32 inches - hype or added value: Facts & opinions on the new MTB wheel size

Hardly any other topic is discussed as emotionally as a new wheel size. 32 inches is no exception - on the contrary. But what do the facts actually say? And what do the experts who have already extensively tested the new size say? We put a 32-inch wheel through the lab and spoke to bike developers. Soberly and objectively. Here are the findings.

>> 32-inch wheels in the test: What the giant tyres can really do

>> Stoll P32: The first carbon full-suspension bike with 32-inch wheels - will the prototype go into series production?

>> Trail-Fully in 32 inch: Actofive I-Train with the 32" world premiere

Grip

Even though some will automatically attribute a larger tyre contact area to larger wheels, this is not the case. With the same tyre pressure and identical carcass structure, the tyre contact area remains the same size. Only the shape of the contact patch changes. Due to the larger diameter, the surface area of the 32-inch tyre is more elongated than that of the 29er. This means that more lugs grip the ground, which increases grip. The increase in traction is clearly noticeable and improves both climbing and braking characteristics.

Inertia

As soon as the diameter of the wheels increases, not only the weight but also the inertia inevitably increases. The lion's share of the additional weight is accounted for by the tyres, rims and longer spokes, while the frame is only marginally heavier due to the longer chainstays and adapted geometry. According to our laboratory measurements, the inertia of the 32-inch bike is 27 per cent higher than that of the 29er. The values are based on a 29-inch Mavic Crossmax wheelset and a 32-inch prototype from Bikeahead - both in a tubeless setup with 2.4-width Maxxis Aspen tyres.

Diameter

Compared to the 29er, the 32-inch bike is 74 millimetres larger in diameter - with the same rim width and tyre model, mind you. This means that the jump in size is on a par with 26-inch to 29-inch tyres. In order to integrate the large wheels into the frame, the wheelbase also has to grow. A chainstay length of less than 450 millimetres will hardly be possible, increasing the overall length to over two metres.

Rolling resistance

The poorer acceleration when the speed increases cannot be ignored and is clearly noticeable. However, the higher inertia and better rollover characteristics help at a constant speed. The 32-inch tyre conserves the available speed better and gets stuck on bumps much less. Our performance measurement confirms a seven per cent higher efficiency on the 32-inch model on climbs - even with a weight disadvantage of currently two kilos.

Weight

In our comparison, the 32-inch tyre weighs an average of 75 grams more than the 29er. The Maxxis Aspen in the test is a sparsely profiled race tyre. Coarser profiles with more rubber on the tread should make a bigger difference. The difference in weight between the wheelsets we weighed was 234 grams.

Running bike evolution: the next big thing?

For decades, the 26-inch size dominated the MTB market and was the standard size for riders of all sizes and disciplines. No other wheel size can boast a similarly long history, from the founding of the MTB until around 2015.

The US brand Niner recognised the potential of larger wheels early on and opted for 29-inch wheels as early as 2005. BIKE tested the first 29er hardtail in 2008: a Gary Fisher Fisher Superfly 29.

>> Gary Fisher's new "Superfly" 29-inch carbon hardtail breaks with the 26-inch tradition.

However, it took until 2010 before the first race victories were achieved with these large bikes. Their establishment was slow and faced a lot of headwind.

The intermediate size 27.5 inch entered the MTB stage well after 29 inches. Nino Schurter piloted a 27.5-inch bike to World Cup victory for the first time in Pietermaritzburg in 2012. Currently, the "intermediate size" is only found on small frame sizes and is used for more freedom of movement with long rear wheel travel.

Maxxis presents a 32-inch Aspen tyre at Eurobike 2025. Individual companies such as BMC, KTM, Stoll and Bike Ahead are also showing the first prototypes based on the giant wheels.

Opinions on the topic 32 inch

Thomas Stoll, owner of Stoll Bikes

We are convinced that 32 inches will replace 29 inches in the cross-country and marathon segment. The first comparison rides with our prototype were already very promising and have shown that 32 inches is not only faster, but also offers much more reserves. And this despite the fact that the prototype frame is still significantly heavier than the planned production carbon frame. - Thomas Stoll, owner of Stoll Bikes

>> Stoll P32: The first carbon fibre fully with 32-inch wheels - will it go into production?

Rene Krattinger, Product Manager at Scott

We have been working on the 32-inch topic for some time now and have been testing it intensively. So far, everyone who has ridden 32-inch wheels has been extremely positive. I can even imagine that the large wheels will also bring real advantages on bikes with more suspension travel, beyond cross-country. However, as we don't want the customer to be the guinea pig, we only bring something onto the market when it works 100 per cent. - Rene Krattinger, Product Manager at Scott

Max Fuchs, Editor BIKE

The rollover behaviour and grip are simply amazing. You feel like you could ride it up the downhill men in Finale Ligure. Even at 1.73 metres, the bike didn't seem too big to me. The extra length was only noticeable in two sharp S-curves. On the other hand, the bike takes an enormous amount of work off your hands and requires much less riding skill from the rider. - Max Fuchs, BIKE editor

Luca Schwarzbauer, World Cup Pro Cross Country

The potential of 32-inch wheels is so enormous that all major racing teams are currently carrying out intensive testing. For very small riders, the question arises as to whether the large wheels allow for a sensible frame and cockpit geometry. But there will certainly be solutions for this too. In addition to the better rolling behaviour and cornering handling, I was impressed by the enormous feeling of safety on steep, technical sections. You have a lot more bike around you and there is no more feeling of rolling over. - Luca Schwarzbauer, World Cup pro

Peter Denk, bike designer

I think it's great to try out 32-inch wheels. The rejection of 29-inch tyres at the time has certainly blinded us somewhat as far as the acceptance of the wheel size is concerned. However, on the current cross-country trails, 32-inch wheels could give you the edge in the race. Even for enduro and downhill use, 32-inch front wheels could be very exciting. In terms of steering geometry, especially in terms of angle and fork offset, there is certainly still potential to get the best out of the large wheels. - Peter Denk, design engineer