Road Cycling - 700c vs. 650c

We have narrowed it down to the Trek 2000 WSD in a 43 or 47cm and the Specialized Allez Vita in 44cm. My wife is going to do a bit of test riding tomorrow. While tracking down the small frames to test one guy said he would not recomend the 650c wheels because it would make it harder to keep up with someone riding 700c wheels. This doesn't make sense to me. What differance would it make? It's true that a 42x17 on a 700c wheel would be 67" gear while a 650c wheel would be around a 64" gear. One upshift would take care of the difference. Any thoughts on the subject and am I missing something?

You just gear accordingly and it solves the problem. However, if all things were equal, a tall person would spin a 67-in gear at 80 rpm while a short person would spin a 64" gear at 85 rpm... or maybe even a 60" gear at 95 rpm.

What the LBS was referring to is the idea that a small wheel has more difficulty going through ups and downs and that therefore, more energy would be lost on the road. It might be true under extreme circumstances, but for the most part it's baloney. St. John's street cycle explains it fairly well here: http://www.sjscycles.com/thornbrochure.asp (look at their brochures for 26" bikes.

Due to the smallness of her frame, she is better with smaller wheels instead of 700c. She is about at the lower limit for which a 700c bike might fit.

My worry about 650 is that 650 tires are hard to find. Not a problem if you plan day rides and such, but if you bring your bicycles to a far-away place, it might be difficult to buy a new 650c tire in a pinch. That's why, for touring or other "off-the-beaten-track" purposes, I would prefer 26" wheels.

Regards,

650 wheels accelerate and stop faster than the larger 700c. They weigh less , so they climb better. 700c maintain their speed with less effort, and give a smoother faster ride over rough surfaces. Its swings and rounderbouts, so dont worry about efficiency.
Squeezing large wheels into a small frame just doesnt work. Either you make the frame too long, to make space for the wheels, or you bodge the steering geometry. With 650c you can make a properly proportioned small frame which handles well.
Note that small cranks also mean you can design a better small bike, and they fit smaller riders better.

The biggest down-side to 650c is availability, so just keep a spare tyre or 2 handy. There is a smaller choice of tyres, and they are not available in larger sizes. You can swap out a 23mm 700c for a 28mm for winter training or touirng. With 650c, the upper limit seems to be 25mm. If you want a wider tyre for winter commuting/tour you should go for a 26"MTB wheeled road bike.

I was in the bike dealer because I'm looking for a new bike and they said if your looking for speed go with 700c. They said even the racers tried it for a while but noew there alll switching back.

Later,
Robin

My wife tried both of the bikes you are looking at and she felt that the Specialized handled rather oddly with the 700cc but she loved the handling of the 650 on the Trek. Regardless of the "speed" factor, the most important thing IMHO is the handling and comfort.

M

Bicycles smaller than 50 cm should have 650c or 26" wheels. Accomodating 700c wheels on a frame that small causes the builder to make several design compromises that aren't worth it...

1. in order to avoid toe overlap the designer must use excessive fork rake.
2. the bike is likely to have a really slack head tube angle, 71 degrees or less. Again, this is to help avoid toe overlap.
3. a really small bike with 700c wheels will likely have a really steep seat tube angle. 74 or 75 degrees.

All of these compromises can be avoided by using 650c or 26" wheels.

I would not get a 650 C simply because most people have a 700c tire, and I ever needed to borrow a spare from a stranger, I would be in a bind- I've only run into one person with a 650 c, and he was on the path begging for a 650 c inner tube.

No one had one.

Koffee

650c wheels work for me! I've ridden them now for 9 years. I'd never go back to a 700c wheel. I'm 5'2" and they are just so much easier for me to ride. Plus, I ride a 44cm frame and I can't imagine a 700c wheel on that frame.

As far as availability goes, I have no problem getting tires or tubes. I always carry a spare tube, just like people with 700c tires do. I keep an extra in my bike bag in the car and have a folding tire for tours.

Not having a tube can happen to anyone. My Significant Other went out one day by himself. He had picked up my tube instead of his 700c. He had a flat tire and wound up having to stop periodically and put air in the tire. He was so frustrated he went out and got a cell phone!

Kathi

How often does it happen that you need to borrow a tube if you are prepared? Rarely, and even if someone does not have a tube they would have a patch kit which will fix your problem due to a flat..

In the end get what feels best to her, that is what matters the most.

I ride a 48cm frame with 700c wheels. Sure there's a slight overlap but it's not excessive and I've seen similar overlap on frames over 50cm. You just learn to live with it. My frame has a 73-deg head-tube angle, 66.5-deg seat-tube angle (okay so that's kinda cheating because it's a curved seat-tube) and top-tube length is 51.5cm.

Mshe felt that the Specialized handled rather oddly with the 700cc

Hmmm... 700cc on a bicycle would indeed make it handle... oddly. ;) I'd save it for a motorcycle instead. :)

Hmmm... 700cc on a bicycle would indeed make it handle... oddly. ;) I'd save it for a motorcycle instead. :)
:rolleyes:
Must not have been awake...fell asleep and hit the c one too many times. :D

Actually, I pulled over to help out the guy with the 650 c tire- he said he was ok, and pulled out his spare and got it on his tire. Got the tire back on the bike and used my CO2 pump to blow it up, and it exploded. The gash was way too big to repair. That's when he started begging.

After that, I made sure to carry patch kits, several inner tubes, and plenty of CO2 containers just in case.

I'm only 5' 1 1/2"... a 700 c tire suits me fine, and besides that, they just are a lot easier to beg for if you happen to get stuck in a bind and need to borrow anything from anyone.

Koffee

Koffee,
I felt the same way as you until I started riding 650's. Now, I'll never go back.

The whole fit of the bike is so much better. The bike feels made for me instead of some average sized man. Of course, Aegis bicycles are special.

Kathi

With 650c could you cram a 700 in the tire in a pinch to get home? Seems like it would work for the short term.

Now the other way around would be a different story.

I'd think that you could, PC- we tried that, but it just seemed like the tube was too big for the tire. :(

I'm sure 650 c works just as well as 700 c. It seems like it's more a matter of personal preference than anything.

Koffee

As for that experience.. he blew up the tire with the Co2 from inexperience with it :) and still had original tube with the flat.. (assuming he did not blow up 2).. of course heard about teing the tub around a stick where the flat is.. to hold long enough to get home.. would not be best riding but always ways around things :)

How do 26"MTB inner tubes work in 650c tyres. Is this a get-you-home or a non-starter ?

650c is a 571mm rim and 26" is a 559mm.

I've also heard of putting a dollar bill or a power bar wrapper around the tube. Don't know if it works, never had to try it.

If he didn't check the tire carefully he could have something in the tire that caused the spare to blow. Also, his rim tape could have been bad causing the spare to blow. That happened to me once, we ruined a patched tube and my spare. Some guys knew what was wrong and wrapped my rim with electrical tape, patched the tube and it worked like a charm. I was able to finish the 35 mi of my 50 mi ride.

Kathi

I'm glad I read this post because I have been wondering the same thing for quite awhile. I own a Terry Symmetry. I'm 5'2". My Symmetry has the small 24X1 tire in the front. I love my bike because it fits me but I have often wondered, especially now that I'm a stronger rider than when I first got my bike if the small front wheel affects my riding. It seems like I work harder to get the same results or less when riding with other women who have the bigger tire. Don't get me wrong, I'm not saying I'm a elite, fast rider, but I think I have improved in the last couple years and it seems that I still struggle to keep up in rides. When spring comes I plan on test riding some other WSD bikes with the bigger tire just to compare. I keep watch on posts like this to see what other women prefer to ride.

Gosh... did I kill this thread ? No response for awhile. Did I say something wrong ??!!??! :(

No, I think the topic just ran itself out.... you're ok! :)

I'm glad I read this post because I have been wondering the same thing for quite awhile. I own a Terry Symmetry. I'm 5'2". My Symmetry has the small 24X1 tire in the front. I love my bike because it fits me but I have often wondered, especially now that I'm a stronger rider than when I first got my bike if the small front wheel affects my riding. It seems like I work harder to get the same results or less when riding with other women who have the bigger tire. Don't get me wrong, I'm not saying I'm a elite, fast rider, but I think I have improved in the last couple years and it seems that I still struggle to keep up in rides. When spring comes I plan on test riding some other WSD bikes with the bigger tire just to compare. I keep watch on posts like this to see what other women prefer to ride.

I think that you'll find the other bikes fit you quite differently. Those Terry bikes are very, very short from front to back. You may find that you prefer the more stretched out feel and, after your experience with the Terry, you may not like it at all. Back when I owned a shop, I never had a single serious buyer test ride a Terry and not buy it so that, alone should tell you something. Terry is also the only bike manufacturer that will pay shipping both ways on bikes for customers to test ride. They told me they get hardly any back so the program must be working for them.

I would not get a 650 C simply because most people have a 700c tire, and I ever needed to borrow a spare from a stranger, I would be in a bind- I've only run into one person with a 650 c, and he was on the path begging for a 650 c inner tube.

No one had one.

Koffee

So you are saying that an event that occurs once over several years (once or twice for me in 50k+ miles) is worth sacrificing handling and bike fit?!?

My wife has 650 wheels and has never had a problem. Get what fits and handles well.

-murray

I'm sure 650 c works just as well as 700 c. It seems like it's more a matter of personal preference than anything.

KoffeeNot personal preference. 650s simply work better on small frames where a 700 won't fit with out compromisimg fit and geometry.

I would not get a 650 C simply because most people have a 700c tire, and I ever needed to borrow a spare from a stranger, I would be in a bind- I've only run into one person with a 650 c, and he was on the path begging for a 650 c inner tube.

Not a big deal to carry a spare tube. I carry 2 in thorn season. The only tire failure I ever had was my fault for trying to get too much use out of a bald one.At least the walk home was short and the learning experience not too painful.

I ride 700c but that shouldn't matter for purposes of this discussion. I carry a spare tube and both a normal patchkit as well as small strip of glueless patches (in case my glue has dried up). I have never had to ask for a tube from someone although admittedly I have given out my spares before to other riders. Like sydney, I've also not gotten an actual tyre failure except for the time I ran mine bald. I also carry a tyre boot.