Corima G30.5 Carbon Gravel Wheelset

'The new benchmark for gravel wheel design and performance.' Big claims from Corima regarding its new G30.5 Carbon Gravel Wheelset, but arguably justifiable. While these wheels don't challenge the competitors massively on weight, they do offer very impressive stiffness while having a ride feel that doesn't shake your fillings out.

One of their few drawbacks is limited tyre compatibility. ETRTO – the European Tyre and Rim Technical Organisation – is who oversees the standardisation of wheel and tyre compatibility for bicycles (among other types of vehicles) and for 2020 there have been some updates.

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Most of these changes have been brought about thanks to the latest technology in the road and gravel cycling world, like hookless rims and tubeless tyres. Corima has developed the G30.5's rims to comply with these new standards and offers a list of six tyres that it recommends the wheels are safe to be used with. These are from Hutchinson, Maxxis, Michelin, Schwalbe and Vittoria.

While I'm not suggesting you go against a manufacturer's instructions, I'm just going to put it out there that I have done about 500 miles on some pretty brutal gravel tracks over the last six weeks with a pair of Zipps fitted and, basically, I haven't died.

The reason for the change of tyres from the Hutchinson Overides they came supplied with is that I use Zipp Tangente Course G40s as my benchmark tyres for every set of gravel wheels. Same tyres, same pressure.

The Corimas have a hookless rim. It's a design that has come across from the mountain biking side of cycling, and what it basically means is that the wheel rim has no hook on it to hold the tyre in place like is necessary for tubed clincher tyres.

Only tubeless tyres can be used as they have a stronger bead than a standard clincher. When pumped up to pressure, this stronger bead will hold the tyre firmly in place. Maximum pressure is limited to just 72.5psi which is one of the reasons take-up has been slow from the road point of view, but for gravel use that is plenty.

Tyre width recommendation is from 28mm up to 60mm, and the 40mm wide Zipps fitted quickly and easily, giving that reassuring pop as the bead nestled up against the edge of the rim.

> Buyer’s Guide: 26 of the best gravel bike tyres

The carbon fibre rim is 28mm wide (internal width is 22mm) and 30.5mm deep. With the Zipp tyres fitted, the profile of the rim and sidewall of the tyre flow nicely into one another.

To get to my local gravel playground I have a couple of miles of road to cover first, with pretty much all of it uphill. It's flippin' steep in places too, which requires a bit of out of the saddle climbing. This showed straight away how impressively stiff the G30.5s are. If you are more of a performance graveller rather than an adventure tourer you are really going to appreciate just how well the Corimas deliver the power down to the road or trail.

With a weight of 1,573g (including tape and valves) the G30.5s are pretty light – combine that with the stiffness and you get a very responsive wheelset.

On faster, technical sections of trail, having a wheelset like this helps the steering as the low weight makes it easier to change direction faster, to dodge things like rocks or potholes.

> 25 of the best 2020 & 2021 gravel bikes & adventure road bikes

After that first stretch of road heading for the gravel, as delighted as I was with the stiffness, I did have my concerns over what the comfort levels were going to be like when I hit the trails.

There was no harshness at all. You still know that you are aboard a stiff, carbon fibre wheelset, and the tyres are taking out the majority of the vibrations, but compared with a like-for-like setup the Corimas just take the edge off a little more – like the Edco Gravel wheels I was testing alongside these, for example, and the Edcos were far from uncomfortable.

This could be down to the fact that Corima fills its hollow carbon rims with a structural foam and a horizontal unidirectional carbon fibre bar. This bar is there to reduce flex in the rims, while the foam core is said to reduce vibrations and sound for a quieter and more comfortable ride. (I tend not to do any reading up on a product's technology or specs until I'm ready to write the review, as I don't want anything to cloud my judgment, so I didn't know about any of these materials on those early rides.)

As for the rest of the build, hub-wise Corima has chosen DT Swiss 240s which I have ridden thousands of miles on over many test bikes and wheels. The quality is very good, taking whatever rubbish the conditions can throw at them, plus I love the rapid engagement of the EXP ratchet freehub body.

The hubs are set up for 12mm thru axles and use the Centerlock design for fitting brake rotors.

The spokes are CX-Ray, with each wheel using 24 spokes, 12 each side of the hub laced up in a 2x pattern.

Value

All of this doesn't come cheap, which is why you're looking at £2,010 for the set.

As I said, though, the G30.5s are built in Corima's factory and that includes the rim being individually moulded by hand using prepreg carbon fibre that has been handmade in its own factory. You also get a wheel bag, spoke wrench and a valve nut tool included in the package, and the rims are fitted with the tubeless tape and valves too.

I'll be honest, though, when it comes to the competition most of it is cheaper.

Another set of wheels I tested which had a very smooth ride was the Sector GCi. Its TeXtreme carbon material results in a very good ride quality. The Sectors are heavier than the Corimas at 1,730g, but a lot cheaper at £1,100.

You can also get stunning gravel wheels like the Hunt 35 Carbon Gravel Disc X-Wides, which weigh 1,548g and cost less than a grand, £899 to be precise.

There are some that make the Corimas look an absolute steal, though: the Enve G23s are a cool £3,100, but also a stunning 1,346g!

Conclusion

Overall, the G30.5s are pricier than most, but the majority of that comes down to the manufacturing processes. These aren't mass produced items. They are high performing and very durable wheels that are stiff enough and comfortable enough that they'll give you the best of both worlds out on the tracks.

Verdict

Not the cheapest but a great balance of stiffness, durability, comfort and handbuilt quality