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Technical Q&A with Lennard Zinn – Staying warm; What pressure is good pressure?

  • By VeloNews.com
  • Published Feb. 10, 2004
  • Updated Oct. 11, 2010 at 2:23 PM EDT

By Lennard Zinn

Keeping important parts comfy
Dear Lennard,
This isn’t a nuts and bolts question, but I thought you might shedsome light on this subject. Most roadies I know (including myself) preferto wear bib shorts with leg warmers instead of tights in cold weather.I can’t understand why nobody makes a short with a windproof panel in thesensitive chamois region. Surely I’m not the first to think of this.
JayDear Jay,
Good question! No, you are certainly not the first to wonder this!Here are somewhat contradictory answers from De Marchi and from Sportful,which also owns Castelli.

From De Marchi
Dear Lennard,
The answer to your reader’s question is actually pretty simple. Panelsmade of either “sandwich” laminated fabrics (such as Windstopper or WindTex)or, even worse, windproof linings (which are the only known alternatives)add bulk in critical crotch areas and are both less stretchy and less breathablethan the material used for the rest of the short. For this reason, a shortwith a windproof front won’t be even close to as comfortable as any non-windproofshorts.

A variety of companies including De Marchi are offering windproof fronttights, taking for granted that a heavier winter pant is less technicalthan a Lycra short.

So, this is not one of those issues that has to do with the limitedsize of target users as happens sometimes in a world like cycling clothingthat is rapidly switching to mass production. It is instead a real technicalissue.
Mauro Coccia
De Marchi
San Vendemiano, ItalyFrom Sportful

The answer why you can’t find windproof shorts is simply Marketing.In this case though, it’s not about us trying to convince you to buy something,but rather about us not perceiving a big enough market demand. It actuallymakes a lot of sense, and since you’re the second guy I’ve heard of askingfor it, we’re going to give it a go and see what happens.

Oddly enough, winter leg covering seems to be heavily by local tastesmore than by predominant weather. I know that in Colorado and California,bib shorts and leg warmers are the preference. Where I come from in theNorthwest, it’s tights over bib shorts. Here in Europe, it’s all bib tightswith chamois: Windstopper if you’re in Germany, and feet stirrups if you’rein Belgium, France or Spain, and lots of knickers in Italy.
Steve Smith
Sportful
Fonzaso, Italy

How wide is too wide
Dear Lennard,
I’m a light rider who has always used high-pressure 20mm wide clinchersfor training due to their low rotating mass and rolling resistance, However,I’m finding that it is becoming increasingly difficult to find anythingbut 23mm tires. A local bike shop salesman told me that this is due tothe current thinking that a 23mm profile and lower pressures (I usuallyrun 140psi) actually result in lower rolling resistance. I’ve heardsimilar comments before, possibly even in your column. Is this true?It seems counter-intuitive; I would think that with a given tire constructionand pressure, a wider cross-section would simply mean a wider contact patch,which should determine rolling resistance. Similarly, I would think thatwith a given tire construction and size, a lower pressure would mean alarger contact patch, and, therefore, increased rolling resistance. Extrapolatingthe “wider and softer is better” logic, we should be seeing Lance in theTour riding balloon tires pumped up to 20psi. Am I missing something oris this a fashion trend?
Langley

Dear Langley,
It entirely depends on the road surface. If it is chip sealed and youride with a 19mm tire at 140psi, there is no question that you will havehigher rolling resistance than with a 23mm pumped to 90psi (assuming thatboth are high quality high-thread-count tires). Every time you deflectthe bike and rider up and back, it costs you energy, as opposed to absorbingthe gravel hunks into your tire. This is the same reason that suspensionmakes a mountain bike, car or motorcycle faster on rough terrain. If youare riding on a smooth track, by all means use a 19mm tire and pump itup to super-high pressure.
Lennard

What’s a little rake?
Dear Lennard,
My daughter rides a little 24-inch wheel road bike and we broke thefork and wheel by riding over it. I can’t get the fork that originallycame on the bike, but found one from Terry. The problem is that the originalfork had a rake of about 3.2, and the Terry fork has a rake of 4.8. IfI get that fork, how will it affect the handling of her bike?
RobertDear Robert,
The greater rake would decrease the fork trail and hence the stabilityof the bike. It will handle quicker and tend to over-steer.
Lennard

Don’t worry, be happy
Dear Lennard,
Ever since reading your recent column advising a reader not to cuta carbon steerer (or seatpost) all the way through, I’ve been sweatingmore on high-speed descents. One cut, as you say, can delaminate the outerlayer of carbon, while two cuts coming in from opposite directions willnot. I regret that I shortened my carbon steerer with the one-cut methodbut have not noticed any visible delamination on the steerer. Does thatmean I got lucky or might the problem be undetectable? And what about filingthe edge after cutting?
White KnucklesDear Knuckles,
You would have seen it when you tried to slip the stem onto it. Noworries.
Lennard

What’s the hang up?
Dear Lennard,
I have a 9-speed Shimano Dura-Ace set-up on a Cannondale CAAD 5. Competebike is about 1 year old (4000 miles). When I am in my mid to lower gearsand shift from my 39 to 53 chainring, my shifter sticks in its far rightposition, I have to actually push it back to the left to its normal positioninstead of it returning by itself. Is this a set-up issue, bad shifteror do I just need some magical lubricant in just the right place? The localbike shops have been unable to fix it and don’t seem to have any solidadvice.
Greg CanfieldDear Greg,
We had a good series on this in the March4 and March11, 2003 columns here. You can squirt lube into that lever. If thatdoes not free it up, you are probably looking at getting a new lever orshifting with two hands.
Lennard

More follow-up on putting a one-inch fork in a head tube designedfor 1-1/8-inch
Dear Lennard,
Chris King also makes a headset that will allow you to run a fork witha 1-inch steerer in a 1 1/8-inch head tube. It’s called the devolutionheadset. They also make a version that will allow a rider to run a 1 1/8-inchsteerer in a 1 1/4-inch head tube.Here’s thelink to the product:I also wrote you a while back about having a stuck pedal. Thanks foryour advice. I finally got it unstuck today using a combination of heat,liquid wrench and a lot of torque. I only destroyed three 6mm hex keysin the process of trying to get it unstuck. When it finally released, itpopped so loud I thought I must have broken the pedal spindle off.
Perry


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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