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Technical Q&A with Lennard Zinn – Frayed ends and that carbon vibe

  • By VeloNews.com
  • Published Dec. 12, 2006
  • Updated Oct. 8, 2010 at 5:21 PM EST

By Lennard Zinn

Mix and match
Dear Lennard,
I presently have a 9-speed Veloce drivetrain with a compact FSA gossamercrank (50/36). I purchased a Record carbon shifters and rear derailleuron eBay (used slightly).Am I correct in that these will work fairly well with my present componentsif I change the ratchet on my right shifter and change to a 10-speed chain?I am looking for the least expensive way to incorporate these new componentson to my bike. I will be eventually changing the cassette and front derailleurto match the 10-speed components, but I need to wait until my wife coolsdown from me spending too much all ready.How can I tell if my chainrings are 10-speed compatible (FSA Gossamercompact 50/36).
Julio

Dear Julio,
You will need to change the cassette as soon as you change the ratchetin the lever. A 10-speed shifter will not work on a 9-speed cogset. And9-speed and 10-speed FSA rings work fine with Campy 10.
Lennard

Compact tri’ guy
Dear Lennard,
I have read plenty about compact cranks for road cyclists, but do compactcranks make sense for triathletes? I have a standard double 12×25. I racerolling to flat courses. No mountains. I’m a more a masher than a spinnerdespite trying to spin.
Peter

Dear Peter,
I think compact cranks make sense for triathletes only on mountainouscourses, since the gear is not high enough unless you use an 11-23 cogset.And for a masher, a 50 X 11 may not be enough for a flat or slightly downhillor downwind course.
Lennard

A little spring for comfort?
Dear Lennard,
I have a ‘cross bike that I use on single track and logging roads.I get a bit beat up from the rides so I was thinking about putting a stemsuspension from Softride on it. My buddies think I am daft for doing this. I think it will smooth out my ride.  We need a comment from the expert.
Rich

Dear Rich,
Go for it. Softride stems may not be perfect, but they will certainlysmooth the ride.
Lennard

It’s not the carbon, it’s the motion
Dear Lennard,
I recently read that carbon only dampens road chatter when vibrationsreach 1200 megahertz, and that most road cyclists only experience around500-700 megahertz of chatter on even the worst of conditions.Is this true? The claim also stated that it is the geometry and tubeshaping that determines ride quality, not necessarily material.
BillAnswer from Easton:

A rider experiences a wide variety of vibrations.  Carbondefinitely soaks up the bumps better than other materials.  We wouldalso agree that the geometry (shape) of the tube would influence the ridecharacteristics more than the material.
John Harrington
Easton Sports

Spacers, retraction and few blank stares
Dear Lennard,
I have noticed that my pistons are not operating correctly.  Theydo not seem to retract all the way thus causing the pad to rub the rotor. I read the Shimano document (Technical Service Instruction SI-8CMOF)and they reference a red and yellow Pad Spacer for working on the brakesystem.  I do not have either of these spacers and was wondering ifyou knew of a source for these parts?  My local shop looks at me witha puzzled look when I asked them.Also any tips you have about disc brake maintenance would be great also.
Glenn

Dear Glenn,
Those are two separate issues, and you do not really need the spacersfor your problem. The red spacer does the same thing as the rotor; it spacesthe pads apart when you squeeze the lever. The yellow spacer is a thickblock that spaces the pistons once the pads have been removed, allowingyou to squeeze the lever without extending the pistons out too far. Bothof these come with every set of Shimano disc brakes, so any shop or anyof your buddies who bought Shimano brakes straight out of the box shouldhave some.But your real question is about pad retraction. My guess is that youhave early XTR disc brakes, as pad retraction is a problem with them. Tofix them, albeit temporarily, first remove the pads, and don’t use eitherred or yellow Shimano spacers, even if you rounded some up. Holding onepiston in place with a plastic tire lever, squeeze the lever so the otherpiston pops pretty far out. Clean and lubricate the exposed piston wallswhere they stick up out of the caliper. Use a light oil. Push the pistonback in with the tire lever and hold it in place while squeezing the leverto expose the flanks of the other piston. Clean and lube that one as well.As for disc brake tips, I don’t know where to start. This one is a prettygood one. Otherwise, check out my bookor DVDon the subject for an abundance of disc-brake tips.
Lennard

Feedback on last week’s column:
Dear Lennard,
In response to Jim who was building up a Ridleyaluminum cross frame as a winter commuter, the cheap kind of braze-onadaptor with a long slot for the derailleur usually allows enough leewayto place the band above or below the bottle cage boss.  The betterquality adaptors from Shimano, Campagnolo or Problem Solvers don’t workin this case because they don’t have a slot only a hole.  If water-bottlesare to be used on the seat tube, then they will still need to be spacedaway from the tube to clear the clamp’s band.  The knurled stainless-steelnuts that come on many presta-valves are just the right size to space thecage away from the frame.
Dave

Regarding the questionof soldering cables, I have to admit to being amazed at the lengthsto which people go to keep cables from fraying while avoiding the use ofthose good old cable ends. Of course, some understand and appreciate thesimple approach.
Lennard

Dear Lennard,
To those wondering how to solder a cable:
1. Crimp a cable cap on the end.
2. Go ride.
Mike

Dear Lennard,
I’ve always hated the crimp on cable ends. Instead, I use a drop ortwo of superglue. I use automotive brake cleaner to degrease the cableend, then put a drop of super glue on the cable. If the degreasing worked,the glue will wick into the cable and the last quarter inch or so willbe effectively fused together. It has worked quite well for me to keepthe ends from fraying, while sill allowing the cable to be withdrawn fromcomponents and the housing if necessary.Another method I’ve used, which works, but isn’t quite as effectiveas the glue is heat shrink tubing used for electronics. One of the downsidesis that heat shrink small enough for a cable isn’t common in the normalconsumer places like Radio Shack.
Barry

Dear Lennard,
I have found a TIG welder be excellent for welding the ends of cables. I have used it on a variety of cables with no special preparation. The only drawback I have found is that it is easy to melt a little morethan you need. This leaves a small knob on the end of the cable. I have found a dremel tool with a small grinding wheel to be the most effectivemeans of cleaning these up.
Tom

Dear Lennard,
Your replies on soldering bring me back to my days as a motorcyclemechanic.I am a bit worried about the reply concerning heating the cable tillit glows red!. Surely this is changing the temper of the cable wire andmaking it rather brittle.The absolute best way to solder cables (in my view and I have done thousands)is to get a small sealed at one end steel container. Heat it up and fillit with solid solder (ie: no flux mixed in). Once you have 1cm or so ofsolder inside. Place the cable end in the nipple. Splay the cable as muchas possible so it holds well. Dip it into liquid flux and then delicatelyand slowly dip the nipple into the heated/liquid solder. The evaporatingflux will draw the solder thru the nipple and it should only be aloud togo a tiny bit along the cable, this will also burn off any oil in the cable.Then slowly remove and let it cool. It will leave a perfect solder andno need file or clean up. Also once you have put the solder in the containerit is ready for many more uses.
Ian


Technical writer Lennard Zinn is a frame builder (www.zinncycles.com),a former U.S. national team rider and author of several best-selling bookson bikes and bike maintenance including Zinn& the Art of Mountain Bike Maintenance, which is now availableas a 4-hour instructional DVDZinn& the Art of Road Bike Maintenance, and Zinn’s Cycling Primer:Maintenance Tips and Skill Building for Cyclists. Zinn’s regular columnis devoted to addressing readers’ technical questions about bikes, theircare and feeding and how we as riders can use them as comfortably and efficientlyas possible. Readers can send brief technical questions directlyto Zinn. Zinn’s column appears here each Tuesday.

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