# Carbon vs Aluminium Frame heavy users



## FoFos (Apr 23, 2017)

So after a browsing on the ''dark side of youtube'' i came across again on the video from Santa Cruz 





and this question came up to my mind instantly . Is a carbon or an aluminium frame MTB more suitable for heavy users ? 
Based on Endurance i believe or give me your thoughts .


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## FoFos (Apr 23, 2017)

any thoughts guys ?


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## TooTallUK (Jul 5, 2005)

People have had good experiences with both, also bad experiences with both. Some manufacturers have weight limits, some don't. It's more about the brand and the way they make it than the material itself. A quality frame in any material is going to be good. Carbon seems to be there these days.


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## DarthBobo (Sep 21, 2016)

Either will do. I would buy Aluminium and go for higher level components before spending extra on Carbon. I picked up a 2017 Giant Trance 2. It weighs 30.1 lbs. Advanced 1 is 29.0 weighed at the shop side by side. Spend an extra 2k ish for a 1 pound lighter bike or spend that extra 2k on fork, shock or groupset upgrades.

Carbon will handle a clyde but unless you are a pro racer why bother?


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## FoFos (Apr 23, 2017)

So seems like both aluminium and carbon are the same in endurance when they are being ride by heavy users on some XC or trails paths . always depending on the manufacturer . I cannot say my opinion on FS bikes cause i know most of the rear suspensions are having very low weight limits compared to the front or i am wrong ?


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## oikeith (Feb 15, 2017)

I think Santa Cruz recommend carbon for heavier riders, not sure where I heard this though.


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## Cavey (Oct 17, 2014)

230lbs and ride steel (Honzo) and aluminum (Tracer). I figure I can lose the pounds I would save on a carbon bike by eating a few less pies! 

I always have concerns about damaging the frame (broken a few in the past) and with the steel and aluminum I'd shed tears but with carbon I'd be wailing like a banshee trail side.


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## Uwibami (Apr 26, 2017)

DarthBobo said:


> Either will do. I would buy Aluminium and go for higher level components before spending extra on Carbon. I picked up a 2017 Giant Trance 2. It weighs 30.1 lbs. Advanced 1 is 29.0 weighed at the shop side by side. Spend an extra 2k ish for a 1 pound lighter bike or spend that extra 2k on fork, shock or groupset upgrades.
> 
> Carbon will handle a clyde but unless you are a pro racer why bother?


with ya there


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## RAKC Ind (Jan 27, 2017)

Depends on your version of heavy too. At my size no way I'd ride a carbon frame. If your considering yourself a Clyde because you weigh 225 at 6ft tall, carbon is fine.

I stick with metal frames, aluminum ATM but might get a steel frame build going soonish.

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## FoFos (Apr 23, 2017)

i am 202cm 125kilos aiming to go again down to 115 . Was considering that if anyone is having any idea about the endurance of the difference between the frames alu vs carbon , since i am having an Aluminium hardtail and i am aiming to get a new XC for my weight/size


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## thesmokingman (Jan 17, 2009)

FoFos said:


> any thoughts guys ?


If you're lucky to have the choice between the two materials, carbon fiber is clearly better.


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## FoFos (Apr 23, 2017)

thesmokingman said:


> If you're lucky to have the choice between the two materials, carbon fiber is clearly better.


based on my size and weight are you sure ?


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## DarthBobo (Sep 21, 2016)

Your weight is not going to hurt quality carbon. You have to decide if your willing to spend the extra money on a component that really wont make much difference in the performance of the bike. If you want carbon because is trendy/cool then go ahead. If your looking for quality and value, Alum with better components will make you happier.


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## drwx (Jun 4, 2011)

I went through this debate when I bought my Bronson. I watched that Santa Cruz video a few months prior to my purchase and it really changed the way I looked at carbon. I got a killer price on the c level carbon that put it on the same price range as the aluminum one with identical specs, plus the carbon bronson has iscg tabs whereas the aluminum one doesn't. The research I did convinced me that aluminum fatigues over the years and becomes weaker even though it doesn't obviously bend and that after some time it could fail suddenly. I think a lot of that depends on how you ride, because I see really old aluminum frames out there that aren't broken.

Even with the research I did, I was paranoid on my first ride and even more paranoid after my first wreck. SC offers a lifetime warranty on their frames with a no fault replacement policy. If it's a warranty fault, they replace the frame. If it's a wreck that breaks it, you can buy the component for cheaper than retail priced frame.

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## thesmokingman (Jan 17, 2009)

FoFos said:


> based on my size and weight are you sure ?


A few years back, they finally realized why different size frames handled differently. Frames behave differently when scaled up vs down, ie large frames were more spongy and small frames were too stiff. The irony is that the principle seems rather obvious but it didn't get put into application for a longtime. Anyways, with carbon fiber they can thru analysis design and make a frame that behaves exactly the way they intended it to regardless of the size because they can adjust the layup to compensate for the inherent effects of simply enlarging or shrinking a medium to large/small.


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## TooTallUK (Jul 5, 2005)

thesmokingman said:


> they can thru analysis design and make a frame that behaves exactly the way they intended it to regardless of the size


'They' can do that with any material - steel, carbon, alu.
Whether 'they' do or not is a completely different matter,


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## thesmokingman (Jan 17, 2009)

TooTallUK said:


> 'They' can do that with any material - steel, carbon, alu.
> Whether 'they' do or not is a completely different matter,


They cannot actually or that is, its just not how things are done. It's a sales issue because frames are sold by tube sets not material stiffness or characteristics. And simply using a larger tube diameter does not equal a proportional increase in stiffness for the size. However with carbon, they can dial in the exact stiffness or give for any given scenario or situation. That is one of the primary strengths of carbon!

For ex.

"All frame builders know that smaller frames are inherently stiffer and larger frames are inherently more flexible. What I found in my testing is that this effect is greater than I thought. Even the lightest tube sets, when made into a small frame, end up nearly the same stiffness as the heaviest tube sets, when made into a large frame! And many frame models, *since the model's identity is often defined by a certain tube set*, do not make use of the lighter tubes in the small sizes, nor the heavier tubes in the large sizes. This problem is compounded by the fact that quite often it is the larger frame sizes which carry the most powerful riders, and are thus in greatest need of the heavier tube sets. In fact, with the exception of oversize welded aluminum frames, *even the stiffest tubing used for large frames did not always make up for the increase in flexibility caused by the larger frame size. In the very large sizes (above 61 cm), the frames are almost never stiff enough to satisfy powerful riders.* It is a challenge to the designer to make the small frames as light as possible and large frames stiff enough."


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## FoFos (Apr 23, 2017)

thesmokingman said:


> They cannot actually or that is, its just not how things are done. It's a sales issue because frames are sold by tube sets not material stiffness or characteristics. And simply using a larger tube diameter does not equal a proportional increase in stiffness for the size. However with carbon, they can dial in the exact stiffness or give for any given scenario or situation. That is one of the primary strengths of carbon!
> 
> For ex.
> 
> "All frame builders know that smaller frames are inherently stiffer and larger frames are inherently more flexible. What I found in my testing is that this effect is greater than I thought. Even the lightest tube sets, when made into a small frame, end up nearly the same stiffness as the heaviest tube sets, when made into a large frame! And many frame models, *since the model's identity is often defined by a certain tube set*, do not make use of the lighter tubes in the small sizes, nor the heavier tubes in the large sizes. This problem is compounded by the fact that quite often it is the larger frame sizes which carry the most powerful riders, and are thus in greatest need of the heavier tube sets. In fact, with the exception of oversize welded aluminum frames, *even the stiffest tubing used for large frames did not always make up for the increase in flexibility caused by the larger frame size. In the very large sizes (above 61 cm), the frames are almost never stiff enough to satisfy powerful riders.* It is a challenge to the designer to make the small frames as light as possible and large frames stiff enough."


thats something most of the cases in their hands of each manufacturer or for most of them atleast? is there a way somehow someone can check how good the frame is before ordering one (like codes of the carbon or something )?


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## thesmokingman (Jan 17, 2009)

FoFos said:


> thats something most of the cases in their hands of each manufacturer or for most of them atleast? is there a way somehow someone can check how good the frame is before ordering one (like codes of the carbon or something )?


There are a few brands at do frame size-specific layups. The biggest of which is Specialized. They might not be the first to address it but they were probably the first to adopt it in large scale applying the principles to whole lineups. Some other brands that did size-specific frames are Salsa, Calfee. Oh last I read Pivot also does size-specific layups. There isn't much literature regarding this, but it's been known for some time in the age of steel, then alu, and now ironically carbon. It's knowledge that was lost and has now been recovered in a way lol.

The other thing with carbon fiber is that by its very nature it makes for the best material to address the size-specific shortcomings. You can change the layup, use different grade fiber or epoxies, extra layers, etc etc and the end result would look no different to the buyer. To do the same with a metal tubing is not as easy. Thus imo, there may be a heck of a lot more makers that already address this issue but they just don't announce it yet. Take Pivot for ex. who as I mentioned does do size-specific layups, except we would never know it had Chris Cocalis not said so during an interview. We might also thank woman's size-specific designs for pushing the frame size-specific layup front, as woman's size-specific designs go hand in hand with frame size-specific designs.


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## ritchief (Sep 23, 2010)

I'm 240-260 lbs and I've been riding carbon fs bikes for the last 10years and never broken the frame.


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## FoFos (Apr 23, 2017)

ritchief said:


> I'm 240-260 lbs and I've been riding carbon fs bikes for the last 10years and never broken the frame.


whats your manufacter ?


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## ritchief (Sep 23, 2010)

FoFos said:


> whats your manufacter ?


I have got 2 Specialized Stumpjumpers Expert Carbons, 2009 & 2013 and about to purchase a Santa Cruz Hightower.


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## axnels2 (May 23, 2017)

Santa cruz did some demo tests of aluminum vs cf nomad frame and according to them carbon was at least 2x stronger, but when it failed it was spectacular! Aluminum was a more progressive. I feel that frame is one of many components that can fail for heavy/strong riders. Handle bars, cranks, wheels come to mine as at least as important.


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## thesmokingman (Jan 17, 2009)

axnels2 said:


> Santa cruz did some demo tests of aluminum vs cf nomad frame and according to them carbon was at least 2x stronger, but when it failed it was spectacular! Aluminum was a more progressive.


That's ignoring the data and only looking at the point of failure. Take the drop tests. Where would you be on the alu which failed at a much lower point, orders of magnitude lower? Another way to look at it is how spectacular of a failure would it have been on the alu frame if it had the same load applied with the carbon frame??? Would the alu frame have been crushed like a soda can?


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## axnels2 (May 23, 2017)

thesmokingman said:


> That's ignoring the data and only looking at the point of failure. Take the drop tests. Where would you be on the alu which failed at a much lower point, orders of magnitude lower? Another way to look at it is how spectacular of a failure would it have been on the alu frame if it had the same load applied with the carbon frame??? Would the alu frame have been crushed like a soda can?


. Aluminum was definitely a weaker material then their cf option and would be crushed like a soda can under the same load. However, it was not practical application that they were testing, the loads that the lab used were thousands of pounds, and questionable if experienced in a real world. If i recall corectly their test were loading up frames with 3000+ lbs.


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## krel (May 9, 2017)

axnels2 said:


> their test were loading up frames with 3000+ lbs.


Hey! Their tests are just big boned.


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## FoFos (Apr 23, 2017)

ritchief said:


> I have got 2 Specialized Stumpjumpers Expert Carbons, 2009 & 2013 and about to purchase a Santa Cruz Hightower.


nice one  send me one of those that you don't use anymore <3


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## drwx (Jun 4, 2011)

One thing that I'd like to have seen I'm their tests is someone stomping on the frame to simulate a fat dude like me landing on the frame in a wreck.

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## FoFos (Apr 23, 2017)

So just my personal question here , since i can take in a very low price carbon bike from the manufacturer Atala or Whistle , i should reassure myself about carbon frames i guess


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## axnels2 (May 23, 2017)

I would contact the manufacturer for the recommended weight limits for their frames .


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## BigKahuna (Jan 19, 2004)

Cant tell which is worse here, paranoia or misinformation.


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## FoFos (Apr 23, 2017)

BigKahuna said:


> Cant all which is worse here, paranoia or misinformation.


what do you mean ?


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## BigKahuna (Jan 19, 2004)

Lots of opinions, posted as fact, with little basis of truth. Carbon is in most cases much stronger than alloy. Sure, a frame designed to be super light is going to be more fragile than a DH or endure bike. But most modern carbon frames are many times stronger than their alloy counterparts. 

The bigger question should be, do you break a lot of bikes and parts? If you answer yes, it's you, not the bikes or parts.


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## NRP (Sep 8, 2015)

Carbon frames are fine for heavier riders. In fact, some people say the ride quality is better than aluminum.

I think rims are a much bigger issue for heavier riders.


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## RAKC Ind (Jan 27, 2017)

BigKahuna said:


> Lots of opinions, posted as fact, with little basis of truth. Carbon is in most cases much stronger than alloy. Sure, a frame designed to be super light is going to be more fragile than a DH or endure bike. But most modern carbon frames are many times stronger than their alloy counterparts.
> 
> The bigger question should be, do you break a lot of bikes and parts? If you answer yes, it's you, not the bikes or parts.


Stronger yes. But alloy can deal with impacts and be fine. Carbon takes a hit in a crash the wrong way it's done.

Issues arent strength, it's durability. And when carbon fails it's often times much more serious failure with little warning.

But seriously these people being 6fy and 200-225, lbs saying there a "big rider" is rediculous. You aren't really big not need to worry about anything until your over 250 and really need to watch it over 300.

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## thesmokingman (Jan 17, 2009)

RAKC Ind said:


> Stronger yes. But alloy can deal with impacts and be fine. Carbon takes a hit in a crash the wrong way it's done.


Again, that's an if and takes a lot of ignoring of data. Any impact damage that could destroy a carbon frame would have also destroyed an alu frame. I would take carbon durability over alu any day especially considering how easy it is to repair carbon. Alu is not so easy to repair.


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## RAKC Ind (Jan 27, 2017)

I have been looking at the data, which is why I don't own a carbon fiber frame. I crash and the frame hits a square edge it's going to go downhill fast. Alloy frames get a ding and keep going.

And if CF was so much better why won't manufacturers offer the same lifetime warranty?

Because under perfect conditions it's better. And to maintain those conditions were taking cutting edge aerospace manufacturing. But under "normal" manufacturing conditions there is always variations (tolerances) that have to be allowed for.

Just like you can easily crush carbon fiber handlebars by over tightening clamps. The force needed to do so for allow would strip the bolt head/clamp threads long before that.

Nothing wrong with carbon fiber, I ride with it. At bike has cf forks and bars.

But until I can take a hammer to a carbon fiber frame like I can an alloy and it not crack the hell out of the carbon fiber (or put a hole) where as alloy only dents, I'll stick with my metal based frames.

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## drwx (Jun 4, 2011)

RAKC Ind said:


> I have been looking at the data, which is why I don't own a carbon fiber frame. I crash and the frame hits a square edge it's going to go downhill fast. Alloy frames get a ding and keep going.
> 
> And if CF was so much better why won't manufacturers offer the same lifetime warranty?
> 
> ...


Santa Cruz has a lifetime warranty on their carbon frames. It was a huge deciding factor for me. Yeti is only 5 years.

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## Nubster (May 15, 2009)

Riding carbon as heavy as 290. 260 now. Cannondale (F29 and Synapse) and currently a Jamis Renegade. I wouldn't give riding a carbon frame a second thought as far as worrying about it holding up except for maybe some of the ultra light weight weenie frames.


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## RAKC Ind (Jan 27, 2017)

Seems I've missed a few frames/brands that make frames suitable for us bugger guys. May have to revisit this later. I've always loved the looks of carbon frames and I know he benefits fro, using carbon bars for a while and forks on my fat and road bikes. 

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## ritchief (Sep 23, 2010)

BigKahuna said:


> Lots of opinions, posted as fact, with little basis of truth. Carbon is in most cases much stronger than alloy. Sure, a frame designed to be super light is going to be more fragile than a DH or endure bike. But most modern carbon frames are many times stronger than their alloy counterparts.
> 
> The bigger question should be, do you break a lot of bikes and parts? If you answer yes, it's you, not the bikes or parts.


Fact vs Opinion.....
As per my earlier post #20 & 22, I ride a carbon mtb bike and Giant Defy Carbon Bike and both have light bicycle carbon rims. The only think to break on my 2008 Stumpy was the *alloy* rear triangle near the cranks after a week of extreme riding in Andorra. The Carbon main frame is still perfectly fine as of today.

Have I broken any other components - NO. Yes components have worn out but not physically broken anything.

Would I buy a Carbon bike, Carbon rims, Carbon Bars again? - absolutely, for me if you can afford the step up, it's a no brainer.


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## Cavey (Oct 17, 2014)

Same as anything right. If you can afford it, then go buy it. If you break it make sure you can afford to replace it. Otherwise your not able to get outside.


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## willtsmith_nwi (Jan 1, 1970)

RAKC Ind said:


> But until I can take a hammer to a carbon fiber frame like I can an alloy and it not crack the hell out of the carbon fiber (or put a hole) where as alloy only dents, I'll stick with my metal based frames.
> 
> Sent from my XT1565 using Tapatalk


 I had a series of quick frame failure on Giant aluminum bikes with hydroformed tubing. I simply ripped them apart from standing climbs. These were failing about one per year then Giant gave me money and told me to go elsewhere. So I switched to Surly Karate Monkeys and they lasted 2-3 years ... except the last one which never failed (it was better built).

Then again I had a Giant 26 aluminium frame from 95 that was overbuilt dented and never failed ... (though I stopped riding it)

Depending on tube thickness, a dent on an aluminum frame will create a stress riser and it will eventually fail. I suspect that on modern butted ultra-light tubing it will cause failure with a powerful rider. Likely .. it will fail regardless with a powerful rider as the frames aren't built for big guys and aluminum will fatigue eventually with enough flexing regardless of the loads. So long as steel and carbon fibre aren't overloaded and are not compromised, they do not fatigue ... and that goes a long way.

The point is that lightweight aluminum frames are typically poor choices for Clydes.


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## willtsmith_nwi (Jan 1, 1970)

NRP said:


> Carbon frames are fine for heavier riders. In fact, some people say the ride quality is better than aluminum.
> 
> I think rims are a much bigger issue for heavier riders.


And freehub bodies. Trandional paws are typically a poor choice.


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## irideiam (Dec 24, 2011)

This might throw a wrench in some theories but check this out from Specialized:

https://media.specialized.com/support/collateral/0000093943.pdf


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## scycllerist (Jul 31, 2017)

Not a frame but good deal for frame and fork combo

Save up to 60% off new Mountain Bikes - MTB - Kestrel MXZ Carbon 29er SRAM NX 1x11 1x11 SRAM NX 1x11, WTB TCS Tubeless Compatible 29er Mountain Bikes

After reading the Specialized document above, the Kestrel might not last too long. Large folks can't be weight weenies. It's hard to compete with a 5'8" 165lb rider whos in very good condition. We just have to go along at our own pace with heavier gear.


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## alexbn921 (Mar 31, 2009)

Frame material has nothing to do with how strong a frame is. When you weigh a lot you can't be a weight weenie. Extra weight puts more stress on bearings, wheels, everything.
Get a strong frame like a Santa Cruz, Canfield, Evil, Ibis.
Most manufactures overbuild carbon because of the way it fails and the perception that it's fragile. Santa Cruz for instance almost doubles the strength of there carbon bikes and still drops weight. You can feel this increase in stability when riding the bikes. 
The new Specialized Epic HT carbon would be an example of a disposable carbon frame. I wouldn't expect it to last years even under a light rider.


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## drwx (Jun 4, 2011)

Fwiw, the carbon version of sc frames isn't that much lighter. I have a 17 Bronson. It's about 1lb between the c carbon and aluminum. It's about 1.5 pounds between the c and cc carbon versions.

I debated between the aluminum and carbon Bronson and went with the carbon for strength, not weight.

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## DocBilly (Jun 3, 2013)

Carbon is more resistant, has no fatigue over time, unlike Aluminum. Take a look at F1 carbon fiber suspension arms and you realize you will be fine. I am 310 pounds and have been riding a Cannondale Flash Carbon 1 for 4 years. Carbon everything. Not an issue. Carbon fiber is not only about being light. It has also better absorbance of terrain roughness and bike builders are able to archirve whatever geometry they intend.


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