Commuting - new bike tire and light questions

I'm looking to get a new city commuting bike. I'm looking at the Breezer Uptown, Specialized Globe, and the Trek L200. They all have good accessories etc. but what I'm really concerned with is speed. Their rim measurements are 26x1.5, 700x28c, and 700x38c respectively.

My first question is on diameter: the difference between the Uptown and the other two is 1.56in. All things being equal, can you really feel 1.56in? Will it give better acceleration and maintain speed easier?

Next is tire width: the Globe and the L200 have a difference of 10cm. How does width affect acceleration? Does the L200 have more noticeable drag because it's wider? Is there a sweet spot for width on a city commuter?

These bikes have integrated lights that are pedal powered. Any one have any experience with something like this? Are they any good or should I go down a trim level and just buy regular battery powered lights?


Thanks inadvance.

some links would be nice, so we can check out the specs.

links:


http://www.trekbikes.com/bikes/2004/citybike/l200.jsp#largerview

http://www.specialized.com/SBCBkModel.jsp?spid=6769&JServSessionIdroot=fi5scrm5mz.j27007

http://www.breezerbikes.com/ then click on town bikes (the first one)



thanks.

1) Between the 2 sizes of wheels, 26 vrs 700c, not terribly much, at least for most commuting distances. Wheel availability is more an issue, since MTBs come in 26" wheels, you may find stronger wheels more readily available than 700c wheels. But with some planning and foresight, both is an option for the commuter. Regarding speed, you would have to look at it as a complete object, including the wheels, rims, tires, etc. etc.. A tire with more mass will have more momentum at speed but accelaration will be slower. Just comparing the rim size is not really that good. And then you add aerodynamics and for the most part, the 700c wheel would be faster due to skinner tires but not necessarily just because it's slightly taller in diameter.

A weird relationship is all these people who modify cars that put these huge 18" rims on civics or so, they're actually hurting acceleration due to tire mass.

2) First, the difference between the widths is not 10cms! that would be like 4 inches, it would be mm and even then it's not really "10mm". But to avoid complexity, there are alternating arguments whether the skinnier tire has less rolling resistance than the wider one. There are even reports that properly inflated wider tires has less resistance than narrow skinnier ones. So the point here is to properly inflate your tire . Would you tell the difference in a commute, most likely not. A wider tire will typically be better for commuting due to comfort and other reasons.

3) as far as integrated lights, I remember hearing alot of the older lights have problems with burning light bulbs due to overvoltage conditions or unregulated power to the bulbs. I imagine the newer ones must have some kind of overvoltage protection or so. But I haven't had any XP on that one so don't know what to tell you. You can always add basic lights to your bike anyway, however, if they're using a generator hub or so, add 1 for complexity and a little weight.

Jay

Tires. If properly inflated they should all work fine. Wider usually means stronger and better traction across grates. Narrower usually gives a slight drag advantage and a rougher ride. These tires are all in about the same size range, so I wouldn't expect much difference among them.

It is very convenient to have a generator on a bike. It makes the bike more like a car -- jump on it and go. If you want the brightest possible lights, however, you will want a high intensity rechargable battery system. The generator lights on the three bikes mentioned should all be suitable for most commuting.

However, the Trek seems to have a sidewall generator, while the other two have hub generators. Sidewall generators often slip in the rain. Even the best are not very good in snow. They make some noise and require periodic adjustment. Not all tires have the molded sidewall treads to work with them. The hub generator is much better.

I've used both sidewall and hub generators. I really like my Shimano hub generator. The sidewall unit worked well for me for two years, but I am not going back.

What you buy reflects your own preferences. If I were to buy one of these, I would first eliminate the Globe, because it has a derailleur. Next, I would rule out the Trek, because it has a sidewall generator. The Breezer is very similar to my own bike, which has stood up well to about 5,000 miles of daily commuting in all weather conditions. Since I have never seen or ridden the Breezer, I cannot actually recommend it. However, it has the best specs of the three for routine everyday use.

The Shimano hub generator has a very good voltage regulator, One bulb lasts at least all winter for me. If you want hub gears and a hub generator, it may be cheaper to find a bike that already has them, rather than trying to add them later.

The hub generator is much simpler than the sidewall generator. My Union sidewall unit had a worn rotorafter two winters of sand and salt. It worked well over that time, but required some fiddling. The hub unit is fiddle-free.

Paul

The width of 1.5" and 38mm is about the same. The 28c tire should be fine for smooth roads and will roll faster, but if you want to hop up and down curbs or if the roads are cracked and potholed go for fatter tires. If you get the 700 X 38c, you would have the option of changing to 35c or 32c at a later date. Besides giving easier acceleration, lighter tires will also make emergency steering easier.

When comparing wheels the biggest variable is tyres. You can get tough, efficient rubber in both sizes, and the differences are marginal with similar styles. I would recomend a 32mm in 700c, and a 1.5" in 26". Both are in the sweet spot for urban utility use.
In the Breezer range, the Villager looks to be a better model, with a simple, lightweight fixed fork, rather than suspension.
Nexus 7 is clean, easy and reliable, but do learn how to remove the wheel for punctuure repair.
The sidewall generator is OK if it is correctly fitted. They get their bad rep from clamp-on style fittings. These rotate under load, and the generator slips. With the generator directly bolted to a frame fitting, and a tyre having radial ridges, it doesnt slip.
I have used an old clamp-on generator , and a modern one fitted to a braze-on, and the difference is huge.
Modern bicycle lamps are designed to optimise the 3watts for cycling, compared to the generic sealed beam units from expensive battery powered systems. They are excellent for urban riding.
Check out the Villager if you can, it looks like the ideal bike.

Hi,
with tires, bigger is nicer but slower. I like the 28-32 sizes. Most lights are there for people to see you. You need several watts of power to illuminate the road. You can get a 2nd light to provide a little more punch. Below $50 you don't get much. Now, some thoughts. Any dealer will swap out the stock tire for a better one. You won't get a lot of credit for the stock tire, but even so I think it's a great idea. Next, pick the one you best like to ride. After that, consider getting a decent bike seat.
My current favorites are the B17 Champion Special and the Selle Italia Trans Am XLP.
Lastly, try a touring bike like the Trek 520. These are bikes designed to be ridden all day. They emphasize comfort and reliability. Bikes are simple once you understand them. Buy a bike you don't want to stop riding. And you won't.