Ultrasonic, non-destructive frame testing is not a reliable method unless one has a perfect reference sample of the same carbon used in the fabrication of the bike frame.
Tech editor Nick Legan also answers readers' questions about using DOT fluid on carbon and new bike nervousness
Here’s a little secret: that beautiful carbon frame is easily repaired, provided it is administered to by the right hands
Nick takes questions about spring classics gear, frame inspections after crashes and how to line up handlebars perfectly.
I’m in the Denver airport about to fly to Italy for the Giro d’Italia. I have enjoyed a lot of the feedback from a few recent columns, and I thought you might as well. Next time you hear from me will be from the Giro, so look for some cool bikes for the team time trial soon.
On fixing carbon frames:
In your Earth Day column there was a question about a cracked carbon frame. Since it is a save the earth day of posting I thought I would ask about the possibility of repairing a cracked carbon frame (small crack obviously). Since you can buy epoxy and carbon, would it be possible to repair a carbon frame? It would be ugly but would it be rideable?
Scott Dear Scott,
Polishing scratched aluminum cranks, tubeless road tires and Scotch-brite pads
Questions about inspecting carbon forks for safety, trying Wippermann chains with Campy 10-speed systems and using Shimano MTB derailleurs with 10-speed road systems. What to do? I'm low on funds and that's the main reason I haven't replaced them as yet. I will add there are no stress fractures or noticeable wear.
One more gear?
We have a 27-mile climb just outside of town that I ride up occasionally. My problem is that I tend to spin out on my way back down and find it difficult to keep up with some of my riding partners. A friend of mine told me that I could swap my 10-speed Shimano cassette (12-25) for a SRAM (11-26), which would give me both a better climbing and descending gear. Although I understand 45MPH is plenty fast, is the swap compatible?
Brian Dear Brian,
TorqueDear Lennard,I recently purchased my first full carbon bike, absolutely love it. Yet, I'm scared of over-torquing the seatpost clamp. Is there a torque wrench you could recommend that works on Allen wrenches? What's the worst that happens, the seatpost clamp needs replacing or I have this fear of the actual seat tube deforming, I'm not doing the Samsonite luggage monkey torque on it, but "hand tighten" is just too open to quantify.ThomasDear Thomas,First of all, carbon frames generally have a separate band clamp to tighten the seatpost, and, yes, the worst that can happen,
Questions, and suggestions, about stuck seatposts, especially carbon posts
Questions about cutting carbon, shifting problems, chain length and more
Questions regarding Hincapie's broken steerer and slipping carbon seatposts.
Questions on mix-and-match components, fraying cables, carbon comfort, compact cranks and more.
Dear readers,I am always amazed how a single reader letter can sometimes generate a flood of follow-up mail. Over the last couple of weeks I have received a good deal of e-mail about the potential problems people encounter when they soak chains in Simple Green for an extended period. Many of those notes focused on SRAM chains, and some writers suggested that it was the steel used in those chains that was the root of the problem.Now that I have learned a lot more about it, I doubt it. I believe that SRAM chains were mentioned most often simply because people who soak their chains for long
Technical Q&A with Lennard Zinn: Using different wheels; more on carbon and damping; and torque-wrench warning
Dear Lennard,I have two sets of wheels I use for my bike with two different sets of clinchers, each with a different maximum-pressure rating. My race wheels have tires with a max pressure rating of 116 psi (Michelin Pro Race). However, my training wheels have tires with a max pressure of 145 psi (Vredestein Fortezza Tri Comp). I use my training wheels as my pit wheels while racing. If I have to change a wheel during a race, will the different pressures between the front and rear cause me handling problems or other dangers? Secondly, I am 175 pounds and use paired-spoke wheels (Shimano
PreservationistDear Lennard;I have several repair books including your “Art of Road Bike Maintenance,”and I can’t find the answer to this question. I have a nice late '80s Stronglightcrank that has the threads stripped on the drive side where you put thetool in to extract the crank. Is there anything I can do to get the crankoff and save the BB and crank?--Drew Dear Drew;Were you ever a trumpeter or other brass instrument player? I was,and I frequently managed to get my mouthpiece stuck in my trumpet. To removeit, you had to slip two notched steel plates around the tube of the mouthpiece,one