Rolling resistance and weight....

Have you noticed that wider rims and fatter tyres on road bikes are all the rage at the moment? Truth is, there's nothing really new about this at all. 

In the 1980s there was a trend towards narrower tyres based on the belief that "thinner is faster". To some extent this was true but to achieve lower rolling resistance the tyres themselves had to be pumped to a much higher pressure resulting in a harsher ride and skittish handling, especially in the 19 or 20mm widths popular at the time. A number of studies were done prior to 1990 which proved conclusively that fatter tyres did, in fact, roll faster and gave a smoother and more comfortable ride at a lower pressure than the ultra skinny versions. I recall that, all other things being equal, 700x28 was actually the optimal size.

So you might think, well why didn't the bicycle industry simply move up to 700x25 or 700x28? The main reasons for this were that manufacturers had invested a lot in the 'skinny is better' concept and most frames had limited clearance between wheel and frame tubes plus the wider rims required to safely mount wider tyres were a lot heavier. With the greater weight of 700x28 tyres over 700x20 this created a wheel package which was compatible with few frames at the time and increased the weight of the complete bicycle.

Fast-forward to the current era and we find that the improvements made in materials used to manufacture wheels have finally delivered on the promise of those studies from the '80s. You can now have great handling, improved comfort and lower rolling resistance without a significant weight penalty and providing your bike has the clearances to allow for today's fatter rubber. 

Brake opinions

With all the talk about disc brakes for road bikes coming soon for professional cyclists, it made me think about how far road bike brakes have come since the 1970s. Until that time, brakes for road bikes were more of an afterthought for component makers than anything else and had changed little in design or functionality since the 1940s. Basically they worked sort of OK in dry conditions but it was a case of 'heaven help you' when it rained. At least things got better when steel rims were abandoned in favour of alloy.

Starting around 1990 or so with the introduction of the double-pivot designs, the effectiveness of road bike brakes took a big leap forward. There have been further refinements through the years with Shimano, Campagnolo and Sram all producing very effective braking systems right down to their entry-level components. Unfortunately, the major bicycle manufacturers don't always spec brakes to match the rest of the components and it continues to be an area where they typically save costs in an effort to offer a bike at a lower retail price. What typically happens is that your new carbon bike with Ultegra 11 speed gears will come with no-name or house-brand brakes which are not much better than the stuff which used to masquerade as brakes in the '60s. Not all non-system brakes are bad though with some decent units being offered by other brands, Tektro in particular. 

Brakes may not make you go faster but they are sure handy when you have to cut speed quickly and safely in any conditions. It may not be the sexiest upgrade you can make on your bike but if you have doubts about your current brakes there are worse things you can spend your pocket money on than a set of decent stoppers or at least some upgraded cartridge brake pads.

And in case you're wondering about disc brakes v. rim brakes for road bikes I'm keeping my thoughts to myself on that one for now...... :)

Wheel musings #2

So, what about hand-built wheels? Hand-built hoops used to come standard on reasonable quality bicycles. If you bought a bike fitted with a Shimano 105 group you usually got wheels built with 105 hubs, double-butted spokes and rims from companies like Mavic, Sun, Wolber, Ambrosio and many others. Sometimes the wheels were built by hand and sometimes by machine but whichever way they were done you could be sure that if you broke a spoke, any bike shop could replace it because they were standard spokes and all shops carried spares. Groupset hubs also typically ran for years with little or no maintenance and when they eventually got grungy your local shop could repack them with fresh grease and new ball-bearings, which were also pretty standard. 

So much for the good old days. Now your 105-equipped new bike is likely to come with wheels which might look flashy but usually aren't anywhere near the quality of the wheels described above. In any case, manufacturers assume that one of the first upgrades a buyer is likely to make will be the wheels so the standard wheels are frequently made with heavier or inferior materials and they wear out or break in a year or two. You then go back to the bike shop and they talk you into a set of $2,000+ wheels which are a different story altogether. Now you have wheels which are stiffer, lighter and might even be more robust than the original versions but your wallet is a whole lot lighter as well.

By now I think you may have figured out that I like hand-built custom wheels so perhaps I should provide some justification. First of all, you can choose hubs from Shimano, Campagnolo, DT Swiss, Chris King or a few other makers to suit your budget. Secondly, you can choose VERY good quality spokes, double or even triple-butted which are strong and fatigue-resistant. Finally, you can select really good and lightweight alloy rims which keep the rotating weight at the outer edge of the wheel as low as possible and thus improve handling and acceleration. You can also decide if you want the same number of spokes in the front and rear wheels or if you want fewer in the front. Front wheels only take about 30% of the load and aren't subject to the same drive forces generated by your legs on the rear wheel through the gears and chain. Talk to your wheelbuilder about lacing patterns although for most purposes three-cross delivers the best performance. To top it off, your hand built wheels will probably be lighter than most similarly priced factory wheels.

Aesthetics are a personal thing for sure and most people these days seem to prefer the industrial, brute-force look of factory wheels. For me, it's the shimmer of stainless spokes in the early sunlight of a Sunday morning that sets the tone for a great ride.

Wheel musings #1

Been thinking about factory-built wheels v. hand-built wheels......again! It seems to me that many of the wheelsets sold today by a large number of manufacturers are awfully expensive for what you get.
Its rare to find a set under a grand that doesn't have some sort of trade-off (or two), such as painted spokes v. genuine stainless spokes. Painted spokes are fine if you live in a very dry climate with low humidity but not so good in a place like Bermuda where a "dry day" is one with 60% relative humidity; and we all know that 60% is the exception rather than the rule. In partnership with the saltiness of our summer breezes, this isn't a very healthy environment for steel spokes with scratched painted surfaces.
It also seems to me that many of these sub-$1,000.00 wheels don't have decent quality hubs or have hubs with mediocre bearings. Frequently they are constructed with minimal spoke counts and at this level that usually means the rims are heavier because of extra material around the spoke holes. This creates wheels where much of the weight is at the outside edge of the wheel and is thus rotating weight (harder to get up to speed and with a negative effect on handling).
While the above issues can be significant, perhaps the most important factor is that many of these wheels don't represent a significant weight savings over standard 32 spokers. In many cases they are actually heavier but riders are prepared to overlook this because they look "flash" or "trendy". If I'm going to slap down a grand on a new set of hoops I'd like to think they might help me get over the hills a little easier!
Next post I'll share some thoughts on handbuilts.

Long time gone.....

I think its about time I started posting to this blog again. Let me see what I can come up with today.