Specialized Air Tool Big Bore review

Does Specialized’s fat inflator get you back riding faster? Our pump bore, Guy Kesteven, has been getting to grips with the latest chubby addition to the Air Tool range

Specialized Air Tool Big Bore
(Image: © Guy Kesteven)

Bike Perfect Verdict

Well made, user-friendly max volume, max inflation speed, tubeless useful ‘mini’ pump but you’ll need big arms to get beyond 30psi


  • +

    Big volume means super-fast inflation

  • +

    It’ll even ‘grab’ and seal tubeless tyres

  • +

    Excellent push-fit valve heads

  • +

    Robust metal construction


  • -

    Getting to 30psi needs some effort

  • -

    Shaft needs keeping clean

Why trust BikePerfect Our cycling experts have decades of testing experience. We\'ll always share our unbiased opinions on bikes and gear. Find out more about how we test.

Specialized’s Air Tool range spans 20 different road and MTB frame fit and ‘mini’ pumps, as well as we ‘track’ pumps. If you want maximum, low-pressure inflation speed from a pocket fit pump the new Big Bore is definitely the way to go.

Construction and use

With a 36mm max diameter, it’s certainly chubby, but it’ll fit in most waist packs and there’s not so much poking out of a back pocket so it’s unlikely to bounce out. It also comes with a rubber-strapped bottle-mount clip for max security and convenience. 

The alloy body and shaft are stiff so it slides smoothly with no flex or handle/head contact even when you’re pumping hard. The handle and body are deliberately roughly machined, with a knurled ring segment for extra grip and the inverted design means the head is long enough that you don’t risk biting an overhanging palm. 

The extendable hose means more room to get your pump on and isolates the valve from stress. The opposing push-fit Presta and Schraeder valve ‘metal sphincter’ head works really well too with a super-secure fit and no risk of unscrewing the valve core when you remove it.

Specialized Air Tool Big Bore

The extendable tube gives freedom to pump without putting any stress on the valve (Image credit: Guy Kesteven)

The combination of solid, interruption-free pumping and the big 90cc stroke means you can push a lot of air into the tyre very quickly. That makes it the only ‘mini’ pump we’ve used that can fill and pop into place a completely unseated tubeless enduro tyre (2.4in Hutchinson Griffus on WTB 29mm rim to be specific). 

It’ll obviously top-up conventional or pre-seated tyres quickly and easily too, so if you’re running fat rubber it’s awesome. The large stroke volume means you’ll have to work hard to get up to 30psi and you’ll be risking the veins in your temple getting close to Specialized’s claimed 50psi. As long as the tyre is properly popped into place that’s enough for all MTB and most gravel purposes though and there are plenty of high-pressure options in the Air Tool family. 

The fact the two halves twist-lock together when not in use means the shaft is more likely to stay clean which is crucial with large-bore pumps where there’s already more seal drag and a bit of grit can lock them solid.


Having had some frustrating, sticky experiences with other fat-body or hose-equipped pumps we approached the Big Bore with doubts. The level of detailing from solid, grippy construction to the secure double head makes it great to use and the big volume is great for fat tyres and super-fast inflation. 

Tech spec: Specialized Air Tool Big Bore

  • Price: £37
  • Stroke volume: 90cc
  • Length: 20cm
  • Max dia: 36mm
  • Weight: 85g
Guy Kesteven

Guy has been working on Bike Perfect since launch in 2019. He started writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.

Current rides: Cervelo ZFS-5, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg