Structure Cycleworks

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Zaf

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Does anyone have a geo chart for the G1, G2 and G3 variations of the bike?
The only thing I can find on the site is the seat tube angle being at 76° and measured from the saddle, not the handlebar.
Curious about the different wheelbases and chainstays, BB height, reach, stack, head angle etc. The common lot. I understand that wheelbase might be a trickier one depending on the growth by that front end during compression.
Also @Structure-Ryan any provision for a gear box on the design?
Edit: or a bottlecage?
 

Structure-Ryan

Likes Bikes
Lollies mate, LOLLIES!
Strut!You can’t expect to crack into the straya market without knowing the lingo.
Also, Firies, stubbies, tinnies, ambo, bottleo, compo, houso....none of us actually know what these mean. We just add ‘ies’ or ‘o’ to random words.
That's what I always suspected.

When comparing traditional, telescoping suspension to a linkage design, would it be "tellies vs. linkies"? Maybe "tellies vs. linkos?" This will, naturally, form the foundation of our Australian marketing campaign, so it's very important we get it right.
 

Structure-Ryan

Likes Bikes
Does anyone have a geo chart for the G1, G2 and G3 variations of the bike?
The only thing I can find on the site is the seat tube angle being at 76° and measured from the saddle, not the handlebar.
Curious about the different wheelbases and chainstays, BB height, reach, stack, head angle etc. The common lot. I understand that wheelbase might be a trickier one depending on the growth by that front end during compression.
Also @Structure-Ryan any provision for a gear box on the design?
Edit: or a bottlecage?
The geometry has been finalized, but there's a question of how to talk about it.

For example, the head angle is 66°, which sounds like typical all-mountain fare or maybe a touch steep for up-to-the-minute enduro geometry. But that's at full droop (topped out). At full bump (compression - and we need to specify pitch vs. heave, so let's use pitch), a "super slack" DH bike with 62° static head angle ends up around 73°, while ours stays 66°. (Interesting note: from XC racers to DH sleds, all telescoping bikes end up around 73° at full bump in pitch.)

Seat tube angle is measured level with the head tube, but no one pedals at that height. A bike like the Evil Wreckoning, as just one example, may claim a 74.8° seat tube angle, but it will be in the 60s once a tall rider has put it up to pedaling height. My 76° is at the actual (assumed) pedaling height for each chassis size.

Even reach is poorly understood. Stack height affects reach at a rate of about 40%, meaning that if two bikes have the same reach, yet one has 30 mm more stack, the bike with more stack is about 12 mm longer. Our bikes have a very high stack due to two head tubes (a flat or low-rise bar puts it back in the normal range), so our reach values look shorter than they feel. The best sizing analogies are the Transition Sentinel, Raaw Madonna, Mondraker Foxy, Identiti Mettle, and Kingdom Hex, with the G1 roughly corresponding to a Small, G3 to XL, and G2 halfway between. To put it another way, G1 is a small by the "new" geometry or medium in more conventional geometry, G2 is a "new" M/L or conventional L/XL, and G3 is a "new" XL.

Keep in mind that a telescoping fork will shorten the front-centre by almost two frame sizes' worth when compressed, while ours holds steady on length. As such, the SCW 1 rides a LOT bigger than the numbers suggest. That's where our "stability on demand" concept comes from: you shouldn't have to ride something with the length of an ocean-going vessel on tame terrain, just to prevent things getting sketchy on difficult terrain or at high speed. Alternatively, if you don't mind a bit of a long bike on tame terrain and you choose to size up, the high speed performance is an entirely new experience.

EDIT: Forgot to mention the bottle cage. As a fan of on-bike storage, it breaks my heart to have to tell you it's under the down tube. I'm working on squeezing one inside the main triangle on a future project, but don't hold your breath!
 
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Structure-Ryan

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@Structure-Ryan - will there be an alloy version? I kinda like the look of the alloy test mule better than the carbon. Looks more like a mountain bike, less like a Hollywood prop.
Only carbon. We don't expect to sell enough bikes to use up our carbon molds, so creating an additional model would drive up the cost on both. If we're going to create a carbon version, then that has to be our only version. Also, the intricate design doesn't lend itself to metal, so an aluminum version would be nearly as expensive as carbon with a substantial weight penalty.
 

moorey

call me Mia
@Structure-Ryan re: stack height and reach, am I insane (not generally, more about here specifically), or just completely missing something, but given a 65 ha, a taller stack will angle the reach back bringing bars closer to you and shortening reach*

*I’m with the masses who don’t fully understand reach.
 
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Zaf

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@moorey , that's kind of how I understood it also. Maybe hes talking a fully pitched stack rather than a drooped one?
 

Structure-Ryan

Likes Bikes
@Structure-Ryan re: stack height and reach, am I insane (not generally, more about here specifically), or just completely missing something, but given a 65 ha, a taller stack will angle the reach back bringing bars closer to you and shortening reach*

*I’m with the masses who don’t fully understand reach.
The fact that you're interested in clearing up a misconception suggests you may be more sane than most!

Have a look at this MS Paint masterpiece I whipped up. Both frames have the same reach and head angle, but the blue bike has greater stack. Notice how the blue frame is longer. This is why I prefer to use "normalized reach", in which all reach numbers are measured at a standard stack.

Normalized Reach.png
 
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Zaf

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I can’t get my head around his that would change it...
Yeah, that was a joke.

The fact that you're interested in clearing up a misconception suggests you may be more sane than most!

Have a look at this MS Paint masterpiece I whipped up. Both frames have the same reach and head angle, but the blue bike has greater stack. Notice how the blue frame is longer. This is why I prefer to use "normalized reach", in which all reach numbers are measured at a standard stack.

View attachment 343151
Everything I've ever known is a lie!!
 

Structure-Ryan

Likes Bikes
@moorey , that's kind of how I understood it also. Maybe hes talking a fully pitched stack rather than a drooped one?
Note: "Pitch" and "heave" refer to the type of compression (front only vs. equal F&R). "Bump" and "droop" refer to the amount of compression.

I'm torn between using these terms, which have existed in motorsports since the forefathers of mountainbiking were still in diapers (that's "nappies" to you ... or is it "diapos"?), and "proper" mountain bike terminology that we invented while we were trying to reinvent every other aspect of suspension design.
 

moorey

call me Mia
The fact that you're interested in clearing up a misconception suggests you may be more sane than most!

Have a look at this MS Paint masterpiece I whipped up. Both frames have the same reach and head angle, but the blue bike has greater stack. Notice how the blue frame is longer. This is why I prefer to use "normalized reach", in which all reach numbers are measured at a standard stack.

View attachment 343151
Diagram not helping my old man brain. If they were laid on top of each other, I’m not seeing the blue longer, just it’s reach shorter.

You are probably right. I’m sure it’s me, not you. Engineering isn’t my strong point.
 
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Zaf

Guest
Okay, as I understand it, reach is calculated by the invisible horizontal line between the middle of the bottom bracket and the center of the TOP of the head tube. Stack is the verticle line between these points.

Unless the HA is beyond 90° (ie, angling back towards your BB), increase in stack height will still shorten reach.
 

Structure-Ryan

Likes Bikes
Diagram not helping my old man brain. If they were laid on top of each other, I’m not seeing the blue longer, just it’s reach shorter.

You are probably right. I’m sure it’s me, not you. Engineering isn’t my strong point.
If the head tubes were overlaid, their tops would no longer be in the same vertical plane; therefore, they would not have the same reach. The drawing shows two frames with the same reach and same head angle. Note the red, right-angle triangle showing the identical reaches.
 
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Structure-Ryan

Likes Bikes
Okay, as I understand it, reach is calculated by the invisible horizontal line between the middle of the bottom bracket and the center of the TOP of the head tube. Stack is the verticle line between these points.

Unless the HA is beyond 90° (ie, angling back towards your BB), increase in stack height will still shorten reach.
You're correct about how they're measured, but not about what happens when stack increases.

If we simply extend the head tube of a given frame, then the reach shortens because the top of the head tube moves back as it moves up. That's not what we're doing here; we're talking about constant reach.

The only way to hold reach constant as stack increases is to slide the frame forward to compensate for how the head tube is moving. This is where the increase in length comes from. Same reach, more length due to stack.

I can only encourage you to try to draw it for yourself. You'll quickly spot the issue.
 
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Zaf

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@Structure-Ryan I think I get where the confusion comes from, you're saying that your design compensates for a stack increase on the frame by increasing the reach to keep it common. But the basic concept of, if you stack spacers under your handlebar, you effectively shorten your reach still holds true, it's just as far as the frame is concerned you keep that number constant and compensate for it in your design.
 

Structure-Ryan

Likes Bikes
@Structure-Ryan I think I get where the confusion comes from, you're saying that your design compensates for a stack increase on the frame by increasing the reach to keep it common. But the basic concept of, if you stack spacers under your handlebar, you effectively shorten your reach still holds true, it's just as far as the frame is concerned you keep that number constant and compensate for it in your design.
"Reach" is a frame dimension. You cannot shorten it with spacers. You're correct that spacers do shorten the distance between the BB and the bar. It's important to be consistent in our use of the term "reach" and not allow it to refer to both the frame dimension (BB to head tube top, as you noted) and the saddle to bar length.

Yes, I do account for the stack effect when designing my reach values. It's the only proper way to do it.

Many frame designers don't even understand this relationship. Kona, among many others, is a good example: their frames have traditionally had the same reach values for each size, regardless of the stack, which produced an inconsistent feel across the size range and between models.

Among 98 companies analyzed, I've only spotted two that showed clear evidence of designing with this in mind: when I calculated "normalized reach" values (i.e. with compensation for stack), these companies' geometries were either consistent across models (i.e. consistent across varying stacks) or produced nice, round numbers at the normalized values.
 
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Zaf

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I think I've grasped the concept now. This kind of feedback from the industry is fantastic!

Now, can it take a waterbottle, and what plans do you have for the future, and when the the Pinion Gearbox version coming to market?
 
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