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the gearbox thread

xy9ine

Turbo Monkey
Mar 22, 2004
2,940
353
vancouver eastside
I'm not sure if this has been brought up yet - (been out of this thread for quite a while) but since we are on the subject of suspension design around a gearbox platform:

How the hell can DW pull off his DW-Linkage system around one of these things? I mean how could he retain all of the necessary geometry points, leverage ratios, and linkage locations of the DW-Link system without doing something drastic?

I was thinking about this the other night and could'nt quite see how it would work.

DW - any thoughts here?... how is it coming along?
there's been speculation that his orion suspension design (moto based) might be developed for a gearbox application - ie, a new dw-esque suspension layout more gearbox friendly than the current design.
 

SOil

Chimp
Jun 24, 2005
82
0
You can add California based Versus Cycles to the list :cheers:

They'll have a G-boxx based frame out at Interbike booth #4063
 

Transcend

My Nuts Are Flat
Apr 18, 2002
18,040
3
Towing the party line.
It's funny how similiar all of the gboxx/vboxx bikes are smiliar, due to the need to use the box as a structural member and get the cranks in the right place.

Has anyone done a non single pivot version yet?
 

WheelieMan

Monkey
Feb 6, 2003
937
0
kol-uh-RAD-oh
It's funny how similiar all of the gboxx/vboxx bikes are smiliar, due to the need to use the box as a structural member and get the cranks in the right place.

Has anyone done a non single pivot version yet?
I was just thinking the same thing.
Having a gearbox standard definitely allows for more companies to jump on the boat, but it sure does a good job of making it more difficult to design the suspension geometry around the gearbox. A simple, relatively lightweight internally geared hub keeps sounding better...
 

MinorThreat

Turbo Monkey
Nov 15, 2005
1,630
41
Nine Mile Falls, WA
I was just thinking the same thing.
Having a gearbox standard definitely allows for more companies to jump on the boat, but it sure does a good job of making it more difficult to design the suspension geometry around the gearbox. A simple, relatively lightweight internally geared hub keeps sounding better...
Has anyone messed around with a Sturmey-Archer XRK8 yet? Or is it destined to blow up the first outing?
 

Inclag

Turbo Monkey
Sep 9, 2001
2,758
446
MA
It's funny how similiar all of the gboxx/vboxx bikes are smiliar, due to the need to use the box as a structural member and get the cranks in the right place.

Has anyone done a non single pivot version yet?
There was that Lawill style gear box bike at Eurobike. Can't remember the name, but pics were posted here.

BTW, like to add that so far, I much prefer visually the look of the Suntour V-Boxx for its lower profile.
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM
It's funny how similiar all of the gboxx/vboxx bikes are smiliar, due to the need to use the box as a structural member and get the cranks in the right place.

Has anyone done a non single pivot version yet?

Yeah, rotec make a lawill bike i have some pics i will post tomorrow.

dead, just got back

alex
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,386
6,465
borcester rhymes
that right there is going to be a winner...the pivot is a little low for me, especially with a gearbox, but I can see a TON of people picking one of those up for the season...
 

Secret Squirrel

There is no Justice!
Dec 21, 2004
8,150
1
Up sh*t creek, without a paddle
o....m.....f......g..... :cheers: :banana: :busted: :happydance: :brows:

That's sooo hawt... I need to start saving now and ride the piss outta my current Rotec....Then I'll have to upgrade....

I'll have to go over to Sully's once he's back from IB and get the 411 on this bad boy!!!
 

Zark

Hey little girl, do you want some candy?
Oct 18, 2001
6,254
7
Reno 911
Not much room for the shock in that layout, could be a real problem in small frames.
 

Zark

Hey little girl, do you want some candy?
Oct 18, 2001
6,254
7
Reno 911
S.S.,I'm not really worried about which shock and how much room it has. I'm talking about making a frame small enough for someone under 5'10" and have a shock mounted above the gearbox.
 

Secret Squirrel

There is no Justice!
Dec 21, 2004
8,150
1
Up sh*t creek, without a paddle
S.S.,I'm not really worried about which shock and how much room it has. I'm talking about making a frame small enough for someone under 5'10" and have a shock mounted above the gearbox.
That's what I was referring to as well...but in a more comprehensive nature. It looks tight now cause it's a frankenbike just like the original RL9 proto. It's all peiced and welded together. The original proto frame was 15 lbs. and had whacky pieces everywhere. Just the fact that a DHX fits on there now (that's a medium in the photo I believe) bodes well for when the production model comes to fruition. *shrug* Time will tell.
 

MrPlow

Monkey
Sep 9, 2004
628
0
Toowoomba Queensland
So Rotek bag out Yeti for not using Mert's concentric BB design, then entirely change the pivot location to suit a heavy gearbox design??
It looks as though they have really slapped that together, how much thought / calculations have theyu put in to the axle path etc?
 

zedro

Turbo Monkey
Sep 14, 2001
4,144
1
at the end of the longest line
So Rotek bag out Yeti for not using Mert's concentric BB design, then entirely change the pivot location to suit a heavy gearbox design??
It looks as though they have really slapped that together, how much thought / calculations have theyu put in to the axle path etc?
its still a concentric design, although concentric to the secondary drive.

axle path is gonna be pretty damn similar to the rest of the high pivots it looks...
 

zedro

Turbo Monkey
Sep 14, 2001
4,144
1
at the end of the longest line
i could be completely wrong, but wouldn't that design give you a vertical or very close to vertical wheelpath? looks quite interesting.
no such thing, Lawills have a fairly marginal variation from a single pivot.

i'm wondering about the lack a brake linkage (floater or otherwise), big no-no. Love the machining and overall design tho
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
The Rotec would appear to use the same sort of tiny brake arm that the Yetis used,transfering brake force to bottom swingarm.
It seems to have a chain tensioner indicating that it would have a similer wheel path to a high (BB7,RaceLink,Lahar)pivot bike,so yes rear to verticalI'm guessing. Best design for the Suntour box yet i recon,looks heavy but I'm sure it's a proto.
The Centurion pictured has no chain tensioner indicating that it in theory is just a single pivot,pivoting around the middle of the gearbax output sprocket at top.
 

WheelieMan

Monkey
Feb 6, 2003
937
0
kol-uh-RAD-oh
The Rotec would appear to use the same sort of tiny brake arm that the Yetis used,transfering brake force to bottom swingarm.
It seems to have a chain tensioner indicating that it would have a similer wheel path to a high (BB7,RaceLink,Lahar)pivot bike,so yes rear to verticalI'm guessing. Best design for the Suntour box yet i recon,looks heavy but I'm sure it's a proto.
The Centurion pictured has no chain tensioner indicating that it in theory is just a single pivot,pivoting around the middle of the gearbax output sprocket at top.
The Rotec design would require the tensioner no matter if the wheelpath is rearward or not...

The Lawwill design makes no sense to me in its conventional application, and even less when combined with a gearbox. The Rotec would not perform any differently if it was a concentric single-pivot, but it would not require the chain tensioner to take up chaingrowth.
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
The Rotec design would require the tensioner no matter if the wheelpath is rearward or not...
Yes true,good point. There would be a slightly bigger arc due to the top arm more rearward front pivot but without being able to see where the top rear pivot is and how long the top arm is it's hard to say,a full side photo would be better to determin this. If the bottom arms rear pivot was lower and further away from the axle it would give a bigger wheel travel arc especially if the top arm was long,but ground clearance issues would be no better or worse than a rear deraileur. None the less it would offer at least a slightly more rearward action.Chain growth would then become an issue,and affect the suspension,so would chain induced anti squat. I think a high single pivot with a roller to relocate the drive output would work better and weigh less if the G-Box housing would permit the chain to exit upwards,you'd then have less chain purchase on the G-box sprocket though. Points for trying.Tyre clearance looks tight,near the shock.
 

davep

Turbo Monkey
Jan 7, 2005
3,276
0
seattle
So Rotek bag out Yeti for not using Mert's concentric BB design, then entirely change the pivot location to suit a heavy gearbox design??
It looks as though they have really slapped that together, how much thought / calculations have theyu put in to the axle path etc?

As other have said, it is still concentric to the output. Same as it is now.

I guarantee that frame is slapped together. It is IB and it is a working concept. The orig. RL 9 was the same way. Chopped and welded together and painted on a balcony in vegas the night before IB. That just seems to be the way that Sully works. Give it a little time and it will be refined, lighter, and much more polished, if history is any indication.
 

thaflyinfatman

Turbo Monkey
Jul 20, 2002
1,577
0
Victoria
no such thing, Lawills have a fairly marginal variation from a single pivot.

i'm wondering about the lack a brake linkage (floater or otherwise), big no-no. Love the machining and overall design tho

It's not a Lawwill, it's a true parallelogram linkage with the CC at the drive output (note the lack of chain tensioner). It won't need a brake linkage/floater.