New 45NRTH Flowbeist and Dunderbeist fat bike tires announced

Tubeless-ready, 4.6in-wide, with front- and rear-specific treads

45NRTH today announced two new tubeless-ready fat bike tires specifically catered to the growing amount of groomed winter terrain. The front-specific Flowbeist and the matching rear-specific Dunderbeist both feature tubeless-ready construction, generous 4.6in widths, dual-compound rubber, and 120tpi casings – not to mention some of the best names in the tire business.


The 6.5mm-tall center knobs on the front-specific Flowbeist feature ramped edges on one side to decrease rolling resistance but sharper edges on the other for braking bite. Meanwhile, a nearly continuous row of well bolstered 8.3mm-tall shoulder knobs and fore-aft grooves on nearly all the knobs promote cornering grip.

45NRTH’s new front-specific flowbeist fat bike tire boasts ramped center knobs and an aggressive shoulder block pattern for secure cornering grip:

The new 45NRTH Flowbeist front-specific tire boasts a serious-looking set of shoulder blocks

45NRTH doesn’t bother ramping the knobs at all for the rear-specific Dunderbeist, instead sticking to sharper edges for better traction – probably a good idea given how tenuous grip can be on snow. Slightly shallower (and more sparsely packed) 7.8mm shoulder knobs should help riders slide the rear end around when needed, while both the center and transition blocks get lateral grooves for drive traction.

The new rear-specific dunderbeist fat bike tire from 45nrth features a 4.6in-wide, tubeless-ready, 120tpi casing with a meaty tread aimed at boosting drive traction:

Get a grip on snow with the new Dunderbeist rear-specific fat bike tire from 45NRTH

Claimed weight is 1,350-1,375g for the Flowbeist and 1,500-1,525g for the meatier Dunderbeist; retail price is set at US$140 per tire. 45NRTH says that both tires will be available in limited quantities beginning in April, with full availability on store shelves in September. Given how well the narrower Vanhelga tires have already been performing for us through a snowy Colorado winter, we’re eager to give these a go.


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