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Technical Q&A with Lennard Zinn freehub fix

  • By VeloNews.com
  • Published May. 8, 2007
  • Updated Aug. 29, 2010 at 10:38 PM EDT

Noisy freehub

Dear Lennard,
I was reading the October18, 2006 TechTalk article about the noisy freehub problem fix. Is thechange from FTS-L to FTS-X as simple as changing to the new pawls? I amexperiencing a noisy rear hub and think this is the problem. Some sitesrecommend replacing the freehub body and seal as well. Would you recommendreplacing these when I replace the pawls?
AndyDear Andy,
Yes, replace them with the new pawls, which are now available aftermarket.
LennardFeedback on previous columns
Dear Lennard,
Regardingyour recent column that discussed a stickyTruvativ bottom bracket. I installed a new Truvativ Rouleur with GXPon a Redline Conquest PRO frame on which the bottom bracket was not faced about 1.5years ago; I had poor chainline, and a bit too much drag I thought.My local bike shop who often fixes my home mechanic problems installed 2 washers onthe drive side between the bottom bracket shell and bearing assembly, to correct thechain line problem.It worked okay, but one season of ‘cross caused the bearing togo quickly, and it was spinning in gravel.When it was disassembled, my other local bike shop measured the bottom bracket width,and the shell was too wide (so with those extra spacers the alignment ofparts inside the bottom bracket must have been terrible). I observed the re-facing(not for the faint of heart!) and it looked to me like there was a lotof paint, which was adding to the width of the shell. Once re-facedto almost exactly 68 mm (with most of the extra removed from the non-driveside to help the chain line), and with a new bearing on the drive side,the assembly went back together very beautifully. And there is almostno drag to the touch, the whole thing feels fantastic.
Your advice to ensure proper facing fits perfectly with what we found,and I can confirm that too wide on the bottom bracket shell is bad.
DougDear Lennard,
Many riders are unaware of the need to face and chase their bottombrackets prior to installing an external bearing type crank set. However,I have had two local bike shops that I frequent tell me that they cannot face titaniumbottom bracket shells with the typical Park tool set.It is my understanding that many high-end carbon frames now use titaniumbottom bracket shells. One local bike shop stated that Colnago, Cervelo, Serotta, among others,use Ti bottom bracket shells. Short of believing the manufacturer when they tell youthe shell is perfectly aligned, is there anything a rider can do to checkhis bottom bracket shell, and if need be, face the shell?
James

Dear James,
You certainly can face a titanium BB shell with a Park BB facing tool. The facing tool needs to be very sharp (in my opinion, you cannot get them sharpened too often, as long as you have a guy you trust to sharpen them), and I recommend using canola oil as cutting fluid. If the tool is not sharp and is not applied with lots of pressure (we sometimes omit the spring and tighten the tool up so it forces the teeth to bite), then the teeth will just glide around the surface, as they told you. And how you tell if it’s faced is by seeing if any material is removed asymmetrically by the facing tool.
Lennard

Airplanes
Lennard,
Regarding bike tirepressure in an airplane hold. I just did a transport to Maui.Magnificent cycling, especially the Hana Road. 100psi at takeoff, safelytucked in their Performance hard cases. 100psi and true at landing.It works.
JohnRegarding brake pads
Dear Lennard,
In response to your article “Carbonand Cork” and the response posted May 1. I am constantly swapping betweenmy aluminum training wheels and multiple sets of carbon race wheels. Ihave found that replacing my stock pads with either Kool Stop’s carbonfriendly compound or the SwissStop yellow pads work great on both carbonand aluminum rims. Both are a “rubber” type brake pad, so they provideample power and modulation for aluminum rims, but are formulated to dissipateheat better, so not to do damage to the carbon rims. With this option Inever have to swap pads, therefore saving time and money.
AdamNew Product News: Make your own one-kilo wheelset
For $800 apiece Lew Racing is now selling the individual boron/carbonfiber rims used in its PROVT-1 wheels. The rims are built with the DEX-LCM™ manufacturing techniqueLew Aerospace developed for the Department of Defense, and applying aerospacetechnology from its unmanned aircraft, Lew Racing Tubular rims have a uniquelow-drag airfoil section. Each 46mm deep, 20mm wide rim is dynamicallybalanced and is manufactured to conform to aerospace and DOD standards.They are drilled 16-hole and 20-hole, but where would you get hubs withthose drillings? DT Swiss, White Industries and Tune all sell custom-drilledhubs. Visit www.lewracing.comfor more information.


VeloNews technical writer Lennard Zinn is a frame builder (www.zinncycles.com),a former U.S. national team rider and author of numerous books on bikesand bike maintenance including the pair of successful maintenance guides”Zinnand the Art of Mountain Bike Maintenance” and “Zinnand the Art of Road Bike Maintenance” as well as “Zinn’sCycling Primer: Maintenance Tips and Skill Building for Cyclists.”

Zinn’s VeloNews.com column is devoted to addressing readers’ technicalquestions about bikes, their care and feeding and how we as riders canuse them as comfortably and efficiently as possible. Readers can send brieftechnical questions directly to Zinn (veloqna@comcast.net)Zinn’s column appears each Tuesday here on VeloNews.com.

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