lungimsam

Now 700c, 26", and 650b are going on.
Weren't the 27.5's good enough? I think they are pretty and just the right size. Don't see a reason for 700c.
Why'd they 27.5's drop off?

Shimagnolo

27.5???
You mean 650b?
https://bicycling.com/blogs/thestraightdirt/tag/27-5/

Jeff Wills

What's a 27.5?

In the U.S., 27" wheels and tires were very common through the end of the '70's. Then "racier" bikes started coming with 700C wheels and tires since they were interchangeable with tubulars. If you had a fast bike, you had a set of 700C clinchers for training and a set of tubulars for race day. So tire companies kept making the better tires in 700C (mostly), until by the end of the '80's "good" tires were 700C and you couldn't get a decent 27" tire to save your life.

If you want to get confused, grab a 29" mountain bike tire. It fits on the same rim as a 700C road tire.

FrenchFit 

If you mean 27" inch rims, I commute on them and they also live on another favorite bike. Lots of tire choices these days.

lungimsam

Oops...sorry, I guess i meant 27".
I guess racing influences alot of bike development.

Trakhak

700c was around long before 27". As I recall, although the size standard was quickly adopted by other bike makers, 27" wheels and tires represented the last of the proprietary sizes introduced by a single bike manufacturer---Raleigh, I think, probably in the late 1940s. Schwinn was big on Schwinn-only sizes, too.

For more wheel size confusion, try installing a 24 x 1 3/4 tire on a 24 x 1.75 rim. Completely incompatible. 24 x 1 3/4 is a Schwinn-only size.

RoadTire 

Huh? Now I'm even more confused. Then I followed Shims' link and got this:

"The term “650b” is an established standard going back decades, and 27.5-inch, while descriptive and fitting within the 26-inch and 29er naming convention, is sort of a made-up standard....In this crazy mix up of standards...26, 27.5, 29—these are all the same unit of measure. ( https://bicycling.com/blogs/thestraightdirt/tag/27-5/ ) "

Yet my 27 in wheels from '75 (convert=685.8 mm,) yet are larger dia than 700c wheels. (That's why converting from 27 in to 700c requires 4 mm longer brake thingies to reach the rim)

Sixty Fiver

700c is a French designation for a rim with a bead seat of 622mm... almost all tubular racing wheels come in this size although you can also find 650C tubulars for smaller wheels on smaller bicycles or time trial bikes where the front wheel is smaller.

The 700c was the standard racing / road rim in Europe.

Schwinn used 27 inch wheels on all but their top of the line racing bicycles which were fitted with 700c, and Raleigh used the 26 by 1 1/4 EA1 (597mm) predominantly until 1955 and then fitted all but their top of the line machines with 27 inch wheels which was a widely used standard. Raleigh's use of 27 inch wheels started earlier but examples of Raleighs with 27 inch wheels in the late 40's and early 50's are much less common.

Sixty Fiver

650b (584mm) is another European / French standard that was not widely seen in North America in past days that is now enjoying a new popularity... this size of tyre was most commonly fitted to French city and touring bicycles as the higher volume tyre offered a plusher ride and better flat resistance than a 700c road tyre.

The modern 26 inch mountain bike tyre came from Schwinn who used the 559 rim on their fat tired cruisers which were the preferred choice for early mountain bikers.

Sixty Fiver

And these are 26 inch / 559 rims... the outer diameter of the tyre is 29 inches.

krome

What happened to 27.5? I dunno, but it makes me appreciate the metric system that much more. I can't stand this 29er, 27.5er, etc. Give me the BSD in metric units please. That and the width, again, in metric units.

puchfinnland

must be a huge energy loss on those big fatboys!

YoKev

I've ridden a Pugsly on tight twisty single track on two occassions. Fun fun fun bike, and not nearly as much energy loss as you'd think.

jkimballcook

Sheldon has a really good page on tire sizes that explains all this.

Bikedued

700 was around before 27". First time I ever heard that before? Please elaborate?,,,,BD

rootboy 

Oops. Someone put motorcycle tires on their bicycle.

ericbaker

and what about continental, those dopey germans like to call their 700c tires 28"

krome

Except those Schwinns that have 571 rims (another 26" fractional size in the US).

Sixty Fiver

The 28 inch measurement stems from the old system of measuring the inflated tyres diameter... higher volume 700c tyres are 28 inches.

The Canadian 28 inch tyre was also a high volume tyre mounted on a 622 rim... the English 28 inch tyre is mounted on a 635mm rim and has a shallower depth so both are nearly equal in diameter.

Sixty Fiver

Those are among the hardest to find rims and tyres there are... they are like a number of other rim and tyre combinations that are obsolete like the French 500a.

The French system originally used the letter to denote width with A being narrow and B, C, and D being wider tyres but now every 622 rim is called a 700c when this was originally a higher volume tyre.

Sixty Fiver

700c / 622 rims have been around for at least 80 years... have handled enough old CCM bicycles from the 30's to know this.

The 27 inch rim came later.

Sixty Fiver

One would be amazed to find that when you have a tyre that is marked 26 by 4.0 and has an effective width of 3.7 inches mounted on an extremely wide rim that the rolling resistance extremely low... the bike is designed to traverse mud, sand, and snow and will float across surfaces other bikes will get bogged down in and climbs loose surfaces extremely well due to it's excellent traction.

Each wheel weighs 8 pounds... the tyre and tube weighs less than 2 pounds while the extra wide rims with an SS cog weighs 6 pounds each.

sauze

I want to go to there... Such a cool bike.

dddd

27.5 refers to a mountain bike-width tire mounted on a 650b rim.

With the wider tire, the outer diameter climbs from "26 inch" to "27.5 inch", for tires listed as 1.5" and 2.0" wide, respectively.

Not sure how accurate or universally consistent those quoted dimensions really are. The bigger tire also has tall knobs which add to it's height.