Avanti Hammer SL (2025)

The Hammer SL is the fast end of down-country.

It runs the same 130mm front, 120mm rear layout as the alloy Avanti Hammer S1, but almost every part that decides how a bike feels when you are working hard has been changed: the mainframe, the fork damper, the shock, and the drivetrain.

If you already know you want a short-travel 29er and your riding is long, climbing-heavy and paced, this is the version worth paying for.

The Hammer SL frame

The Hammer SL uses an HMF carbon mainframe paired with an SL 6011 alloy swingarm. It is worth being clear about that, because plenty of listings just say "carbon frame".

Carbon earns its place in the front triangle. That is where the largest, least-supported tube sections are. So it is where the strength-to-weight advantage of carbon converts into real weight saved and real pedalling stiffness gained.

The rear triangle is a different problem:

Short tubes, high impact loads, pivot hardware, chain slap and rock strikes.

Alloy handles all of that with less risk and less cost, and the weight penalty at the back is small.

The frame takes tyres up to 2.6in, runs a PF92 bottom bracket and modern Boost 148x12mm rear spacing, and carries the same longer-reach, slacker-head-angle down-country geometry as the rest of the Hammer platform.

The suspension is where the money went

This is the real difference between the SL and the alloy bikes.

Fox 34 Float Performance Elite, 130mm, remote lockout. Performance Elite is the tier where Fox stops giving you a simplified damper. GRIP-X is a proper adjustable damper with usable low-speed compression, which means you can actually tune support for how you ride rather than living with a factory setting.

The remote lockout is the main feature:

A bar-mounted lever that firms the fork on the spot. On a bike built for long climbs, being able to lock out without reaching down to the crown is the difference between using the feature and forgetting it exists.

Fox Float SL Performance Elite trunnion shock. Trunnion mounting bolts the shock directly to the frame instead of through an eyelet. This shortens the whole assembly and lets Avanti fit a longer stroke shock in the same physical space. The Float SL is Fox's lightweight air can, matched to the 120mm rear end.

But:

A remote lockout adds a cable, a lever and some bar clutter. If you ride terrain where you never think about pedal bob, you will not use it, and that is part of what tells you whether this bike or the S1 is your bike.

Shimano XT and SLX, mixed the sensible way

The drivetrain is XT shifter and rear derailleur with an SLX cassette and crank. This is the mix experienced riders build for themselves.

XT at the shifter and derailleur is where you feel the difference:

Crisper lever action, better clutch, faster shifts under load when you are grinding up something steep and have left it slightly too late.

XT cassettes and cranks cost significantly more than SLX for a few hundred grams and no functional gain, so Avanti have spent the money where your hands are and saved it where they are not.

Same 10-51T range either way, and every part is cross-compatible with Shimano's 12-speed range when it comes time to replace something.

SRAM DB8 four-piston brakes on 180mm rotors carry over from the rest of the Hammer platform. Four-piston stoppers on a 120mm bike is more brake than the category usually gets, and the DB8 uses mineral oil rather than DOT fluid, which makes servicing far less unpleasant.

Wheels, tyres and cockpit

Alex DP-27 double-wall tubeless-ready rims on Formula Boost sealed-bearing hubs, wrapped in Kenda Regolith Pro 29 x 2.4in 120 TPI tubeless-ready tyres.

Set these up tubeless from day one.

Running tubes on a tubeless-ready wheelset means carrying the weight without the puncture protection or the low-pressure grip, and it is the single cheapest performance change you can make to this bike. We can do it before you collect, and we stock the tubeless sealant and valves to maintain it.

The cockpit is full Syncros: Fraser 2.0 low-rise bar, FL 20 stem, Pro lock-on grips, Belcarra 2.5 saddle, and the internally routed Duncan dropper post.