Ralf Grösel - behind the design of the Juice

Juice Duotone Kiteboarding Ralf Grösel

We catch up with Ralf Grösel to go behind the design of the new JUICE. The Juice sets the benchmark in light wind kites. Ralf takes us through the refinements to the new 2021 model.

Hear the full interview

Juice Duotone Kiteboarding Ralf Grösel

Hear the full interview

Hi Ralf, tell us about the development process of the Juice.

Within the last two years, we have been able to reduce the weight of the Juice by 25%. That's a huge weight saving, but that's not the only point that makes the Juice so special. The Flex Strut which is the flexible tip strut is something that is extremely important to ensure that the handling characteristics of the kites are highly improved. When you fly a kite in low winds, there is always a mass that you have to accelerate and the tip that creates the turn has to be as fast and responsive as possible. With a combination of lightweight materials and flex struts we have been able to achieve a kite that when you loop it, it really pulls you and helps you up on to the board, regardless if you are riding a twin tip or a foil board.

Juice Duotone Kiteboarding Reno Romeu
Juice Duotone Kiteboarding Reno Romeu

The current Juice we are seeing comes from the conceptual project phase of the Ultra Light Wind Kite, tell us a little about that.

The Ultra Light Wind concept was an essential milestone for the development process of the Juice. With the ultralightweight kite I have been experienced in developing the lightest inflatable tube kite ever, 13m? at around 1.9 kg. That kite flew in literally no wind! All the experience we gained during the development process gave us the chance to experience these new flight characteristics and have been leading us in the direction to integrate these construction details and performance attributes into our commercially available product line.

The power delivery is quite amazing and it feels as if the kite can fly off apparent wind alone, it seems if you can launch it you can get going on the water!

With the Juice, the moment the kite flies you are ready to go! Of course, it depends on the board you are using, the wind density and of course your skill level. Generally, it is a kite that gives you the feeling that the moment you crank it and turn it you have enough power to generate the apparent wind you need to go upwind. It would make no sense to have a ‘truck’ that is just pulling you downwind, you would have a very limited kite session and experience with something like that. With the Juice it’s all about the efficiency, it’s all about the handling and the connection between you (the rider) and the kite. You’re able to generate the speed out of the kite and regardless if you are riding a big twin tip board or a foil board, it's the sensation that you have a clear connection to the kite. Being able to generate speed and pull by the direct feeling of the kite.

Juice Duotone Kiteboarding Reno Romeu
Juice Duotone Kiteboarding Ralf Grösel

It seems many features and construction techniques that are featured on the Juice then find their way and become staple features of the whole Duotone range of kites. Is the light wind kite design the best proving grounds for pushing the performance?

I would say yes, clearly. I would compare it to developing a very niche product, there is the requirement to push the boundaries on one side and on the other that it is as commercial as possible. Being commercial is a good thing, it means the kite is popular and successful on the market. Having a kite that more people are able to use the product and access the sport as well as appealing to higher-level riders is important. The Juice will always be in the forefront of the development of new technologies. Also, with the material we are currently developing, the Juice is one of the modules we use to see what we can gain out of new materials.

The Juice has been designed where you just need one size dependent on your board and rider weight, could you talk us through what sizes are suited for which riders?

For the Juice, we currently have three sizes, 13, 15 and 17 square meters. Depending on if you want to use a foil or twin tip board there is a very easy separation. Let’s take the average guy, let’s say 75-80 kilograms, if you want to go as early as possible and with a twin tip, I would highly recommend you take a 15 square meter in combination with a board upwards of 155cm. If you are above 80 kilograms, let's say 100kg, then you should take the 17 square meters alongside again taking the biggest board. Definitely, a Spike Ultra 165cm if you want to be riding as early as possible. The lighter you are, the smaller the kite can be. If you are 60 kilograms a 13 square meter and you will be fine with a Select 141 or 138cm board.

Juice Duotone Kiteboarding Reno Romeu

It’s a completely different story if you are riding with a foil board. With the foil, it’s more about the fact you need the initial hook of power to get you up and onto the foil. Once you are on the foil, the size of the kite doesn’t matter anymore as you are able to generate so much apparent wind. With foiling in the lightest conditions, the size of your board will make a difference in the kite size needed. The more volume the easier it will be to get up and onto the foil. Once you’re up and going, the 13 for example will generate the same amount of apparent wind as the 15, so it’s all down to how much initial pull you need to get you up and going. If you are used to riding smaller kites and you think you have the skill level then you could size down to a 13, if you are a larger rider and need the extra power, take the 17.

For people looking at the Duotone range, there are two light wind kites, what kind of kiteboarder will be best suited to the Juice?

I think the Juice should be in every quiver, because it's the guarantee you'll hit the water first. So, if for example you go on a two week holiday and you really want to have the best experience on the water for as long as possible, take the Juice. In terms of riding styles, if you have really low winds it’s about riding back and forth, but as the wind increases to even 12-13 knots, you are able to make really nice jumps, lofty, floaty, easy, you can do old school manoeuvers and therefore I would say it is a super versatile kite and it should be in ever kiters quiver. Depending on your skill level, it’s quite possible to take the Juice in overpowered conditions to try and boost higher. This is actually what we do, ( Ralf Grösel, Aaron Hadlow and Marian Hund) we take the 15 meter in 20 knots of wind just to get the sensation of flying through the air like a paraglider. The Juice for me is really an all-rounder kite.

How has your paragliding design background influenced your kite designs?

Paragliding designs have influenced me quite a lot. In recent years in paragliding, the focus is to make the equipment as light as possible due to the hike and fly style of flying. You take your gear and hike up a mountain and fly down, or just fly the thermals if they are working good. To reduce the weight, we have to achieve this without reducing strength in the glider as every glider has to be certified always, it is flight sports equipment and this always needs to be certified. The material has to last as long as a heavier glider. It’s absolutely a challenge to reduce the weight without reducing the strength. By developing the ULW concept kite I have been implementing ideas from the paragliding scene, for example, the way the pigtails are developed, the way we are splicing the lines to make them more durable, robust and shock absorbing. I would say it’s a very good match and it was very interesting to combine materials to the point where we could save 25% of the weight from the Juice from two seasons ago but still maintain a kite that is as strong, resistant and long-lasting as we had before. I think this is a great achievement and Paragliding has definitely been an influence.

What were the design goals with the Juice?

The design goals for this year's Juice was to take the market feedback into consideration. We had the feedback that the Juice was the benchmark in light wind kites which were very positive. That was the goal, we achieved it and I think that is something we could really build on. We had feedback that the kite in the very high end when riding powered with regular-sized twin tips had increased sheeting and steering forces and this is what we have been working on. We have stabilised the arc of the kite and the tips in a way that when you are fully powered that you still have the same responsive feeling as you have in the medium wind range.

Juice Duotone Kiteboarding Ralf Grösel Aaron hadlow
Juice Duotone Kiteboarding Ralf Grösel Aaron hadlow marian hund

I (Toby Bromwich) was just in Union Island with Stefan Spiessberger who was amazed at the light wind performance and how fast and responsive it was, performing powered freestyle in barely 13-14 knots on his regular twin tip with boots. He also mentioned how the hang time was pretty amazing in moderate winds, tell us a little about the performance as conditions pick up.

For me, the Juice is like an Evo, it's an all-round kite. What Stefan has experienced, riding in boots and using the kite for wakestyle riding is possible. It’s always depending on the rider and skill level, it’s not that you just take the kite and you become a professional kiteboarder. It gives you the chance to experience that kind of session in conditions you thought were not possible and this is the greatest achievement of the last years. We have increased the range of not only when you can get going on the water, but also having fun on the water, the same way you experience it in higher wind conditions.

Thanks again for your time today Ralf.
Thanks! I hope you have some useful information, if you have the chance to try out the kites, I think you won’t be disappointed!