've done the changes to version2)
if other people want to buy a frame they can have a frame with custom geo for their need.
adjustability often result in more weight i'm afraid.
but sure if some one wants a frame with the same adjustments as the ION then thats no problem. just 30minutes extra in CAD
 
Wilhelm

Wilhelm

Monkey
Aug 10, 2003
444
19
wuchi said:
Wilhelm. the geometry is exactly what I want from a dh-frame.(when i've done the changes to version2)
if other people want to buy a frame they can have a frame with custom geo for their need.
adjustability often result in more weight i'm afraid.
but sure if some one wants a frame with the same adjustments as the ION then thats no problem. just 30minutes extra in CAD
Click to expand...
wuchi (besides: what is the meaning of your droll nickname?), I agree, most add-ons for adjustment bear the load of some weight penalty.

However, we are curious to get any news about your project in the time to come.
 
Wilhelm

Wilhelm

Monkey
Aug 10, 2003
444
19
Ian Collins said:
split pivot plus chain tensioners = way too much going on in one small space
Click to expand...
In the case of a gearbox bike like wuchi´s project with a secondary drivetrain including a fixed gearing as well as the main pivot around the sprocket shaft you won´t need any chain tensioner.
 
EVRAC

EVRAC

Monkey
Jun 21, 2004
757
19
Port Coquitlam, B.C., Canada
P.T.W said:
How would you adjust the chain tension?
Click to expand...
True. It seems we need to distinguish between the 2 types of tensioners. One type is spring-loaded, like a little derailleur, for bike with chaingrowth, the other is for initial setup, like a chain-tug and horiz. dropout setup like a BMX.

Suggestions for simpler terminology?

Anyways, as far as I know, no one has created a split-pivot design with adjustable chainlength yet. I'm working on it myself. It would be easy enough to do a box-style dropout slider like the diamondback sabbath, and then mount the seatstays outboard on bearings on the axle itself. Not very compact though and the bike would sort of fall apart when you take off the wheel.

I'm sure DW's got something cooking...
 
Wilhelm

Wilhelm

Monkey
Aug 10, 2003
444
19
Ralf TRÖGER, the creator of the nice CENTURION branded LAWWILLish looking parallelogram G-Boxx 1 bike "Stonedigger" unveilled at Eurobike 2006, seems to proceed with his project. Just visited his advanced, interesting website: http://www.troeger-engineering.de. Hope that his parallelogram suspension conception will be realized and enriches the future market of gearbox bikes. He seems to plan an entire range of parallelogram suspension gearbox bikes ("Stonedigger" DH, FR, Enduro, AMS), even though without further teaming up with CENTURION (they would continue to stay in the CC market only). Ralf is looking for a capable manufacturing partner now and focuses a frame set price of about € 4000-4500. Until then he offers to build custom made frames by preorder with prepayment of 50 % of the total price.



 
P.T.W

P.T.W

Monkey
May 6, 2007
599
0
christchurch nz
EVRAC said:
Anyways, as far as I know, no one has created a split-pivot design with adjustable chainlength yet. I'm working on it myself. It would be easy enough to do a box-style dropout slider like the diamondback sabbath, and then mount the seatstays outboard on bearings on the axle itself. Not very compact though and the bike would sort of fall apart when you take off the wheel.

I'm sure DW's got something cooking...
Click to expand...
But if you where to do that you would be adjusting both your wheel rate and changing your progression curve.Also an eccentric adjuster as mentioned on the split pivot thread would render the whole idea behind the split pivot(being concentric) moot
 
Nately27

Nately27

Monkey
Jul 29, 2003
121
0
im boggled. they claim 1.5kg with 8 speeds. It looks like a spur gear box like the suntour or chain style like the new G-boxx, but its SO SMALL! How do they handle the torque?
 
L

LMC

Monkey
Dec 10, 2006
683
1
^^^ metzys rig i presume? its like a cromo laharesque setup isnt it? i always thought the all mountain carbon rig he had posted earlier in this thread would have been a good one to go into production with, it looked stunning.

my friend emailed me this, a lego rohloff trigger shifter.

http://www.flickr.com/photos/tfj77/2835624019/
 
W

Whoops

Turbo Monkey
Jul 9, 2006
1,011
0
New Zealand
LMC said:
^^^ metzys rig i presume? its like a cromo laharesque setup isnt it? i always thought the all mountain carbon rig he had posted earlier in this thread would have been a good one to go into production with, it looked stunning.

my friend emailed me this, a lego rohloff trigger shifter.

http://www.flickr.com/photos/tfj77/2835624019/
Click to expand...
Yep - Metz/Dodds proto. Production version eta end of the year(?)
 
G

gruczniak

Chimp
Apr 25, 2008
21
0
While i really love the idea of triggered Rohloff i think this trigger looks weird. It is a proto so it may and hopefully will change before production.
 
no skid marks

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
I still think the trigger mechanism should be mounted under the stem(from face plate bolts)with a trigger each side, simple.Probably better for multiple gear changes also. I don't have a problem with the Twit shifter for the Rohloff, it's good for dumping gears and I've never mis shifted, it's not like a Shimanno one.
 
L

LMC

Monkey
Dec 10, 2006
683
1
no skid marks said:
I still think the trigger mechanism should be mounted under the stem(from face plate bolts)with a trigger each side, simple.Probably better for multiple gear changes also. I don't have a problem with the Twit shifter for the Rohloff, it's good for dumping gears and I've never mis shifted, it's not like a Shimanno one.
Click to expand...
yeah about a year ago i was working on a rohloff based gearbox/trigger shifter.

the shifter was a left/right paddle affair with the actual workings inside the stem. one or two shifts at a time similar to the SRAM/Shimano units. I shelved it because i couldnt get the weight of the gearbox below 3.5kg but ive still got the 3d printer parts.. and they seemed to work ok. it was just a case of fine tunung the spring weights and tolerances for the sliding parts.

my digital camera isnt working just now but ill have one in a few days and ill fire photos up
 
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