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Technical Q&A with Lennard Zinn – Orthotics; broken bars and white carbon

  • By VeloNews.com
  • Published Jan. 6, 2004
  • Updated Sep. 28, 2010 at 4:49 PM EDT

By Lennard Zinn

Dear Lennard;
I’ve seen many times when you recommend a pair of custom orthoticsto alleviate many common cycling issues. I plan on having a pair made formyself, but therein lies my question: when shopping around for a podiatrist(I’ve heard too many stories about people purchasing expensive orthotics,which then turned out to not be effective), what does an athlete need tospecifically ask or have done to maximize their monetary efficiency?

I know that all custom orthotics will be different based on the individual’sneeds, but I’d like some advice from a man who’s had effective orthoticsmade. Are there methods of creating an orthotic that are more effectivefor cyclist than other methods? Do I need to ask specifics about theirtechniques? I’d appreciate any information on this you’ve got as I’m willingto shell out money for an effective treatment of my leg length problems.

Thanks for all the information and help you give on the site.
Devin

Dear Devin;
Custom orthotics (also known as custom footbeds) can address pain inthe feet as well as in the knee and hip; they will help with biomechanicsjust like a good bike fit will. If there is less unwanted motion in thefoot and ankle, then there is less unwanted motion in the knee. For cycling,you need a full-length orthotic, and, yes, you should ask about “theirtechniques.”

A pedorthist, or orthotic maker, needs a cast of the foot in order tobuild an orthotic. “I prefer to cast people¹s feet myself, but halfof my business I receive through the mail, usually from health care professionals,”says Russel Bollig, owner of Podium Footwear in Boulder, Colorado.

Bollig has built custom footbeds for me that worked out great, as wellas for many cycling stars, including Lance Armstrong and Tyler Hamilton,as well as for top athletes in other sports (he makes all of the orthoticsfor the U.S. National Nordic Ski Team, for instance). The orthotic’s shapecan be determined standing on a soft casting pillow with a heated moldableplastic piece or isolation foam placed under the foot that solidifies tothe shape of the foot or with a fiberglass resin-impregnated sock encasingthe foot. Another option is to use a foot impression box with a dry foaminside that the feet press into and leave an imprint like a foot in sand.If you are standing on it, it is called a neutral or semi-weight-bearingcast. The pedorthist then pours plaster into the impression in the pillowto make a positive of the foot. Then he or she would vacuum form hard plasticonto the plaster form.

Most podiatrists will do non-weight-bearing plaster forms by wrappingplaster strips around the foot without weight on it. Since the arch compressesand the foot spreads out when standing, the orthotic cannot be the sameshape as the unweighted foot or the arch would be uncomfortably high. Dependingon how you look at it, it takes either craftsmanship or guesswork to gofrom a non-weight bearing cast to the proper orthotic shape.

“I only accept semi-weight-bearing casts except in special cases likea broken foot where they can¹t stand on it but still need to startthe orthotic process,” said Bollig.
Lennard

How much is the right
Dear Lennard;
Just got my new Specialized Epic disk mountain bike with Fox Shocksfront and rear. After reading the maintenance manuals for both, I findmy toolbox lacking. A search on the web for said tools yields, either impossibleto find or outrageously expensive. Specifically, I need a 8mm crowfootand a 26mm 6 point socket. Yikes, forget about Craftsman or any other commontool maker. I didn’t want to spring for the Snap-on $180.00 Crowfoot setor the $275 large metric socket set. Any good sources for tools would beappreciated.

If only Fox would have taken into consideration the tools required totheir scheduled maintenance. Buyer beware!
Gregg
 

Answer from Fox:
At Fox, we take pride in designing the highest performance lightweightbicycle products that are serviceable with readily available tools froma hardware or tool store. If your local Hardware or Tool store does nothave a 26mm socket, you can purchase an individual socket at the followingonline places.

You can order a very inexpensive 26mm 6-point 3/8-inch drive socketfrom the luxury of your home computer at the following company:

1. Type in www.mcmaster.com

2. Type in #5849A113 in the “FIND” search window.

3. The socket is $5.56 plus tax and shipping.

If you like Armstrong Tools, you can order a 26mm 6-point 1/2″ drivesocket from the luxury of your home computer at the following company:

1. Type in www.protoolsdirect.com

2. Type in #39-026 in the “SEARCH” window.

3. The socket is $10.44 plus tax and shipping.

If you like Craftsman Tools, you can order a 26mm 12-point 1/2″drive socket, again from the luxury of your home computer at the followingcompany:

1. Type in www.sears.com

2. Type in #0944272 at the “SEARCH BY KEYWORD OR ITEM #” search window.

3. The socket is $6.99 plus tax and shipping.

4. A 12-point socket is OK to use although a 6-point is preferred.

To perform a complete service and oil change on any FOX Fork, you onlyneed the following simple tools:26mm socket

10mm socket

3/8 drive ratchet

torque wrench

plastic mallet

small straight-blade screwdriver

1.5mm Allen key

2.0mm Allen key

drain pan

clean cotton rags

Shock Air Pump

Fox Forx OilTo perform a complete air sleeve service on a FOX Brain Rear Shock, youonly need the following simple tools:19mm wrench

8mm Allen key

4mm Allen key

22mm wrench

clean cotton rags

Shock Air Pump.Bill Becker
Fox Racing Shox

Beefy wheels for a beefy guy
Howdy Lennard
I’m a big guy, 6 foot 6 and pushing 300 pounds, and all but the heaviestand most overbuilt wheels feel flexy under my weight, especially in theturns. Can tied-and-soldered wheels offer me any performance advantageon road or off?
Ryan

Dear Ryan,
Yes, I think so. I have tied and soldered my own disc-brake mountainbike wheels for years now, and I notice a difference not only in lateralstiffness but especially in application of the disc brake. But then, Iam your height but weigh only 170 pounds, though. Are there heavier readersout there who have noticed the difference? The folks at DT Swiss have beenexperimenting with the concept for years.
Lennard

 
Response from DT Swiss
The performance advantage of tied and soldered wheels is difficultto quantify, but some riders claim to notice an improvement in wheel stiffness,ride quality, and wheel life. The effect of tying and soldering would beminor, however, compared to the differences between various rims and spokesthat you could choose. In the past, tying and soldering was very popularfor track racing, where strong side loads can be exerted on the wheels.It also helped to make up for inferior spoke quality. Now that rims andspokes are significantly improved, the benefits of tying and solderingare less tangible. You could certainly try it on your current wheelsetand see if it makes a difference, but most likely you will have the bestriding experience using heavier rims and spokes.
Paul Aieta
General Manager
DT Swiss, Inc.

What the fork!?
Dear Lennard;
I suspect this may have been addressed before. I have a great steel700c frame that I have tried to convert to a time trial frame. However,due to the standard geometry, and my shorter stature (it’s a 50cm c-c,54cm top tube), it’s just too difficult to get the bars low enough foran optimal time trial position. What kind of short/long term damage amI going to see if I put a 650c fork on this frame?
Marvin

Dear Marvin,
Don’t do it! When tipping the frame down by installing that short fork,the head angle will be so steep that the handling will be extremely quick.The bottom bracket will also get dangerously low. The seat angle will besteep, too, but maybe you want that.
Lennard

Strength through diameter
Dear Lennard,
I am considering purchasing a 2004 Road Frame that has a 31.6mm seatpost.It seems obvious that a larger seat tube can lend more strength to thebottom bracket, but what are the benefits, or negatives of the seatpost?

I would think you could get the BB stiffness without having to changethe seatpost (i.e., larger seat tube and shim to fit the ubiquitous 27.2seatpost). It seams that many MTB bikes are shifting, and a few road bikes.I believe that the flexing strength of a tube increases by the cube ofthe radius, but is this an advantage that Seatpost MFG¹ers are takingadvantage of, or is necessary (i.e., stronger seatpost, but not heavier)?Is this more a frame benefit, or seatpost benefit?

I don’t want to buy a frame that will have a funky seatpost size thatwon’t be available in a few years!
John

Dear John;
For compact-geometry (i.e., sloping top tube) frames, there is moreseatpost extension. A larger post lends greater rigidity. Otherwise, itsaves weight when inserted in an oversized set tube, rather than sleevingthe seat tube down. I would bet on 27.2mm seatposts disappearing beforeI¹d bet on oversized ones going away. That said, there is no tellingwhich size, if any, will shake out as the “standard” the way 27.2mm didfor a number of decades.
Lennard

Scary ceramics
Dear Lennard;
I have just replaced the badly worn Mavic Mach 2 rims on my cross bike.I felt lucky to find a (very dusty) pair of the same rims, but with ceramicsidewalls. The back wheel is great, but applying the brakes to the frontis pretty scary. The forks vibrate quite violently. The bike is an oldAlan, with a Vitus Futural fork. I weigh under 140 pounds. The same set-upworks fine with a set of wheels with Open Pro rims with machined sidewalls.
Martin

Answer from Mavic:

Dear Martin;
I found the following in the user guide delivered with every set ofthese wheels:

A squealing noise may be produced when braking on ceramic rims. This noisewill diminish as the brake pads become “run-in;” When the Ceramic coatingis wearing out, after installing the second set of pads, the noise is reduceda lot. In fact, the pads will work like super fine sand paper on the Ceramiccoating to make it “less aggressive.”

For lasting and efficient braking, we advise the use of brake pads speciallyrecommended for Ceramic braking surfaces. It does exist in the MTB rangeof most brake manufacturers and as to be confirmed if it exists in theirRoad range too (check Shimano).

Respect the perfect pad alignment with the rim (parallel)

By the way, the Mach 2 rim was in the Mavic product range in 1993.
Michel Lethenet
Mavic SA

My mutated Mutant
Dear Lennard;
The 3T Mutant handlebar on my commuting bike recently broke at thestem. The bar was three seasons old and had seen about 18,000 kms of riding.Unlike me, my local bike shop was not surprised. They would recommend replacingan aluminum bar every two years similar conditions. Fortunately I was goingslowly up hill when the bar broke, but the prospect of a handlebar snappinglike a twig at high speed is more than a little frightening. Should I bereplacing aluminum bars so frequently?

The Mutant is not a high quality bar. Would a high quality aluminumbar be more secure even though they tend to be lighter than the Mutant?Should I expect better security from carbon bars like the Cinelli Ram onmy road bike and the Easton Monkey Lite on my mountain bike? If size andweight are factors, I am 6 foot 1 inch and weigh 165 pounds.
Steve

Answer from 3T

Nothing lasts forever.
This is not the title of a song but the destiny of all things. Theuse of new materials and technologies for the production of light and highperformance products has brought a deep change in the way designers andengineers develop new products. Fail safe, safe life, condition monitoringare all concepts and new way of design techniques that come from the aeronauticalfield and mean that you cannot install and use critical and high performanceproducts and then forget about them.

These methods are based on a simple, but fundamental concept: Maintenance.This concept means to follow all the operations after a component is installed,that guarantee its safety.

Every material that is nowadays used for the manufacturing of high endbicycle components (steel, aluminum and magnesium alloys, titanium, carbonfiber, plastics) has good and bad properties that can be increased or decreasedby the choices and the skills of the engineers. However when we talk abouthigh performance components, nothing can be ignored. For the safe use ofthose components, following the instructions described in the users’ manualsbecomes of basic importance.

This the only possible way to design products that can be safe for theirwhole expected life. Too many times we have seen overtightened bolts, notlubricated chains, worn cables, rusted tubes, ignored warnings. Only theusers’ manual and applying its instructions can guarantee a happy and safeuse of those products. With our products we include a 95-page manual writtenin four languages. I think it’s important.

In this particular case, considering that normally the cause of breakingfor handlebars is fatigue, a periodic inspection of the handlebar wouldhave shown the beginning of the damage and the handlebar changed. Alsothe kilometers, according to our manual, were in the end of the life rangefor the kind of use (Intense amateur use).
Fabrizio Aghito
GRUPPO SpA

How did they make it white?
Dear Lennard,
Hey I know this sounds funny, but the term Carbon Fiber indicates thatthe fibers are actually reinforced with carbon molecules. This being thecase, all carbon fiber has been black. I know several companies have putessentially coloured clear coats overtop to give the black a differentsheen, but it is still black carbon. The thing I don’t understand is howBianchi has made white Carbon fiber and it is still called carbon. Howdo you make white carbon? Have they come upon something unique here oram I missing something? Is there any change in the strength propertiesof the fibers when they are white?
Chris

Answer from Selcof
It’s special treatment. Of course carbon fibers are black, but afterthe treatment they change color. But it’s our intellectual property, andI can’t say anything about the working process!
Fabrizio Mocellin
Sales & Marketing Manager
Selcof
WWW.SELCOF.COM
 


VeloNews technical writer Lennard Zinn is a frame builder (www.zinncycles.com), 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.

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