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21mm internal width rim launched for the rising popularity of wide tyres on endurance and gravel bikes

Stan's No Tubes have launched the new Grail rim to cater for the popularity of wider tyres, such as those that we're seeing on the latest endurance and gravel bikes. 

The Grail was actually developed when GT approached Stan's about a year ago when developing their new Grade road bike. GT wanted a wider disc-specific rim to cater for the wider tyres the bike can accommodate. The Grail was the result.

With a 21mm internal width and 24mm external width, it's the company's widest rim to date. Weight is a claimed 460g, Stan's telling us they built it to be durable for the sort of all-terrain riding the Grade, and bikes like it, are capable of, so weight wasn't the main focus, strength was.

The Grail is wider then than the company's Iron Cross cyclo-cross rim but about 75g heavier. However, where the Iron Cross has a maximum inflation limit of 45psi, the new Grail can take up to 125psi, making it more suitable for road and mixed terrain. 

The rim uses Stan's unique rim profile, which incorporates their Bead Socket Technology. This is essentially a sidewall that is 2-4mm lower than a regular rim, and which secures the tyre bead firmly into place. Once it's locked in there it's not budging, and in our experience makes running road tubeless a doddle.

Wide tyres are becoming much more commonplace in road cycling, even the pros are starting to ditch their 23mm tyres in favour of 25mm. And away from the racing world everyday riders with no interest in racing, but an interest in comfort, durability and exploring trails away from the road, are starting to embrace wider tyres. Wider tyres though need wider rims, and that's where the new Grail comes in.

The rim will be available in 24 to 32 spoke hole drillings, with GT using a 28-hole rim on their new Grade.  No word on pricing or availability yet. 

www.notubes.com

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.

4 comments

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bikeandy61 [524 posts] 1 year ago
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Having heard horror stories on mtb forums about how hard it is to get tyres on and off Stans rims. Any thoughts on your experience with the iron cross rims? Personally I have no plans to go tubeless but am interested in wide disk specific "road" rims.

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vorsprung [279 posts] 1 year ago
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it does 125psi (8.5 bar) so it's about the same as a velocity A23

as I understand it there is still no standard for road tubeless tyres

all the ones I've seen have been Stans rims + Hutchinson tyres

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fukawitribe [1585 posts] 1 year ago
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vorsprung wrote:

as I understand it there is still no standard for road tubeless tyres

all the ones I've seen have been Stans rims + Hutchinson tyres

There are standards - the two that come to mind are UST and Road Tubeless. The bead and rim shapes seem compatible (as far as the ones i've tried and heard from others) - the main difference being the degree of sealing (UST don't require sealant, Road Tubeless recommend it).

Personally i've rarely seen road tubeless set-ups on Stans outside of CX in the UK (probably due to not seeing many people with Stans rims full stop) and the tires have been mostly split between Hutchinson and Schwalbe, with a smattering of Bontrager.

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IngloriousLou [139 posts] 1 year ago
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fukawitribe wrote:
vorsprung wrote:

as I understand it there is still no standard for road tubeless tyres

all the ones I've seen have been Stans rims + Hutchinson tyres

There are standards - the two that come to mind are UST and Road Tubeless. The bead and rim shapes seem compatible (as far as the ones i've tried and heard from others) - the main difference being the degree of sealing (UST don't require sealant, Road Tubeless recommend it).

Personally i've rarely seen road tubeless set-ups on Stans outside of CX in the UK (probably due to not seeing many people with Stans rims full stop) and the tires have been mostly split between Hutchinson and Schwalbe, with a smattering of Bontrager.

I've been running road tubeless this year, Schwalbe One tubeless tyres on Easton EA90 RT rims, it's been great.

I've done 7000km or so and only one puncture that didn't seal due to a piece of glass that put a 15mm L-shaped cut across the tyre, no tyre would have survived that cut.