One of my big cycling goals for this summer was to spend more time with my wheels on dirt. With that in mind, I decided the time had come to upgrade my 11-year-old downhill bike.
One of the big choices I had to make was something I hadn’t had to think about during previous bike purchases: What is the ideal wheel size?
Those who regularly ride off-road will be familiar with the increased range of wheel size options that have become available in recent years. Traditionally, mountain bikes came with 26-inch wheels. Then about five years ago, bikes with behemoth 29-inch wheels started to appear on the market and these were followed by 27.5-inch (or what some call a 650b) mountain bikes, which attempted to find the ideal middle ground between the existing sizes.
(The inches measure the diameter of the rim and the tire goes around the outermost edge. Tires can also be specialized, depending on the terrain you’ll ride most.)
So what is in a wheel size? Why would you opt forĚý 29 inches over 26? These are the key points to think about:
26er advantages
- Smaller wheels and a smaller fork add up to a lighter bike, which is less weight to push uphill.
- Smaller wheels are more manoeuvrable, which can be a big asset on technical terrain where you need to react quickly.
- 26ers accelerate rapidly from a standing start.
26er disadvantages
- A smaller contact patch with the ground means less traction.
- They’re not as forgiving as bigger wheels when going over obstacles.
- They’re as efficient as 29ers on climbs
29er advantages
- A larger contact patch with the ground means significantly increased traction.
- Larger wheels have a greater ability to roll over obstacles, making them feel far more forgiving. A more forgiving ride means less suspension is needed, increasing the overall efficiency of the bike. This results in less energy lost in “pedal bob” as the suspension moves.
- 29er disadvantages
- A large wheelbase means that these bikes can feel too big for smaller riders.
- Big wheels are not as manoeuvrable in tight and technical terrain.
- They are heavier and slower to accelerate than 26ers.
Sitting in between the 27.5ers:
- Higher top-end speed than 26ers and faster off the line than a 29er.
- More forgiving than a 26er; more manoeuvrable than a 29er.
- Good for smaller riders who want some of the advantages of a 29er without the full increase in wheelbase and stand-over height.
After much thought, I opted to take the plunge and go for a 29er since I spend a lot of time on the longer cross-country style trail rides to which these bikes are suited.
The more I’ve gotten to know the bike, the happier I’ve been with this choice. It’s noticeably more efficient on the climbs, but the improved traction and rollover capacity have also increased my confidence descending, cornering and getting over small obstacles. It’s definitely a less agile bike than my former 26er, but I’ve only really noticed this on very tight switchbacks and corners.
I was curious to see if I would run into difficulties as a smaller rider making the transition to a 29er, but this hasn’t been an issue. Although the big wheels make the bike look huge for me, even with a small frame, it doesn’t feel that way when I’m on it. In fact, the additional size translates to a feeling of extra stability.
For anyone new to trail riding who isn’t planning to focus purely on the downhill trails, I would definitely encourage you to give a 29er a try. I, for one, am a convert.
Kay Cahill is a cyclist and librarian who believes bikes are for life, not just for commuting.
Ěý
