Zinn Cycles’ B.I.G. 32er is one of the first production full-suspension mountain bikes to be fitted with 32in wheels; a diameter starting to gather momentum in the industry.
Specifically, however, the B.I.G. is designed for riders 193cm tall and above, rather than any-sized rider looking for the largest-diameter wheels available.
However, catering for tall riders is a niche that’s Zinn’s bread and butter, and has been for a long time.
The specific components needed to make 32in-wheel bikes a viable product are now more available –such as Maxxis’ Aspen 32in tyres, wheels, spokes and forks. So Zinn decided it was time to bring such a bike to market, but it’s left me wondering whether brands have learnt from some of the mistakes of early 29ers.
A 29er but bigger?
Long chainstays accommodate the 32in rear wheel. Zinn Cycles
The B.I.G. 32er builds on Zinn’s 29in-wheel full-suspension MTB, adapting its tubes slightly to accommodate the bigger wheels.
Most importantly, the chainstays have grown from 460mm on the 29er to 473mm for the 32er. This gives the space required to fit that massive rear hoop.
Stack heights are also up, by 12mm for the biggest 4XL and 5XL B.I.G. to a whopping 682mm.
But there are some figures that seem anomalous to Zinn’s intentions, even given the B.I.G.’s XC focus.
Reach figures start at 475mm for the 2XL and 3XL and lift to 500mm for the 4XL and 5XL.
Modern bike geometry has progressed to a point where neither of these numbers would look out of place on a large-sized 27.5in or 29in bike, even if it’s designed for cross-country.
Conversely, however, effective top tube lengths dwarf most normal bikes’ XL sizes, coming in at 680mm and 704mm for the two smallest and biggest sizes respectively.
Lessons from the past
The B.I.G.’s geometry is reminiscent of the first full-sus 29ers. Zinn Cycles
Some of those numbers will raise a few eyebrows – especially for those seeking a more aggressive, trail-focused ride.
It’s hard to imagine how traditional reach figures found on size-large frames – usually for folk who are 180cm tall – will transpose onto a bike designed for people who top out at 218cm without negatively impacting the ride.
Those who have been around long enough have seen it all before.
When 29in wheels first launched, the bikes they were fitted to had perilously short and tall geometry, riding with the uncertainty of a galloping newborn foal.
But the industry learnt, albeit slowly.
29in-wheeled platforms have developed into some of the best full-suspension mountain bikes you can buy, regardless of discipline.
Maybe that’s a clue about where 32ers are heading.
We’ve seen BMC athletes riding a proto 32er at rounds of the XC MTB World Cup in 2025.
KTM also appears to be working on a hardtail 32er designed for World Cup racing, with the brand teasing 32in wheels can be “for every rider, no matter their size”.
Being fair to Zinn for one second, it states it “can make 32ers in smaller sizes as well, like M, L, XL upon request”.
But working backwards from its 2XL to 5XL reach figures, I’m concerned those bikes would just be too small.
Proportionality
Wren Sports’ Inverted fork can handle a 32in front wheel by reducing travel without shortening the axle-to-crown length. Wren Sports
Maybe there’s more to it than reach and frame figures alone, though.
Zinn has specced an upside-down Wren Sports Inverted fork that’ll fit a 32er front wheel while still having up to 120mm of travel. Currently, offerings from other manufacturers are limited to one-off prototypes not ready for commercial sale.
Wren Sports claims that the added benefits of improved bump roll over from the big wheels more than make up for the reduction in travel, compared to a 29er fork with 150mm of squish.
It’s unsurprising that the B.I.G’s rear axle uses the 12x157mm Super Boost standard – shared with bikes from Pivot among others – to boost frame and rear-wheel stiffness.
The bigger the wheels, the stronger they need to be. Zinn’s custom spokes should help with that. Zinn Cycles
Zinn ordered custom-length spokes to build its 32in wheels, stating they need to be immensely strong.
Nextie – a carbon specialist based in China – supplies Zinn with its Unicorn 32in carbon rim.
Leaving no stone unturned, the B.I.G. runs custom-length cranks, designed with taller riders in mind.
Starting at 180mm (175mm is a traditional crank’s longest option) and rising to 210mm, for optimum rider pedalling efficiency and comfort, the cranks should be between 1.95 per cent and 2 per cent of a rider’s inseam, according to Zinn.
How much does Zinn’s 32er cost?
Zinn’s B.I.G. 32er has four models in its range.
Prices start at $7,250 for the most-affordable M1 decked out with Shimano’s SLX kit. A Shimano XT model retails for $7,550, and there’s a SRAM GX Eagle AXS-equipped model for $7,950.
The range-topper is fitted with Shimano’s latest XT M8200 Di2 electronic, wireless gearing, and retails for $8,350.