By Seb Kemp
Photos and Video by Mike Gamble
It’s a bewildering time, what with so many different wheel sizes to choose from. They all offer advantages and disadvantages, and yet there is no clear winner.
That is, until you use science.
To try and unravel the confusion we sent our trail correspondent, Everett Burl-Sap to scientifically test 26-inch and 650b wheels against one another using the Banshee Spitfire as the test rig – a 140-millimeter travel mountain bike that features interchangeable dropouts that can accommodate both 26″ and 650b wheels. This test practically dripped with science!
We timed our test pilot on three sections of trail, then changed the wheels and did it all over again. We used identical wheels and tires, as well as wheel-size specific forks. This is the closest we think you can come to doing empirical testing of mountain bikes; all the opinions that are floating around out there about 650b are just nonsense without facts to back it up…
Of course, we still had one problem: we still had to use a human test pilot for the test and in doing so we could never eradicate errors, inaccuracy and just silliness, as the video demonstrates.
The Banshee Spitfire was the first trail bike that had really exciting geometry. Bike tested it within the 2010 Bible Of Bike Tests and came away absolutely besotted with its slack and low geometry, which made reformed downhill riders feel like they had found a trail bike that matched their attitude.
However, the original version was a little sloppy and flexy. Which is why some members of Bike are really excited to see that Banshee has revised the Spitfire for 2013, but retained the very aggressive character they fell in love with.
• 140-millimeter travel. Rear travel has been slightly increased due to customer demand. The bike can accommodate up to a 160mm-travel fork.
• 66-67 degree head angle and 13.25-13.7-inch BB adjustment through a three-stage chip system in the dropouts.
• KS Suspension is more reliable and stiffer than prior design. Shorter links mean increased stiffness and, according to Banshee, plusher suspension.
• Interchangeable dropouts – 135, 142, 150-millimeter, plus 26-inch and 650b options.
• Available in red, black and raw finishes.
• $1,999 (with Fox CTD +$200 for Cane Creek DBAir
What Banshee has now is a 140-millimeter travel mountain bike that (thanks to those interchangeable dropouts) can accommodate both 26er and 650b wheels. Sure, if your current 26er has generous rear tire clearance, you might be able to swap the wheels and fork out for 650b versions, but doing so has a tendency to addle the geometry. According to Banshee, the interchangeable dropouts allow you to choose the size of wheel that suits you without banjaxing your geometry and suspension tune.
But let's not overshadow the bike itself with all this talk of wheel sizes because the Spitfire really is a great trail bike, no matter what size of wheel you bolt onto the thing. The Spitfire is poised for action and, thanks to its relaxed and confident geometry, perfectly suited to wringing the most fun possible out of the most technical sections of trail. Thankfully, the Spitfire feels much stiffer than previous iterations and the reduced flex bodes well for the bike's potential reliability. Longer-term test to come, we hope.
-A downhiller's trail bike
-Adjustable geometry and wheel size
-No bottle cage mounts
-It's not in exotic carpet-fiber flavor, so it might lose points to similar bikes in this category
STAGE 1 was a smooth, climbing trail with a 5-percent grade. There are a few rocks and steps, but not much. This kind of trail promotes a steady tempo, or in the case of this test, going as hard as you possibly can. There was a huge difference between the two wheel sizes, with the 650b being 50 seconds slower. Why? Well, it was the second lap so fatigue might have been introduced into the equation. Or perhaps it was that the heavier wheels slowed the rider down.
RESULT: Strongly leaning towards 26-inch iteration, but it is inconclusive. Our tester (er, me) might have just been knackered by the time we slapped on the 650b parts.
STAGE 2 was a fast-flowing section of trail where some erosion had created steps in the trail, followed by several tighter turns. The times were almost exactly the same. However, on the stepped section I felt a little more stable on the 650b wheels, leading me to think I was going a little faster.
RESULT: Dead heat on the clock, but 650b felt faster and more stable, giving a feeling of confidence and perhaps, over a longer distance, less fatigue. This was the only area I felt any difference between 26-inch and 650b wheels. Or was it that the suspension tune on the Spitfire is suited to 650b wheels?
STAGE 3 was a steep, rocky, jagged hell of a trail. Greasy rock slabs lead into tight turns and curbstone rock gardens. This time there was a time difference of five seconds in favor of the 650b wheels. However, I rode the 650b wheels on the second lap, meaning that I could have got used to the damp conditions or become familiar with the better line choices on the downhill. I felt no difference between the wheels.
RESULT: Five seconds over an eighty second section of trail is considerable, but was it the wheels that gave this advantage or was it just knowledge and confidence gained from giving this technical stage a second pass?
On a purely qualitative basis the advantage of 650b wheels is negligible . Unlike 29ers, where there is a huge difference in ride characteristic, feel and performance, 650b offers little obvious advantage on the trail. If there is no difference in ride quality, then perhaps the advantage would be just in how fast the wheels rolled on the trail, which is why I wanted to time test 650b versus 26er.
The findings, however, seem to suggest that 650b isn't such a big advantage after all, and possibly more of a hindrance (heavier wheels). We will be seeing lots of racers using 650b wheels in 2013 because their testing has shown some advantages over 26-inch wheels. Their testing might have being far more scientific or perhaps it is only racers that need to find all the minor advantages when racing against the clock.
There are two major things to consider before anyone makes any grand statements about either the brilliance or crappiness of 650b. Firstly, I've always suspected that if the advantage of 650b is purely quantitative, then it really isn't much of an advantage to the majority of riders. Or to put it this way: if you need to get out a stop watch to tell the difference between the two wheel sizes, 650b probably isn't an upgrade that is going to blow your mind.
Most riders don't race and aren't looking for advantages to make them faster. Most riders want to feel like better riders and to improve the trail experience. Secondly, our test wasn't scientific enough to really pull apart this thorny issue. The whole wheel size 'debate' or 'argument' is starting to get a little boring, and more often than not is fueled by riders' feelings, rather than firsthand experience on the trail.
Puppets and talking dogs might be utterly ludicrous, but what is truly ridiculous is that so many people have formed strong opinions—for and against 650b—without having actually ridden the wheels.