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Just seen the new Marin gravel bike and see they have a heat sink on the brake adaptor to dissipate heat from the fork. Is this an issue now? What would happen if a carbon fork got too hot, could it de-laminate?
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I suspect it's more to stop the caliper (and rotor) getting too hot than to prevent the fork overheating.
a normal metal fork will act like a big heat sink due to conducting heat but a carbon one won't so the caliper gets a lot hotter.
but I've not had the issue on my carbon forked mtb's, it has to be said.
I think it's more so it [i]Looks the part[/i] than actually does anything.
The calliper body or the pads themselves would dissipate more heat than that "Heat sink". If heat build up is that much of an issue on a gravel bike I'd be expecting them to fit finned pads first...
I thought it was odd...
Ooo, perfect for the mud...
Ooo, perfect for the mud...
Ah it's only for use on gravel apparently 🙂
If you're doing long descents (especially loaded up) with small discs, it's probably a sensible precaution.
Bearing in mind the default disc size seems to be 150mm, seems reasonable to me. Heat from braking could affect the strength of the carbon composite (Even relatively modest temperatures will have a negative effect), depending on the resin used, and on the front end a failure would not be nice.
More likely is that the heat would have no heat sink of a big metal frame to go to as others have said, and could overheat more easily, but the carbon itself could be an issue.
The calliper body or the pads themselves would dissipate more heat than that "Heat sink". If heat build up is that much of an issue on a gravel bike I'd be expecting them to fit finned pads first...
Problem is that there's very little heat transfer from the pad, it's insulated from the calliper by the piston which is usually phenolic or ceramic, almost all the heat dissipation is done by the disk.
But......
As part of the manufacturing process for composites they're cured. Typically with boats the rule of thumb is you cure at the maximum temperature you expect it to encounter. So for a white boat that's about 50C in direct sunlight, if you want to paint it black then you'd better go to about 85-90C. If you don't then epoxy resin continues to shrink as it cures, and once out of the mould this leads to wrinkles forming.
So it might not be there protecting against acute overheating but keeping the temperature down would be a good thing over the long term. I wonder if manufacturers would put heat shields between the disk and the fork too?
The worst offenders are Lasers in the southern hemisphere, almost all will have the mast step poking through the bottom of the hull after spending any time upside down in the sun and the whole hull shrinks around it.
Dunno how dangerous that would be, on a boat it's just considered unsightly and a bit slow, you'd solve it by sanding back through the paint/varnish/gelcoat and fairing the hull.
What TINAS said is basically right, but you will begin to lose strength well below the cure temperature. 180°C cure temperature and I wouldn't be too worried, 120°C cure you could have a potential issue, even by about 50°C the stuff I've encountered in my work has got significantly less strong.
combined Solar and disc brake heating, induced, composite, de-lamination now is it? 😆
Still not buying it, if the composite fork's design was actually that marginal WTF would you then paint it black?
And how come Marin are the only company who's forks require this new wonderful heat dissipating brake adaptor? There's a fair few other companies with composite, disc forks in their range now should we be sending them all back?
It's been done purely for aesthetic reasons and you know it...