What the Wheel Size

June 16 — 2020

An unprejudiced look at the various wheel sizes and why it doesn’t pay to play favorites.

A popular mountain biker trope is “to pick a wheel size and be a dick about it.” That means to choose a side and furiously argue for its superiority over all other options. 

There’s a bunch of things that you could accuse Santa Cruz of many things but being partisan about wheel size isn’t one. We’re open to all wheel sizes, which is why we offer bikes in nearly all travel and wheel size configurations. There’s an enormous overlap in our offerings – for example, do you want the Bronson with 27.5-inch wheels or the Hightower with 29-inch wheels, both bikes having nearly identical amounts of travel (the former has 150mm and the latter has 146mm)? 

The reason for this is because we don’t believe in a universal, absolutist approach to bikes. We don’t think there’s one best travel figure, one ideal geometry set and the perfect wheel size. Instead we build bikes, a lot of different bikes, so that an individual can find their match made in hero dirt heaven. Every rider is slightly different, from their physical attributes to the style of riding they prefer, so we make bikes with different characters to match different people. 

How does wheel size fit into this mythical decision making matrix? Well, every wheel size has its merits, it’s own characteristics, and depending on who you are and what you want to get from your riding there’s likely going to be a wheel size that most suits you. 

27.5" - The fun-sized wheel size

27.5 is the most versatile of wheels. It’s great for all disciplines, except maybe XC racing where you want the most efficient wheel for transferring watts to forward trajectory. It’s also suitable for riders of all sizes, but especially if you’re on the shorter side then this wheel size might give you some more real estate to play with (extra butt clearance when negotiating steep trails or for bikes with a lot of travel). 

27.5 has been around for a very long-time, but only really found its footing in mainstream mountain bike setups around 2013 when it eclipsed 26-inch as the ‘standard’ mountain bike wheel size. Before that, the choice had been the smallest of wheels (26-inch) and the largest (29-inch) but 27.5 was seen as the Goldilocks option because it decreased the roll-over resistance (something 29-inch wheelers were celebrating) but kept the nippy, lithe handling characteristics of the smaller wheels. 

In terms of ride characteristics, it’s best for riders who enjoy the most agile wheel configuration possible, those riders who seek out the playful lines on the trails, who like getting airborne and who are looking for the most responsive, quick handling kind of bike. 

So if you’re looking for a wheel size that is easy to get to grips with, if your trails are very tight, if you like to pop and play or if you’re on the short side then 27.5 might very well be the one.

29" - Fast and smooth

29-inch is the biggest wheel size, with the largest range of benefits and with it a sizable number of unique traits that will make or break your heart. 

When they were first introduced few people believed 29-inch was appropriate for mountain biking but that’s partly because the bikes they were mounted to weren’t quite finished. If people complained about more flex (from longer chainstays, forks or spokes) or an unwieldy feeling that made it hard to make the bike turn on tighter terrain then it was likely because the geometry, frame and chassis of the time weren’t optimized. Even our founder Rob Roskopp once said we’d never make a 29-inch bike, but then in 2009 we released the Tallboy and many people had to reevaluate their previous experiences. 

You see, 29-inch wheels are surprisingly maneuverable when paired to the right geometry and chassis. It was clear larger wheels would provide monster trucking ability to roll over more trail debris with less effort, but what wasn’t obvious at first was that changing fork offset, bottom bracket drop, and any number of other geometry numbers could actually allow big wheels to feel not just fast in a straight line but able to carve lines down any shape of trail. 

The reduced rolling resistance and larger footprint of 29-inch wheels does inspire confidence and helps riders cover ground efficiently. So for people looking to maximize their speed for chasing podiums or bragging rights, 29-inch is the obvious choice. But also for relatively novice riders who want more trust when terrain is unpredictable 29-inch is a fantastic choice because it can provide a more stable base of support. 

Mixed wheels - a mix of both worlds

A third configuration, and a relatively new option, is mixed wheel (also known as ‘mullet’). This is when a 29-inch wheel is used for the front wheel and a 27.5-inch is used on the rear. The leading 29-inch wheel creates a large contact patch that generates a lot of traction and lowers the rollover resistance. While the smaller diameter rear wheel gives more butt clearance (a factor for some shorter limbed riders) and creates a quicker handling bike. The result is a bike that still feels composed like a 29er but requires less input energy to lean the bike over or place the rear wheel where necessary. 

One thing that’s overlooked in all this wheel size debate is the axle height, both wheel axle and BB axle. 29-inch wheels, if paired with a frame with good BB drop, can feel very stable because the rider feels ‘between the wheels’. However the mixed wheel setup means that the reduced BB drop (BB to rear axle) at the rear allows the rider to pivot over the rear wheel and unweight the front end more easily, which might aid getting over obstacles at short notice (lifting over roots or manualing, for example). 

Mixed wheel has been something our downhill racers on the Syndicate experimented with and found to be beneficial. Loris Vergier found it to be a good balance of traction and agility that he was looking for, as well as giving him more butt clearance when the V10s large wheels and lots of travel came into play. Greg Minnaar, however, is sticking with the larger wheels because he wants absolute speed and felt no hindrance of having 29-inch wheels. This goes to show how individualistic wheel size is as a choice and how particular some riders can be. 

One note about mixed wheel setups is that we’ve found that “bodging it” by putting a wheel into a frame designed for a different wheel doesn’t work too well most of the time. As we said earlier, wheel diameter is just one variable and how the wheel size is integrated into the geometry is vitality important. Not just for frame clearances but for creating the right dynamics. A very small difference in any of the geo can have a big effect, so putting a smaller (or larger) wheel in your frame will change the geo a lot, and that changes the character of the bike. 

The wheel answer you’re looking for…

Reserve wheels offer options for all size and specifications. Go check out the full range of wheels on our Reserve Wheels page.

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