lovemyswift

I posted this in the women't forum but also decided to post it here so everyone can see it.


I know this is going to open a can of worms but:

This afternoon I demoed a Serotta Fierte Ti and a Serotta Nove. The Fierte wa a 46 cm frame, with 650c wheels. The Nove was a 48cm with 700c wheels. The LBS had my specs from my Serotta fit so they were able to set both bikes as close to my fit as possible.

On the Nove I was a little stretched out, the tt is 2cm longer than mine, and the crankarms were huge (172.5 vs. my 165's).

I was evaluating the frames so I didn't pay any attention to the wheels. First I rode the Fierte with the 650 wheels, then I rode the Nove with the 700 wheels and then I rode my bike, also with 650 wheels. I rode all 3 bikes though the same route, up and down sidewalks, through a parking lot and over a gravel road. When I took the Nove back to the LBS to pick up my bike for comparison I realized that I could tell absolutely no difference between the 650's and the 700's!

After all that, the shop let me take the Nove out for a 10 mile ride and I didn't ride any faster, I didn't go downhill any faster, the bike didn't handle any different than a bike with 650's. It did wobble on the downhill but that was due to the bike being too big for me, not the size of the wheels.

The guys in the LBS also agree, there is no difference between 650 and 700's!

Kathi

bhh

except standover height?

trayer350

There is a difference. The 650s are smaller. If the bike you get is too tall for you, the smaller wheels might help.

Patriot

My wifes custom Centaur machine has 650c Velocity Uriel wheels. She is 5'3", and has no trouble keeping up with me on the flats going 20+.

fogrider

a good bike is designed to ride well. if it is designed for a small person, 650 wheels could help with toe overlap and standover. a friend has a terry with 24" front wheel and it rides right for her. I rode my friend's bike friday and it is designed around 20" wheels and it rides like a road bike! back in the day, team time trial bikes were built around 650 wheels because they could draft closer to the rider in front of them! track bikes and tri bikes were also built around 650 wheels because they were smaller which meant they were lighter at the rim. 650 rims could feel faster because of this. so, if you can't get a bike built around 700 wheels, 650 wheels could be the answer.

the thing about a 650 wheel is that it limits your choice of tires. for the most part, this should not be a big deal, there are enough 650 tires around, but if you get a gash in your tire and you're in some farm town, you're be lucky to get a 700 tire. so just be prepared.

StanSeven

There are two slight differences in ride quality. 650's feel a little different in tight, low speed turns and on quick accelerations. The feel is mostly subjective and I doubt you can find any real measurable variation.

sestivers

Not really true. Tri bikes that use the 650c wheel do it because for many of the frames, the larger 700c wheels would not fit in the rear triangle due to the geometry tri bikes use. Many newer tri bikes are using 700c wheels if they will fit in the frame because they probably determined that there aren't other advantages to using 650c. Weight is not really a factor for tri bikes because for the most part the race is done at a relativly constant speed.

As for how they ride, I don't have any experience with 650c wheels... there are tradeoffs either way. 650c weigh less and are theoretically more aerodynamic due to being smaller, but their rolling resistance is higher because they have to rotate more times in a given linear distance and the aerodynamics are probably affected due to the spokes traveling at a faster rotational speed for the same reason.

Trsnrtr

I've been riding 650 wheels the last couple of years (after 20+ years of 700c) and honestly can't tell a difference. Quality tires are available from most mail order shops and my LBS carries a few brands as well. I do admit to keeping a couple around just in case but it's no big deal because Performance usually blows out a couple models cheap a few times a year.

I've got about 12,000 miles now on 650s and really like them.

merlinextraligh

as mentioned above, For a given tt length, the 650c wheel bike will have less toe overlap. Personally, toe overlap doesn't seem to be much of a concern. (You only turn the front wheel enough to hit your foot at about 3mph).

If you can get a bike that fits you with 700c wheels, I would definitely go with the 700c. Much easier to find parts and tubes, and a lot easier to borrow a spare tube on a group ride.

Ineedhelp

I stand just over 5 foot, and will keep my 650c wheels, thank you. However...

I've read all the arguments and done the math, and you will lose a little downhill momentum with 650 wheels. If I am recalling correctly, it's somewhere around 10%. This doesn't bother me personally. I'm not in a race with anyone, and don't care to go any faster down the hills anyway.

But you can also accelerate faster, and as far as I'm concerned, they are more stable at higher speeds, tighter on the turns, and do make the toe overhang a little less annoying--and if you're turning at more than a 90 degree angle you will still have this problem, even at higher speeds. On smaller bikes, we just have to stay conscious of this problem and adjust our riding accordingly....

And keep parts, tires and tubes stocked. An extra wheelset ready at home is advised as well--and when stopping to help another cyclist on the road, well they better just need a patch because neither my spare tube, nor my husband's mountain bike tube is going to work. Our cell phones however do work nicely, and there's always someone we can call...

All in all, think I'll stick with the 650s.

white lobster

You'll need bigger gears to make up for the difference in wheel size on a 650C bike. It's been a long time since I did the math, but to match a 55 tooth ring on a 700C bike, you'll need around a 55 tooth ring on a 650C bike.

People used to gawk at the 56 tooth ring on my 650C road bike, but it was actually pretty much the same gear as everyone else was riding.

Dahon.Steve

Each time you go to a smaller wheel, you lose comfort. I have bikes with 16' 20' 26' 27' and 700cc wheels. The most rough ride in my stable is the 16' inch wheel but comfort gets dramatically better by the time you go to a 20 inch wheel.

I think you'll notice the difference in comfort after 40 miles on the condition of 650's. I suspect the 650 tire should have a shorter life than the 700cc since it makes more revolutions.

snowy

I agree with you Kathi, on my bike its 700 wheels and I test rode bikes with 650. I'm short too 5'3 and honestly I couldn't tell the difference but I have heard the argument by many on this forum.

Dahon.Steve

I would like to see how you did the math. Those folder heads on the other forum swear their 20 inch wheel bikes go just as fast as the 700cc wheel.

a77impala

Just a quick question, don't you need to use shorter cranks because of the decreased clearance with the 650 tires? I can see the pedals being more apt to hit the pavement on turns with the smaller wheels.

Mentor58

I just ran the numbers over on sheldons site, 52/39/30 with a 12-25 cassette. 700X25 vs 650X25, MPH at 90 RPM. the 52x12 on 700c gets you 30.6mph, the 650 gets you 28.4mph. Giving up 2 mph at the very top end at same RPM, but the thing that I noticed was that pretty much across the board the smaller tire was just about a 1 gear difference in the back compared to the 700 wheels, ie 52x13 with 650's is the same as 52x12 with 700's, 39x16 700's match to 39x17 650's.

I think for 99 percent of the time it wouldn't be a difference, and if you need that extra bit, then you go to an 11 on the 650's.

Steve

Ineedhelp

It's posted on the internet--start with Sheldon Brown. I don't remember any longer what site it was I found all the engineering specs on...

StanSeven

The chief reason tri bikes used 650 wheels was a belief that smaller wheels reduced drag. After much testing, that proven invalid.

MichaelW

The answer is yes, but not for that reason.
The only sensible use for 650c is for small riders who generally have small legs which work better with small cranks.
The height of the bottom bracket is determined independantly of wheel size to give adaquate pedal clearance. If a designer wants to provide 30cm of clearance for the bottom bracket, that is what they build in to the design whatever size wheel they chose.

Given that short riders use small cranks, you would think that the designer would incorporate this fact and lower the BB height in smaller size frames to provide a pretty constant pedal clearance across their range of bikes. Not so:
The std Trek road bikes vary in BB height by 2mm between the XL (26.9)and XS (26.7). The WSD frames all have the BB height of 26.9.

The result: If you fit 180 cranks onto the XL frame, you get more pedal strike. If you fit 160 cranks onto the smallest frame you have far more pedal clearance than you need.

lovemyswift

I'm planning on building a custom frame and I was evaluating the bike for the frame material, not fit or the wheel size. I know the bike was too big for me and the crankarms to long but it was the smallest bike they had in that frame material

I've ridden 650's for 10 years and always thought the fit of the frame and not the wheels made the difference. There have been numerous debates on this forum over the pros and cons of 650's some being "I didn't like the feel" or the wheels made the bike feel to small.

The Fiete with the 650's handled better but that was because the frame was a better fit, not because of the wheels. However, the ride on the Fierte was worse, but again it was the frame material, not the size of the wheels, there is no comparison, my cf frame with 650's was a far superior ride.

The person in the LBS told me to focus on the "feel" of the bikes not how they fit, components, etc.

I felt slightly higher on the 700c wheels but it wasn't a significant difference. When I took it out on the 10 mile ride I did notice the longer tt, it wasn't terribly uncomfortable but I could tell it was too big.

That's another point, for the first 15 minutes on the bigger bike the fit didn't feel that bad, but the longer I rode it I could tell it was to big. It was in the tt length where I was feeling the differences, not height.

I've been an advocate of 650's on smaller frames for years and this just proves to me what I thought all along. The difference is in the fit of the frame, not the size of the wheels.

When I build my custom bike there is no question which I'll chose the 650's. Fortunately, the LBS's I've talked to agree with me.

So what I'm saying to those who worry about the size of the wheels don't. Take wheel size out of the equation and focus on the fit and feel of the frame.

Kathi

lovemyswift

I know the frame is too big for me! I was only trying it to evaluate the frame (CF/Ti combo). The frame could have had 650c wheels and it would have still been to big for me.

It's how well the frame fits that determines how the bike feels not the size of the wheels. The standover was a little high but the tt length was 2cm to long and that's where I felt the difference, not in the height of the bike. That's why I'm saying that in feel there is no difference in the 2 wheel sized but its the fit of the frame that matters.

Kathi

lovemyswift

Hmmm, lots of my rides are 50+, I've done centuries, tours, lots of hill climbing, etc on 650's. Getting tired after a certain number of miles is due to fitness level, saddle, bike fit, etc., not the size of the wheel. Sometimes I feel better at 80 miles than I did at twenty. I did 4 tours last summer, most of the mileage was 50 - 70 miles a day. One tour in Maine crossed the Appalacian mtn range 4 x's in one day. Sure I was tired but so was everyone else.

As far as wearing out tires faster, maybe, but at my weight 100# it doesn't make much difference. I get over 3,000 miles out of my tires.

I do notice some difference with different wheelsets. I got American Classic Sprint 350's last year and I like them a lot better than the Mavic Open Pros.

Serpico

swift,

you should post this at that other forum

they would eat it up, a few of the guys there are really pushing the 650b 'renaissance' that is going on right now with classic/french-style bikes (rivendell, heron, tournesol, jitensha, etc)

good post, always like to see myths debunked by someone that actually has experience (ie actually rides 650's) with the equipment being discussed--too many of the people that talk about 650 pros/cons have never even ridden them

chet0213

Can anyone explain why Bianchis via niore has 650cc tires on a 55 frame? I noticed that all the other bikes I have been looking to purchase have 700cc. As a rider 6'1" 190lbs. I wonder why they would put me on a bike with 650's. The bike is comfortable and I have seen no difference in the lemond that I test rode

CAAD5AL

I'm just a believer that bikes for smaller people should be scaled down in every possible dimension. I've never talked to anyone at or under 5' or so who missed their 700Cs once they made the change. Who am I to second guess them and tell them they're wrong?