Are carbon curved forks going extinct?

[drgonzo]

The only curved forks I see widely available are the Columbus Minimal and Ritchey Comp. Neither one is offered in a tapered design. What gives?

[drgonzo]

Ok so now I'm going down the rabbit hole and I found this article that explains a few things, some I knew, some I didn't. But the take away seems to be that straight carbon forks are easier to manufacture than curved carbon forks.

https://physics.stackexchange.com/qu...nt-wheel-forks

[ERK55]

Seven still makes curved carbon forks.
The Pegoretti Falz is also slightly curved.

[Mike Lopez]

Over the years we’ve made both styles and one is not more difficult to make or stronger than the other.

The article is speculative and not based on manufacturing experience.

BTW...We were the original source for Seven’s above mentioned fork ...

[mcteague]

Originally Posted by Mike Lopez

Over the years we’ve made both styles and one is not more difficult to make or stronger than the other.

The article is speculative and not based on manufacturing experience.

BTW...We were the original source for Seven’s above mentioned fork ...

Interesting. When I bought my Seven 622 SLX, back in 2013, they told me the frame's carbon tubes were made by Rock West Composites in UT but they were cagey about where the 5E fork came from.

Tim

[tv_vt]

Originally Posted by Mike Lopez

BTW...We were the original source for Seven’s above mentioned fork ...

Are you referring to the 5e, Mike? I love that fork, and Seven doesn't sell it anymore. Don't suppose you have any in the warehouse, do you? (Like a 42mm rake long reach brake model...)

[Mike Lopez]

[QUOTE=mcteague;2673021]Interesting. When I bought my Seven 622 SLX, back in 2013, they told me the frame's carbon tubes were made by Rock West Composites in UT but they were cagey about where the 5E fork came from.

The original Reynolds Composites was sold to MQC which later split into Rock West and the wheel company know as Reynolds. Don't know where Seven's fork went after my crews involvement.

And to the other gents question. No old stock that I'm aware of.

[Mark McM]

Originally Posted by drgonzo

Ok so now I'm going down the rabbit hole and I found this article that explains a few things, some I knew, some I didn't. But the take away seems to be that straight carbon forks are easier to manufacture than curved carbon forks.

https://physics.stackexchange.com/qu...nt-wheel-forks

Unfortunately, there's a lot wrong in the answers given in the above article. A straight fork can give just as much compliance as a curved fork; straight forks do not have "sharp turns" that create stress concentrations; and as Mike Lopez pointed out, its no more difficult to create a curved carbon fork than a straight carbon fork.

[zzy]

There's no real reason to use steel-style rake with a carbon fork as they don't flex like that. In fact most modern carbon forks are so sturdy the fork blades barely flex at all. And my favorite steel fork (of many) is a straight blade IF unicrown fork.

[drgonzo]

Thanks, some interesting info in this thread but I'm still left wondering why curved forks are almost non-existent? Several of the leading mfgrs don't carry a single curved fork - Enve, whisky, 3T, etc.

Is this a performance thing? Are straight forks superior? Are they cheaper to manufacture? Am I just part of a very small market of users that prefers the look and ride of curved forks?

[Old School]

Originally Posted by Mark McM

straight forks do not have "sharp turns" that create stress concentrations

I strongly disagree. No offense, we may just have a difference in the perception of terms.

distributed stress:

I
(

not as evenly distributed stress:

I
\

source: engineer whose senior project was stress /strain curves of fiberglass laminates

[Mark McM]

Originally Posted by Old School

I strongly disagree. No offense, we may just have a difference in the perception of terms.


distributed stress:

(
)

not as evenly distributed stress"

/
\

source: engineer whose senior project was stress /strain curves of fiberglass laminates

It's not quite as simple as that. The largest loads are at/near the crown, and are a combination of bending and torsion. Carbon forks, being made of layers of carbon strands, tend to have smooth transitions in this area. There isn't much difference in the shapes of forks in this area between straight and curved blades. Besides which, the sharpest transition in the fork is typically at the junction between the crown and the steerer, and this junction is the same regardless of whether the blades are straight or curved.

source: engineer whose master thesis was on stress/strain analysis of flexural structures for multi-axis load sensors.

[NYCfixie]

Originally Posted by Old School

source: engineer whose senior project was stress /strain curves of fiberglass laminates

Originally Posted by Mark McM

source: engineer whose master thesis was on stress/strain analysis of flexural structures for multi-axis load sensors.

Is their a PHd in the house who can be the tie breaker?

And I am sure you both know that academic papers written using other academic papers as sources is not always the same as actual lab work or real world testing (not implying either of you have not done this pre or post writing your papers).

[Mike Lopez]

Originally Posted by drgonzo

Thanks, some interesting info in this thread but I'm still left wondering why curved forks are almost non-existent? Several of the leading mfgrs don't carry a single curved fork - Enve, whisky, 3T, etc.

Is this a performance thing? Are straight forks superior? Are they cheaper to manufacture? Am I just part of a very small market of users that prefers the look and ride of curved forks?

Performance...No. Superior...No. Cheaper to make...No. Mostly it's a matter of current fashion trends. Perhaps with the exception of disc forks and thru axles. Those might be a bit easier to do with fatter, straighter, legs.

Regarding your previous question about tapered steerers along with curved blades. Having made both, I'm willing to bet the manufacturers aren't willing to spend the money on new tooling for what they may perceive as a diminishing market. Molds and new processes cost money. It's a business decision. If enough folks wanted them they'd do it. But they don't. I've had to make that decision myself many times over the years.

[Old School]

Originally Posted by Mark McM

It's not quite as simple as that. The largest loads are at/near the crown, and are a combination of bending and torsion. Carbon forks, being made of layers of carbon strands, tend to have smooth transitions in this area. There isn't much difference in the shapes of forks in this area between straight and curved blades. Besides which, the sharpest transition in the fork is typically at the junction between the crown and the steerer, and this junction is the same regardless of whether the blades are straight or curved.

source: engineer whose master thesis was on stress/strain analysis of flexural structures for multi-axis load sensors.

I'm not being argumentative, and certainly don't want to get into an escalating diploma measuring contest, but I think I can explain my contention in a different way.

Let's try this:

Assuming a 100% equal load, and each designed to have equal displacement ("flex") at the same load.

Assuming we agree that "the sharpest transition" is also the point of the highest stress concentration.

A curved fork will have less stress at the singular highest stressed point, by virtue of the curved legs "flexing".

A straight fork will have more stress at the singular highest stressed point, by virtue of the straight legs not "flexing".

Thanks.