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Technical FAQ: Reader follow-ups on chamois allergies and Zencranks

  • By Lennard Zinn
  • Published Sep. 17, 2013
  • Updated Sep. 17, 2013 at 4:54 PM EDT
Lennard Zinn hopes to see a detailed review of oddball tech like the Zencranks with a large sample size. Photo: Lennard Zinn | VeloNews.com

I received a lot of feedback on my last two posts, a column on allergic reactions to chamois and a feature on my tests of the Zencranks. Some of your notes were very informative, so I’m passing on a number of those e-mails. You’ll be reading this while we editors are deeply focused on new products at the Interbike tradeshow, so you’ll have a week of all tech all of the time on VeloNews.com!

Regarding allergic reaction to chamois

Dear Lennard,
Excellent response. You always do a great job of reaching out to others, in this case manufacturers and DZ. As someone who has suffered from this malady, I’d like to offer some advice to John.

You are suffering from diaper rash. If you’ve raised a kid, you already know everything you need to know. Here is a refresher:
1. If the chamois is dirty, get out of it. Don’t sit around in it during your post-ride beer. Would you leave your kid in a loaded diaper?
2. If you are at a race/ride where you’ll have to drive home before you can shower, buy some baby wipes, clean up, and put on some clean shorts.
3. If you have a rash, get yourself some Desitin or some Zinc Oxide. Since your mommy might not be around to apply it, you can either find someone else who loves you unconditionally or buy a hand mirror.
— John

Dear Lennard,
I enjoyed the article/letter on chamois allergies. This doesn’t solve your reader’s issue, but I thought this info was worth passing along, since so many manufacturers referenced “antimicrobial.”

Drier Sheets and Fabric Softeners block or inhibit the desired properties of antimicrobial, moisture management, etc. Washing/drying again fixes the issue, so the effect is not permanent. If you want to get the most performance features out of your fabrics, don’t use fancy soaps with fabric softeners or drier sheets.

I work in textiles, so this is how I came to learn this. My wife loves drier sheets, so all my gear hang dries.
—Gifford

Dear Lennard,
I think that washing cycling shorts in a washing machine is a bad idea. Not only do they wear out a lot faster as a result, but it is also very difficult to get all the laundry soap out of them unless you wash them by hand. John should definitely try a different soap, too. I have had excellent luck with Trader Joe’s lavender and tea tree oil dish soap.

Not only should he get new cycling shorts, but he also needs to have two or three pairs, so he always has at least one clean, dry pair. I always dry my shorts on a clothesline in the sun, inside out, with the chamois facing the sun. Is it also possible that he has diaper rash, or prickly heat instead of contact dermatitis?

Not a dermatologist!
—Louis

Dear Lennard,
I found a few years ago that my bike clothing lasts a lot longer if I hand-wash in the sink with Woolite instead of using the washing machine. Only takes a couple minutes to wash bike shorts after each ride. I air dry shorts hanging inside out from a hanger.
—George

Regarding Zencranks

Dear Lennard,
In your recent Zencranks article you referred to “BSA” bottom bracket threading. Regardless of what Wikipedia says, I’m surprised to see you perpetuate that error.

BSA stands for “Birmingham Small Arms,” and yes, at some point they manufactured bicycles, along with motorcycles and, of course, guns. However, they did not standardize bicycle threadings. The correct nomenclature for English bottom bracket threading is “BSC” which means “British Standard Cycle” and is 1.370 inches x 24tpi. Even more correctly, though, the ISO standard BB for threading is now 1.375 inches x 24tpi, identical to ISO freewheel thread. (Incidentally, the 56tpi spoke threading also comes from the BSC standard.)

The story about BSA threads seems to come from the late Sheldon Brown’s website, to which the Wikipedia entry refers. Though he is referred to as St. Sheldon by many, he was not known to be infallible. As best I can tell, BSC threading was based on an earlier standard from the Cycling Engineers’ Institute (CEI). I have read nothing yet besides Sheldon’s website that substantiates a link between the BSC or CEI standards and the BSA company.

FYI, the BSC entry in Wikipedia is also in error, as it says 26tpi is the standard pitch for BSC threads. This is not the case. It is true that 26tpi is used from diameters of ¼- to 1-inch, but diameters smaller and larger than that use different pitches, hence the 24tpi in the bottom bracket. Raleigh’s use of 26tpi in many of its bottom brackets is an anomaly, and does not follow BSC.

Even if I am wrong about the connection to BSA, BSC would still be the least obsolete way to refer to English threaded bottom brackets. CEI would be the next least obsolete. BSA would be the most obsolete and least established reference.

So, you can properly refer to it as “ISO” or even “British” or “English” thread. “BSC” is close enough albeit obsolete (as the thread profile is different from ISO) but “BSA” thread does not exist.
—Greg

Dear Greg,
Thanks for your great letter! The “BSA” that I wrote came from the information emailed to me by the Zencranks marketing agent. I just cut and pasted some of the crank specs from that document and then edited them, without noticing that it wasn’t “BSC.” I’m glad I did, because I just learned a lot of cool history from you.
―Lennard

Dear Lennard,
Interesting reading your Zencranks review. Hmm … I feel like, whether or not these are different from Newby-Fraser’s setup of old, the fact remains that the crank affords you torque given its length from BB to the pedal-end pivot. The manufacturer’s diagram correctly refers to the “trajectory” of the foot rather than referring to the torque. It’s not like you get a variable lever arm around the pedal cycle.

Another way of phrasing it would be that the torque at the pedal pivot must equal zero, so therefore, any torque generated between the shoe and the pivot must be countered by a torque generated at the ankle, which seems to contradict the suggestion that muscle effort is reduced.

Thus, you get into a bit of trouble when you write, “At the point of highest power, namely 3 o’clock on the crank circle, it is equivalent to a 200mm crank with its consequent 11-percent increase in leverage over the 180mm. The effective crank length effectively decreases from 3 o’clock to that of a 180mm crank by bottom dead center.”

Same problem when you write, “For the rider on a stock bike with standard crank length, the Zencranks have the advantage of offering the leverage of an 8mm-25mm longer crank through much of the power phase of the stroke without the large decrease in pedaling clearance and reduction in cadence that such a crank length increase would ordinarily bring.”

I am saying that the leverage of the crank is, in fact, constant throughout the pedal cycle.

Personally, when I see the numbers Zencranks claims, like “25 percent” or whatever on its “Performance” web page, my immediate reaction is, “Bullshit.” Even your basically crude road test comes up with vastly lower numbers, which we have to expect unless the crank has a motor!

I would challenge the manufacturer to express what the optimal length of that short arm should be. I doubt it has that answer, or at least the correct answer.

As you note, your road test would never pass academic review because the study control was inadequate. However, rather than criticizing you for that, I think my suggestion would be that a properly controlled study is in order. It might be that comparing gastrocnemius EMG between crank types would reveal differences, though the differences would have to be large to overcome the inherent issues with quantifying the EMG signal. A VO2 measurement paired with a power meter might help. So might an instrumented pedal paired with motion capture, from which you would calculate joint torques at the hip, knee, and ankle to see what the mechanical outputs are at each joint using each crank.

Anyhow, big guy, I am largely thinking out loud here and hope that my note comes across as anything other than criticism. It’s an academic discussion of a current topic. Ideas like this crank should never be squashed at first sight, because most great inventions started out as something crazy or accidental. However, ultimately, if something is for real, then solid testing should establish that.
—Saunders

Dear Saunders,
Thanks for taking the time to think this through so deeply. And I agree completely about not squashing ideas that seem out in left field before really trying them. When I saw my first mountain bike in 1979 (one of the original run of five Ritcheys, proudly purchased by my road team’s main sponsor), I thought that nobody was going to want to ride a bike on hiking trails. And when I saw my first Camelbak, I thought that nobody was going to want to drink water out of a tube and ride with a backpack on.

I learned from being totally wrong about those things and have attempted over the years to give ideas like Zencranks, mid-foot cleats, super-long and super-short crank lengths, wide or narrow stance widths, articulated cranks, non-round chainrings, pedals that only rotate one direction, and disc brakes on road bikes a good, honest try. That has required not listening to the voice in my head saying, “nobody is going to want this thing,” and, equally importantly, facing my own reluctance to go to the trouble it’s going to take to give it an honest try.

It often takes a lot of work to set up a bike to test new products and ideas that are out of the mainstream, as they often require massive re-configuration of the bike, or even starting from scratch with a new bike design. And it’s harder to get it done while having an internal conversation doubting their validity. There have been frames I built to test somebody’s idea and eventually got rid of when I concluded that I just couldn’t ride that way anymore and was stuck with a frame specific to that idea. Two that come to mind: a super-steep road frame to test Alexi Grewal’s late-1980s belief that tall riders like him were faster and more comfortable on a super-steep seat angle, and a road frame with a super-slack seat angle to be able to ride a “bunner” saddle without putting myself way forward on the bike.

What you are proposing is exactly what I would like to see — a thorough and independent test of Zencranks (and the same for mid-foot cleats, super-long and super-short crank lengths, wide or narrow stance widths, articulated cranks, non-round chainrings, pedals that only rotate one direction, and disc brakes on road bikes), with a large number of test subjects and improved data collection methods, rather than just me (a sample of one at the tall end of the bell curve of human height) doing a limited number of rides up a mountain and comparing times with other setups. I hope somebody does these tests.
―Lennard

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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