Enduro/AM - The Weight Game

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Enduro/AM - The Weight Game
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flag PHeller
O+
Posted: Oct 2, 2019 at 14:17 Quote
Why does the Crowbar utilize such a funky shaped swingarm? I've never seen a Radius Arm that either wasn't straight, or in the case of bikes, have a nice flowing curve to it.

For example, the top of the swingarm has 3 bends in it, while the bottom only has two. Your steel protoype was similar.

Is there some sort of analysis happening behind the scenes that tells you that shape is superior, or could the swingarm be more straight ala Orange or Marino and accomplish the same thing?
flag newbermuda
O+
Posted: Oct 2, 2019 at 14:58 Quote
PHeller wrote:
Why does the Crowbar utilize such a funky shaped swingarm? I've never seen a Radius Arm that either wasn't straight, or in the case of bikes, have a nice flowing curve to it.

For example, the top of the swingarm has 3 bends in it, while the bottom only has two. Your steel protoype was similar.

Is there some sort of analysis happening behind the scenes that tells you that shape is superior, or could the swingarm be more straight ala Orange or Marino and accomplish the same thing?

i think its dope. reminds me of the old marin quad link
flag PHeller
O+
Posted: Oct 2, 2019 at 15:02 Quote
Haha or my old Cannondale Prophet!

Actually the Prophet hid some of the curves by running a straight tubes across the top of the swingarm.

...but man those Quad Link bikes had every shape conceivable over the years...
flag thuren
Posted: Oct 3, 2019 at 9:29 Quote
PHeller wrote:
Why does the Crowbar utilize such a funky shaped swingarm? I've never seen a Radius Arm that either wasn't straight, or in the case of bikes, have a nice flowing curve to it.

For example, the top of the swingarm has 3 bends in it, while the bottom only has two. Your steel protoype was similar.

Is there some sort of analysis happening behind the scenes that tells you that shape is superior, or could the swingarm be more straight ala Orange or Marino and accomplish the same thing?

There are a few points in the swingarm design that are there for structural reasons, absolutely, but honestly MOST of the shape is based around cosmetics. You'd be shocked how many different variations were drawn up, and assessed, to come up with something acceptable. With the swing arm being as long as it it, it's just such a big part of the whole, that if it were too thin, too straight, too bulky, it just stood out WAY too much. You can't really compare it to an Orange or any other bike and the arm is SO long and low. The shape it is now was the one that was the most visually accepted, by far.

I knew the bike design worked great with riding and racing the steel prototype for a season, but knowing how big of a player the bikes visuals are when it comes to a bike being accepted, the visual profile of the swing arm was the biggest hurdle to overcome early on. Deciding if it was worth moving forward with a rather expensive project like this, was a lot of thought and stress, haha!
flag R-M-R
Posted: Oct 3, 2019 at 10:02 Quote
thuren wrote:
There are a few points in the swingarm design that are there for structural reasons, absolutely, but honestly MOST of the shape is based around cosmetics. You'd be shocked how many different variations were drawn up, and assessed, to come up with something acceptable. With the swing arm being as long as it it, it's just such a big part of the whole, that if it were too thin, too straight, too bulky, it just stood out WAY too much. You can't really compare it to an Orange or any other bike and the arm is SO long and low. The shape it is now was the one that was the most visually accepted, by far.

I knew the bike design worked great with riding and racing the steel prototype for a season, but knowing how big of a player the bikes visuals are when it comes to a bike being accepted, the visual profile of the swing arm was the biggest hurdle to overcome early on. Deciding if it was worth moving forward with a rather expensive project like this, was a lot of thought and stress, haha!

Don,

Love the honesty! It's a bit of a faux pas to admit that, as bike consumers seem to think everything down to the placement of the decals is engineered, simulated, and tested for MAXIMUM PERFORMANCE.

It's not.

Story time, regarding one of the bikes I was called in to redesign:

The process to that point had been:

• Company owner without any engineering education drew a picture with pencil crayons
• Industrial designer sketched up something swoopy
• CAD draftsman converted the sketch into CAD
• CAD was to be handed to the factory, which was to be told to layer on the carbon until it passes ISO impact testing

Problems:

• No calculations or simulations
• ISO impact standards are a poor reflection of real-world loads
• No riding!

The draftsman had drawn only road bikes. He said to me "There's no need to get worked up about it. We just draw whatever looks good and the factory fixes it with lay-up." Road bikes are easy because a rigid double-diamond frame is inherently strong. Swoopy bikes with pivots require engineering. I analyzed the frame and determined it wouldn't have been strong enough even if some tubes were solid carbon, rather than hollow. I did my best to fix it within the customer's constraints. This was an extreme example, but it's indicative of the "just wing it" approach of the industry - even from most of the companies that would have you believe their products involve more engineering than F1 cars.

If the general dimensions and shapes are sensible, aesthetic touches typically add less weight than paint. Thanks, Don, for not bullshitting consumers!
flag sherbet
Posted: Oct 3, 2019 at 10:47 Quote
I wish you could name and shame a little bit, but completely understand where you're at. Thanks for the post man.
flag thuren
Posted: Oct 3, 2019 at 10:55 Quote
R-M-R wrote:
thuren wrote:
There are a few points in the swingarm design that are there for structural reasons, absolutely, but honestly MOST of the shape is based around cosmetics. You'd be shocked how many different variations were drawn up, and assessed, to come up with something acceptable. With the swing arm being as long as it it, it's just such a big part of the whole, that if it were too thin, too straight, too bulky, it just stood out WAY too much. You can't really compare it to an Orange or any other bike and the arm is SO long and low. The shape it is now was the one that was the most visually accepted, by far.

I knew the bike design worked great with riding and racing the steel prototype for a season, but knowing how big of a player the bikes visuals are when it comes to a bike being accepted, the visual profile of the swing arm was the biggest hurdle to overcome early on. Deciding if it was worth moving forward with a rather expensive project like this, was a lot of thought and stress, haha!

Don,

Love the honesty! It's a bit of a faux pas to admit that, as bike consumers seem to think everything down to the placement of the decals is engineered, simulated, and tested for MAXIMUM PERFORMANCE.

It's not.

Story time, regarding one of the bikes I was called in to redesign:



Great to hear that real world stuff much appreciated!

Yeah it's funny to me how the videos of a frame on a simple ISO testing machine is a selling point, when in reality, especially with a mountain bike that is going to see CRAZY loads from all angles, most of those test don't mean much...

I initially told my manufacturer what amount of carbon was needed in the front section of the swing arm, and heavy wall thickness in the upper tubes being in compression(not carbons strong point), and respected their engineers effort to tell me I did not need that much carbon per their calcs...... I cracked the first 2 Crowbar rear swingarms sent to me, just simulating a "not pulling a whip back on a big jump and landing flat", type sideload force. In the end I ended up needing as much carbon as i originally asked for, haha.

We did pretty extreme front impact drop testing on the Crowbar front triangle, just to make sure that part of the design was super burrrrrly, especially with the 63.5 HA. With my first venture into a carbon frame I didn't want to risk failures, so there is more carbon than NEEDED, for sure. It's not a weight weenie in any way, but it's not made to be one.
flag shirk-007
O+
Posted: Oct 3, 2019 at 11:10 Quote
I'd love to run one of my homemade frames through the test process and see where it fails.

ps loving the bar / stem combo Don. They feel like just the right amount of flex.
flag Circe
Posted: Oct 3, 2019 at 16:46 Quote
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...
flag shirk-007
O+
Posted: Oct 3, 2019 at 17:19 Quote
Circe wrote:
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...

You can't be a huge bike nerd if you can't figure out what it is.

IF you were really a huge bike nerd you would have seen this back in the summer of 2018.

https://theloamwolf.com/2018/09/06/something-new-is-brewing-in-bend/

You need to work a bit harder on your bike nerding.
flag Circe
Posted: Oct 3, 2019 at 17:42 Quote
shirk-007 wrote:
Circe wrote:
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...

You can't be a huge bike nerd if you can't figure out what it is.

IF you were really a huge bike nerd you would have seen this back in the summer of 2018.

https://theloamwolf.com/2018/09/06/something-new-is-brewing-in-bend/

You need to work a bit harder on your bike nerding.


A google search of the product name doesn’t even pull up the company website.....

Try harder.
flag thuren
Posted: Oct 3, 2019 at 17:44 Quote
shirk-007 wrote:
Circe wrote:
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...

You can't be a huge bike nerd if you can't figure out what it is.

IF you were really a huge bike nerd you would have seen this back in the summer of 2018.

https://theloamwolf.com/2018/09/06/something-new-is-brewing-in-bend/

You need to work a bit harder on your bike nerding.

I'll do you one even better haha!

https://www.pinkbike.com/news/the-eyecatchers-2019-6-new-bikes-that-stand-out-from-the-crowd.html
flag thuren
Posted: Oct 3, 2019 at 18:05 Quote
Circe wrote:
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...

Brand new in a way. Just named. Was in prototype for a long time...

http://terraincontrol.com/crowbar1.html
flag thuren
Posted: Oct 3, 2019 at 18:06 Quote
Circe wrote:
shirk-007 wrote:
Circe wrote:
So, what the heckity heck is the TCI Crowbar. I'm a huge bike nerd and had never seen it before this forum. The website has almost zero info, no reviews, etc...

You can't be a huge bike nerd if you can't figure out what it is.

IF you were really a huge bike nerd you would have seen this back in the summer of 2018.

https://theloamwolf.com/2018/09/06/something-new-is-brewing-in-bend/

You need to work a bit harder on your bike nerding.


A google search of the product name doesn’t even pull up the company website.....

Try harder.

Seems to... I'm actually surprised it does haha!!!

2nd link down from the top on my screen.

https://www.google.com/search?q=tci+crowbar&oq=tci+crowbar&aqs=chrome..69i57j69i59j35i39.4486j1j7&sourceid=chrome&ie=UTF-8

 


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