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Carbon coil springs

Trekrules

Turbo Monkey
Apr 12, 2007
1,226
148
After Steel and Titanium coil springs:


What do people think about Carbon used for a coil spring
 

rollertoaster

Monkey
Aug 7, 2007
730
179
Douglassville , PA
it sure looks cool, but I'm pretty sure it wouldn't work for long. I think dirt on the spring seats would wear thought the epoxy and make the carbon fail prematurely. Could be totally wrong but it's just my thoughts.
 

trib

not worthy of a Rux.
Jun 22, 2009
1,456
388
it's made by solid bikes components company Reverse components, cant find it or any info on their website though unfortunately...

Im sure it works well, but cant imagine the swarms of riders who dont trust carbon frames and bars will be jumping to get a carbon spring
 

LMC

Monkey
Dec 10, 2006
683
1
the finish on the one in the pic looks a bit rough, hand laid proto perhaps?

this is the only company ive seen who make composite coil springs
http://www.sardou.net/accueil4.htm

Carbon fibre leaf springs have been around for a while, i see no reason why carbon fibre coil springs wouldnt be legit.
 

jonKranked

Detective Dookie
Nov 10, 2005
85,558
24,181
media blackout
Idk, carbon fiber can be worked in some interesting ways. If designed properly, it will flex and not fail (c'dale scalpel). I don't think that something like this is outside the realm of feasibility, but some solid and thorough testing will be needed for these to take off.
 

Sghost

Turbo Monkey
Jul 13, 2008
1,038
0
NY
Idk, carbon fiber can be worked in some interesting ways. If designed properly, it will flex and not fail (c'dale scalpel). I don't think that something like this is outside the realm of feasibility, but some solid and thorough testing will be needed for these to take off.
To the props for carbon fiber, Ive never seen the chainstays broken, only some where they weren't glued in properly by the bottom bracket.

It should work for a spring. People who just post pics of their bike and never ride it will be all over it like a fat kid on a smartie.
 
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RMboy

Monkey
Dec 1, 2006
879
0
England the Great...
Think it looks nice, and nice innovation

Would like to hear more form someone who knows alot about material science to know if its a viable product...??
 

buildyourown

Turbo Monkey
Feb 9, 2004
4,832
0
South Seattle
Completely viable product. I'm not sure why somebody hasn't already been on this. CF is a great spring material. Much more so than most metals.
I'm betting cost vs weight savings have kept companies out. I'm thinking the savings are only going to be 50-100g. Huge in bikes, but not so huge in other spring markets like airplanes. The tooling cost is also much bigger. Ti springs are easy one you're setup. CF springs would require a different mold for every size and rate.
 

dropmachine

Turbo Monkey
Sep 7, 2001
2,922
10
Your face.
Yeah, I'm gonna say no. You can't seriously tell me that bikes are more forward thinking then motocross, rally, or anything else really with a big budget. The weight savins on a moto cross bike size spring would be pretty decent I'd imagine, so if it worked I think you'd see it there first.
 

syadasti

i heart mac
Apr 15, 2002
12,690
290
VT
I question why they make the display model the same as metal coil spring. Why not make it like a can or something easier to make?
 

Whoops

Turbo Monkey
Jul 9, 2006
1,011
0
New Zealand
leaf spring = bending
coil spring = torsion


one is easy to lay up to cope with strain, the other... not so much. Might be feasible, but of the list of things that carbon is good for I'd guess this is not at the top.
 

wood booger

Monkey
Jul 16, 2008
668
72
the land of cheap beer
Actually carbon is an excellent material to use because it has a virtually infinite fatigue life (compared to steel), spring rate can also be "tuned" in mfg process, and it's light as shiat.

There is a Norcal company that has been making carbon coils for years for use in military drone aircraft and other uber expensive trick applications. Maybe that is where this one came from? I know they were looking for applications in the bike industry. One of their engineers is a sick mtn biker.

The main hold back for bikes would be cost I imagine. As previously stated tooling for different lengths/rates/diameters would be costly. Steel coils are cheap, Ti coils are easy to make.

One day all you knuckle head carbon haters will see the light (literally). Most problems w/ carbon are due to faulty design and/or manufacturing. Any moron can make a bar/frame/post from carbon in their garage, the hard (say $) part is doing it right.
 

DHRracer

Monkey
Sep 29, 2004
371
0
Basically correct,But depending on pitch angle and stroke/deflection the material in a coil spring needs to bend as well.The diameter of the body will get bigger and the end coils typically will bend where they contact the inactive coil.What really needs to be made are coil springs out of tubes/hollow material.
 

DirtyMike

Turbo Fluffer
Aug 8, 2005
14,437
1,017
My own world inside my head
I would trust a carbion spring, long before a carbon DH frame.


And TJ, in a responce.....Carbon used in air craft, boats ETC.....Lives in a much more contorlled environment than that of out Mtn bikes. But then again, it comes back to how its layed in teh first place, will it be strong in Multiple directions? Will it be weak in another? Just more to think about.
 

MrPlow

Monkey
Sep 9, 2004
628
0
Toowoomba Queensland
Yeah, I'm gonna say no. You can't seriously tell me that bikes are more forward thinking then motocross, rally, or anything else really with a big budget. The weight savins on a moto cross bike size spring would be pretty decent I'd imagine, so if it worked I think you'd see it there first.
Moto could also use a lot lighter frame techniques etc but don't. It is probably cheaper to make more power from the motor. I think the motor discounts some of your theory there.
 

Patan-DH

Monkey
Jun 9, 2007
458
0
Patagonia
I see it working well on the bikes from the Sub 40lbs post.

For the rest of us mortals, Titanium will continue to be the only way
 

dilzy

Monkey
Sep 7, 2008
567
1
That would be a bloody complicated manufacturing process. Carbon is fantastic for leaf springs, not so sure about coils, due to the extra layup complexity of filament wound tubes and the number of coils required (for a given stroke) due to carbons very high stiffness and very low elongation (titanium is completely opposite, which makes it fantastic for coil springs.)

The bloke that said carbon is used in higher stress applications than mtn biking needs to do a little reading on basic mechanics of materials principals. Holding up a feather is a high stress application if you make the beam 1 micron thick.

Also, there's no way moto is ahead of dh bikes in terms of both suspension and frame technology. Forks, mtb is ahead, frames mtb is way way way ahead and shocks well mx has ttx shocks, we have db, so its much the same.
 

MrPlow

Monkey
Sep 9, 2004
628
0
Toowoomba Queensland
I would trust a carbion spring, long before a carbon DH frame.


And TJ, in a responce.....Carbon used in air craft, boats ETC.....Lives in a much more contorlled environment than that of out Mtn bikes. But then again, it comes back to how its layed in teh first place, will it be strong in Multiple directions? Will it be weak in another? Just more to think about.
Sorry for derailing a bit into another "carbon = weak DH frame" but main problem I see with a CF DH is not its strength for the riding, but its impact resistance to rocks etc in a crash. carbon obviously has a rep for breaking from the early days and Road bikes. But ride a ally road bike down a DH track and I am sure it would crack too ;)

I have layed into a carbon laminate with a hammer as hard as I could and it barely marked. The beauty of carbon IMO is you can make it whatever you need it to be.

As for this spring. great idea, but holy crap I would hate to do the lay up. I had ideas of laying up a CF spring that would be a flat profile (like an auger flight) why does it need to be round sectioned??
 

xxFRESHxx

Chimp
Jun 21, 2008
40
0
Germany, BY
I have layed into a carbon laminate with a hammer as hard as I could and it barely marked.
be careful with that. problem with carbon fiber composites is, that they may look all right after the impact from the outside but on the inside they will probably look like in the pictures below. that delamination causes an immense weakening to the whole structure.
in glass fiber composites you can see the damage from the outside (see third picture) but CF just remains black.

I'm not saying CF shouldn't be used for DH frames, I'm just saying that it is extremely hard to see possible damage after an impact.
metal dents but with CF you'd have to run ultrasound tests to make sure if the laminate is all right or not.
 

Attachments

dropmachine

Turbo Monkey
Sep 7, 2001
2,922
10
Your face.
For discussion::

Whats worse, carbon haters that fear the fancy plastic, or carbon fanboys that think it will cure everything including hemorrhoids?
 

xy9ine

Turbo Monkey
Mar 22, 2004
2,940
353
vancouver eastside
For discussion::

Whats worse, carbon haters that fear the fancy plastic, or carbon fanboys that think it will cure everything including hemorrhoids?
good question. at least the latter group is forward thinking. having lived with a carbon dh bike for 3 years, i'm fully convinced of the capabilities of the material for this application. whether it ever becomes viable in a production based / somewhat cost effective scenario is another question. offshore carbon manufacturing is bringing prices down; i suppose a major player could pull it off. i'm predicting a full carbon (world's edition) v10 for 2011...
 
Apr 16, 2006
392
0
Golden, CO
For increasing CF's torsion properties, it could be applied on the "skin" of a composite spring (or rod of composite before winding) beforehand, then 'claved to attain proper strength. However in order to effectively be applied to the outside of a composite rod it would have to be then coiled up and the inside wall (ID of the coil shape) of the wrapped CF would shrink in length, the outside wouldn't stretch most likely if it was still wet with resin, so that would leave you with a wrinkly spring, and even viagra can't help that.

Perhaps the shape of the spring needs to be reconsidered? And maybe we don't need wheels in the future...

But I think MTB would be an ideal test bed for CF springs, we use low spring rate's and smaller springs... much lower than a rally car would, and smaller in size than an mx bike would require.
 
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MrPlow

Monkey
Sep 9, 2004
628
0
Toowoomba Queensland
be careful with that. problem with carbon fiber composites is, that they may look all right after the impact from the outside but on the inside they will probably look like in the pictures below. that delamination causes an immense weakening to the whole structure.
in glass fiber composites you can see the damage from the outside (see third picture) but CF just remains black.

I'm not saying CF shouldn't be used for DH frames, I'm just saying that it is extremely hard to see possible damage after an impact.
metal dents but with CF you'd have to run ultrasound tests to make sure if the laminate is all right or not.
Thanks for the pics, I am aware of that though.
I laid up with a few outer layers, then some absorbing material, then continued with my layup, the idea is the outer layer is a shield for impacts, the structure is the inner protected layers. It seems to work quite well too.:thumb:
 

ChrisKring

Turbo Monkey
Jan 30, 2002
2,399
6
Grand Haven, MI
It's cool. However, I don't think they can hit a price point that will sell enough to pay for the development. Anyone here ever priced out the capital equipment to make that? Easton probably has the equipment to do it minus the dies.

Actually, I would be less concerned with running a carbon spring than a carbon handlebar due to the failure mode. If the spring breaks, the shock should keep the bike in one piece and somewhat rideable. Carbon bars are fine too. You just need a larger safety factor than with a metal bar.
 

top_dog

Monkey
Jan 27, 2006
209
0
Australia
I'm all for carbon generally, and can see no reason why this wouldn't work. But there must be a reason why F1 cars still use Ti coils and torsion bars. They have the money, knowledge and freedom to do it, but haven't for some reason.
 

blackspire

Monkey
Jul 19, 2007
115
0
Completely viable product. I'm not sure why somebody hasn't already been on this. CF is a great spring material. Much more so than most metals.
I'm betting cost vs weight savings have kept companies out. I'm thinking the savings are only going to be 50-100g. Huge in bikes, but not so huge in other spring markets like airplanes. The tooling cost is also much bigger. Ti springs are easy one you're setup. CF springs would require a different mold for every size and rate.
the finish on the one in the pic looks a bit rough, hand laid proto perhaps?

this is the only company ive seen who make composite coil springs
http://www.sardou.net/accueil4.htm

Carbon fibre leaf springs have been around for a while, i see no reason why carbon fibre coil springs wouldnt be legit.
No, there is no one using carbon fibre leaf springs. However there are composite leaf springs (on some Corvettes for example). Not even close to the same spring characteristics.

The reason why you can not use carbon fibre springs is that carbon fibre is very stiff. The springs on your bike use the steel (or titanium if you have those) ability to twist (it's a torsion spring). Carbon fibre can not do this without breaking. Composite leaf springs however handle bending very well, which is used in leaf springs. This is not the same as torsion. I doubt we will be seeing carbon fibre torsion spring on bikes.
 
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