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Technical FAQ: Carbon in the sun

A reader asks whether the heat of a closed car or exposure to direct sunlight can damage a carbon frame.

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The sun poses few risks to your carbon frame ... as long as you stay about 150 million km away from it.

Dear Lennard,
I often put my bike in the back seat of my car in hopes that I can squeeze in a ride after work. I live in Southern California, so it gets pretty hot and there’s usually direct exposure to sunlight.

I own a Time carbon frame with an unpainted carbon finish. Should I be concerned about the 130 plus degree temps inside the car or the prolonged exposure to direct sunlight?

Dear Mike,
My friend Bert Hull, former Product Development Manager of True Temper’s Alpha Q Composites division and now of, and says, “no problem whatsoever, on both counts.” He goes on to say (he is referring to Alpha Q products when he says “our”):
“We have actually measured temps over 170 degrees in a black car with black leather interior (our R & D center is in San Diego), and even that is not too hot.

It may vary a little from brand to brand, but with our resin system you can safely get up to 275-300 degrees F before you start to see any damage. The paint on the fork may not like temperatures that high, but structurally there is no problem with the carbon composite.

As for ultra violet rays, our paints contain inhibitors to block a lot of the UV. The UV is not damaging to the carbon composite, but without the UV inhibitors, you would get some yellowing of the resin on the surface of the part. You may have seen this on the carbon hoods of street racer cars. This is only a cosmetic concern, not structural.

Our R & D director did a long-term test. He took some of our hockey shafts and fabricated a rooftop carrier for his car. He drove that around San Diego for five years. We took the rack down and performed our standard 3-point bend test which we do as a standard test on a sampling of our production (so we have a lot of data on sticks over the years). There was no decrease in strength or stiffness after five years on top of the car in Southern California sun and heat.

So there are no worries about the sun degrading the strength of those carbon frames or forks in the back of a “hot” car.

As for paint, it would vary with manufacturer and type of paint. With our PPG brand clear coat paint that we use, the cure temp we use is 180 degrees F. Sitting in the hot sunlight, the paint is just continuing to cure. No damage.”
-Bert Hull

A follow-up on 11-speed chains

Dear Lennard,
I was installing a new Campy 11-speed chain a few weeks ago and while doing so the pin cocked sideways then launched across the garage never to be found again. I was truly in a bind as I was racing the next day and did not have a spare chain or pin. I grabbed the pin I pushed out to shorten the chain and carefully inserted it with the virgin side out. It seated into the outer plate with a little extra sticking out on the backside. I used my Park 11-speed peening tool and peened the pin. Next I pushed the pin in slightly, wiggled it side to side a few times and the chain link moved freely. I raced that weekend on it and have put about 300 miles total without any problem. I’m not a “sprinter” but a decent climber at 165lbs. and 6-foot-2. Am I risking my life on this or do you think I could get away with putting my usual 2000 miles on it?

Dear Stan,
I have no idea. You’re in uncharted waters. Seems a bit risky to me, though. If it broke and you were injured, would it have been worth the money you saved by not replacing that pin right now with the correct pin or with the 11-speed SuperLink? Can you even find which pin it is anymore?

Dear Lennard,
I just upgraded to Super Record and I have a question as to when I should start thinking about replacing the chain. First of all I am 6-foot-3 and weigh 210 and I have put in about 500km on over the winter.

I will probably log 5,000 km by September and then I am participating in a 7,000 km, 15 day, relay ride across Canada. It’s a pediatric cancer fund raiser and I will be riding about 2,800 km of the 7,000. Obviously I want to have the smoothest drive train possible and to make sure nothing has to be replaced during the ride.

What sort of mileage can I expect out of the Campy 11-speed chain? If I need to change the chain should I change it 1,000 km before my National ride to ensure it is broken in properly? Also what about the cassettes? I have two wheel sets. I use Fulcrum Racing 1’s with a Chorus cassette for early season miles (its 5 below this morning) and a pair of Zipps for the long fast club rides? Should I be changing my cassettes when I change the chain? That could be incredibly expensive. What would you recommend for lube?

Dear David,
Different people of similar weight and riding schedules get different mileage (or kilometerage?) out of the same chain due to differences in riding style, environment and maintenance. I can’t imagine that with decent maintenance you’d get less than 3000km on a chain, but I would be loath to guess how much you would get. Rather, I highly recommend that you get this tool or this tool and check your chain weekly.

The Rohloff Caliber is a go/no-go gauge; brace the hook end against a chain roller, and if the opposing curved tooth falls completely into the chain so the length of the tool’s body contacts it, the chain is shot. You are to use the tooth marked “S” for steel cogs and the tooth marked “A” for aluminum and titanium cogs, but I just use the “A” side. I find that if the “A” edge comes down to the chain and I replace it right then, I get almost infinite life out of my chainrings and cogs, even titanium ones. There’s the answer to your question about replacing the cogset.

With the ProGold chain gauge, brace the hooked end against a chain roller and let the long tooth drop into the chain. I find that if it drops in close to the “90%” mark, that is equivalent to the “A” side of the Rohloff Caliber dropping down flush with the chain.

You should definitely put the new chain on in advance of your big charity ride and run both wheels with it to make sure it meshes well with both cogsets. However, I see no reason to do this for 1,000km. I’d give it enough time that if something didn’t work, I had time to replace it without great drama before the event.

I recommend ProGold ProLink for lube and put it on every day. I’m sure there are others as good, but I have no experience with anything that lasts as well for me as ProLink.

Dear Lennard,
I have the 11-speed Superlink in use now. Works great with no issues.

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Technical writer Lennard Zinn is a frame builder (, a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides “Zinn and the Art of Mountain Bike Maintenance” – now available also on DVD, and “Zinn and the Art of Road Bike Maintenance,” as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Zinn’s column appears here each Tuesday.