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The Bontrager GR1 Team Issue Gravel Tyre is a dedicated dry-weather gravel tyre designed for one purpose – going fast in the dry. They do that very well – if you can guarantee such conditions in typically muddy, soggy Britain.
Reflecting the 'Team Issue' label, Trek does indeed issue the 40mm GR1 to its team riders – Sven Nys rode the GR1s on the second 50 miles of his ill-fated Dirty Kanza 200 attempt this year, after his chosen tyres suffered repeated flats. The GR1s performed well, but he pulled out after suffering stomach issues.
Weighing in at a claimed 430g apiece (our test pair weighed 850g), the GR1s are light for a tubeless gravel tyre – comparable offerings from Schwalbe weigh a bit more – the 455g G-One, for example (and those are £58.99 rrp). The GR1 comes in just the 40mm size, matched by the slightly more open-tread and heavier 40mm GR2 at 440g.
I found the GR1 looser than most tubeless tyres I've fitted; it took an extra five layers of tape to build up a workable rim bed on some non-tubeless-specific Mavic Open Pro rims to get them seated. This is a wheelset I've had half a dozen tubeless tyres on over the last two years, so yes folks, the turkeyshoot that is tubeless tyre-rim compatibility continues.
Once mounted, they sealed up fine using Stan's, and didn't leak any.
They feel fast on the road, corner well and are pretty quiet for a treaded tyre, so no complaints there. If you need to transit on road to a trailhead you'll not feel let down by rolling resistance or handling.
Testing in autumn, in Scotland, finding stretches of actually dry gravel proved a bit of a challenge. Cornering with no side knobs to speak of isn't overly inspiring, but on dry-ish clay/gravel they didn't let go except once on a very off-camber section, and I was able to hold it together without too much squealing.
Dry leaves foiled them on a 15 per cent pitch, the rear wheel spinning out where other gravel-orientated tyres have stayed stuck. I found them to be good enough on dry gravel attacks, but put even a thin layer of silt over the top and things get slippery really fast as the tread fills. (The GR2 might be a better bet for such conditions, full review to come.)
Control on fast descents is okay, with 35psi more than enough to hold the shape in corners and prevent any rim dings with 40mm of volume to play with, but again the lack of any decent edge means when you do spot a smoother section to regain control in, chances are if it's wet you could be up for a quick course in counter-steering.
Braking over loose rocks and slabs of granite was predictable, if not as confidence-inspiring as a grippier tyre would be.
I could have seen myself using the GR1s at the Dirty Reiver race, IF there wasn't a hint of rain forecast.
The GR1 is definitely a tyre for drier, smoother gravel/road expeditions. It will handle flatter bridleways and towpaths just fine, but don't expect much grip on damp, grassy, leafy or silty surfaces – which is pretty much all of the UK for six months of the year.
A fast tyre in the dry on the firm and dusty, but not in damper, less-gravelly conditions
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road.cc test report
Make and model: Bontrager GR1 TLR Team Issue Gravel Tyre
Size tested: 700x40C
Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
It's a tyre for race use on dry gravel.
For the roads less travelled
The GR1 Team Issue gravel tyre is designed for fast rolling performance and consistent traction on the roads less paved. It has proven success at the most demanding gravel races, and features Inner Strength Casing for lightweight puncture protection while maintaining a smooth, supple, fast feel. Plus, you can go tubeless for better performance and even more puncture protection.
A gravel tyre that excels in fast and firm conditions
Fast-rolling and predictable cornering with consistent traction
Tubeless Ready (TLR) for easy tubeless setup and puncture protection
Supple and strong Inner Strength casing provides lightweight sidewall protection
Lightweight 12 TPI casing provides great ride feel and tyre performance
Tell us some more about the technical aspects of the product?
700C x 40mm
430g (GR2 is 440g)
For UK purposes these aren't the best – but in the dry they are pretty good.
After a month's bashing they still look like new.
Claimed 430g for a 40mm tyre is pretty darn good; our pair came out at 850g so even better...
The pliant sidewalls make for a smooth, grippy ride in the dry.
Cheaper than the Schwalbe G-One Bite Microskins (£58.99), but in the UK their value is questionable.
Tell us how the product performed overall when used for its designed purpose
If that purpose is dry gravel, they're great.
Tell us what you particularly liked about the product
On the road they roll fast and quiet.
Tell us what you particularly disliked about the product
The tread pattern, when used in anything other than dry rides.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
Pretty much on a par with other high-end tyres of this weight, but perhaps more focused on the dry.
Did you enjoy using the product? Yes, ish.
Would you consider buying the product? Maybe
Would you recommend the product to a friend? For specific, dry use, yes.
Use this box to explain your overall score
For British conditions the GR1 isn't really a contender – unless you're aiming for Dorset farmroads at midsummer. In the right conditions the GR1 could be a race-winner, but as with anything 'Team Issue' it's the performance orientation that will let it down in more varied conditions.
About the tester
I usually ride: Merida Ride 5000 Disc My best bike is: Velocite Selene
I've been riding for: Over 20 years I ride: A few times a week I would class myself as: Expert
I regularly do the following types of riding: cyclo-cross, club rides, general fitness riding, mountain biking, Dutch bike pootling.
Living in the Highlands, Mike is constantly finding innovative and usually cold/wet ways to accelerate the degradation of cycling kit. At his happiest in a warm workshop holding an anodised tool of high repute, Mike's been taking bikes apart and (mostly) putting them back together for forty years. With a day job in global IT (he's not completely sure what that means either) and having run a boutique cycle service business on the side for a decade, bikes are his escape into the practical and life-changing for his customers.