Category Archives: 36er

Is bigger better? 29er vs 26er and wide vs skinny tyres

Are bigger wheels and tyres better? In this post I’ll share some thoughts and experiences of testing different wheel sizes and different tyre sizes.

I’m at least a decade late to the wheel size wars, but I wanted to test for myself whether the recent bandwagons of larger wheels and fatter tyres are the real deal or just industry hype designed to sell more bikes.

I’ve tested four different set ups:

  1. A 90s Raleigh Dynatech MT4 with a Girvin Flexstem and rigid fork and 26×1.8 Panaracer XC Fire tyres (~23 lb)
  2. The above bike with 2.35 Maxxis Larsen TT rear and 2.35 Maxxis Ignitor front (~24 lb)
  3. A 2017 KTM Aera Pro carbon 29er hardtail, with 2.4 Schwalbe Rocket Rons, and 2×11 Deore gearing (~25 lb)
  4. A rigid steel Salsa El Mariachi with 29×2.35 Maxxis Ikon rear and 29×3.0 Maxxis Chronicle up front (~28 lb)

The test course consisted of a ~10 km off-road loop with ~200 m of ascent, broken into 4 individual climbs, some flatter sections and some downhills. Being Portugal, the conditions were bone dry with a mixture of weathered bedrock, a kind of gravel made of fist-sized stones, and dusty hard-pack. Basically, these are fire roads but built without bothering to condition the surface for vehicles.

The climbs are somewhat technical in places to due rocks, and their average gradients range from 6% to 13%, and the downhill sections are similar in character.

Before discussing the results — a word about the wheel sizes. Set up #1 (26×1.8) used the smallest wheels, with the 26×1.8 tyres resulting in an outside diameter of just 25.6 inches. In setup #2, the 26×2.35 tyres gave a diameter of 26.7 inches, more than a whole inch larger. To put this into context, the difference between 26×2.1 (22.2 inches) and 650b x 2.1 (27.2) is slightly less than 1 inch. This means that, in effect, my comparison between #1 and #2 is also a test of whether the size difference between 650b and 26 results in a noticeable difference in speed, even if it isn’t actually a test of 650b itself.

Setup #3 is fairly standard in that it used 29×2.4 (29.3 inches) on both wheels, and setup #4 used an unorthodox combination of 29*2.35 on the rear and a 29*3.0 on the front. The 29+ front wheel has an outside diameter of 30.5 inches, which is 1.2 inches larger than the other 29er wheels used in this test.

The results are very straight-forward: the bigger the wheels, the faster I climbed. My 26×1.8 setup was the slowest, but felt the fastest. Next was my 26×2.35 setup, which climbed about 10% faster. The carbon 29×2.4 hardtail was approximately another 10% faster still, and my 29×2.35 / 29×3.0 bike was 4% faster than that, but felt the slowest. All in all, the fastest setup was about 26% quicker than the slowest.

In general terms, these results aren’t too much of a surprise, as it’s been claimed (perhaps even known) for years that larger wheels are generally faster for XC type riding, even if the industry has been strangely unable (or unwilling) to prove it with transparent testing.

There were two big surprises in this data. The first surprise is that just by opting for widers tyres, I was able to get an extra 10% of climbing speed from my 26er. In the more realistic case of a 26er with 2.1 tyres, switching them to 2.35 ones should still mean a climbing speed increase of ~5%.

The second surprise is that the heaviest bike of all was the fastest climber. Naively, I expected that it’s steel frame and forks, together with its heavy 29+ front wheel, would result in a bike that’s a bit slow for a 29er, but still loads of fun. The best explanation I have is that the 30.5 diameter front wheel rolled over obstacles and bumps even better than  a “normal” 29 inch wheel – the same “science” behind 29ers being faster than 26ers, but with a bigger wheel.

Another interesting point is as far as I am aware, this is the first test to compare a 29+ front with a 29er rear against a normal 29er. Some magazines have tested proper plus bikes against “skinny XC” equivalents, usually concluding that the plus bike is fun but slower. This might be because the rear wheel suffers more rolling resistance because it’s this wheel that the riders applied torque to when they pedal, resulting in greater losses due to tyre deformation. By combining a fast rolling real wheel with a 29+ front wheel, maybe I got low rolling resistance where it counts more, and a large diameter wheel for rolling through obstacles where that counts more.

And it certainly does feel like the 29+ wheel can roll over anything in its path. In fact, during a recent marathon race I found I was able to pass riders on the climbs by taking the slightly rougher, outside line to overtake, thanks to the amazing rolling capabilities of that wheel.

On a more general note, the results show that bike weight is not such a big deal as long as you have the right technology on your bike. In the tests described here, it is clear that any time penalty from running a 29+ front wheel is outweighed by the speed increase provided by this wheel. Likewise, the extra weight of setup #3 (normal 29er) over #1 (26×1.8) is outweighed by the benefits of the 29er wheels.

Some technicalities:

I started each session well hydrated and with a good breakfast (identical on each day) 2 h behind me, and an energy bar eaten a few minutes before starting. During the climbs I maintained a 95% level of effort, determined using a heart rate monitor. I rested for 5 minutes between each climb.

When doing this kind of test it’s important to be honest and state that it’s next to impossible to run a side by side test of two different bikes or components in a completely controlled manner. Variables like the weather conditions, trail conditions, nutrition, hydration level, tiredness etc. are likely to differ between runs, and as a rule of thumb I’d say the uncertainty in speed differences are likely to be around 2% or more. It must be frustrating being a pro racer trying to figure out which tyres or bike set up makes them faster, because  even a few tenths of a per cent is enough to make the difference between winning or coming second, yet detecting a 1% difference over a test course is technically very challenging.

Nevertheless, in this case it is clear that my results are statistically meaningful, not only because the difference in times are quite large, but also because these differences were consistent across all four climbs. What’s more, my times consistently decreased each time I tried larger wheels and/or wider tyres.

36er versus 26er

This photograph nicely illustrates the difference in wheel size between 26 and 36 inch mountain bikes. In case you are unable to tell the difference, the middle one is the 26 inch MTB…

Truebike_2x10XT_16

Photo courtesy of Robert at truebikes.eu.

To find out more about the benefits of riding a 36er, check out my 36er FAQ page.

36er mountain bikes: what you need to know

Recently, I’ve found myself harbouring a growing interest in the concept of the 36 inch wheeled mountain bike. Suitable for all but the tallest riders, 36ers are still very niche and require a significant outlay to have one custom-built, yet they could very well be future for taller riders who do longer-distance cross-country riding.

Truebike_3x10XT_01

Truebike_SS_17

The bikes shown above are custom built steel 36er, from Truebike. Go and check out their webpage for prices and further details.

While I’ve been convincing myself to go ahead and get a 36er MTB built (later this year, hopefully), I’ve read up on just about every possible aspect of this type of bike. I’ve weighed up the pluses and negatives, investigated options for suspension, possible tires, frame materials, frame-builders … and so on.

This blog post is an attempt to distill all the relevant information about 36er mountain bikes into a single reference guide, which I hope can be useful for others who may also be pondering whether to try a 36er, or to raise awareness of the great possibilities of large wheeled MTBs.

What is a 36er?

A 36er is, as the name implies, a mountain bike built for 36 inch diameter wheels. This wheel size is not plucked out of thin air at random, but is chosen due to the availability of components for unicycles, which have 36-inch as one of their wheel-size standards. (32-inch is another standard size, for which the same principles discussed also apply, but which won’t be discussed here to avoid complicating things.)

For the wheels, conventional wisdom among builders of 36ers seems to be that a combo such as 36-inch, 36 hole, aluminium rims from Nimbus (the market leader in 36 inch rims), with 14 g straight spokes in a 3-cross pattern, on 29er-specific shimano hubs.

Until very recently, owners of a 36er would have been forced to make do with heavy, and not particularly grippy unicycle tires. But there are already a few MTB-specific 36er tires available now, including this tire being sold by Waltworks, which they describe thus:

Vital statistics:
Size: 36″ x 2.25″
Weight: 1625g +/-40g
Tubeless Ready: Yes
Max PSI: 65
Bead: Wire
TPI: 36
Durometer: 60 Shore A

These tires are significantly lighter (you’ll save more than a pound per tire) than the competition, which help you accelerate more quickly and reduces the weight of the wheel at the rim allowing for faster/longer rides with reduced effort.  They are tubeless ready and setup well allowing for lower pressure and more grip. Bicyclists have found 18-23psi to be a good range while unicyclists have gone a bit higher to 32-40psi.

Tread pattern lies between a Kenda Nevegal and Schwalbe Racing Ralph in terms of tread depth and design, creating good grip across a wide range of terrain and conditions while maximizing speed off-road and on.  Tapered and ramped center knobs along with ramped transition knobs provide traction and control, while tie bars connecting the triangular transition knobs to side knobs help with cornering.

That’s most probably the tire I’ll be ordering for  my 36er.

A 36er MTB is also going to need a frame and fork that can accommodate the giant wheels. At the time of writing (2015), 36ers are a niche variety or MTB that are not manufactured by any of the mass-producing bike companies. Fortunately, there are plenty of excellent custom frame-builders to choose from worldwide, working predominantly with steel tubing. Some are even able to adapt suspension and other components for use on a 36er. (At the end of this page I’ve compiled a list of frame-builders who are known to be willing to build 36er frames.)

The other components can basically just be a mix and match of regular MTB parts, depending on your own preference and budgetary constraints. In terms of gearing, a 22 tooth front chainring with a wide range rear cassette (i.e., 11-36) seems to be what many recommend (bigger wheels require lower gearing).

An overall price is hard to define, since it depends on the components and materials chosen, but somewhere in the ballpark of 1500 GBP / 2500 Euro / 3000 US Dollars should be roughly the lower limit for a compete 36er.

Who can or should ride a 36er?

The minimum height to be able to ride a 36er is probably around 5 foot 8 (173 cm). To put things into context, this would be roughly equivalent to a quite short rider on a 29er.

A rider who is 6 foot (183 cm) or taller should have no real problem with a 36er, and anybody above 6 foot 9 (206 cm) or so would probably find a 36er to be their optimal choice of mountain bike.

If in doubt, it may be best to go for a 32er MTB instead.

Summary of the positives (as I see them)

The benefits of riding a 36er ought to be, in effect, an accentuated version of the benefits that 29ers bring:

– The larger wheels give smoother ride (rolling resistance, flexibility, momentum).

– Larger tire contact patch may provide greater traction.

Such a unique bike cannot fail to be a talking point on the trails (I see this as positive, but some may disagree).

Summary of the negatives

Heavier than smaller-wheeled mountain bikes, predominantly due to the larger wheels. Expect a 36er to weigh in at around 30-35 lb (13-16 kg). This might sound like a lot of extra weight, but in mitigation one must consider that the higher body weight of the taller riders who might opt for a 36er makes the weight of the bike somewhat less important.

Their heavier wheels are harder to spin up, and are more difficult to decelerate when reducing speed.

Reduced maneouverability, and more body language required on tight turns.

High cost – the lack of mass-produced frames for 36 inch wheels means having a frame and fork custom made.

Limited choice and availability of rims, tires and spokes. In many cases, these parts are optimized for unicycle use, rather than MTB use.

Normal MTB drive train components can be used, but this may result in sub-optimal gearing.

Except perhaps for giants, even a negative rise stem may leave the handlebars significantly higher than the saddle. Higher bars may not be to the taste of traditional cross-country riders.

A list of known builders of 36er mountain bikes

This is not an exhaustive list, but the idea here is to maintain a list of frame builders who are able to build complete 36-inch wheeled mountain bikes. I’ll add to this over time as I discover more.

Dirty Sixer (USA)

Keener Cycle Works (USA)

Poetry In Motion Cycles (United Kingdom)

Waltworks Custom Bicycles (USA)

Truebikes (Slovakia)

Thomag (Switzerland, links to his youtube video)

Wheeler (Taiwan) It’s not entirely clear right now, but it seems theirs may be the first production 36er MTB to come to market. Very exciting if true!

Forget 29ers, how about a 36er!

There’s more choice than ever these days when it comes to mountain bike wheel size. The 26er, 29er, or the inbetweener 650b wheels all have their advocates, and a long list of pros and cons exists for each of them.

One of the main recognized benefits of using a larger wheel is the ability to roll over bumps or obstacles more easily, together with some increased traction which may help to offset the extra weight that a larger set of wheels and larger frame would otherwise burden you with.

But why stop at 29 inch wheels. Isn’t it time we asked ourselves (and the bike manufacturers) whether even larger wheels are even faster, and even more fun?

Luckily for a steel enthusiast like me, there are already a bunch of framebuilders who are playing around with 36 inch wheeled mountain bikes!

Yes, that’s right: thirty-six-inch wheels!! Here are two rather exquisite 36er mountain bikes, both handbuild from finest steel, by Walt of Waltworks.

waltworks36

waltworks36_2

Speaking for myself, I think they look absolutely awesome, and I hope to commission Waltworks, or a more local frame builder if I can find one willing to build such a beast.

As you can see, you’d probably need to be fairly tall to ride one of these leviathans. Being 6′ 4″ in height (193 cm), I reckon I’d manage it without looking like a circus act, and certainly no sillier than a short rider on a 29er.

I’ve already mentioned the positive aspects of riding a 36er, which are basically just a bigger helping of the advantages of 29 inch wheels. There are, however, some drawbacks (for many riders, at least):

  • A 36er will be somewhat heavy – Significantly more than 30 lbs or 14 kg. Those heavy wheels may also feel a bit sluggish when trying to accelerate.
  • Cost – A hand made steel frame and the custom wheels (adapted from unicycle components) will bring the price tag to at least 2000 Euro / USD for a typical build.
  • Lack of suspension options. Although Waltworks (and others, I expect) offer the possibility to build a Head Shok, this would give limited travel and raise the front end of the bike such that the bars would be higher than the saddle, except perhaps for riders taller than 7 feet.
  • More sluggish handling than a more nimble, smaller-wheeled MTB.

The first three points could, in time, be mitigated if 36ers ever get taken up and built by more mainstream manufacturers, in the same way that 29ers have eventually become dialed in regarding geometry and components, and competitive in terms of weight.

But despite the potential problems, I do plan to commission a 36er at some point in the near future … but not until I add a new 29er to the collection.