shimmy

This week, Lennard Zinn answers questions about bike positioning and shimmy

Lennard Zinn answers questions about installing disc brakes, inter-brand combinations for hydraulic brakes, and more on high-speed shimmy

Lennard Zinn takes a new look at the old problem of brake chatter in cyclocross.

Can stem height affect high-speed shimmy?

Torque wrenches and temperature ranges Dear Lennard, I own both deflecting beam and click-type (Giustaforza) torque wrenches. They are stored in my garage where the temperature can get below freezing in the winter and over 100 degrees Fahrenheit in the summer. Do torque wrenches need to be stored and used within a certain temperature range to maintain accuracy? Gary Answer from Effetto Mariposa:

Side steppin'Dear Lennard,Regarding your April 10, 2007 article "Whatis it?", I was wondering if you had any thoughts or opinions on modern-daypedal systems which are attempting to bring the ball of the foot directlyto where the pedal spindle typically is. The two that cometo mind are SideMount pedal (SMP) of Pasadena, CA and VistaMagic X of France.DavidDear David,I have not used the Vista Magic X, but I’ve used Steve Lubanski’s SideMount Pedal and Tom Slocum’s HighSierra dropped pedal built into a Speedplay. Both of them feel absolutelyfantastic to pedal with; most riders would be amazed

Why does my bike shimmy at high speed?

Water SolutionDear Readers,It seems that whenever it is raining somewhere in the USA, I get questionsabout drain holes in the bottom bracket and rims. In the past, I have advisedpeople to drill their own if they are not present, but of course that isat great risk of voiding their warranties. However, here is a solutionthat might appeal to those whose bikes are filling up with water as wellas for those who do not want to void their warranties.LennardDear Lennard,I recently discovered it's not difficult to drill a hole down the centerof the set screw that holds the cable guide in place

Savings options? Dear Lennard, My question is regarding CO2 inflation cartridges. Is it okay to use CO2 cartridges that are labeled for use in BB guns and paint ball guns? I have been told that they contain a small amount of oil in them and because certain oils or lubricants can sometimes breakdown rubber that I should not use them. Is this true? These CO2 cartridges are sold at your local Wal-Mart or sporting goods store and are considerably cheaper. A box of 15 or 20 usually runs around 10 dollars as opposed to three or four dollars a cartridge at you local bike shop.

Screeeeeetch!Dear Lennard,I have a brand new Santa Cruz Blur equipped with Avid Juicy 7 discs. After a few rides in dry weather where the brakes performed flawlessly and silently, I rode the bike in the rain. I almost had to abandon braking altogether and just drag my feet to stop as the squealing sound was so loud it was shaking out my fillings. Since then, even in dry weather, the brakes continue to squeal on and off, and frankly I am afraid to use them in the wet again. The brakes are properly installed and bled. Did I not break them in long enough (three rides of easy road riding with

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

What about that tape?Dear Lennard,I think I do a pretty good job of gluing my tires securely, and I re-glueevery year. However, on some of my tires the actual tape is separatingin some places from the tire (the layer between tire and rim). Isthere any way to fix this, or is the tire done for?RyanDear Ryan,I have had good luck in the past using Bargecement. This is a contact cement I have been using since childhoodto patch rafts and I first got some from a shoemaker who used it to gluesoles on. I would guess that it’s widely available at hardware stores or whitewater equipment stores.

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

Dear Lennard,I recently converted to wheels with bladed spokes, and now my speedometermagnet no longer fits onto the spoke (I have a Performance brand Axiom8.0C). Is there any solution where I don't have to buy an entire new computer?If I do have to upgrade, can you recommend one that will mount to a bladedspoke?AndrewDear Andrew,You can buy separate magnets for this type of spoke. For example, lookingin the Quality Bicycle catalog, and estimating the retail price, it lookslike you could get a hand-tightening Campagnolo magnet for $27 that I ampretty sure I have used on bladed spokes, a

Oh my achin' backDear Lennard,My bones are getting stiff and achy, and I am looking for a way tosoften my every day/training bike, a Cannondale CAAD 5 with the stock all-carbonfork. The bike fits me like a glove and is very responsive.Would a carbon bar and stem combination damp the ride and add comfort,or are carbon bars just as stiff and noncompliant as alloy bars?Are any carbon bars "softer" than others? Have you ridden Specialized'sRoubaix? Is there a significant improvement in the ride? Isthere a real tradeoff in performance? My 59-year-old neck, arms andback thank you!Bill Dear Bill,I

Where is that table?Dear Lennard,Where can I find the torque charts that the latest issue of VeloNewssaid were on the Web site?CharlesDear Charles,Hereyou go!LennardAsking SantaDear Lennard,I'm suggesting an inch pounds torque wrench from Santa for Christmasand I'm a little confused on which to put on my list. The one I want isa 1/4" twist knob type US, but they have a few options on the increments.Should I go with a 40-200 or 10-50? I'm most doing all the stuff onmy road and mountain bike, stems, cranks bolts etc.PaulDear Paul,Sorry if my answer is too late for Santa, but click on the torque

Rake, trail and the difference between the twoDear Lennard,In your November9 Technical Q&A you said that a 44/45mm rake would steer less quicklyand be more stable than a 47mm rake. Is that a typo? I thought shorterrake would tighten up the wheelbase and make the head tube angle feel steeper--yieldingquicker handling and a more "twitchy" feeling bicycle.Jeremiah Dear Jeremiah,Sorry, but the statement is correct and your interpretation about forkrake’s effect is wrong. Indeed, a steeper head angle does make the bikehandle more quickly (reduces fork trail), yes. However, a reduced forkrake

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

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

Dear readers;I am writing this from Italy, a few days after I had the chance to visit Milan for what has to be one of the world’s best bike shows. So if you don’t mind, I would like to start my weekly column with a look at fewof the treasures I spotted at Milan’s EICMA show. Conducted under gorgeous warm, sunny weather, the 61st EICMA bicycleand motorcycle show marks the official launch of a new road season. Italy is a great place for a show, and Milan in particular, because of the heritage of great design. As always, gorgeous Italian bicycles are in abundance, and the theme of ever more

Dear Lennard Zinn,I currently suffer from iliotibial band syndrome, which tends to affecthigher-mileage runners and cyclists. It causes a pain on the outside ofthe knee due to the repetitive motion of bending the knee. There is quitea bit of info on the problem with regard to runners but very little concerningcycling. I have gone to physical therapy and received a cortisone injectionfrom a knee specialist. Not much has helped. Have you heard of this affectingother riders? If so, do you know of any potential treatment options thatI have not tried? I can give up running but not cycling.

Dear Lennard;I remember a while back you mentioned some auto part glue that worked well for glueing on sew-ups. What is it and any tricks to using it? --Ignacio Dear Ignacio;The glue is 3M Fast Tack.Except on Continentals (which have no coating over the base tape), scrape the base tape (instructions in “Zinn and the Art of Road Bike Maintenance”). Layer the glue on the rim and tire, letting dry between coats. After the final coat on the rim, stick the tire on. Fast Tack can be problematic with Continentals, as it has a solvent in it that can soak through the base tape and loosen the glue

Dear Lennard Zinn;I am looking for a recommendation for a good chain to use with a '95 Campy Chorus 8-speed EXA-Drive system. The cassette and chainrings are previously unridden, but a new SRAM PC-58, which I believe is intended to be an 8-speed chain, runs a little rough. Any better suggestion? --Bill Veihmeyer Dear Bill;I have found that 8-speed Shimano chains always worked great on that system. --Lennard A mystery skipDear Lennard;I have Campy record 10-speed on two of my bikes, the chain started skipping on one of them, so I figured it was the cog set, I put that same wheel on the

Dear Lennard Zinn;To date I have not had much experience with threadless headsets. Howdoes one adjust (raise) the handlebar height on a threadless headset system?--Craig Dear Craig;If you have spacers on the steering tube above the stem, you canraise it. You pull off the top cap and the stem and move spacers from abovethe stem to below it. If there are no spacers above the stem, you do nothave enough length of steering tube to allow raising it. If you have adown-angled stem, you can flip your stem over so it angles up. Or you getanother stem that has more up angle to it. --Lennard  That

VeloNews 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. Zinn's VeloNews.com 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 each Tuesday on VeloNews.com. Question:I have a question on the durability of the RockShox World Cup carbon steer tube. I am very comfortable on my MTB with a low front end but it is causing problems on steep descents. I am

VeloNews technical writer Lennard Zinn is a frame builder, aformer U.S. national team rider and author of several books on bikes andbike maintenance. Zinn's VeloNews.com column is devoted to addressing readers'technical questions about bikes, their care and feeding and how we as riderscan use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn. Zinn’s column appears each Tuesday on VeloNews.com.Carbon road forks:I get so many questions about carbon forks that I have decided to focus this column entirely on questions related to

VeloNews 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.This is Zinn's regular VeloNews.com column devoted to addressing readers'technical questions about bikes, their care and feeding and how we as riderscan use them as comfortably and efficiently as possible. Readers can sendbrief technical questions directly to Zinn. We'll try to print a representativesample of questions regularly.First, some follow-up from previous columns:Comment on rim weight:Froma July, 2002 column,"As an aside- the old wheels

VeloNews technical writer Lennard Zinn is a frame builder, a formerU.S. national team rider and author of several books on bikes and bikemaintenance. This is Zinn's VeloNews.com column devoted to addressing readers'technical questions about bikes, their care and feeding and how we as riderscan use them as comfortably and efficiently as possible. Readers can sendbrief technical questions directly toZinn. We'll try to print a representative sample of questions regularly.Question: One of my riding partners had a ticking (not a creak)sound in his ride.  It would only happen when pedaling

VeloNews technical writer Lennard Zinn is a frame builder, a formerU.S. national team rider and author of several books on bikes and bikemaintenance. This is Zinn's weekly VeloNews.com column devoted to addressingreaders' technical questions about bikes, their care and feeding and howwe as riders can use them as comfortably and efficiently as possible. Readerscan send brief technical questions directlyto Zinn. We'll try to print a representative sample of questions ineach column.Follow-up from previous discussions:There was plenty of input from readers on the subject of mixing

Does increased fork rake or rider position affect high-speed shimmy?

VeloNews technical writer Lennard Zinn is a frame builder, a formerU.S. national team rider and author of several books on bikes and bikemantenance. This is the third of Zinn's weekly VeloNews.com column devotedto addressing readers' technical questions about bikes, their care andfeeding and how we as riders can use them as comfortably and efficientlyas possible. Readers can send brief technical questions directlyto Zinn. We'll try to print a representative sample of questions eachThursday.First, some follow-up from our last columnA few more reader comments on the creaking bottom bracket