Tuesday, December 30, 2008

SF MoMA - Biomega bike

I took a little trip to the San Francisco Museum Of Modern Art recently. I was surprised that I didn't see more industrial design. There was some graphic art and ID in one small exhibit, and one of the things on display was this Biomega bike from Denmark:

As I looked it over, it appeared to be a folding bike with a laid back riding position, some serious hydraulic disk brakes and some sort of integrated cable lock. I checked it out on the web and they call this model the "Boston" and claim that the cable is a structural component of the frame, and that if cut, the bike is "unrideable…but repairable". The cable didn't look like it was under any tension to me, so I'm assuming that the frame either flexes enough once you get on it to put it in tension or that claim is not entirely true. If it were in tension (a la the cable on a Slingshot frame) while no one was on the bike, I don't know how you'd get it unlocked. Also, notice no valve stems on the tires. I'm assuming that to avoid that wilted-tire look after a few months on display, they either filled the casings with something that doesn't leak out or put some sort of alternate tube (like Tire Balls) in.

Monday, December 29, 2008

Chrome Industries - Retail Store

I rode the train up to San Francisco this weekend and while walking towards downtown, the storefront of Chrome Industries caught my eye. I think that SF holds a special position in the bike world, definitely because of the regional legacy created by Gary Fisher, Joe Breeze, Tom Ritchey and Mike Sinyard but also because of the continuing innovation by companies like Swobo, Timbuk2, SOMA and Chrome.

I wasn't in the market for a new messenger bag, since I've got a Timbuk2 model that is serving me fine, but I was impressed by the quality of their clothing. I would especially like to try the Shins knickers. I should be impressed, they run a cool $160. I frequently wear a pair of knickers when I should wear bike shorts (long city rides) but don't want to look like I'm wearing bike shorts. You know, for those moments when you have to get off the bike and you don't want people staring at your lycra swaddled junk.

The shop itself was fun. They had a mish mash of frankebikes and parts bolted to the walls, a couch with some magazines for reading and a hot messenger doll plastered on the wall behind a vintage Honda cafe racer.

If you're in the city, check them out. They've recently moved. Their current address is at 580 4th street, south of Market, between Bryant and Brannan.

Wednesday, December 24, 2008

Santa Mountain Biking in the Sunshine

Sent in by reader Brian down in San Luis Obispo from the web site: Santa Comes to SLO-Town. Even if it's not sunny, dry and downhill where you're at today, we here at nippleworks hope you're having a Merry Christmas.

Zoolander's Helmet

Would a successful male model be caught dead letting this thing ruin his perfect coif?

Hell no.  He'd be wearing this:

Photo from http://www.yakkay.com/

What you're looking at there is the Yakkay Tokyo in striped denim.  The base helmet is basically a black BMX helmet with rope (instead of webbing) ear loops.  There are four covers to meet your fashion needs: 

  • The Luzern (furry)
  • The Dublin (canvas toque)
  • The Paris (ball cap)
  • The Tokyo (bucket hat)
The underlying helmet is rather unsophisticated.  It apparently has adhesive foam segments for customizing fit (no twist-lock here).  You could wear it alone in the summer since it's vented, then add a fabric cover for the winter (or when you are cycling in a fashionable European city) for warmth. I'm not going to buy one until they come out with a busby cover.

In the everything old is new again department, I recently found this picture of the 1986 Coors Classic:

From BIKEMONKEY Magazine

These guys are mostly wearing hairnets and have covered them with cycling caps.  For the one guy in the middle with the wraparound sunglasses (Bernard Hinault?), it's sort of ridiculously tight.  As long as there have been helmets, people have tried to cover them up with hilarious results.

Tuesday, December 23, 2008

Super duper cold weather riding gear

Cyclists have a lot of downtime in winter.  I'm on a few mailing lists (racing club, Bay Area cyclocross, etc) and there's much more email traffic on rainy days.  One topic that get's beat to death - cold weather riding gear.  Maybe it's preparedness, maybe it's wishful thinking, but everybody wants that magic pair of gloves or socks that will make a cold commute or Sunday morning ride seem like summer again.  To that point, here's a picture I snapped with my cell phone cam at the recent San Francisco bike swap.  

These are Bar Mits that look like they might have been inspired by similar products meant for people who ride their snowmobiles to the bar in Fargo, or by kayaker's pogies.   I'm sure they really cut the wind and let you ride in thin, dextrous gloves, but they pretty much lock you in to riding on the bar hoods.   There are some other similar products out there.  For example, AMF Threadworks Moose Mitts:
These gigantic mickey mouse ears of warmth look like they'd let you ride with your paws protected in the drops, on the tops and on the hoods.  I've got to believe that they'd flap like a dog's ears in the wind.

To those die hards who are riding their bike with enormous forearm cozies, we solute you, that's hard core.

Monday, December 22, 2008

Boulder Velodrome Revisited

Got an comment on the blog over the weekend from the people behind the blog, 303Cycling.  Thanks for reading!  They gave us some insight on the new Boulder velodrome.  It looks like the velodrome builder is putting up a half height wall between the apron and the infield, and the aforementioned pole of doom is part of that wall.  The pole does not stick out the apron as they have it built.

Check out the picture and blog here.

Friday, December 19, 2008

Linear pull brakes with drop bar levers

Saw this setup on a Specialized Tricross Singlecross and did a double take. Where was the Travel Agent? Could drop bar brake lever (which is usually short-pull) work a set of linear pull brakes (which are long-pull) without a travel doubling pulley? According to the Specialized web site, the bike comes with "Aero brake levers for linear pull brakes". Did such a thing exist? If so, why are all those cyclocrossers running 1x9's (or 1x10's) still using cantilever brakes on the front end and suffering the unavoidable brake chatter (1)? They could be using nice, strong, chatter free linear pull brakes and these levers. I did some research. BAM! It's true! Aero levers for linear pull brakes exist, and Tektro is not doing nearly enough to market them. Here they are:

photo from tektro.com
And, they have that sweet little brake cable quick release pin. That could be a godsend in fast and frantic wheel pit changes. Spread the word folks, you heard it here.

Why not just use your shifter/levers with a pulley? Because that pulley gets gunked up with dirt and becomes absolutely useless really fast. Kind of defeats the purpose of putting brake bosses on a cyclocross bike in order to use mud resistant brakes.

The owner of the Specialized seemed to like the way they worked. Any one else have any experience?

1 A good explanation of the symptoms and causes of front brake chatter can be found here.

Thursday, December 18, 2008

What's hot in observed trials

Here's a topic you don't hear too much about on the popular bike websites - observed trials. What are these guys out there doing? They're building up some strange machines. The one above belongs to my old friend Kevin. While pretty much every bike out there, including your kid's trike has a carbon fork, Kevin's still rocking aluminium. He's also got rim brakes in the back and a disc in the front, probably for better modulation in the rear. Notice that the rims are also drilled out with some pretty big speed, er, lightening holes so he can hoist those things up onto walls and get them spinning and stopping in a hurry (low rotational inertia). There's no seat at all, not even a seat post clamp if you wanted to put one on. There's also very low gearing for slow speed motion and a chain tensioner/single speed arrangement out back. Go to youtube and check out some observed trials videos. These guys will blow you away.

Wednesday, December 17, 2008

Holiday Cycling Gift Guide - Part 2 (Green Edition)

If you are still in need of gift ideas for cyclists, or are a cyclist in need (or want) of some new gear, here is the second installment of the Nippleworks Holiday Cycling Gift Guide. This guide focuses on the eco-friendly stocking stuffers out there. Enjoy!

Grocery Getter:

From http://www.chicobag.com/, these convenient reusable bags pack down smaller than your computer mouse in their own integrated pocket. They even have a little carrabiner if you wish to clip it to anything. Toss them in your backpack or messenger bag for those spontaneous trips to the store, then carry them in your panniers, basket, or hands on the way home (...or if on a tandem, make the rider in the back do all the carrying!) Cost is $5 each and multiple colors are available.

Brew Tool:

Made from recycled bicycle components, this keychain opener from http://www.resourcerevival.com/ comes in multiple colors and runs $14. This is a perfect stocking stuffer for most cyclists because when they're not thinking about bikes, they're drinking about bikes.


Dumonde Bio Green chain lube is 100% plant based and biodegradable. It's a green lube that actually works. Get it for $10 at http://www.rei.com/.

Hopefully, your holiday shopping is wrapping up (so to speak) and that you have plenty of bike-related gifts. Keep an eye out for the next installment of the Gift Guide!

Monday, December 15, 2008

Derailler Spring Tension

So, I had a problem. My cyclocross bike chain was falling off pretty much every race and my homebrew chain keeper just wasn't cutting it. So, I first added an N-Gear Jump Stop (which is a quality product, by the way). That minimized chain drop to the inside of the crank, but couldn't stop chain drop to the outside. I run a 42t single chainring with a 42 tooth equivalent BBG outside chain guard. I wondered if I could go bigger on the outside chain guard, but that would rub against the chain when I was in the 11t sprocket. Then I thought to myself, why doesn't the chain ever come off on my mountain bike? It's a hardtail and I do some much bumpier terrain on that thing, it has a similar rear cogset and I'm frequently descending in the middle ring. The answer- chain tension.

I run a fairly low budget Deore rear derailer because it can handle the 11-32 cogset and has a 'high-normal' spring to match my road shifters. I suspected that the long cage geometry might give lower chain tension, allowing the chain to more easily slip while coasting (over bumpy descents).

How to test my theory? Borrow a digital force gage from work (you can substitute your everyday fishing scale if you want to repeat the experiment) and go to town tugging on derailers over a pre-defined travel range.


CX Bike (Deore) - 2.4 lb
Road Bike (Campy Centaur)- 2.6 lb
Mountain Bike (Deore XT) - 3.0 lb
Touring/Commuter Bike (Deore) - 2.3 lb


Cage length matters not. My Campy Centaur rear derailer is a very short cage road model. My Deore XT rear derailer is a long cage model. It's all about the torsion spring that pulls the cage back. Until I can get my hands on a high normal rear derailler that can handle big cogs and has a high spring tension, I took a couple links out of the chain and called it good. After a few races, things have turned around and there have been no more dropped chains.

On a related note, I used the digital force gage to get a real accurate read on my road bike's weight. (Bike+Pedals+Pump+Computer)+Saddle Bag = 22 + 1 = 23 lbs. Heavy or not, you know what they say... it's the Indian, not the arrow.

Saturday, December 13, 2008

Cycle Snack: Blog Tag? You're IT!

Cycle Snack: Blog Tag? You're IT!

My first blog "tagging".  Mark at Cycle Snack wants 5 personnal revelations.  Although I don't want to compare myself with the mysterious Bike Snob NYC, I too wish to remain in relative obscurity.  I can however, tell you the following:
-Steel is real
-Bike to work, work to bike
-A nut butter and jelly sandwich beats any bar shaped food item with 'energy' printed on it
-It's spelled 'derailer'
-Neutrogena Shower and Shave is the best leg shaving product ever

Friday, December 12, 2008

Holiday Cycling Gift Guide - Part 1

Photo from http://www.christmasspiritshop.com/

Holiday time is undoubtedly here, so all cyclists should use it as an excuse to amass as much bike related gear as possible. With the broad amalgamation of cycling genres (mountain, road, fixie, bmx, downhill, dirt jump, cyclocross, cruiser, etc.), the gift options are endless and can really be catered to the style and preferences of each rider. Here is our first installment of gift giving ideas for you to pass along to your friends, relatives, coworkers, spouse, etc. Alternatively, if you can stomach the envy of passing a cycling gift to another individual, you may find these ideas useful in your gift giving (...you can always buy in pairs...):

Decorative (makes your X-mas tree look fast):

From http://www.rei.com/, a 4-pack of ornaments with a jersey, helmet, shoe, and water bottle/cage - currently on sale for $14.93.

Apparel (casual/track-standing):

From http://www.swobo.com/, a hat and scarf combo for ultra-sheik casual winter riding - currently on sale for $39.

Apparel (riding/hob-nobbing):
From http://www.bicyclinghub.com/, a wool Castelli jersey for winter riding and spending your apres-ride aside a fireplace sipping a hot toddy (...like if Aspen was a bike town instead of a ski town) - currently on sale for $99.99.

The Bike Itself (retro & classy):

If you're giving a very generous gift to someone who wants to cruise in style, ride to the grocery store, commute to work (short distances), or just add bike to the collection, the Batavus Old Dutch is reasonably affordable for a dutch-style city bike. It comes with 3 speeds, coaster brake, frame pump, and headlight. Approximate retail is $800. Check it out at http://www.batavus.com/.

Stay tuned for more!

Wednesday, December 10, 2008

Brake Lever Legality, Vintage Single Speed Crosser

Seen at the Sagebrush Cyclocross race in Reno, Nevada. What you see here is a single speed cross bike (well, road bike with decent tire clearance) with time trial style brake levers mounted to a shallow drop/mustache bar. They point forward. Is this legal? Many cyclocross races don't allow mountain bike bar ends or "forward facing bar ends" so you don't create any new orifices for yourself or your competition. Does that rule apply to brake levers? Not that I need a cycling federation to tell me what to do, but it would be interesting to hear the logic on some of these rules. I don't know that logic is ever explained with sports rules (instant replay, no disc brakes in cyclocross, why female beach volleyball players have to wear bikinis) so don't hold your breath for the answer. Just sit back and appreciate the wild variety that is cyclocross racing equipment.

Sunday, December 7, 2008

Vintage front derailler and trick brake cable hanger

While I was walking through the parking lot at this weekend's cyclocross race (last in the Bay Area Super Prestige Series) I noticed a fun Hunter bicycle. By the way, check out the sandy beach track just behind it. I noticed that it had a 70's vintage Campagnolo front derailler. How was he shifting it? Not by ergo-lever. Bar end shifter. Also, notice the nifty front brake cable hanger wrapped around the stem:

Friday, December 5, 2008

Crazing Saddles

First, let me explain crazing. When you flex plastic enough, the surface in tension first develops microcracks (which look like little white-ish lines) before failing. This process is called crazing. If you stress the plastic enough times, the cracks will propogate (spread) and coalesce (join up) and create a fracture. This is what happened when my dense derrière remounted my cyclocross saddle over a series of probably 10 races. Result - cracked straight through:

The fracture finally competed it's journey through the shell of my saddle during a race in Livermore, California this year. On the first remount of the first lap, I heard a loud crack which I thought was my seat post slipping. I kept racing (since all the important parts were still attached to the bike) and eventually realized that I was sitting on the ass-hammock you see in the picture above. It probably dropped my saddle-pedal height about 2cm. The pounding of my heart in my ears pretty much drowned out all other sounds so I had plenty of inner thought time to consider how I was going to get a saddle and fix it before the next day's race. I have now broken three saddles racing cyclocross. Two shell failures and one rail failure (via bending). Anyone got any ideas? My remounts are pretty smooth, not too much high flying.

Thursday, December 4, 2008

Boulder Velodrome Pole of Doom

I hear that the Boulder indoor velodrome is nearing completion. I checked out the website and saw some pictures of their 142 meter track under construction. While looking at the photos, I noticed a pretty sketchy looking pole right on the what will be the apron of the track.
That looks like a sturdy pole that's probably necessary to hold up the roof.

On pretty much every trip I've taken to the velodrome, I've seen a crash. Some are no big deal, everybody gets up and walks a way. Some are kind of crazy with riders flying up over the rail, or sliding down onto the infield like in this picture I snapped in July of this year:
That bike flying through the air and the riders in the white and red jerseys would both be headed for that pole if they were riding in the new facility in Boulder.

I salute the guys building the new track. If America needs anything it's more physical activity and less Play Station. I would also advise them to do a little brainstorming on how make their facility as safe as possible.

Photo form www.boulderindoorcycling.com

Tuesday, December 2, 2008

Dingle Cross

The dingle is a rare breed. This bike I saw was an Independent Fabrication cross bike with horizontal dropouts and S&S travel couplers. Sub note here, if you can race cross on a bike with travel couplers, they should be pretty much bomb proof. Anyway, this bike is a double gear ratio single speed. Hence the dingle name. You can rig it up in either of two gear ratios, one being lower than the other, but both requiring more or less the same chain length. It does require you to loosen the axle nut to get some slack on the chain, so I don't think this guy is shifting during races. Why build a dingle bike? I read an article by one guy who had to ride downhill to work and uphill and into the wind to get home. This reminds me of my bike commute in Boulder which was East (downhill and down wind) in the morning and West (uphill and into the wind) in the afternoon. Why not put a shifter on you ask? Well, winters in Boulder are kind of hard on drivetrains, and I'm sure the East Coast or central Europe is worse. Also, you get rid of cables which really do not like gritty road spray. Could be of benefit to single speed racers too. It allows you to pick the better drivetrain for the course once you get a chance to pre-ride it, unlike a true single speed setup that requires a tool-intensive cog change or money-intensive rear wheel change.

On as historical note, this reminds me of the original Campy suicide shifter:
picture from Rock The Bike
How long before we see the re-introduction of the seat stay mounted quick release?

Monday, December 1, 2008

OG Carbon Frame

How many of you were riding monocoque carbon frames in the age of downtube shifters? This guy was. Follow up question: how many of you would ride a carbon frame this old?

Carbon is not the only bike material to fail over time. It doesn't take much research on the web to read stories of failed steel, titanium and aluminum frames. In fact, even good lugged steel bikes (which use a manufacturing technique that really gets the most out of the material strength) fail after enough use. So why do I suggest that this older carbon bike is not trustworthy? UV degradation and catastrophic failure. Although steel rusts, you can see that form on a bike. UV degradation of plastics (not the carbon, just the resin) isn't something that most people can gauge by looking. Also, ductile metals usually give way a bit (deform) before failing completely (fracturing). Carbon fiber tends to fail catastrophically, which is to say it fails all at once without much warning.

I saw this bike at the San Francisco bike swap this weekend and I hope the guy sold it because bikes should be used, not just looked at, but it's not a buy I wanted to make myself. On a related note, it was a good history lesson for me. I thought that carbon frames really began with tube-and-lug manufacturing (with metal lugs at first and carbon lugs later) so it's enlightening for me to see this early monocoque model.

Thursday, November 27, 2008

Kennedy Trail Turkey Ride

My legs are still tired from this year's Kennedy Trail Turkey Ride. I didn't know about it until this week, but apparently every year, people ride their bikes up the very steep Kennedy Trail in Los Gatos, CA and bring Thanksgiving treats to eat and drink at the top. I have ridden and hiked this fire road several times in the past, but never with the kind of crowds that turned out today. The climb is probably a solid 2000 vertical feet. It starts bright and early, so if you do it, you might also make it over the river and through the woods to Grandmother's house for an evening supper. Things to bring, besides food and drink, include an extra layer for the ride down and a bell for your handlebars to signal hikers and bikers on your descent.

All sorts of fun, wacky bikes show up at the starting point in downtown Los Gatos. This Retrotec model was recently acquired by its owner (although it looks rather vintage) and the stiffness of the rear 'triangle' is adjustable by tensioning the cables/rods that go from the seat tube to the rear dropouts.

More weird wild bikes include this leopard print tandem with moto style upside down forks. A tandem would be fun for this ride since you enjoy the added power of two riders on 1.5 bikes and the downhill is not very technical.

The leopard tandem also had a festive gecko idler gear just sort of floating in the timing chain between the pilot and stoker.

This "Yokota Project USA" tandem was built at the dawn of mountain bike suspension. The "Shock Blades" fork offered about 18mm of travel (unless it was locked down in some way) and the bike made use of elastomer shock stems for both riders. Put a rack on this thing and you have a mean turkey toting machine.

It wasn't all contraptions and tandems. A few riders showed up on cross bikes, lots of people pushed excessively suspended downhill bikes up the trail, and one guy rode his very fancy LOOK carbon fiber race machine.

Happy Thanksgiving to everyone from nippleworks.

Wednesday, November 26, 2008

The squeeky derailler pulley gets the grease

My cross bike recently developed a mean case of squeak. I figured out it was the derailler pulleys. They get pretty wet and dusty, so I can't blame them. To pull them out, I first removed the chain (since I've got a SRAM Power Link this is easy, can't recommend that enough) and undid the hex shoulder bolt (shown in the picture below). It's a Shimano Deore derailler, by the way. I figured that I'd have to lube the bushing, but after messing with the parts, I figured that the cause of the squeak was debris and a lack of lube between the side plates (silver discs shown below) and the pulley. I greased those, slid it back into the derailler, tightened the shoulder bolt, and removed it's brother. Only do one at a time unless you want to also disassemble the derailler cage. 

I just had another thought on this subject.  Be careful with how much you tighten the shoulder bolt.  Too tight and you'll pinch the pulley, making it hard to spin.  Test it as you tighten.

Monday, November 24, 2008

Custom carbon franken-hanger

What you're looking at there is:
-A hoop of carbon, probably the cut-off end of a 1 1/8" steerer tube
-Drilled through and threaded with a brake straddle cable
-Drilled from above and threaded with the front brake cable
-A straddle cable pivot end (probably from a TRP Euro-X brake) tightened on to the end of the brake cable
-A zip tie to somehow give it that finishing touch

Make it yourself chain tensioner

Check this out. A Deore XT rear derailler with a derailler cable end (ferrule still intact) holding it in the appropriate position to act as a single speed cable tensioner. It was on a cross bike which may explain the extreme spring tension being used (since those bikes get a lot of bumping action at speed).

This would be a great way to cheapen up your old bike -> single speed conversion. I'm sure any derailler would work.


1) Find a derailler nobody wants (probably easy if said derailler is a 7 speed or 8 speed model)
2) Mount derailler to frame
3) Cut the last 4 inches off a derailler cable you were going to throw out anyway because it's roached
4) Pull the derailler to the right position (upper jockey wheel under your single sprocket) and have an indefatigable person or zip tie hold it there.
5) Install the cable with the ferrule in the derailler adjuster barrel (turned out half way) and the cut end under the clamp screw
6) Have the indefatigable person let go, or cut the cable tie
7) Turn the adjuster barrel in or out to get that jockey wheel lined up just right with the sprocket
8) Thread your chain and pull the ends together such that you get the desired tension (remember, you can always start loose and cut some off)
9) Remove the unnecessary links with a chain pin tool
10) Use a SRAM Power Link* to put the chain back together
11) Ride

*awesome piece of kit

Thursday, November 20, 2008

Night riding lenses

One of the Bay Area cyclocross race promoters (Pilarcitos) decided to run a night race under lights right on the shore of the Bay last weekend. Check out a great video of my race here. I have a pair of decent no-name photochromatic riding glasses but since the race would go from dusk to night, I really didn't need glasses that changed on me. You can buy clear lenses for your Oakleys or Brikos, but the best option, is to use a pair of plain old safety glasses. These wraparound models can be had at pretty much any hardware store for a few bucks:

You can chuck them off if they get covered in mud and also work great for night commuting. You can also get them tinted yellow or gray if you need some shade, and like all ANSI rated safety glasses, they offer UV protection. Finally, as you can see in the picture above, they look dashing.

Photo by J. Hadley

Wednesday, November 19, 2008

La Ruta de los Conquistadores

The ultimate adventure race, La Ruta, has just ended. If you're not familiar, La Ruta is a coast-to-coast endurance race across Costa Rica. The riders battle their way through the jungle and often encounter raging waters, rickety bridges, and just plain exhaustion. The multi-day stage race attracts many riders from all over the globe, but most notably Heart Akerson. Heart's story is quite unique. He basically left the United States for a simple, natural, holistic lifestyle on the Costa Rican coast. He has competed in La Ruta since 1998 and has finished every year. What's more amazing is that he does it shirtless, in jean shorts, and SPD sandals. Why? Well, this article may shed some light. Congratulations to Heart on his 10th anniversary of La Ruta.

Also, special congrats to our friend Jim Gibson (above, center) of Absolute Bikes in Flagstaff, Arizona. He completed his second La Ruta after his 1st place 2006 finish in the veteran's circuit. Heart also made the podium that year (guess which one he is...)

Tuesday, November 18, 2008

Trigon Cross Frames

I saw this Trigon all carbon cyclocross frame hanging on a tent at the recent Pilarcitos night race in Brisbane, CA. See pictures here. I had never heard of the company before so I checked it out on the web. They're straight out of Taiwan, R.O.C. and someone in the SF Bay Area must be importing them. Check out their 'Copmany Profile' here. It looks like they've got a variety of frames including some carbon/aluminum bonded models as well as carbon cyclocross forks with disc brake mounts. They also appear to make a hardtail carbon/aluminum 26" MTB with a rigid carbon fork. I'm thinking that can't be too popular, at least in this country.

Anyway, if someone knows more, post a comment.

Monday, November 17, 2008

Spokester - Spoke noise maker

When I was a grommet, the kids on the block would get a crappy baseball card and one of mom's clothes pins and clip that card on their bike frame so that the spokes would slap it around and you'd get a sweet BRRRRRRRRR motorcycle noise.  Apparently, today's kids are too lazy, baseball players have Myspace pages instead of cards, and moms don't use clothespins any more because someone's selling the Spokester - bicycle spoke noise maker.

The makers of the thing claim it is a safety device because drivers will hear your kid better. Spokester doesn't necessarily promote bicycle helmet use though.  If your kid has a Huffy and has already installed all the aftermarket accessories available (streamers, license plates, baskets, bell/horn), teach her how to make a proper spoke noise maker and she'll be the envy of the neighborhood.  Or, buy one for your $3000 road bike to make it sound like a $5000 road bike with fancy new Zipp hubs.

Friday, November 14, 2008

Super Clicky Hubs

Ever noticed how loud and clicky some high end bike hubs are? Why? The picture above gives a clue. The pawls on this Zipp brand hub are large, thin and sprung by a long leaf spring. They are bound to make more clicking noise as you coast. Compare that to an older style hub:
Why do the Zipp pawls make more noise?
Each of those little pawls is like a diving board (or extended simply supported beam). Each one vibrates as it clicks through the teeth of the mating part (the black hub body in the picture), much as a diving board vibrates after the diver jumps off. The frequency of that vibration is dictated by the following equation:
\omega_0 = \sqrt{k/m}
where wo is the natural frequency, k is the spring constant of the beam and m is the mass bouncing on the beam. In this case, the mass is the beam itself, and the Zipp pawl has much less mass than the old style pawl. This means that the Zipp pawl vibrates at a much higher frequency than the old pawl, giving it more of a 'tick' noise and less of a 'thud' noise.

Although I don't know this for sure, I imagine that the Zipp hub comes packed with less heavy grease than an older style hub since lower rotating resistance is much more important than longevity to the owner of the Zipp hub. That grease would act to deaden the sound of each pawl strike.

I hope you enjoyed today's nerd-out. Tune in next time for a discussion of flux capacitors.

Pictures from http://www.pezcyclingnews.com/ and http://www.roadcyclinguk.com/