Carbon lowers, crown, steerer...
Why not carbon stanchion with ultra durable resin coat, milled and polished?
Do carbon lowers sheath an alloy chamber to hold suspension fluid & bushings in. Can carbon fibre cope with suspension oils?
Bike Forum
Why are there no carbon stanchion forks?
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Posted 7 months ago #
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I'm obviouly not 100% sure, but I'm unaware of any inner liner fitted to Lefty Carbon fork(s), so supposedly yes it can cope with suspension oil... or at least, it can be laquered to resist it.
Posted 7 months ago # -
crazy, eh? and why no carbon tyres?
Posted 7 months ago # -
GW - Member
crazy, eh? and why no carbon tyres?
Posted 7 months ago # -
Can carbon fibre cope with suspension oils?
yep, see all pace and dt-swiss forks - the lowers have lots of carbon.
I thonk it's getting the surface finish and durability needed for sealing that's the issue - even 'smooth' carbon is pretty bumpy.
Posted 7 months ago # -
crazy, eh? and why no carbon tyres?
you say that like Im missing something obvious. Care to enlighten?
Posted 7 months ago # -
I thonk it's getting the surface finish and durability needed for sealing that's the issue - even 'smooth' carbon is pretty bumpy.
fixed with "carbon stanchion with ultra durable resin coat, milled and polished?"
Posted 7 months ago # -
yep, see all pace and dt-swiss forks - the lowers have lots of carbon
knew that. But was wondering if there was a metal tank in the lower to deal with the fluids.
even 'smooth' carbon is pretty bumpy.
cant be too tricky to lay up a CF tube in a thick outer resin coat that is then machined back perfectly cylindrically.
Posted 7 months ago # -
cant be too tricky to lay up a CF tube in a thick outer resin coat that is then machined back perfectly cylindrically.
Technically that is quite a challenge - vac bagging during cure will try and minimise the resin thickness, to somehow have a thick outer layer, but still have a high volume fraction for the tube is going to be hard in one operation. Post-fab machining will have its problems as well.
Sure it could be done, but can't see how it will be cheaper than a metal tube.
Posted 7 months ago # -
But was wondering if there was a metal tank in the lower to deal with the fluids.
no, it just sloshes about.
Posted 7 months ago # -
precast resin cylinder, internally coated with wet resin, then laid.
I wont be beaten by complications....
Posted 7 months ago # -
Machining carbon....gotta love that!
Posted 7 months ago # -
Sure it could be done, but can't see how it will be cheaper than a metal tube.
Why would it have to be cheaper?
Posted 7 months ago # -
wwaswas - are the bushings still interference fit in the inner face of the CF or is a bushing sleeve resined into the lower and replaceable buhsing inserted into that?
Posted 7 months ago # -
who mentioned machining carbon?
Posted 7 months ago # -
Machining carbon
machining RESIN.Silly inkblot.
Posted 7 months ago # -
precast resin cyclinder, internally coated with wet resin, then laid.
I wont be beaten by complications....
You will be beaten on cost
Why would it have to be cheaper?
You have seen the cost of decent forks as it, yes?
Posted 7 months ago # -
My mate's carbon seat post looks a scratched mess after just a few raisings and lowerings...
Posted 7 months ago # -
there must be an uber resin out there.
Also, seat tubes and seat post clamps arent known for their low-friction surfaces.
A top quality hard resin, polished to within a micron of it's life, running in lubed foam rings and teflon coated bushings. Knock out!
Posted 7 months ago # -
A top quality hard resin, polished to within a micron of it's life,
Moon-on-a-stick at the moment, for a thermoplstic polymeric resin, AFAIK...... if you want to get uber-bling, then metal matrix composites would be the way to go to get a stiff tube and hard outer surface, but they are even more outrageous cost-wise
Posted 7 months ago # -
there must be an uber resin out there.
Why?Posted 7 months ago # -
Moon-on-a-stick at the moment
defeat conceded
ALso, why do Fox make such a noise about the corrosion resistance of their kashima coating? When was the last time anyone saw rusty fork stanchions? How about making them more resiliant to abbrasion instead!
Posted 7 months ago # -
just a push fit from memory when I had a peer inside.
Posted 7 months ago # -
Why?
because thats what men in lab coats are paid millions of pounds and given ferraris and prostitutes to invent.
Posted 7 months ago # -
Prob because an aluminium metal tube will do the job more cheaply, better for longer. You may also lose internal oil volume if the leg wall thickness has to be increased for CF, hence existing damping kit wouldn't fit in there.
Posted 7 months ago # -
INRATS but resin's never going to be as "hard" as anodized aluminium.
Stoner: how about diamond coated carbon stanchions?
Posted 7 months ago # -
couldnt afford the CNC milling bits needed to machine it.
Stupid idea.
Posted 7 months ago # -
may also lose internal oil volume if the leg wall thickness has to be increased for CF, hence existing damping kit wouldn't fit in there.
45mm stanchions then
Posted 7 months ago # -
may also lose internal oil volume if the leg wall thickness has to be increased for CF, hence existing damping kit wouldn't fit in there.
Unlikely - purely from a stiffness point of view, the wall thickness of a CF leg could be thinner for the same OD and as the modulus of CF is a lot higher than aluminium alloys. I accept it is more complicated than that (strength, manufacturability, impact resistance blar-de-blar-de-blar....), but that would be the theory.
Posted 7 months ago # -
because thats what men in lab coats are paid millions of pounds and given ferraris and prostitutes to invent.
Clearly it's the lack of such incentives which is why it hasn't happened. If only engineering wasn't so undervalued.Posted 7 months ago # -
Stoner - Member
may also lose internal oil volume if the leg wall thickness has to be increased for CF, hence existing damping kit wouldn't fit in there.
45mm stanchions then
Too much friction. See ZZYZX for further info
Posted 7 months ago # -
where's scientific altruism when it's needed eh?
Posted 7 months ago # -
ZZYZX
Is that sleepy physics?
Posted 7 months ago # -
Stoner - Member
ZZYZX
Is that sleepy physics?
In my house it is the tool of choice for owning:
Alas due to the friction from the massive stanchions it was rubbish as a suspension fork.
Posted 7 months ago # -
You need a word with your plumber. The drains arent supposed to come out of the lawn like that.
Posted 7 months ago #
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