Like a metal concert with earplugs - that's a heretical way of describing the riding sensation that accompanies bikers on plus tyres through the stone field. The fact is that with wide tyres from 2.8 inches upwards, impacts of all kinds only reach the rider in a filtered form. But is that a good thing or a bad thing? The figures from our reader survey speak for themselves: just three per cent of BIKE readers ride plus-size tyres, and the voluminous grip-bringers have not really caught on with the masses. Is this the reason why tyre and bike manufacturers are united in their call to upgrade for the coming season? Many 2.6-inch tyres are now tumbling out of the Schwalbe, Maxxis and Continental presses. The shrunken tyres are already rolling into the shops on complete bikes from Merida, Pivot and Ibis. By the way: Wide tyres are not only an issue in the 27.5 inch size. 29ers will also roll on 2.6 tyres in the future. The new size 29+, long dismissed as rubbish, is paving the way into the market. Scott, Ibis and Drössiger will be using these powerful tyres in 2018.
The fact is that the trend towards wider tyres is here to stay. Industry giant Scott even goes so far as to say that no bike beyond 130 millimetres of travel will be fitted with tyres smaller than 2.6 inches. What's more, the new Boost dimension, which will be used almost everywhere in 2018, means that more and more bikes are blessed with tyre clearance that allows at least 2.6-inch tyres - a new perspective for the number one tuning part. Reason enough to end the guesswork about the perfect tyre width: Which dimension makes the most sense for enduro, trail and touring bikers? Because the annoyed question of many mountain bikers is justified in view of the unchecked urge to innovate: Why the hell is there yet another new tyre size?
The approach of the wide tyres is clear: less air pressure brings more traction and comfort. Anyone who has ever sat on a fatbike will have experienced this effect in the extreme. However, the first wave of Plus tyres with a width of 3.0 inches brought unpleasant side effects in practice: Susceptibility to punctures due to thin-walled carcasses, spongy ride feel. "We understood that a trail tyre has to be robust and durable and have made improvements in terms of stability. The first Plus tyres were rather useless in this respect," reveals Wolf vorm Walde, responsible for tyre development at Specialized. More stable designs are the result, not only at Specialized, but also at industry leader Schwalbe. The successful Nobby Nic model now comes in a 2.8-width tyre exclusively with robust Apex reinforcement. Side effect: The latest generation of wide tyres has to put up with the accusation of being significantly overweight, at least the trail-compatible models that we tested. On the other hand, they are far superior to their narrower brothers in terms of puncture protection and riding stability.
But how does 2.6 inches perform on an MTB tour and on the trail? Have the developers found the long sought-after happy medium with this middle ground? We got to the bottom of this question in extensive laboratory and practical tests and have broken down the results of this comparison into the decisive criteria.
Model overview MTB tyres in 2.6 inch
2.6 tyres are on the rise, also for retrofitting. We have compiled an overview of which MTB tyres will be available on the market in the new intermediate size. From lightweight touring tyres to massive enduro bruisers.
The MTB tyres in the comparison test:
Schwalbe Nobby Nic
Specialised Butcher
Test result 1: Rolling resistance | acceleration
Wide tyres are associated with tired legs and sluggish acceleration. The combination of various laboratory and practical tests shows the truth of these prejudices.
On asphalt and hard surfaces, wide tyres that are ridden with low air pressure are at a disadvantage, as the laboratory results show. The more you move from hard ground to off-road terrain, the better the voluminous tyres perform. But even there they reduce the bikes' climbing ability. Due to the high weight of the rotating mass, acceleration suffers, which is just as noticeable in the practical test as on the inertia test rig in the BIKE lab. The 2.6 inch also has to put up with this criticism: In the laboratory measurements, the newcomers landed closer to the sluggish 2.8" rollers than to conventional 2.3" tyres. However, the high weight is not solely due to the increase in width, but rather to the carcass reinforcement that both manufacturers give their 2.6 and 2.8 models. Schwalbe also offers the 2.6 Nobby Nic without Apex reinforcement (785 grams) - this almost 100 gram lighter version would be significantly closer to the 2.35 version in the acceleration ranking. Of course, with significant losses in puncture protection and driving stability. By the way: A 2.35 in 29er size with the same tyre and comparable wheel ends up behind the 27.5 x 2.6 tyres in terms of acceleration.
¹Measured on the Schwalbe roller test bench, watt values comparable to rolling resistance on asphalt,
²Measured in the BIKE laboratory, values for complete front wheel incl. tyre, inner tube and brake disc: the higher the value, the worse the acceleration.
Test result 2: Grip | Traction
Does it hold or does it slip? Does it grip or does it spin? The question of grip is the supreme discipline of any tyre and the main argument for width. Where does a 2.6 inch tyre fit in?
The dominance of wide tyres! More contact area means more grip - that's not just the grey theory, but also the practical comparison on trails on a wide variety of surfaces, both uphill and downhill. The 2.8 series clearly takes the lead here, which is just as noticeable during braking manoeuvres with brute and carefree deceleration as it is when cornering. The difference between the 2.3 and 2.6 tyres is also clearly noticeable; width brings safety. The conventional tyre size drops noticeably in direct comparison. Remarkable: The limit range not only occurs much later with the wide tyres, but also much more gently. With the 2.8 tyres, there is hardly any sudden skidding when cornering or during an over-motivated braking manoeuvre. Less experienced drivers in particular benefit from enormous safety as a result! We were somewhat surprised by the differences on the climbs. Although the 2.8 rollers build up a little more grip on nasty roots, the difference is small.
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Test result 3: Comfort | Rollover behaviour
Roots and obstacles are the salt in the mountain bike soup. What full-suspension bikes have been defusing for years, wide tyres should reduce even further.
The most incisive moment of our practical test was the change from very wide to very narrow: aim for the root field - and get scared! The section that had barely raised an eyebrow just before suddenly resembles a rodeo ride and forces you to ride cleanly. The trail feels wilder and heavier than with the wide rollers. The large volume and low air pressure allow the 2.8 mm tyre to wobble over obstacles and the rider receives fewer impacts. This phenomenon is even more noticeable with the very wide rollers than with the 2.6 tyres, which lie pretty much in the middle between the two extremes. A 2.8 tyre can give a hardtail in particular unimagined comfort.
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Test result 4: Driving stability | Precision
THE argument of sporty drivers against plus tyres: spongy ride feel, little precision and feedback. How do the 2.6 tyres perform in this discipline?
"Rides like jelly", or "doughy ride feel": these comments are often found about plus tyres in our test questionnaires for complete bike tests. The carcass of the current 2.8 models has been reinforced, which also has a positive effect on the trail. However, at high speeds, in berms and compressions, the 2.8 tyres still buckle at an air pressure of 1 bar. In our test, this was particularly evident on a classic bike park track with wooden berms - an extreme case. If you tend to ride at a moderate speed, you won't have any stability problems with the wide 2.8 mm tyres. This applies to less experienced riders as well as bikers who prefer very technical trails to fast tracks. The reinforced tyres are also more precise than their predecessors. Nevertheless, the 2.8 tyres are far from perfect for every line. We were particularly curious about the stability of the 2.6 tyres. During the entire ride, we were unable to confirm that the intermediate size tyres did not buckle or tip over. The very narrow version follows exactly what the rider specifies, which requires a higher level of riding skill and precise handling. So in terms of precision, 2.6" has hardly any disadvantages. Coupled with the added safety, the intermediate size is a great combination.
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Test result 5: Agility
Speed and safety are one thing, riding fun is another. How does the tyre width affect the agility and playfulness of a bike?
Quickly weave around bends, use waves for small jumps, playfully lift the front wheel: What is not crucial for racers and pure speed on the trail is what makes riding fun. The main finding is quickly explained: If you like to play with your bike in the air, 2.8 tyres can be a real fun killer. The tyres only move into the air with considerable effort, and the handling inevitably feels sluggish and sluggish in direct comparison to their narrower counterparts. With the lighter and more direct 2.3 tyres, you almost feel like you're on a toy bike. Even when cornering, the wide tyres require noticeably more pressure to take the new direction. And the golden mean? The 2.6 tyres don't negotiate trails and jumps as effortlessly as their narrower and lighter counterparts. However, the bulldozer feeling of the very wide tyres remains absent.
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Test result 6: Puncture protection
For a long time, low puncture protection was a major argument against plus tyres. Manufacturers have responded with reinforced carcasses - with success.
The guillotine in the Schwalbe test laboratory knows no mercy. Sooner or later, all tyres react to the dull blow of the drop axe with a whistle that indicates a knockout due to air loss. We tested the different tyre widths with the practice-relevant air pressures of 1.6 bar (2.3" or 2.35"), 1.3 bar (2.6") and 1.0 bar (2.8"). Contrary to preconceptions, the wide tyres lasted significantly longer, which is primarily due to the stronger carcasses. On average, the 2.6 tyres offer more than 50 percent higher puncture protection than their narrow counterparts, despite the significantly lower air pressure. This puts them at the top of the rankings. With a good 43 percent lead over the narrow tyres, the 2.8 tyres are only just behind. With regard to the carcass equipment, it can be said that the greater the focus on puncture protection, the heavier the tyre. With these values, the 2.6 version of the all-rounder Nobby Nic is a contender for really rough terrain.
*Measured on the Schwalbe drop centre test stand. The values indicate the drop height at which the tyre suffered a puncture; the higher the value, the better the puncture protection.
The test results at a glance
The 2.6 tyres don't have any significant weaknesses, a good compromise for all those who value fun and safety on the trail. The decisive question when choosing tyres remains: Is the focus on weight and climbing strength, or off-road capability?
CONCLUSION Florentin Vesenbeckh, BIKE test editor:
2.6 inch wide tyres have the potential to win the hearts of trail bikers. They offer noticeably more grip than narrow tyres and the best compromise between touring suitability and downhill strength. In contrast to 2.8 tyres, there are largely no compromises in riding precision. Only those who focus fully on safety and comfort on descents and who ride at moderate speeds on trails will find tyres around 2.8 inches the perfect companion. This size will primarily prevail on motorised bikes, where the greater effort required when climbing and accelerating plays a subordinate role. If you want to chase Strava best times uphill or on flat terrain, you won't be able to avoid conventional dimensions any more than bikers who go on long tours. Tyres larger than 2.3 inches accelerate less quickly and are heavier - which saps your strength.
TUNING TIPS
Boost axles and wide rear triangles give tyres a new perspective as the number one tuning part. BIKE shows which requirements are necessary for 2.6 or 2.8 tyres.
Tyre clearance: What tyre width fits my bike? There should be at least 7 millimetres of clearance between the rubber on each side and the seat and chainstays or fork bridge. This results in the following guide values for the models tested: 82 mm for 2.8" and 75 mm for 2.6" wide models.
Rim width: A wide tyre needs a wide rim! If you don't pay attention to this, you won't be able to lower the air pressure appropriately and will be punished with buckling tyres. 2.6 tyres work from an inner width of 28, better 30 millimetres, for 2.8 tyres the rim should be even wider, ideally 35 millimetres or more. If low air pressure is important to you, you should also choose an inner width of more than 25 millimetres for 2.3 tyres.
Geometry: Many manufacturers offer bikes that are suitable for both 29 inch and 27.5+. The argument: the diameter or radius hardly differs. However, if you look at the radius of the different tyre widths under load (rider weight 83 kg), you will notice that the bottom bracket height only changes marginally with increasing tyre width (4.5 mm from 2.35" to 2.8"). On the other hand, there is an enormous jump to the 29er (21 mm from 27.5 x 2.35 to 29 x 2.35). As long as the tyre clearance allows it, you can change from 2.3" to 2.8" tyres without noticeably affecting the bottom bracket height. However, changing from 29 to 27.5+ tyres without geometry compensation is critical.
Air pressure: The wider the tyre, the more sensitive it is to changes in air pressure. If you ride a plus-size tyre with too much air, you are wasting enormous potential. It is difficult to make general recommendations, as rider weight, area of use and riding dynamics play a major role. As a guideline, 1.3 bar can be used for 2.6 tyres and 1.0 bar for 2.8 tyres.
You can read this article or the entire BIKE 11/2017 issue in the BIKE app (iTunes and Google Play) or buy the issue in the DK shop reorder:
Florentin Vesenbeckh
Editor CvD
