Islabikes is most known for their well put together children’s bikes. But one of the troubles of spec’ing quality kids bikes is getting good components. In order to get quality cyclocross tires for their little bikes, they developed their own – the Gréim. And instead of making them available only in 24″ or even 26″ for the little bikes, Isla realized they could build a lightweight, supple tubeless cross tire for us big kids too…
Islabikes Gréim Pro tubeless-ready cyclocross clinchers
Isla seemed pretty proud of their Greim Pro cross tires when we were discussing kids bikes with them. After I mentioned that I did a lot of trail riding on cross bikes & a decent amount of amateur cyclocross racing, they asked if I would want to give the Greim Pros a try.
Now, I’ve had mixed results trail riding with cross tires set up tubeless (never finding the perfect balance of durability, lightweight & ride feel). And for racing, I’ve yet to ride anything that comes close to the performance of proper handmade tubulars.
But the open blocky design of the Greim looked promising, and the claimed weight of 325g for the 32mm tires wasn’t bad either. I figured I could start out on some tame singletrack & gravel riding with latex tubes, and go from there…
In the end I put almost half a year of riding in on the 700c Greim Pro tires. I covered gravel roads, hardpack singletrack, and even a good bit of soft, loamy fresh cut trail. From the end of summer, into fall & colder weather, I rode the tires on both steel & full carbon cross & gravel bikes with both tubes and tubeless setups. In the end I never properly raced them, although I did take them to a couple of local cross courses to use for training. And to get a sense of how they stacked up against my race tire setups.
Tech Details
One of the first things we do with a new set of tires is throw them up on the scale to see how close the manufacturer was when they told us what to expect. Surprisingly the two tires that showed up for us to test ride were 37g different in weight. Now more than 10% variation in product weight between two outwardly identical looking pieces is not very common, and I was a bit skeptical at first. With most parts that might suggest a quality control issue. But having a close look at both of these tires, neither looked to the naked eye to have any obvious issue.
I might chalk it up to the fact that Islabike has these contract manufactured by a third-party. (They are made by Vee Tire in Thailand, which is a reputable, albeit sometime budget tire maker.) And perhaps the tires we got were preproduction versions before final serial production was set in stone. In any case, more weight in a tire generally means more material. So I mounted the heavier one out back where it would suffer more abuse, and rode off without looking back.
As to the construction of the kevlar-beaded vulcanized tires themselves, Isla says they use a 185tpi casing. That’s quite a fine threaded sidewall for a vulcanized tire, and even decent for something not made under high temps. Isla rates the tires for tubeless-ready setups, although they don’t print that on the sidewall. And the bead shape is large & uniform, although not an overly boxy, lokcing tubeless-specific shape.
The Greim Pro tread design has three different block zones, all using angled L-shaped knobs. The center line uses two sizes of almost continuous Ls for decently quick rolling. The next row of intermediate blocks are small, rotated ~90° & widely spaced to dig deep into soft ground, while also shedding mud well. The shoulder knobs are the largest (& thickest) to offer confident, secure cornering and to dig deep into soft terrain. The whole thing is directional, with Isla suggesting to run them both pointed with the long edges forward on hard surfaces. On softer trails they say to run the front tire forward, and flip the rear tire the other direction.
The tires sell for £35 in Europe (only ~40€ these days, making them a steal on the continent) or for a bit more at $60 in the US, no matter the size. They are available in one width per wheel size – 24″ x 1.25″, 26″ x 1.22″ & 700c x 32mm – with the idea of being less than 33mm to be CX race-legal. We tried only the standard 700c, with them measuring true to 32mm on a 16mm rim and 33mm on a 19mm internal rim.
Riding Impressions
To be honest I was surprised with how well the Greim Pro tires handled a wide range of riding conditions. Soft conditions performance of the tread design wasn’t that big of a surprise. They remind me of the tread block shape of the reliable Challenge Limus mud tires, minus a small leg, and a bit more broken up looking.
But this more segmented design seems to crossover much better as an all-conditions tread, rolling quickly on hard surfaces. There were enough central blocks that the tire never felt like it was dragging me down, except in really soft, wet grassy riding. And in the deep mud I still was able to claw out as much traction as you can realistically expect at tire pressures around 30psi (and rider weight of 82kg/180lb).
I did manage to clog them up when I specifically sought out fresh, soft boggy trails to do some cyclocross mud practice drills. But even in normal wet & muddy trail riding they self-cleaned fairly well (see below.)
I was even more impressed with how they managed set up (and stay) tubeless. As I alluded to in the intro, I’ve had problems where tubeless CX tires that were supple enough to run low tire pressure (at or below 30psi) tended to lack casing durability in the sidewall and under the tread. I would routinely find another nice tubeless tire and then less than three rides later I would cut/scratch/scrape little holes in them, that would seal at first. But flexing around at 25psi the latex seal/plugs just wouldn’t stay put. And I would keep losing a couple of pounds of air at a time and end up smashing my rims.
To be fair, the Isla Greim Pro tires are not the most supple I have ever ridden. But they feel soft & flexible in the hand and do reasonably well to conform to most uneven terrain and off-cambers. The 185tpi vulcanized construction seems like a good compromise all-around, for a tire I could forget about and just ride.
I generally rode them tubeless between 28-32psi depending on conditions, and had zero issues with burping or flats over a mix of terrain. For rougher singletrack riding I pumped up to 38psi max. And they felt stable and survived plenty of carbon rim strikes over rocks & roots.
The rubber compound itself seems to be a happy medium as well. Not as soft & sticky as high-end racing CX tubulars. But at the same time a better balance of trustworthy grip (on all but slick, slimy wet wooden bridges). And tread that hasn’t worn away substantially after a season of trail riding, with pavement kms to & from the trailhead.
Are the Greim Pros the fastest riding, or grippiest cross tires I’ve put on a bike this year? No. Are they as supple or do they corner like the latest cotton & silk tubulars that I have been racing with this season? Of course not. But what they are, is the tires currently mounted on my cross bike that is parked by the door. Waiting to go out and hit the trail for some after work or weekend morning riding.
The Greim Pro has become a reliable favorite. A tire I don’t have to think or worry about. I have better tires for a mud fest. I have much better tires for cross racing in deep sand or on ice. I even have slightly better tires for fast hardpack trails. But I don’t really have time to be constantly swapping out tires. The Greim tires are fun & predictable in almost any conditions. And with a tubeless setup that works well, there is a lot to be said for not having to think about my tires, when I just want to get out and ride, and there isn’t much daylight to spare.
