Wheel sizes

[EGHama]

I know this has probably been discussed ad nauseam, but being a total newb to both this site and touring, I plead ignorance and beg forgiveness.  Can someone explain the pros and cons of the different wheel sizes, i.e. 26" vs. 29" vs. 700cc.  I'm sure each is better for specified uses, but what are those specific uses?  I'm in the very early stages of bike shopping, with the thought of doing a long road tour in a year or two.  Thanks for the help.

[John Nelson]

I just picked up the sample issue of ACA's "Adventure Cyclist" magazine at REI last night. It has an article entitled "Wheel Size Matters." They concluded that 700C wheels are best for narrow tires up to about 30 mm, and the smaller 650B wheels are better for wider tires, 30 to 42 mm. There is a lot more interesting information about wheel sizes in the article, so you might see if you can find a copy.

[DaveB]

First, 29" and 700c are the same diameter rims (ISO 622) and take the same bead seat diameter tires.  The differences are that 700c rims are usually narrower and suited for smaller width road tires up to say 700-32 or so.  29" rims are usually wider and intended for MTB use with much fatter tires, 1.5"(700-38 mm) and above.  However, there is a fair bit of overlap and reasonably wide tires can be fitted to 700c rims and reasonably narrow tires to 29" wheels.

MTB-type 26" wheels (ISO 559) used to be the universal size on mountain bikes and were generally wide enough to take wide tires.  Some smaller frame touring bikes came with this size wheels and somewhat narrower tires to suit shorter rides as they make the bike lower. 

There are a bunch of different bike rims all called "26" and none of them are interchangeable but the ISO 559 is by far the most common these days.

[Pat Lamb]

I just picked up the sample issue of ACA's "Adventure Cyclist" magazine at REI last night. It has an article entitled "Wheel Size Matters." They concluded that 700C wheels are best for narrow tires up to about 30 mm, and the smaller 650B wheels are better for wider tires, 30 to 42 mm.

Would that article have been written by Jan Heine, aka the lead advocate for 650B?  Either way, I'd view that recommendation with suspicion.  I've seen a total of two 650B bikes.  They're not common.  Tires for them are even less common -- I've only ever seen them available through the web / mail order.  I'm leading up to this: if you're going to ride 650B, take a spare tire, or, if/when you have a problem, be prepared to wait (over a long holiday weekend?) for a replacement to get to you.

700C wheels and tires are everywhere.  So are 26".  You can get 700C tires from ultra-skinny to way wide; 26" you can get only from pretty skinny to pretty wide.  If something goes wrong on the road, you can replace either at the next bike shop.  Maybe not with your preferred width or tread, but if something happens you can get back on the road.  There's a lot to be said for standard parts, and 650B is anything but standard.

[Cyclesafe]

OP, there is very little functional difference between 26" and 700c (AKA 29"), despite confusing and contradictory bicycle industry propaganda.  Of more import is the width of the rims and the availability of parts (tubes, rims, tires).

The rougher and slicker the surface, the more one wants wide rims for wide tires.  This meaningfully favors 26" as appropriate parts for these conditions are more widely available than for 29"/700c.

However, if one plans to only be on smooth certain surfaces, one wants narrowish rims for narrowish tires.  This more meaningfully favors 700c as parts appropriate for these conditions are much more widely available than for 26".

Most would agree with the above when the following caveat is added:

If for overall bike fit, one needs long crank arms and rides on rough and slick surfaces, a 29" (wide rimmed 700c in marketing parlance) wheel will afford more pedal clearance with the ground, partially negating the inferior availability issue.  Also, for any rider, pannier clearance with the ground will be a little better with 29"/700c.     

For example, my hard tail "tourer" has been described as the largest mountain bike anyone has ever seen.  I run 29'er Sun Rhyno Lite rims with 37mm tires when touring on degraded chip seal or better and 2.5" when rougher conditions are anticipated.  I'd hesitate to run narrower tires on this rim.   

[DaveB]

Would that article have been written by Jan Heine, aka the lead advocate for 650B?  Either way, I'd view that recommendation with suspicion.  I've seen a total of two 650B bikes.  They're not common.  Tires for them are even less common -- I've only ever seen them available through the web / mail order.  I'm leading up to this: if you're going to ride 650B, take a spare tire, or, if/when you have a problem, be prepared to wait (over a long holiday weekend?) for a replacement to get to you.

I remember when Sheldon Brown first advocated for 650B wheels/tires and I don't know if he or Jan Heine had priority.  That said, they are beginning to catch on in the MTB world where they are called 27.5" and are getting increasingly common.  Most of the major bike and tire manufacturers now have that size wheels/tires in their MTB product line.   AFAIK, no road or touring bike has adopted them so far.

[John Nelson]

Would that article have been written by Jan Heine, aka the lead advocate for 650B?

Yes.

[EGHama]

Thanks all, for the education. There is just so much to learn and consider when making this purchase.

[DaveB]

OP, there is very little functional difference between 26" (AKA 650b) and 700c (AKA 29"), despite confusing and contradictory bicycle industry propaganda.  Of more import is the width of the rims and the availability of parts (tubes, rims, tires).

This is incorrect.  650B wheels are not 26" wheels in today's lexicon.  26" wheels are ISO 559 and take 26" MTB tires.  650B is 27.5" in today's terminology and they are by no means the same. 

[Cyclesafe]

OP, there is very little functional difference between 26" (AKA 650b) and 700c (AKA 29"), despite confusing and contradictory bicycle industry propaganda.  Of more import is the width of the rims and the availability of parts (tubes, rims, tires).

This is incorrect.  650B wheels are not 26" wheels in today's lexicon.  26" wheels are ISO 559 and take 26" MTB tires.  650B is 27.5" in today's terminology and they are by no means the same.

Yes, thank you for correcting me.  A brain fart, I guess.  Sorry.  Edited my post above......

26" is ISO 559.
650B is 27.5" and ISO 584.
700c is 29" and ISO 622.

[mbattisti]

I believe given 2 wheels built with similar quality components and width of hub, a 26" wheel would be stronger than a 700 due to the geometry of the spokes in relation to the hub flanges (when viewed crossways the triangle created is shorter therefore stouter)

[Cyclesafe]

I believe given 2 wheels built with similar quality components and width of hub, a 26" wheel would be stronger than a 700 due to the geometry of the spokes in relation to the hub flanges (when viewed crossways the triangle created is shorter therefore stouter)

True.

[zerodish]

Mountain bike wheels are stronger. 700C wheels are faster I calcuated a .25 to .5 mph gain in speed at 10mph using formulas in bicycles and tricycles by Sharp. Mountain bicycle and 700c tires are available at walmart in the United States and Mexico. 650B tires are rare in the United States and they will be fat tires only. 650B tires can be bought in 35 to 42mm widths at bicycle shops in Canada England and France.

[TwoWheeledExplorer]

A couple of years ago, every MTB magazine was shouting from the rooftops that 26 was dead, get your 29ers now! Now in their market-driven madness they are the biggest advocates of the 27.5/650B. Even so, some of the big names, like Giant, are pushing the 650B as their primary entry. Will the 29er go the way of the 26? I hope to heck not, because I looked at a lot of different 29ers , including the Salsa Fargo and Co-Motion Divide before I bought my Volcanic Vx7. I like it. That's my story and I'm sticking to it.

[DaveB]

. Will the 29er go the way of the 26? I hope to heck not, because I looked at a lot of different 29ers , including the Salsa Fargo and Co-Motion Divide before I bought my Volcanic Vx7. I like it. That's my story and I'm sticking to it.

No, 29 won't go away as there is still a lot of new stuff being introduced for it.  The real marketing ideal is you will buy all three MTB's sizes; 26, 27.5 and a 29.