It’s only May, but for UBI frame building classes, the year is almost over.
We have just a few frame building classes that still have space in them. Here are the pickings:
It’s only May, but for UBI frame building classes, the year is almost over.
We have just a few frame building classes that still have space in them. Here are the pickings:
What was Bespoked Bristol last year has become Bespoked – The UK Handmade Bicycle Show. It just finished up, and Oregon’s bike industry did some representin’. Cielo/Chris King were there, as was UBI-Portland brazing instructor Joseph Ahearne. And we’re happy to report that UBI grad Eric Estlund, builder of Winter Bicycles, took the award for Best Track Bike. This is very fitting, considering that this year’s show took place in the infield of the stunningly beautiful velodrome at London’s Lee Valley Velopark
For some candy, check out the vid:
We just heard from our partners at Fox Racing Shox about the fork choices for the next Fox Master Tech Clinic, scheduled October 25 at UBI Portland. Clinic participants will be able to choose among 50 – that’s five-oh – different 2015 Fox fork models and configurations.
How does this work? The Fox Master Tech clinic is a one-day seminar team-taught by UBI instructors and Fox technicians, designed to bring students up to date on servicing Fox’s latest and greatest forks. When a student signs up for the clinic, he or she chooses a fork, which will be waiting for the student on the morning of the class. After working on the fork for the entire clinic, the student leaves with it! The $600 cost of the clinic is, in many cases, less than the pro-deal cost of the fork. The clinic is open only to mechanics working at authorized Fox dealers.
“Where do I sign up?” you say. Just click this link.
And the fork choices? Feast your eyes:
SRAM’s new cassette-to-driver body interface is called XD, and allows you to run a cassette with a 10-tooth cog. SRAM made this new interface an open standard. This means that other manufacturers can develop an XD-compatible body that works with their own ratchet system, making their hub compatible with SRAM’s XX1 10-42 11-speed cassette.
This week we’ll show you how to convert DT Swiss’s 240/350 series rear hub with a Shimano splined freehub body to a SRAM 11 speed XD Driver. Our example is a through-axle, but the process is the same for these series hubs equipped with QR systems or Campy-splined freehub bodies.
Step 1: Clamp the drive-side hub end cap in a 0.75” tubing block for 12mm through-axles. For quick release setups, use a 10mm axle vise. This will provide sufficient support for the end caps so you don’t get all Gojirra and crush or damage them. Use a wiggling action to free the end cap from the axle. Make sure to keep your fingers on the freehub-body/driveshell while lifting upwards. Failure to do this can result in damage to the end cap.
Step 2: Lift the freehub body off the axle and set aside. Lift off the top conical spring, star ratchets, ratchet collar, and lower conical spring. Lay out all the parts in the fashion shown. Clean them with isopropyl alcohol and a lint-free rag.
Step 3: Apply a thin coat of DT Swiss Star Ratchet Grease to the inner conical spring. With the spring taper pointing up, drop the spring over the axle.
Step 4: Apply a coating of Star Ratchet Grease on the centering collar and place the star ratchet centering collar onto the axle.
Step 5: Apply Star Ratchet Grease to the ratchets and place one star ratchet over the axle and centering collar, ramp side facing up.
Step 6: Place the second star ratchet onto the first ratchet, ramps facing down.
Step 7: Place the second conical spring onto the star ratchet stack, wide end facing up.The centering collar should nest inside of the spring.
Step 8: Install the new XD freehub-body onto the axle, paying attention to align the star ratchet splines into the freehub body and hub shell.
Step 9: Place the new axle end cap supplied with the XD freehub body onto the axle. The cap should provide an audible click when it snaps into space. Test the hub for proper function.
The hub should now be ready to be laced for wheel building, or, if it’s already part of a wheel, to receive a SRAM 11 speed cassette. Time to ride!
The guys from NSMB were on their way from Canada to Sea Otter and wanted to ride some singletrack in Ashland. So, via our friends at Santa Cruz bikes, they hooked up with UBI instructor Nathan Riddle, who served as tour guide. Oh, the humanity!
More over at NSMB’s web site.
We are happy to announce the first two winners of the QBP/SRAM/UBI Female Mechanic scholarship. The winners will attend UBI’s Professional Repair and Shop Operation class at our Ashland location.
Elizabeth Jose: Elizabeth works at a shop in NYC, and is starting a non-profit focused on supporting women riders. She teaches a mechanic class in Spanish to women in Queens. These women earn a bike at the end of the class.
Vanessa Buccella: Vanessa is in the process of starting a women-focused bike shop in Chicago. She serves on the board of the Illinois Cycling Association.
We had over 300 applicants for these scholarships, which is an amazing response. We want to thank our partners, QBP and SRAM, as well as the many women who applied for this scholarship. You can read more about it in Bicycle Retailer.
Watch our blog for news about next year’s scholarship process!
Bicycle Tire Treads
The tread is where the rubber meets the road (or trail, if dirt is your preferred medium). This article will discuss what constitutes an ideal tread pattern for your intended usage.
Contrary to popular belief, tread on a road racing tire is not needed. In fact, the addition of a tread pattern onto a road racing tire takes away material that would otherwise be in contact with the road. At any given point, no more than about a dime-sized portion of the tire is in contact with the pavement. This is called the contact patch. Since such a small amount of rubber is in contact with the pavement, the removal of rubber in the form of tread pattern actually decreases grip.
Have a look at the tires on cars used for racing such as stock-cars or dragsters.
“But they don’t race in the rain”, you say?
Look at the smooth tread and rounded profile of motorcycle or aircraft tires. The rounded profile of these tires displaces water very efficiently, like the hull of a boat or ship. Mechanical engineer and bicycle wheel expert Jobst Brandt explains it like this:
It is important to understand though, that not every bicycle that is ridden on the pavement will benefit from an entirely slick tread. Touring, cyclocross, and hybrid bikes are often ridden on a variety of surfaces, including less than perfect pavement and dirt. In these instances, a perfectly smooth tread pattern may not be ideal; it may be detrimental to maintaining grip. Instead, a tire with a “negative tread” can be beneficial. Negative tread patterns may best be described as patterns where the relieved portion of the tread is smaller than the raised portion.
Off-road, or mountain bike tires require an entirely different set of considerations. It is first important to understand that unlike road or pavement oriented tires, the surfaces being ridden on can be both much softer, and highly variable. A tread pattern that performs very well in soft, loamy dirt, may not perform as well on hardpack, let alone mud.
Braking grip vs. traction –
The forces that a tire is tasked with handling off road are more pronounced than they are on the pavement. Grip is not the sole consideration. For example, when riding off-road a tire’s tread is tasked with providing forward momentum (traction), control under deceleration (braking), and maintaining traction while turning (side grip).
Picture a short section of trail consisting of a descent into a hard turn, and exiting into a short steep climb. Within the section of trail the tires of the bicycle are required to handle braking, turning, and acceleration. If a tread breaks free under hard braking (skidding) grip, and consequently control, is lost. Imagine losing grip while trying to slow down to enter the turn. Steep inclines and hard cornering are common occurrences when riding off road.
Unlike pavement, which whether wet or dry is still pavement, conditions found off road can pose a much larger question. While the dirt underneath the tire may still be dirt, the degree of moisture in it, as well as its composition, can have a drastic effect on the type of tread pattern that is needed. Dry conditions can warrant anything from small, tightly-spaced knobs, to large, widely-spaced chevrons depending on how hard or soft the ground is. Wet or muddy conditions might warrant a tire that does not “pack-up” with mud or debris, but still has pronounced enough knobs to bite through to firmer ground; while at the same time being narrower in order to cut through the mud.
There is no “perfect” tread pattern for any specific tire usage. Certainly there are many similarities that can be found between different manufacturers, but every tire maker puts their own spin on a given type of tire. If you are unsure about what will work best for the type of riding you do, consult with your local bike shop for what works best in your area!
Bicycle Tire Casings
The characteristics of a bike’s tires — profile, tread pattern, and running pressure, for example — can have a dramatic effect on the ride quality of the bicycle. At the heart of the bicycle tire, though, is its casing. The casing gives the tire its structural integrity, shape, and in large part is responsible for how well the tire will ride.
How it is measured
Bicycle tire casings are usually measured in Threads per Inch (TPI). Just like bed sheets, tires with a higher thread count are usually considered desirable. Higher thread counts generally translate to a thinner, more supple sidewall that allows for decreased rolling resistance and increased grip. An example of this would be if we were to drape a piece of burlap cloth over a bowl of fruit on a table. We would not be able to discern the individual pieces of fruit in the bowl; we would just see a lump under the cloth. If we were in turn, to cover the same fruit bowl with a piece of high TPI cotton or silk, we would be able to see the contours of the fruits in much higher detail. The higher thread count cloth conforms to the surface it is draped over much better. In tires, this translates to better grip through greater contact between the tire and riding surface as well as a more comfortable ride.
Modern bicycle tire casings are most often made from nylon. Nylon lends itself well to this application because it is light, strong, and inexpensive. Some high performance tires still use cotton or silk in their casings; however, these tires are often quite expensive and are designed for performance over longevity.
Density and plies
Any bicycle tire is at least two plies thick. Two plies equal one layer of casing. This is necessitated by the fact that the fibers used in tires are unidirectional, they are not woven. In order for the tire to have structural integrity, the plies must be laid on a bias (45 degree angle), perpendicular to each other.
Some tire casings are made of multiple layers. Multi-layered casings can be found in tires for almost any discipline of riding. They are found in downhill racing tires all the way to road racing tires. Multiple layers of casing increase the tire’s sidewall strength and overall durability. It is important to realize though, that the flexibility of a multi-layer tire is still dependent of the thread count of the base plies. For example, a two ply 60 TPI tire does not equate to 120TPI. Some companies will call out a number such as 3/330 TPI, this is referring to a 110 TPI casing multiplied by 3 layers, it does not equate to a 330 TPI casing.
Punctures resulting in a flat tire have been the bane of cyclists since the advent of the pneumatic tire. As such, many methods are available to aid in preventing punctures. One is the addition of some sort of material to the laminate of the tire, sandwiching it between the casing and the cap, or tread; this layer is called the “breaker”.
Breaker materials are varied – synthetic woven materials such as Kevlar® or Vectran® are used, though some tires use some sort of solid plastic belt or solid layer.
What is the right tire?
The right tire for you is the tire that most closely suits your needs: the intended use, performance, puncture resistance, and price point are all factors that need to be considered in choosing the tire that is best for you. The casing is just one factor in choosing what best meets your needs. If you’re unsure, talk to your local bike shop!
UBI Portland brazing instructor and all-around framebuilding wizard Tony Pereira and his partner Ira Ryan, who together are Breadwinner Cycles, took top honors at last week’s NAHBS for Bad Otis, their 27.5 hardtail.
Congrats, Tony and Ira, from the UBI crew!
Tony moves from the NAHBS award podium to the UBI teaching podium in June, when he will teach a session of our Steel Brazing Frame Building class. Class dates are June 2 – 13, and we still have two spots in the class. One of them is yours! You can register on line.
Editor’s note: Craig DeAmbrose, an instructor at UBI-Portland, is the newest member of our staff. We posted the following picture of one of Craig’s bikes to our Facebook page last week and it caused quite a flutter in the hearts and minds of bike geeks. So we asked Craig to expound on his bike for the benefit of bike nerds everywhere.
What you’re looking at is my home-made version of a retro-direct, 2 speed drivetrain. I built it after reading about the idea in The Dancing Chain, Frank Berto’s excellent book chronicling the history and development of the derailleur. I enjoy reading about the history of bicycle technology and thought it would be fun to build up a retro-direct bike to get in touch with my cycling roots. Yep, I’m that much of a bike nerd.
Before rear derailleurs had been refined to the point that they became ubiquitous on bikes, there were many different contraptions that allowed a rider multiple gears. Many of them came and went rather quickly due to their clunkiness and poor design. The retro-direct drivetrain in the late 19th and early 20th century was one of the more elegant and robust solutions to equipping a bike with multiple gears. The idea was first patented in in 1869 by Barberon & Meunier and was made popular by companies like Hirondelle and Magnat et Debon. Once derailleurs (and Internal Gear Hubs) started to be reliable and affordable in the 20′s and 30′s, the retro-direct drivetrain quickly faded into obscurity.
The concept behind the retro-direct is pretty simple. A rider pedals forward for one gear ratio and then pedals “backward” for a different gear ratio while still moving the bike forwards. This feat is typically achieved by having the bottom span of chain, which exits a chainring and normally returns to the freewheel from which it came, goes instead to a second, independent freewheel right next to the other one. Instead of the chain being routed to the “bottom” of the second freewheel it gets routed to the “top” where it can drive the freewheel forward as you pedal backwards. This is how mine is set up, but there are a couple of other variations on this idea — it only takes a quick search on Google to see a few other iterations. Most historic examples have the “backwards” gear as the low gear, but you can customize this depending on preference. You’ll notice on my example I have the “backwards” gear as the high gear.
One of the nice things about the retro-direct direct drivetrain is the lack of a shifter. The two gears are achieved simply by changing pedaling direction. No shifter also means no cable and housing to wear out which makes for a very robust (if somewhat limited) system. When the retro-direct was still something found on production bikes one of the purported benefits was that the backwards pedaling motion worked different, opposing muscles in the legs. Having ridden mine regularly I’d say the jury is still out on this aspect, as pedaling backwards seems comparatively awkward. This is especially so if you try to pedal backwards while out of the saddle. You’ll look as graceful as a hippo in ice skates. One of the drawbacks to the retro-direct was the tendency for the pedals to un-thread themselves while pedaling backwards. The problem was such an issue on production bikes of the era that if you look at some historical examples you’ll find that the pedal spindle was actually welded to the crank!
If you’re interested in making your own, it’s surprisingly easy with some basic bike knowledge. You can usually convert an existing bike with commonly available parts. There are a number of easy to follow “how-to’s” on the internet to get you started down the path to bicycle drivetrain nerd-dom. Just make sure to to tighten your pedals every now and then! For more information on the retro-direct drivetrain you can read Frank Berto’s aforementioned book or check out the brief but informative article on Wikipedia: http://en.wikipedia.org/wiki/Retro-direct.