On 6/17/06 1:16 AM, "Sheldon Brown" <CaptBike@sheldonbrown.com> wrote:
> Doug Fattic wrote:
>>
>> What makes more sense for today is using two 650c wheels - a size made
>> popular with the tri crowd but rare back 25 years ago. This has several
>> advantages besides not having to carry two different size spares. First it
>> makes a small bicycle look proportional. The lugs are not crammed together
>> like they are on a small 700c frame giving the impression something isn't
>> fitting right. Smaller wheels are also lighter wheels which provides
>> advantage for the less powerful rider. I've heard a lot of people say they
>> think 26 inch wheels are harder to pedal because of the gearing (you've got
>> to pedal faster to cover the same distance) or there is noticeably more
>> rolling resistance or some other nonsense. I trust CR members are smarter
>> than to believe those things. Another advantage of 650c wheels for women is
>> that, unless they are racer types, it steps down commonly available gearing
>> (that often starts with a 53/12 or 13) into a more useable range for someone
>> not on a training ride. A 52/13 gear on a 650c bike is about the equivalent
>> of a 52/14 on a 700c bicycle.
>
Sheldon Brown wrote:
> The trouble with the 571 mm (650C) wheels is tire availability.
> There are only skinny tires available in this size. Until recently
> 25 mm was the widest 571 you could buy, and even finding them was
> difficult.
>
> Now there is Terry's 28 mm Tellus, the one and only choice that
> begins to get reasonable for non-competitive riding. Don't forget
> that the smaller wheels inherently ride harsher than larger wheels,
> so a 25 mm 571 will be noticeably harsher than a 25 mm 622 (700C)
>
> For me, the much more practical choice for road bikes for smaller
> riders is the 559 mm (26 x decimal) size, same as used on mountain
> bikes. There's an enormous range of tire widths and styles available
> in this size, and you can find them anywhere.
Actually one advantage I usually build into a women's frame that uses 26" wheels is the ability to use both 650c and MTB wheels. I make the fork length and the height of the rear brake bridge to accept both a 571 and 559 rim. The larger 650c rim uses a 39 to 49 brake and the MTB rim takes a 47 to 57 brake. This accommodates lots of biking options in one bicycle. I've discovered that once a person uses a custom frame, they don't like to ride something else and want it suitable for all occasions. A women that can afford a custom frame is not likely going to pinch pennies on the rest of her components. It's not uncommon to spend a few extra hundred on a special paint job alone. I am more likely to put tubular tires than clinchers on her bike because they are looking for optimum cycling performance with their extra money. Continental has several of their top end models in a 22 mm width. A tubular tire rides less harsh and has a lighter rim weight. Because these are usually fit women that might weigh somewhere between 100 to 130 lbs, a really good tubular typically lasts a very long time for them. The experiences of big strong heavy guys buying cheap tubulars (and always wanting to give their superior advice) with too many flats does not apply to people half their weight. And if they are going on a trip somewhere (like our Ukraine bike ride :), their go fast wheels can be swapped out for go anywhere ones.
Tire availability is always an issue with non standard wheel sizes. A
little thinking ahead by requesting 2 tires or tubes instead of 1 solves
that problem. Smaller people are used to not having everything their size
at any store.
>
> Now that 11 tooth sprockets are so readily available, there's no
> problem getting decent high gears out of wheels in this size range.
>
> Sheldon "559" Brown
That's a big man's gear that I bet you need but seldom in the useable range on a small women's bike. It's a rare women rider that will find many situations where she will spin out a 52/13 using 650c wheels. With a cadence of a little over 100 rpms she would be going 30 mph. Easily possible of course but not typical. They want the maximum number of gears available in a 13 to 20 mph range. My philosophy is that it is better to sacrifice those few opportunities to have the right gear going downhill with the wind on your back for closer spaced gearing at normal speeds. That often means having the 17, 18 and 19 sprockets instead of 17, 19 skipping the 18. With a cadence of 85 on 650c wheels and a 53/18 she will be going about 18 mph. If she is in the small 42t ring on the 18 her speed would be 14. In other words an 18 sprocket is often used in average speed situations.
Doug Fattic pondering how to make women happy in Niles, Michigan