I just read it and it says exactly what I did. Wider tires have lower rolling resistance due to less deflection.
I'm currently ~170# and when I last ran tubulars (2011?), I inflated them to 85/95 F/R. Back when I was racing, I only weighed 151-155#.
When you say "paper thin", I immediately think wall thickness, not depth of the rim, which explains the discrepancy. The numbers above sound correct.
Spokes stretch very little and not all when the wheel is subjected to a shock load (a sharp bump or pothole).
This has always been the case. When a wheel is loaded, the tension in the spokes in the load-affected-zone (LAZ)
decreases. There is no increase in tension in the spokes from shock loads or normal rolling loads.
Rear wheels do experience changes in tension due to
drive torque. Disc brake wheels also experience changes in tension from
braking torque.
Spokes don't fail from excessive stress (you could hang your entire body weight on a single spoke), they fail from
fatigue. Fatigue is caused when the tension in a spoke is reduced to zero and reloaded repeatedly. In a properly built wheel, this should not happen. A few random cycles from shock loads should not fatigue spokes enough to cause failure.
These are basic facts about bicycle wheels that are documented in numerous places, the classic source being "The Bicycle Wheel" by the late Jobst Brandt. Unfortunately, few cyclists understand how wheels actually work, because it's really counter-intuitive.
Of course.
Put 'em on Ebay. Tubulars are VERY popular for 'cross. I forget what the green tread tires are, but I've seen them at 'cross races.
There were actually some pretty decent clinchers on the market as far back as the early '80s, but they were still
somewhat heavy and clincher rims back then weighed a ton, so nobody raced on them. The only bike I had with clinchers back then was a "winter bike" that also had fenders. For that purpose, I didn't care about the weight and didn't want to be dealing with tubular flats when the weather was frigid.
Tom,
this simply is not true. I don't know where you got this information from, but
it is just plain wrong.
First off,
rims don't flex much, period. Unless you hit something hard enough to damage the rim, we're talking about
small fractions of a millimeter of flex in normal use.
Second,
a good glue job will not fail, even if the rim is severely dented. If you can find a team mechanic or even a good shop mechanic with tubular experience near you, ask about this and they'll tell you exactly the same thing.
If you experienced glue bond failures, the glue jobs weren't done properly, end of story. I don't care who did them.
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The only other possibility is that the glue job was so old that the glue crystallized and became weak. That was not uncommon with the glues used decades ago. I've seen it happen with Clement red cement (my glue of choice at one point) and with Tubasti, but it typically takes at least a couple of years for it to become a problem.
I agree with this, but previously you were claiming that the major compliance was in the
rims. Technically, carbon frames still have some lateral flex, but the bulk of the designed-in flex is in the vertical plane.
That may be true for
some manufacturers, but not all by any stretch of the imagination. Manufacturing technology has improved to the point that catastrophic failures in normal use are essentially non-existent in quality frames. Failures in quality frames are nearly always caused by either some form of overload or physical damage from an impact. We're talking about overloads and impacts that would bend metal frames. The only difference is in the failure mode of the material.
Carbon forks have always been built strong; in recent years they've been getting lighter and more compliant, except on disc-brake-equipped bikes.[/QUOTE]
Wider Tires Are Slower
For almost a century, cyclists ‘knew’ that narrower tires roll faster. Some people realized that in theory, wider tires are faster due to their shorter contact patch, which deforms less as they roll. But the thinking was that in practice, the lower pressure at which wider tires must run limited their performance. If you wanted to go fast, you chose narrow tires
That is what we thought when we started testing tires almost 12 years ago. And yet, as long-distance riders, i wondered whether the narrowest tires, pumped to the highest pressures, really were optimal for us. What if wider tires were a few percent slower, but their greater comfort reduced our fatigue? Remaining fresh toward the end of a long ride would help us put out more power, so we might go faster in the end. What we needed to know was how much speed we would give up by going to wider tires.
Aerodynamics
What about the aerodynamics of wider tires? Many riders believe that wider tires will be slower, because they have more wind resistance. I tested this in the wind tunnel and found that the difference between 25 and 32 mm tires was too small to measure reliably in a real-world scenario. The German magazine TOUR built a sophisticated setup with a motorized dummy rider and found that a 28 mm-wide tire had the same wind resistance as a 25 mm tire when the wind was coming from straight ahead. With a crosswind, the wider tire was very slightly less aerodynamic. Even then, the wider tires required only 5 watt more – on real roads, the reduced suspension losses probably make up for that.
I tested our tires on smooth pavement at 29.5 km/h (18.3 mph), and found no speed difference between narrow and wide tires. If you ride much faster, then it’s possible that wider tires roll a little slower, but the difference will be so small that it’ll get lost in all the other factors that influence your bike’s speed. On the other hand, if you ride slower, then the advantage of wider tires will be even greater.
Spinning up
Wider tires are a little heavier than narrow ones. The difference is smaller than many cyclists imagine – air doesn’t weigh anything – but a wide tire has a little more rubber and casing. Won’t this make the wider tires harder to accelerate? The answer is “No.” The reason is simple: Bicycles don’t accelerate very quickly. Even a professional bike racer’s power-to-weight ratio is far less than that of the slowest economy cars, and those don’t exactly push you back in the seat when you floor the throttle. Bikes don’t accelerate fast enough for small changes in wheel weight to make a difference. That is why professional sprinters can use relatively large wheels (which inherently are heavier) and still win races. The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.)
What this means for us riders is that we can choose our tire width freely, without having to worry about performance. Of course, this doesn’t mean that a wide ‘touring’ tire will perform as well as a narrow ‘racing’ tire. Casing performance determines 95% of a road tire’s speed, and to get good performance, you need a supple high-performance casing. (The other 5% come from the thickness of the tread.)
Tire width influences the feel of the bike, but not its speed. If you like the buzzy, connected-to-the-road feel of a racing bike, choose narrower tires. If you want superior cornering grip and the ability to go fast even when the roads get rough, choose wider tires.
