Gears & Gadgets:  Does (Wheel) Size Matter?

By David Cohen, Maryland National Capital Park Police Reserve Unit

One of the frequent topics of discussion when it comes to bicycles is the choice of the most ideal wheel size.   At the dawn of the mountain bike era, there was no choice.  You could get a mountain bike in all kinds of shapes and sizes, but they all had one thing in common:  the 26-inch wheel.  In the beginning of the 21st Century, a new competitor came onto the scene – the 29er.  It certainly had its advantages, but there were also some drawbacks.  A few years after that, a third choice emerged:  the 27.5 wheel. 

If you’re looking to acquire more bicycles for your department fleet, or perhaps want to purchase a new bike for yourself personally, the variety of wheel size choices can be simultaneously exciting and daunting.

26-Inch Wheel

In the beginning, there was the 26-inch wheel.  There was no specific rhyme or reason to it, other than it was a fairly common wheel size used on the early “Breezers” that the mountain bike pioneers were riding in the 1970s.  With a narrower diameter and a lower center of gravity, it offered a slight advantage over the 27-inch wheel that was fairly commonplace on adult 10-speeds at that time.  For mountain biking applications, the lower center of gravity was certainly welcome.  The size also allowed manufacturers to build compact bicycles that were very agile on twisty trails.  When you observe the evolution of mountain bikes from the 1990s through the first decade of the 2000s, you can see how much freedom the 26er allowed.  The 26-inch mountain bike seemed to be like a good Swiss army knife.  It wasn’t until a viable alternative emerged onto the scene that riders began to understand the shortcomings of the 26 inch wheel.

29-Inch Wheel

The 29-inch wheel, dubbed the 29er, starting making its appearance in mid-2000s.  An important selling point was that it was based on the same 700c design which had pretty much become the international standard for road bicycles.  The concept was simple – a larger wheel would be able to roll over larger obstacles with less resistance.  It would also, in effect, give a rider taller gearing for the same number of revolutions, which gave the 29er advantages both at its very low and very top ends.  Larger tires could hold a greater volume of air at the same psi, reducing pinch flats.  Compared to the 26-inch wheel, riding a 29er is like riding in a monster truck.  It worked as advertised; it definitely could clear obstacles that would catch a 26-inch wheel. 

The initial problem with the 29er was that the bike manufacturers had not yet figured out the geometry.  Many of the early 29ers were somewhat clumsy in their handling compared to the 26 inch bikes.  Eventually, the bike manufacturers figured it out, but compared to a 26er, the clearances, particularly for the rear wheel, are much tighter.  The 29-inch wheel has a higher center of gravity and can be more “flexy” because of the longer spokes.  

27.5 Inch Wheel

In response to the shortcomings of the 29-inch wheel, the 27.5-inch wheel (650B) began to emerge.  It actually was not a new wheel size; European bikes had this wheel size dating back to just after World War II, when it was adopted by French bicycle builders, and it saw fairly widespread use in Europe in the 1950s.  It never quite completely faded away, and some early mountain bike designs utilized this wheel size

What warranted the second look at the 27.5 was that it was the literal midpoint between the 26-inch and 29-inch wheels.  It was, in effect, the “best of both worlds” – able to roll over obstacles more easily than a 26er and more maneuverable than a 29er.  

26, 27.5, or 29?

As I’ve mentioned in previous G&G columns, while the mountain bike and the public safety bike have a common ancestry, the directions of their development have been diverging over the course of the last decade.  Developments in the mountain bike world do not necessarily translate into more effective public safety bikes. 

The advantage of the 26-inch wheel is primarily an economic one.  If you have a fairly large fleet of older bikes that are equipped with 26-inch wheels, it would make sense to keep the fleet consistent rather than have to stock multiple sizes of tubes and tires.  There’s also the ability to swap wheels and/or tires from out-of-service bikes to keep another bike in service.  But keep in mind that at some point in the near future, the 26-inch wheel public safety bikes will likely disappear as most bicycle manufacturers have all but abandoned the 26-inch wheel bicycle, except for their entry-level offerings.   

The 27.5 inch wheel certainly does have an advantage over the 26-inch wheel in terms of rolling over obstacles.  It also tends to work better for bicycles ridden by personnel who are shorter than 5’ 6”.   Several electric bike manufacturers have picked the 27.5 tire size to keep the center of gravity lower, but the subject of electric bikes is a completely different matter.   My opinion on the 27.5 is that unless you have personnel who are smaller in stature, or your patrol area includes significant amounts of off-road riding, the 29er is the better pick.  The 27.5 does make for a very fun bike to ride in off-road situations, but the vast majority of public safety cycling does not take place in an environment which maximizes the advantages offered by the 27.5-inch wheel.

That brings us to the big wheels – the 29ers.  There is no doubt that I am a huge fan of the 29-inch wheel for public safety applications.  Moreover, my off-duty mountain bike of choice is a 29er.  Given that that a majority of public safety bicycles are operated in urban or suburban environments where obstacles like curbs and stairs are far more common than twisty, wooded singletrack, I would want a bike equipped for that environment, and that means big wheels.       

There you have it.  Size does matter.  It comes down to a matter of preference and the cycling environment.  The do have one thing in common:  regardless of which size wheel you choose for your public safety cycling needs, you need to keep the rubber side down!  Until the next column, stay safe! 

Gears & Gadgets is a blog written by David Cohen #1116.  It features various repair tips and tricks that David has picked up in nearly 25 years of cycling, including 12 years of public safety cycling.  Gears & Gadgets will also periodically review some of the latest “gadget” items of potential interest to public safety cyclists.   The advice and opinions in this column are solely the author’s and should not be interpreted as IPMBA mandates or recommendations unless explicitly stated. 

About the author:  David Cohen is a 12 year volunteer with the Maryland-National Capital Park Police.  When he isn’t riding or tinkering with bicycles, David can be found tinkering with vintage cars or World War II airplanes.  An avid historian, David enjoys researching and writing as well.   He can be reached at onyxsax@aol.com.

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