Bike Clinic

Reminder - If you bought a road or tri bike from B&B, and a set of HED wheels, book use (no charge) of the HED Bastogne Wireless Power Tap wheel. Easy set-up, take it out for a day of power training. Call ahead to reserve. Free swim clinics, free use of a $2000 Power Tap, the best bicycle set-up in the Atlantic provinces - no other shop does as much to help their customers achieve PBs.

NEW TIME TRIAL BIKES - Be Careful About Buying Into the Hype.
I was reading a cycling mag the other day with a comparison of some of the time trial bikes that were used in the tour this year. Many had some common features such as brake and shift cables hidden in the frame, hidden brakes, horizontal top tubes, and some very cool and slick looking integrated fork/stem/bar systems.
One notable feature is that many of these bikes had rear offset seatposts so that they would be under UCI regulations. This means that the bikes are designed with steeper seat tube angles because it is the triathlon market that purchases a majority of these machines. That is why you rarely saw a Trek TTX, because the carbon models were all designed for Armstrong's riding position, which requires a slack seat tube. This is great news for triathletes.
Specialized new Shiv has replaced the transition and has done away with the un-aerodynamic sloping top tube in favor of a horizontal one. They still keep the riduculous braking system but make the front brake harder to set up by adding a cowling over it.
Trek has radically changed its TTX, also adding a cowling over its front brake.
Giant hides its front brake behind the fork, but has to use a version of a BMX brake (which never work well). Fuji and Argon18 are also using this dumb system on the top level TT bikes.
The Scott Plasma is the only one using a tried and proven dual pivot brake on the front without having these other idiotic systems. However, they have placed the rear brake under the bottom bracket like the others, which makes it impossible to mount in a workstand.
Anyway, the point is - don't get caught up in these fads. Look at the Softrides, Lotus and Hottas that are going for a song on e-bay - these guys trying to unload them also got caught up in the hype of that period.
Look for a TT bike with aero lines, hidden cables are great (as long as they are easy to service), brakes that are proven to actually stop (we don't race on closed courses like the pros), and a design compatible with either a traditional or time-trial specific workstand (in order to make adjustments and basic maintanence easier).
Proper positioning on any bike will go a lot further than any of those little aero features.

CARBON BRAKING vs ALUMINUM BRAKING surfaces, pros and cons.
The earliest bike wheels had rims made of wood. Wood was cheap, easy to form into a hoop, and lightweight. Tubular tires were glued on. The disadvantages of wood rims were obvious - they were delicate, could shatter or split, and needed great care to maintain.
Steel rims came along but were quite heavy and did not stop well, usually due to the chrome finishing process. Some steel rims had indentations to aid in braking.
Most wheels that we use these days use rims made of Aluminum and therefore the braking surface is obvoiusly Aluminum. Aluminum dissipates heat from braking well, was lighter than the wood and steel versions, and could be formed to either tubular or clincher usage.
Early Carbon wheels had an aluminum braking surface. In order to save weight tubular wheels were the first to use a carbon braking surface, however, the nature of carbon in braking is very different than that of aluminum. The brake pads tended to grab the carbon in dry conditions, but in wet conditions there was almost no braking. Special compounds were developed for brake pads intended for use on carbon rims.
Over the past few years clinchers with a carbon braking surface have also become availabe, although they typically have maximum inflation pressures in the 120psi range.
The main disadvantage to the full carbon rim with the carbon braking surface is that the wheel is more prone to road damage due to the brittle nature of carbon and braking. Although braking can improve with brake pads specifically designed for carbon rims, these pads can also be used on aluminum rims - although they wear quite quickly due to their softer compound (many of these pads are made of a treated cork).
If a carbon wheelset is run for races and an aluminum set used for training, it is recommended that the brake pads be switched with each change of the wheels, the reason for this is that the aluminum rims shed small slivers of aluminum into the brake pads when braking, this results in the pads losing some of their braking ability on the carbon rims and becoming abrasive to the carbon rim which may in turn shorten its life.
All in all, a full-carbon wheel may be usefull in reducing weight for races or events that have a certain amount of climbing, or even to lower the weight of your bike for bragging rights. However, if your race or event requires a great deal of cornering and braking, many may prefer the more familiar feel of a lightweight aluminum rim.
I do use a full carbon rim on my race bike (which never sees an aluminum rim) and I am quite comfortable alternating the pressure of my hands to modulate the braking pressure. On the bikes I use for training I always use an aluminum rim for its ease of use and consistency, especially when riding in a group.

TUBULARS vs CLINCHERS: WHICH IS THE BETTER CHOICE?
Many times I have been asked (even before I had my own shop) which is the better option TUBULAR rims/wheels and tires or CLINCHERS.
First let me define these 2 wheel choices and then talk about a third option that has entered the debate recently.
Let us start with that we are most familiar, the CLINCHER system. This is composed of a CLINCHER rim, CLINCHER tire and an inner tube. The rim has a bump that acts as a "hook", while the tire has a wire or kevlar bead (the kevlar being lighter and allows the tire to be folded - found on more expensive clincher tires).
The main advantage of the CLINCHER is ease of use and low cost. Even though some Clincher tires may cost as much as tubular tires, very often in the case of a flat the tire may be re-used with the simple change of the in-expensive inner tube. Also, the cyclist may take multiple tubes on a ride since they are easily stored in a small tool bag.
The main disadvantge of the CLINCHER system is that it will always be slightly heavier than the same wheel with a TUBULAR SYSTEM. This is mainly due to the construction of the rim needing to have the slightly thicker hook extrusion on the rim. The Clincher system is also more prone to pinch flats if the tires are not kept at the recommended pressure.
TUBULAR rims have a slight concave shape, the tires have the tubes sewn into them (that is why they are also referred to as sew-ups). The tires are fastened to the rim with an adhesive glue (although some companies also offer a double sided tape). This mainly acts to adhere the tire to the rim until it is inflated, tire pressure does the main job on holding the tire to the rim.
TUBULARS are used by Pro cyclists and triathletes Pro. They do make for a lighter wheel. They are also very comfortable to ride (although many high-end clinchers approach the ride quality of the best tubular tires, that is why some are branded as "open tubulars".
Why does not everyone use them then? Quite simply they are not easy to mount and expensive to maintain. To glue a tubular properly you need at least 4 days. Each layer of glue must dry for 24 hours. Also, pros like to have their tubular tires "aged" that is they will store them in a special place for a certain amount of time before using them - Eddy Merck would age his tires for 2 years before using them.
But I have seen them change tires so quickly in the Ironman? Yes, as long as the mechanic gluing the wheel left a small section opposite the valve hole free of glue - remember Norman Stadler a couple of years ago not being able to get his tire off after he flatted. In this case the athlete is also depending on the residual glue on the rim and the tire pressure to hold the tire on until the end of the bike leg. By the way, in the tour the mechanics jump out of the team car with a whole new wheel when there is a flat, or a domestique will give the team leader one of their wheels - each tour team prepares about 100 wheels before the start of the race.
Unless you keep warm by burning money in the fireplace you would not want to train on them - each flat will set you back the cost of a whole new tire ($120 on up). Tubular tires are just as prone to road debris as any other tire. If you have plenty of time you could take the cotton backing off the tire, cut the stiching, place a new tube in and sew the tire back up, regluing the cotton backing over the stiching at the end - yeah it does sound like a lot of work.
And while tubulars are lighter, remember, in a longer race you can place at least 2 clincher tubes in a nice little tool kit, you will never get a tubular tire in a neat little seatbag. Since you have to take the whole tire this often negates any static weight savings you may have gained. In addition, there is probably a slight negative aerodynamic penalty having the spare tire poking out from the back of your seat.
A newcomer to the debate is the TUBELESS system. The rim is similar to a clincher rim, but the spoke holes are sealed. The tire is similar to a Clincher as well but is designed to hold air pressure without a tube. This system also sometimes requires a special sealant. The rim tends to be a little heavier than the Clincher but when you consider you do not need a rim strip or tube the overall weight is about the same. In the event of a flat you can use a traditional inner tube.
Unless you are a capable bike mechanic, do not mind getting glue all over the place, or perhaps have your own personal mechanic, I recommend the Clincher system for 99% of cyclists. The ease of use and cost benefits far outweigh any slight weight savings.
NEXT DISCUSSION WILL BE CARBON BRAKING SURFACES vs ALUMINUM BRAKING SURFACES (on rims/wheels).