Mini 4WD B-MAX GP UK (May 2025) Event Diary

For the very first time, on the 3^rd May 2025, a Mini 4WD B-MAX GP was held in the UK. This first B-MAX event was held at St George’s Church Hall in Morden, London. We entered the competition with two of our A.I Mini 4WDs. This is a diary documenting what happened on that day.

The Racers

Around 30 racers from across the country turned up for the event. They came from different parts of the world including Australia, Hong Kong, Italy, Japan, Philippines and Thailand etc… ; Male and Female racers of all ages; A mixed of experienced and beginner racers. It was a truly multinational, multi-level and multi-generational event. Everyone shares the same passion and interest for Mini 4WD.

The Race Format

There were 3 classes of race: Box stock, B-MAX and Open Class, with Open Class in time attack only. Each racer can enter multiple cars per class (up to two) to give them a better chance of winning. Care was taken to avoid double entry i.e. racing two cars at once, also known as, left hand vs right hand. The organiser utilised a multi-round system so that every entry has at least 3 to 4 goes for each class. The winner of each race went through to the next round whereas the losers would get another chance or 2 to race again for a place in the next round. If a car was accidentally bumped out by a “flying off” car, the unfortunate car would get another chance to go around the track again. As a result, there were plenty of races on that day, which was the whole point of the event – to race!

The Race Track

The track was made up of 6 boxes of Tamiya Mini 4WD Junior Circuit, some straight sections, several slope sections and 20 degree banks. The layout was a high-speed track. It was designed with a simple goal to accommodate all race classes without the need to change the track on the day. The total length was 99.24 metres. It was great to see that many people turned up early and volunteered to help setting up the track and the pit area – a great community spirit.

The Schedule

The schedule was to start setting up the track at 10am, followed by an hour practice session at 11am. The official race would begin at noon starting with boxstock. All races should finish at around 5pm with prizes given to the winners. Everyone had to vacate the venue by 6pm.

The Practice

With the experience of the organisers and the help of fellow racers, the track was ready before schedule. So there was more time for people to test their cars. Even though everyone really wanted to have a go, people were very polite and patient. Racers queued up orderly (perhaps an English trait), with plenty of courtesy and consideration taken to make sure everyone had a chance to practice.

There were stock, B-MAX and open class cars in the practice mix, but care was taken to avoid as much collision as possible. Many racers were busy tweaking their cars, run in motors and charging batteries at their pit station. They bought pretty much everything with them including their collection of cars, bags of spares and high tech tuning kit and charging equipment. Some decided to build their Boxstock car on the day. Some took the opportunity to catch up with old friends and meeting new ones. It was full of energy and activities.

Registration and car inspection were open during the practice session. The organiser prepared some very nicely designed race cards for the day (see photo above) and it was a nice souvenir to keep too. For prizes, we had racers from Hong Kong and from Japan who brought along some nice Mini 4WD souvenirs which were added to the generous collection of prizes for the winners. 

The Race

Box stock

The practice time flew by and it was time to start the Box stock race. Despite being the slowest class, it was very exciting to watch. There were plenty of close wins and everyone was cheering. Racers took turns to help out as track steward. There were plenty of entries with a variety of cars, including a classic Dash! Yonkuro Dash 2 Burning Sun with Type 1 chassis, which got a lot of attention.

Time flies when you had a nice time, it wasn’t long when the Boxstock final race commenced. Mini  4WD is big in the Philippines, so no surprise the final was made up of three racers from the Philippines. The cars were neck to neck from the start. But after a few jumps, one car was leading. It managed to keep the lead and ran stably till the finish line.

B-MAX

After Boxstock, the B-MAX race began. This was the main event of the day and probably had the most entries. The cars were clearly faster and as a result, there were more “accidents”. So more work for our volunteering track stewards. Certainly, there was plenty of drama: some cars landed in the wrong lane after a jump; some even turned around and went the wrong way. The funniest moment happened when a car was unfortunately bumped out by another car, the unlucky car was given a second chance to run around the track again. As long as it could finish successfully, it could go through to the next round. Unfortunately the car flew off after the first corner. What a drama!

I entered the BMAX race with our Tamiya Kumamon MINI 4WD (95281) car modified in B-MAX spec. It was paired with our latest Mark 8 computer but with the AI set to measurement mode only to make it fair to other racers.

The first round went smoothly. The car managed to go around the track without any drama and it won by a good margin.

In the second round, I was racing among some good friends, which was cool. We exchanged some wishes and got down to business. Like the first round, the car ran well from the start, but it had “a moment” at the final jump where it didn’t land perfectly. It tilted and was moving sideways for a brief moment. Luckily it managed to self-correct (due to lower centre of gravity) and didn’t lose too much time. So with a bit of luck, it won race and off to the next round.

In the third round (the semis), one of the racers had a faster car so our car was running in second position pretty much from the start. Unfortunately for him, his car was going too fast and it crashed out after a jump. Our car managed to run smoothly until the end beating the other car and it secured a place in the final. 

The final was a competition among four racers. There were a total of 4 races and each race ran in pairs (instead of three). After some nerve wrecking races we had our winners. Find out more about how it went for us in the Final Words chapter.

Open Class

After all the exciting Boxstock and BMAX races, we had just enough time for open class time attack race. The organiser set up the classic Mini 4WD lap timer and it was ready to go.

Each entry can have up to 3 goes. The best lap time was used as final. Many racers had a go and tried to get the best time. So many racers were pushing their cars to the limit. But with faster cars came bigger risks, many flew off the track and some ended up with quite big damage. However, not long we had a lap record. A record in the 17 seconds range. It was unbroken for quite sometime until a racer managed to get it down to the 16 seconds range. When we thought that was the limit, a racer from Japan managed to get it down to 16.20 seconds, beat the last best time by a mere ~0.03 seconds! What a close win!

We entered our Tamiya MINI 4WD Shirokumakko GT (95304) car to the Open Class with A.I. turned on and ran on e-brakes only (no brake pads). The goal was to benchmark against the best racers. Despite not finishing at the top, the data collected was invaluable.

Our A.I. Mini 4WD in an Open Class Race

Winners and Prize Award Ceremony

Well done for the racers for winning the race. Many congratulations to them. It was a good race. Despite Mini 4WD not being a common hobby in the UK, the standard of the race was high. We noticed that many winning cars ran on FMAs on that day.

Packing Up

After over 7 hours of fun, it was time to pack up and clear the space. It was great to see many people stayed behind and volunteered to help out. With lots of hands, it didn’t take long to pack the track back into boxes and getting the space cleared to a good standard.

After The Event

Some of us got together for a celebration dinner in the nearby area and continued talking about Mini 4WDs and other things.

Final Words

A big thank you to B-MAX GP UK for organising UK first B-MAX Mini 4WD race. It was well organised and everyone had a wonderful time.

It was nice to meet follow racers. There were plenty of discussions and ideas exchanged. The camaraderie was wonderful to see. There were plenty of laughter and surprises during the day. Although Mini 4WD is a competitive sport, everyone was nice and considerate.

We entered the BMAX race with our Kumamon GT racer modified in B-MAX spec, paired with our Mark 8 prototype and AI set to measurement mode only. Despite carrying extra 28 grams of weight (around 17% more than average), we managed to get through to the Final and came 4th!

Our goal was to collect as much valuable running data as possible. So in order to do that, the strategy was to go for a steady setup (taking less risk) which should give us a higher chance of keeping the car in the race.

We applied all the science we know from all the previous experiments including:

• motor selection
• gear selection
• tyres selection
• rollers selection
• brake pad selection and placement
• flight prediction and adjustment of centre of gravity
• etc…

We ran many experiments to find the ideal brake setup and weight balance to get the most stable flight and landing.

We didn’t spend a lot of time doing car maintenance such as greasing bearings and rollers, running in motors and conditioning batteries etc… We were using our old Hyper Dash Pro motor and some old rechargeable batteries. Interestingly, our car is the only BMAX car that didn’t have mass dampers installed. Despite all these and with a bit of luck, the car was stable and fast enough to get into the Final. So this is a win for science.

While many racers had to rely on experience, knowledge and gut feel to tweak their cars, I was able to examine the data collected by the car and tweaked the car accordingly.

Running Data

Some fellow racers mentioned they were interested in the telemetry data we collected, so here are the data as promised. Hope you find them useful for your setup:

• Round 1 (outer lane)
• Round 2 (mid lane)
• Round 3 (mid lane)
• Final 1 (mid lane)
• Final 2 (mid lane)

Column headings description:

• time_ms (Time of record in milliseconds)
• distance_cm (Distance travelled in centimetres)
• speed_mps (Current speed of the car in metre per second)
• targetspeed_mps (Target speed of the car in metre per second)
• accel_fwd_mps2 (Accelerometer: forward and backward acceleration in metre per second square)
• accel_side_mps2 (Accelerometer: sideways acceleration in metre per second square)
• accel_up_mps2 (Accelerometer: up and down acceleration in metre per second square)
• yaw_inverted_dps (Gyroscope: turning left and right in degree per second)
• pitch_inverted_dps (Gyroscope: pitching up and down in degree per second)
• roll_dps (Gyroscope: rolling to the left and right in degree per second)
• motorpower_% (power in percentage i.e. how hard the accelerator was pressed)
• motorspeed_rpm (motor rotation speed in number of rotation per minute)
• sector (car location in sector map)

Hope you enjoyed reading this article. Please feel free to leave a comment on our Facebook page @Mini4Science or through our contact us page.

See you all at the next event.