Reviewed: Bontrager GR1 Team Issue Gravel Tire 700 x 40mm, 35mm – Cyclocross Magazine

In 2018 at Dirty Kanza, we saw none other than Sven Nys unveil prototype Bontrager gravel tires after starting on Challenge Gravel Grinders and suffering multiple flat tires.

That prototype tire, the Bontrager GR1 TLR Team Issue, is now available, and we’re rolling on a set. Today, we take a first look at both the 35mm and 40mm versions. Could the GR1 be the right choice for your next gravel adventure or perfect tire for your next dry conditions cyclocross race?

The GR1 is a blunt point file tread tire, with three different knob shapes. There’s a row of arrow-shaped center knobs, three rows of six-sided parallelogram-type knobs on each side, and a slightly larger, better-supported side knob of similar shape.

Bontrager’s new GR1 TLR Team Issue 700 x 40mm gravel tire features small, tightly-spaced blunt edge knobs. © A. Yee / Cyclocross Magazine

The small, tightly spaced, squared-off knobs offer a similar knob height and size as the excellent Panaracer Gravel King SK, with a bit more of a directional suggestion and tighter density. Compared to the pointed knobs of the lightweight Challenge Gravel Grinder TLR, the Bontrager GR1 should be longer-wearing, and similar to a Gravel King SK. Knob heights measure just over 1mm tall.

The tire comes in two widths, and two colors. There’s a 40mm wide version, and a 35mm version. Trek’s website lists the 40mm as available in black and brown sidewalls, while the 35mm version is only available in black. Lucky us, we also landed a version of 35mm in brown sidewall, so you know it’s coming. Currently it’s just in a 700c diameter. No 650b/27.5″ version yet.

Bontrager’s new GR1 TLR Team Issue gravel tire also comes in a brown sidewall option. © A. Yee / Cyclocross Magazine

Bontrager GR1 TLR Team Issue Gravel Tire Specs

First, as we’ve long maintained, you can’t trust labeled widths from any brand, so we’ve measured the tires bead-to-bead (read why here). The 40mm version is 103mm bead-to-bead, which matches the versatile Teravail Rutland 700x42mm gravel tire, but is a whopping 10mm smaller than the 42mm Challenge Gravel Grinder TLR. The 30mm version measures out at 89mm bead-to-bead, which is 5mm narrower than a 38mm Gravel Grinder (3mm in bead-to-bead equates to about 1mm inflated).

Bontrager’s new GR1 TLR Team Issue 700 x 35mm gravel tire tips the scales at 381 grams. © A. Yee / Cyclocross Magazine

Our pair of Bontrager’s new GR1 TLR Team Issue 700 x 40mm averaged 444 grams. © A. Yee / Cyclocross Magazine

The 120 tpi tires are relatively light. Our pair of 40mm tires averaged 444 grams (nearly identical to the Rutland 700×42), while the 35mm version averaged 381 grams.

Bontrager’s new GR1 TLR Team Issue 700 x 40mm gravel tire measures 103mm bead-to-bead and just over 39mm on a 19.2mm wide rim at 30 psi. © A. Yee / Cyclocross Magazine

Inflated at 30 psi, the 40mm tire on a 19.2mm internal width rim measured out at just over 39mm wide. By our calculations, on a 22mm rim, you’d be right at 40mm wide.

Bontrager GR1 TLR Team Issue Gravel Tire Installation

If your fingers and ears are guides, the GR1 Team Issue tires aren’t the tightest fitting tires in the world. Any rim with a decent channel will make for tool-free installation. With a compressor pump on a Vision Team 30 tubeless disc rim, it only took one try to inflate the tire, but it didn’t happen with the satisfying audible snap typical of tight-fitting tubeless tires.

Perhaps in part due to the looser bead, our first inflation didn’t hold long, but with a bit of shaking and spinning, a second inflation up to 60 psi did the trick.

Bontrager GR1 TLR Team Issue Gravel Tire First Impressions

The tight, small knobs of the GR1 create a fast-rolling tire with consistent grip on hardpack dirt and fine gravel. Unlike some tires with a smooth center ridge, the GR1 isn’t so bipolar in terms of traction. You don’t need low pressure or to lean the tire over to get more bite.

Bontrager’s new GR1 TLR Team Issue gravel tire comes in two widths (40mm and 35mm) and two sidewall colors (black, brown). © A. Yee / Cyclocross Magazine

If you’re used to bigger side knobs, cornering on really loose surfaces, or on anything damp will require more attention. Of course, as a gravel tire, it’s not really designed for mud, and most typical gravel tires slip in really loose, steep conditions. (In loose, dry conditions, we’re often counter-intuitively reaching for mud tires or gravel tires with more aggressive tread.)

While our initial rides haven’t been in areas filled with sharp, sidewall-cutting rocks, so far we’ve enjoyed flat-free and burp-free riding. Only a long-term test will reveal long-term durability. However, once the bead seated and sealed, the tire did not leak air or sealant, suggesting a well-sealed sidewall with plenty of butyl protection.

Stay tuned for a report on durability.

Bontrager GR1 TLR Team Issue Gravel Tire Specs

Tire Tested: 700c x 40mm, 700 x 35mm
Casing: 120 tpi, black or brown
Price: $64.99 (40mm), $54.99 (35mm)
Weight: 444g (actual, 40mm), 381g (actual, 35mm)
Width: 103mm bead-to-bead (700c x 40mm), 89mm bead to bead (700c x 35mm)
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