Making the XRAY XB2: Part 2 – By Martin Bayer

Following on from Part One is the second installment of Martin Bayer’s brilliant account of the ‘journey traveled’ in developing XRAY’s 2WD 1/10 buggy challenger – the XB2.

“In a last-minute decision, Juraj suggested that our touring car ace Bruno Coelho should try to race 1/10 off-road at the EOS season opener, and if he performed well we could take him to the Worlds.”

Prototype #3

Despite all the challenges we were facing and the recent disappointments, we were all fully motivated to finally break into a new direction. At this point I realized how “crazy” Juraj is when it comes to accomplishments, the more we continued to struggle the higher motivation he had and the harder he worked. Sometimes it seemed like there is nothing he cannot do. I do not know where his motivation comes from, but despite our continued struggles the increased motivation was transferred to me despite myself being completely exhausted with no time to relax. As such without taking any extra time to cry about the current situation, we were back in the R&D stage – again, delaying the project.


Top shaft semi products

I started to feel the pressure from the public and rest of the team. The competition level had in the last year increased again, and the XB4 2WD was hardly competitive in most conditions. Drivers and customers required 2WD and 4WD from the same manufacturer and since we did not have any serious 2WD it was obvious that we started to lose customers in the 4WD class despite the XB4 being one of the best 4WD off-road cars out there. At every event we were getting the same questions, we had mailboxes full with the 2WD questions, and of course the pressure from distributors on XRAY was increasing. And yes, all of this pressure was transferred back onto me as well. Thing were getting critical, and we had to act quickly… and correctly. The world was watching.


With the two different versions of prototypes and dozens of different composite mixture combinations and different chassis material and flex characteristics we already tested, we knew exactly which combinations were good for which conditions. It was pretty much clear that it is impossible with one car to cover all different track conditions. However, we still kept the idea and goal to have one platform that would allow us to have the car for each track condition even if we would need to change some key parts on the car.


Turnbuckle semi products

After brainstorming, analyzing, and thinking about everything what we did in the last 2 years, we decided what we needed to do. The main change was again in the gear box and motor mount assembly and the weight balance of the car, and we needed to change the flex adjustment of the chassis as well. The previous prototype worked great in high-traction conditions so we needed to keep all the configuration from previous prototype but to make it in such a way that it could be changed for low- and medium-traction conditions.


Shock body semi products

As we started to redesign the gear box we changed the concept to make it easier to access the differential without needing to disassemble the whole rear end of the car – which was one of the main things I did not like on the previous. In addition we have reworked the steering and Ackermann geometry and suspension arm shapes to allow the arms to flex more in the low traction conditions. The key area that we reworked significantly was the way how chassis flex is adjusted together with the side guards and front braces and other parts.


After we redesigned the car, new different moulds had to be created so again several months were spent on production after which I got the new gearbox, new arms, new side guards, new middle brace and also a composite chassis together with aluminum, fiberglass, and graphite alternatives to test. With the load of parts I received, we were back where we were the year before. The positive was that I already knew what was working and what was not, so firstly I confirmed that what worked on Prototype #2 also worked on Prototype #3 and only then did I focus on areas which needed improvement.


With the design of this prototype, I could easily swap all the different components so either I came to low, medium, or high-traction conditions, I could easily change chassis, side guards, shock towers, suspension parts to the configuration I needed for the particular track conditions. This has worked great and it was really a joy to quickly adapt to the track.


A small part of brass electrodes for mould production of arms

The first outdoor track we tested on was a medium-traction clay track and luckily the car worked very well. I spent another huge amount of time testing the favorite and selected composite combinations, and it confirmed what we knew from previous testing and experiences: different composite mixtures would have to be used for low- and medium-traction tracks, and different hardness parts for high-traction tracks. To confirm our test results, we visited another outdoor track and the results were pretty much the same so we knew we were finally on the right path.


Diff outdrives semi products

After more extensive testing back & forth, we were much more confident that we had achieved what we needed. As we have successfully made long term tests in low, medium and high-traction tracks, we were finally convinced we had the car we were looking for. The only track we did not test the latest prototype was the very dusty, low-traction conditions. We were confident that the car would work well in such conditions as well, but to be again at the very top performance we knew from previous testing that we would need to have the motor configuration like on our Prototype #1 which has the top shaft above and a possibility to install the motor in middle or in rear behind the rear suspension. After some time we got to a dusty, low-traction track and it confirmed what I expected. Prototype #3 worked very well but for the highest level competition racing it still needed some more traction and cornering speed.


Checking the first Gear Box from mass production

We made some modifications to the chassis and some other parts to allow the installation of the gearbox and motor mount from the Prototype #1 which put the top shaft in a higher position which transfers the weight balance to the rear and generates more traction at the rear of the car. As expected, this configuration greatly helped the car in super-low traction conditions. Finally after almost 3 years of never-ending testing and development, I was completely satisfied and I knew that now I finally had the winner in our hands.


Gear box brass electrode, mould and finished product

Final Design Decision

During the above 3 different prototype stages, we made several prototype pieces for the team so the entire feedback does not rely on my personal feelings only. As prototype production is extremely expensive, we made several pieces only and distributed them among the team. However, some of the prototype parts broke or wore out and the amount of running cars was decreasing, so at some point we were in a situation that we had to ship the last few prototypes left among the team depending on who had a race on which weekend. This was of course a minor issue that set us back a little and required extra logistic management. However, of greater importance was that it was not only myself but everyone else testing the car that confirmed the same performance experiences in different track conditions.


First gear box final mass production sample

As time passed quickly, we had to decide what to do for the final design of the car for mass production. Almost all composite parts were still made only from rapid aluminum moulds so we had to make final decisions for every single part. After several years of development changing and testing so many different parts and ideas, we finally came to that point that we were ready. The stress and pressure was lifted, or more truthfully was shifted back onto Juraj who now had to work out everything from a projection point of view, to ensure that everything would progress as needed.


Firstly we fine-tuned the entire XB2 approval process to determine which parts would make it to the final design, and which final changes and improvements would be incorporated. One significant last-minute change was the change of the chassis design to allow the mounting of two different gearboxes and motor mount holders that would allow placement of the motor in all 3 different positions so the car worked great in every single track condition including the dusty super-low traction conditions or super-high traction astro tracks. This was one of the main features that I really like and I am sure everyone else will appreciate on the production car.


Note graphite, composite and aluminum chassis prototypes

Final Design Production

After we chose all the final parts, the details and dimensions were updated, improved and fixed in 3D, and then after that the most time-consuming and expensive part of production started – the production of the moulds. Being involved in the production process, I can assure you that despite all the parts that are seemingly easy to produce, reality is quite the opposite and it is often quite difficult.  Mould production and the way XRAY places the absolute highest focus on the finest of precision detail is an extremely time-consuming but ultimately worthwhile process. At the end the final product looks and works as perfectly as everyone is used to with XRAY composite parts. To fine tune the holes and important sizes the same mould goes on- and off- the machine, endless corrections and changes are made, pre-production pieces are moulded and then measured and modified accordingly. All the artistic and skilled hand work that the staff incorporates is incredible to watch. To the untrained eye, it all seems like a precision Swiss watch production with absolute focus on the smallest details.


Our goal was to have everything for the XB2 produced and ready for release with the new XB4, and as such to have final production cars and enough spare parts for the World Championship in Japan. With XRAY’s in-house production at maximum capacity, producing all the aluminum, steel, CF, and moulded graphite parts for all their other expected race projects – X12, T4, X1, and XB4 – pushed production expectations well beyond what was realistically possible, so to our great disappointment some of the XB2 steel and aluminum parts even did not start in the (mass) production. Sadly, as time was coming close to the Worlds, we knew there was no chance to finish all the moulds on time, so we had to leave without the production version for the trip to Japan.


First XB2 Race Debuts

After production analysis and a “best scenario forecast” for production was calculated, it was clear that there was no chance we make everything on time for the first EOS season opening race nor for the Worlds, not only for mass production but also for all of the moulds to have at least some team cars. This was very bad news, as the entire prototypes production was so expensive. Sure we were happy that we finished the entire development and were looking for mass production already, but unfortunately we had to accept the situation and with the upcoming World Championship there was no other option than to again produce several team cars separately just for the travelling international race team. Juraj was not happy about this and all the extra costs involved, but there was no other choice and we could not pack up after 3 years of insanely hard work.


Suspension holder production

In a last-minute decision, Juraj suggested that our touring car ace Bruno Coelho should try to race 1/10 off-road at the EOS season opener, and if he performed well we could take him to the Worlds.

Bruno came to our indoor track for private testing, and after some practice days it was clear that his talent would allow him to compete in this class as well. In early September we got the team cars out of production and made our first debut at the EOS with a great result. To the surprise of the entire crowd, the XB2 worked absolutely brilliantly and Bruno showcased his talent by taking TQ honors in qualifiers and we got 3 cars qualified into the A-main. This was certainly a satisfying moment when finally the first real achievement arrived after so many years of brutally hard, never-ending work.


Aluminum shock bodies production

After the debut race at EOS we travelled to Japan for the World Championship where the XB2 confirmed it was fully competitive amongst the world’s best drivers. Not only for the XB2, but also for me and Bruno this was the first World Championship in this class. In qualifiers, Bruno unfortunately had some wrong electronics setting that caused a few problems through a special small-bump section (which we found out after qualifications). At the end I was able to make it to the A-main final and was at the same pace with everyone else but could not make it to the podium. But most importantly, after 3 years of work we had a car that was fully competitive among the world’s best drivers, and as such I could rest a little and hand over the final stages of the XB2 production to the incredible XRAY manufacturing team.


Note two different Gear Box designs

What’s Next?

So this is my story and a small view into the last 3 years of my life. They were extremely tough & demanding, but I learned a lot and improved my knowledge & skills to an all-new level. All of this would not have been possible without the guidance of Juraj as my mentor, the one who got me involved and put his trust in me. To be part of a complex project like this has been a great experience, and I cannot wait for the next projects.

At this moment, the production just finished everything, the design team is working on the instruction manual, the web site and everything else necessary for a successful product release, and I am enjoying the last moments of this project before it goes public.


Am I nervous? Hell yeah!  This will be the first time that a complete start-to-finish project I was responsible for will get into the hands of public who will judge and evaluate my work. I did my best to make the car that measures up perfectly to my expectations and high-performance racing style as well as for any club, regional, or national-level driver. The rest of the judgment is up to you, my friends. So once it becomes available, get your XB2, give it a try, and let me know how you like it. I will be travelling with Team XRAY to all major races around the globe. Not only to race, test, and help customers, but to back up my own creation. Please come to see me at any time with any questions or comments. And finally… enjoy your new XB2, knowing that I put all my best efforts into this project. ‘Til next time.


From right: Bruno Coelho, Martin Wollanka, Martin Bayer, Ales Bayer