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Technical Q&A with Lennard Zinn – Easy to follow assembly instructions

  • By Lennard Zinn
  • Published Oct. 21, 2003
  • Updated Aug. 29, 2010 at 10:39 PM EST

By Lennard Zinn

Dear Lennard;
I have used your book “Zinn & the Art of Road Bike Maintenance”quite a bit and love it. I just bought a road frame and am building a bikefrom scratch. Your book has lots of useful information, but I probablyneed more instruction on building up a bike (what order to do things in,etc.). Is there anything you can recommend?
–JohnDear John;
I can certainly recommend my “Mountain Bike Performance Handbook” ifyou are starting out with tapping and facing the bottom bracket and reamingand facing the head tube. You can buy that book from me directly, sinceVeloPress/VeloGear does not stock it (Motorbooks does stock it, so bookstoresshould be able to order it in the normal fashion, too).
If you are just going to start putting parts on the frame and forkwithout reaming, facing, and tapping, then “Zinn & the Art of RoadBike Maintenance” will be fine, with a few tips on order that I will giveyou now. The tools you will need are detailed in the instructions in thebook.Clamp the seatpost in a bike stand after installing it in the frame.Install the bottom bracket, crank and pedalsInstall the headset and forkInstall the stem, bar and wheelsInstall the brakesInstall the derailleurs and chainInstall any other itemsCheck your positionTape the barGo for a ride.–LennardLocked in Laramie or wobbling in Wyo.
Dear Lennard;
I am a 51 year old roadie and live in Laramie Wyoming. Hence, it ishard to get good service/advice on road bikes. A year ago I purchased aMerlin Extralight Campy record equipped bike from Excel Sports in Boulder(50th birthday splurge – didn’t know that you built Ti at the time). Theyhave been great to work with but it is a 280-mile round trip to their shop.The closest competent mechanics are a 135 mile round trip (and I have beenthere once to no avail). So, I thought I would address a technical questionto you about my fork/headset “problem.”No matter how hard I try I can not get the headset (Campy integrated)correctly adjusted. It is either too loose (slight movement fore and aftwith front brake clamped) or too tight (binds when turned – worse whenturned to right than to left). Visual inspection shows no damage and allparts correctly installed. The fork is a Look HSC 4. Under the top capit has a small diameter, stiff spring rather than just a bolt for adjustment.Questions:

1. Have you ever seen this set up?
2. If so, have others experienced the same “problem.”
3. Is there a solution?
4. If not, am I correct in assuming a bit too tight is betterthan a bit too loose {better to possibly damage the bearings than damagethe head tube}?

–KimDear Kim;
Your headset cups likely are not parallel, thus causing the bindingwhen you turn it. On a standard headset, the head tube would need to befaced (possibly the fork, too, but not likely). With a Merlin or Litespeedintegrated headset, the bearing race seats are titanium rings pressed intothe head tube bore and may not have been pressed in straight. There isa cutter that faces and chamfers integrated headset seats, or those couldbe pressed in straighter.A different headset could do it, too. Integrated headsets are notoriouslyfinicky, since they do not depend on the normal head tube ends. Campy integratedheadsets have loose balls in retainers and separate bearing races. Youmight try one with cartridge bearings.
–Lennard… and a follow-up from Kim
Dear Lennard;
Just wanted to let you know that I installed the Cane Creek headset(which Excel provided at no cost) and I fixed everything. Amazing whatthe right parts will do!!!!!!!!!!!!
–KimShake and shimmy
Dear Lennard;
You mentioned in the Pinarello response (see “A blast from LZ’s past“) that reducing rake increases the tendency of a bike to shimmy. I always thought that increasing trail would do the opposite. Please could you elaborate further on this assertion?
–ColinDear Colin;
You are confusing shimmy with stability. Greater fork trail gives thebike greater stability, but it does not necessarily reduce shimmy.Trail is the distance between the intersection of the steering axiswith the ground and the tire contact patch. As long as the tire contactsbehind the steering axis intersect, trail is a positive number, meaningthat the wheel actually is trailing behind the steering, just like thecaster on a grocery cart trails behind its (vertical) steering axis. Ifyou don’t believe that the wheel is actually trailing behind (it doesn’tlook like it, being out there in front of the bike), note that you canpush the bike along forward by holding the saddle. Now try wheeling itbackwards by pushing on the saddle! You can’t do it if your bike has positivefork trail.Shimmy, on the other hand, mostly has to do with the resonant frequencyof the bike. If you increase fork trail by reducing fork rake, you transfershocks more directly up into the frame, which will tend to set off theoscillations more. Generally, more fork rake decreases the tendency forshimmy because more shock is absorbed in the fork flexing along its length.
–LennardIs carbon good for ‘cross?
Dear Lennard;
I have just a quick reliability question here: bonded forks versusall carbon forks (specifically Wound Up vs. Alpha Q). In terms of the ‘crossofferings from these two manufacturers- have you ever heard of or experiencedany bond failure at the crown (Wound Up) or failure in general from theintense use ‘cross puts these forks under? Carbon’s a great technologicalinnovation, but I’ve never been able to talk to anyone who’s used a composite’cross fork so I’ve got no real world experience on which to base my opinion.
–DevinDear Devin;
You should be clear that, other than a few exceptions, all-carbon forksare bonded. The dropouts are always bonded in, of course, but the carbonsteering tubes are generally bonded in as well. There are a few true monocoques,where the steerer and the legs are molded simultaneously all together,but these are the exception. In other words, you do not avoid bonding whenyou choose between an all-carbon fork and an aluminum-and-carbon one.I have not heard of a WoundUp ‘cross fork ever coming apart, and, otherthan our first sample, I have never experienced or heard of problems withAlpha Q ‘cross forks, either. The first Alpha Q ‘cross fork we revieweda couple of years ago, the steerer pulled out of the crown, although thecarbon “root” held it all together. This was the result of not roughingup the steerer properly, and we were assured that this was a singular occurrence.The replacement we got has been perfect ever since. Charles Pelkey’s reviewof this fork detailing this problem was in the Oct. 8, 2001 issue of VeloNews.Whilethe failure was a bit unnerving, Pelkey continues to use the same modelof fork on his ‘cross bike and has not encountered a problem since.
–LennardFrom triple back to double
Dear Lennard;
I have a Bianchi Veloce with Campy Veloce components. Right now I havea triple chainring set. I plan to change to a double chainring set (53* 39) I used to have many years ago. What adjustments should be done forthe shifting? Do I need to buy a new chain and rear cassettes as well?
–ArnieDear Arnie;
You should certainly change the chain when you do this. You probablywant to change to a double rear derailleur (shorter cage) for crisper shiftingand a shorter chain. The chain length may still actually end up a linklonger with the double (to make the jockey wheels vertically one abovethe other when on the big ring and the smallest cog). And if the rear cogsskip, you waited too long to change the chain and will have to replacethem as well.
Using the triple front derailleur is probably fine.
–LennardFeedback on October 8 column:
Dear Lennard;
I have seen a couple posts lately where people have ovalized head tubesfor one reason or another. For the most part you have suggested that thereis no fix outside of a frame builder building up new material and thenreaming it back out. Understandably, in most cases this will not pay foritself, especially on an older frameset. Furthermore, if the head tubeis Aluminum or Titanium, it is not possible in any case with normal methodsand heat treating issues.Actually I think there are a couple other options, one of which is quiteinexpensive. On the costly side, one would have to know a good machinist.They could bore out each side to be slightly oversize, and fabricate andinsert a press fit liner to recreate the correct ID of the tube. Of courseunless the machinist is your buddy, this is probably a $500 job, and carewould have to be taken not to remove too much material and overlay weakenthe head tube. This could be done on any Metallic Frame material if themachinist knows what he is doing.A much cheaper, though one time solution is to use Loctite 660 Quick Metal to fill in the gaps between the headset cup and the head tube. Thisis a product that both fills gaps and bonds the headset cup in place. Ihave used it to repair failed keyways in Miata Crankshafts (A very highlyloaded, high rpm repair) as well as for other apparently terminal casesof bearing housing damage. However, I have not tried this on a bike headsetmyself, though I am fairly confident it would work quite well. The onecaveat is that without applying heat (About 350F), you will never be ableto remove the headset cups in the future, this stuff is really strong.You might want to use a pseudo-lifetime type headset such as a King ifyou did this. A tube of this stuff if not even $ 10 and might be wortha try on a last ditch effort. It would be important to keep the races centeredside to side to preserve wheel alignment, but since most ovalization isfore and aft, this should not generally be a problem. You can buy thisfrom McMaster-Carr if you cannot find it locally.
–RogerDear Lennard;
I think I can help with a problem in October 8th’s Technical Q&Acolumn:
Before Elton performs this repair on his 2002 LeMond Zurich, he’d bettercheck whether the accident horizontally ovalized the top and down tubesas well as the head tube (assuming that the Zurich didn’t come from thefactory with vertically ovalized top and down tubes). He should comparethe vertical and horizontal diameters of the tubes, measuring about aninch out from the head tube. (If a set of measuring calipers isn’t handy,a Vice-Grip will serve, believe it or not; the screw gear in the handleallows delicate adjustments in the spread of the jaws.)The tube measurements (again assuming that the tubes started out round)should differ by no more than an eighth of an inch, if that. If the measurementsaren’t at least that close (and if the horizontal diameter of each tubeis larger than the vertical diameter), the head tube angle is now steeperthan it was before the accident.Reynolds 853 top and down tubes are amazingly strong, and many 853 frameshave head tubes made of a less exotic alloy, so chances are that the forkand the head tube took most of the damage and that there’s no head tubeangle problem. But if there is, it’s still worth taking the bike to a framebuilder to see whether aligning the head tube to the original angle isan option; alignment costs a lot less than replacing a frame. And it’salways a good idea to get a frame checked out by an experienced frame builderafter a bad crash.
–JoeNew use for old tool
Dear Lennard;
The perfect tool for removing cranks with stripped extraction threadsexists – a cottered crank remover. Just a 2 pronged fork with an 18″ rod,that can be inserted between the bb shell and crank arm. Remember to bangout the cotter pin and pull. Of course, no pin to remember on a cotterlesscrank.I doubt the tool is made any more, I took mine with me when I quit shoplife several years ago.
–No nameFinally, lots of readers wrote in about sewup tire repair, all ofwhom had the same suggestion, so here is one.
Dear Lennard;
In a recent column on the VeloNews website, you asked if anyone knewof a company specializing in repair of tubular tires. I recalled an articlein the July 1, 2003 issue of Bicycle Retailer about “Tire Alert”. Theyspecialize in refurbishing tubular tires with new tubes. Their websiteis at www.tirealert.com


Technical writer Lennard Zinn is a frame builder, a former U.S. national team rider and author of several books on bikes and bike maintenance including the pair of successful maintenance guides “ Zinn & the Art of Mountain Bike Maintenance” and “Zinn & the Art of Road Bike Maintenance.”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. Readers can send brief technical questions directly to Zinn. Zinn’s column appears here each Tuesday.

FILED UNDER: Bikes and Tech / Technical FAQ TAGS: / / /

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance 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. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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