4 Hour & J90 Race


 ACERBIS 4 HOUR & MOTOMUCK JUNIOR 90: Date: 2nd November 2019!

Congratulations to Brad Groombridge winner of the Acerbis 4 hour 2018, a record six-time outright winner of this race, and an incredible five times now as an ironman rider!

All detailed results at: www.silverbullet.co.nz

The Taupo 4-Hour endurance race event has been the best supported motorcycle race event of its kind in the country since 2009- Here is a list of the overall winners since this popular race began:

2009: Team Rhys Carter/Nick Saunders
2010: Team Brad Groombridge/Daryl Hurley
2011: Team Peter Broxholme/Chris Power
2012: Team Jesse Donnelly/Rhys Carter
2013: Ironman Brad Groombridge
2014: Ironman Brad Groombridge
2015: Team Liam Draper/Hadleigh Knight
2016: Ironman Brad Groombridge
2017: Ironman Brad Groombridge
2018: Ironman Brad Groombridge

The 2018 Epic season will finish in style with the endurance race of the year on Saturday October 27th. This years race is shaping up to be even better than ever with a fantastic XC style track in a stunning location! We expect the event to prove once again to be the most popular and best supported premier motorcycle endurance race in the country with an estimated 300 riders taking on the challenge. We'll have a great cross section of fast and not as fast riders in the mix and anyone of these either Ironmen or Teams, could take out the overall place…it’s going to make an exciting race!

For all detailed event information view the PDF entry form below:

The venue is 25 minutes west of Taupo, and comprises a 30km flowing forest & farm track within gum, pine & native forest, close to the lake edge, with sweeping turns, hill climbs and drop offs, connected with a series of existing old farm tracks - it's going to be an awesome ride!

There's heaps of great parking, pit area and a fantastic race start, all on a disused farm airstrip, and with fantastic viewing points to watch parts of the race.

You don't have to be an all time racer to enter the 4 Hour - just a well prepared bike and some basic fitness. There's always a great atmosphere at the 4 Hour as many of the riders are just mates racing mates!
There is only 1 bike per individual, but remember teams may use 2 bikes.
To spice it all up there are heaps of awesome prizes - all to be given away after the race at the race venue! 

  • Fantastic pumice base incorporating a 30km flowing forest & farm trail within the trees with loads of variation.
  • Iron-Man pit bypass route
  • Teams can choose to ride their own bike or share
  • Loads of class options including Father/Son team class
  • Vets team - now with combined age 80+ - Great fun making that choice!
  • Trophies, prizes and spot-prizes galore!
  • Prizegiving directly after the race at the race venue so you all get a chance to win.
  • Motomuck Junior 90 Race for ages 11-16
  • Purpose built 20km flowing, forest & farm pumice trail
  • Novice Woman class 17+ - so come on girls, this is your chance to have a load of fun and test those skills without the pressure!
  • All Motomuck J90 race finishers receive a medal PLUS loads of prizes to be won!

Congratulations to Brad Groombridge winner of the Acerbis 4 hour 2017, a record five-time outright winner of this race, and an incredible four times now as an ironman rider!

2017 Results click here : Silverbullet                                     


For all results for Acerbis 4 Hour & Motomuck Junior 90 2016 - check out:


Check out the story of the race:


Check out some wicked video footage:


CONGRATULATIONS  to the winners of the Acerbis 4 Hour! 

Overall 1st Place to Ironman Brad Groombridge of Taupo - Suzuki
2nd Adam Reeves/Chris Power - Yamaha
3rd Greg De Lautour/Cam Dillon - Honda

Congratulations to all the other winners and the finishers of this 6th annual Acerbis 4 Hour endurance race!

CONGRATULATIONS to the Junior riders in the Motomuck J90 race!

Overall 1st Place to Ashton Grey - KTM
2nd Place - Duncan Summerfield - KTM
3rd Place - Jackson Walker - Yamaha 

For all official results go to: http://www.silverbullet.co.nz/news.php?id=4952

CONGRATULATIONS  to the winners of the Acerbis 4 Hour 2013! 

Overall 1st Place to Ironman Brad Groombridge of Taupo - Suzuki
2nd Callan May/Adrian Smith - Yamaha
3rd Hadleigh Knight/Aaron Wiltshire - KTM

Congratulations to all the other winners and the finishers of this 5th annual Acerbis 4 Hour endurance race!

CONGRATULATIONS to the Junior riders in the Motomuck J90 race!

Overall 1st Place Waren Bartlett of Taupo - KTM
2nd Place Taylor Grey of Cambridge - KTM
3rd Place Reyben Steens of Tauranga - Yamaha 

For all official results go to: http://www.silverbullet.co.nz/news.php?id=4828

 Taupo's Brad Groombridge - Creating history by winning the Overall Acerbis 4 Hour Endurance race as the first man to win it as an Ironman!

It wasn't all plain sailing for Brad riding his Suzuki RMZ450 for 4 hours and a gruelling 7 laps of the 30km course. Hundreds of bikes created a massive dusty log-jam after the shot gun start and the riders headed into the forest for the first lap, with Groombridge finding himself trapped in the traffic. Fortunately he managed to avoid any carnage but with 18 riders in front of him he had a lot of work ahead to claw his way to the front.

By the end of lap 3, Groombridge rocketed through to take the lead ahead of holeshot winner Scotty Moir, and followed closely by Morrinsville's Simon Lansdaal. He kept pushing on and eventually won the race from the hard-charging Yamaha two-rider tag team, Adrian Smith and Callan May, and KTM riders Hadleigh Knight and Aaron Wiltshier.

Groombridge had a winning margin of just less than a minute which made for one heck of a close and very thrilling finish!

Video: Many thanks to all those who made a big effort out there with their cams during this event....great job! 





The Epic Endurance Race of the Year
THE ACERBIS 4 HOUR & Motomuck Junior 90 2013!

  • New Venue and purpose built 30km track through forest all on pumice soil!
  • New Team Father/Son class!
  • New Team Vets class with combined age of 80+!
  • Motomuck J90 Race for juniors 11-16
  • Fantastic Prizes, spot-prizes, trophies!


NZ’s premier Endurance Race, Taupo’s Acerbis 4 Hour, draws a huge field of riders from across the country. Back for 2013 with a brand new venue and purpose built track, the Acerbis 4 Hour will roar into life with around 250 bikes exploding into action at the shotgun start.

Junior riders wanting a piece of the action can enter the Motomuck Junior 90 Race, run as a prequel to the main event. This is the 3rd year for this increasingly popular junior race, without the pressure of MX! Great prizes and spotprizes!!

At the 2012 Acerbis 4 Hour there had been loads of rain in the weeks leading up to the event, but the day was picture perfect, hot and dry. Of the 24km track, the 12.3km amongst the trees held up well and the shade was a welcome relief during this challenging race. With the dry and the heat and shear rider numbers, the open pumice track in the cutover quickly whooped up, making the race competitive and tough and leaving most riders drained after 4 hours.

Changes had been made for 2012 allowing all teams to have the option of either sharing a bike or riding their own, also ruling that all teams must swap riders after every lap. Lap times were taking over 35minutes, even for the fastest riders. This gave the ironman a slight advantage if a fuel stop wasn’t required at every lap as they could roar down the pit bypass lane at race pace.
Holeshot winner was Greg De Latour,  riding his KTM 350XC, who also achieved one of the fastest lap times of 35:08. But on his 3rd lap he suffered a broken fuel line and was out of the race.  
So it was Rhys Carter and Jesse Donnelly, sharing a Suzuki RMZ250, that stole the lead soon after the holeshot, had over a 2 minute lead after lap one, and an impressive 4 minute lead 2 laps later.  Despite the fact that they had not read the rules prior to the race and had only brought one bike to share, making pit stops very lengthy compared to rivals Reece and Allan Burgess, Husaberg FE450 and KTM 350SXF, holding 2nd place all the way till lap 5. Team Suzuki’s Mark Penny on his RMX450 and Josh Jack riding his RMZ250 on fire and chasing hard after what they described as a “shocking start”.

Penny took advantage of Reece Burgess’s small error on the fifth lap, and finished the race after 7 laps  in 2nd place overall, and 1st for the Big Bore Teams class. The Burgess brothers  finishing 3rd overall.
But it was Carter and Donnelly in the end and throughout the entire race taking the big win with just under a three minute gap, and winning the small bore teams class with an impressive margin of 20 minutes!
Taupo’s Brad Groombridge, riding his Honda CRF450 was one of the hardy breed of individuals who chose to ride the ironman option. After a fantastic 7th place overall as ironman in the recent Suzuki 6 Hour, Groombridge was determined to achieve even better than this as a one-man-band. And he certainly did, winning the ironman big bore after 7 demanding laps, and 4th overall behind the two-man teams Carter/Donnelly, Penny/Jack and Burgess/Burgess. Groombridge finished almost 9 minutes ahead of runner-up ironman rival Sam Brown, Honda CRF450, from Hamilton.
Another fantastic result were junior riders Jason Dickey and Matthew Quirke, KTM 350XC, winning the junior team trophy with an average lap time of 36:27 and 7th place overall, three minutes ahead of junior rivals Hadleigh Knight and Aaron Wiltshire.
South Waikato’s Edwina Wooderson tackled this gruelling race as an ironman woman, riding her tiny Yamaha YZ85, defying all odds and taking the ironman womans crown ahead of Tauranga’s Ashley Bond on her KTM 150SX.
The Tui girls were looking sharp handing out ice-cold Tui’s under the Acerbis Arch at the finish line. All those riders certainly deserved a drink!

   2012 Winners

Congratulations goes to everyone for their big efforts on a demanding track!

Motomuck Junior 90

For the second year running, The Motomuck Junior 90 race was run as a prequel to the main event for junior riders and novice women. This scaled down version of the Acerbis 4 Hour proved a big hit with entries having doubled last years lineup.
An early start of 8.30am saw almost 80 riders and bikes fire into life, with Taupo’s Hadleigh Knight winning the holeshot and the entire 90 minute race on his KTM 125SX. This talented 16 year old MX rider is certainly somebody to watch in the future of this sport, as after winning the Motomuck Junior race, Hadleigh joined with team mate Aaron Wiltshire and went on to race the demanding 4 hours of the main event to finish 10th overall.

 Hadleigh Knight scoring the holeshot in the Motomuck J90 race

Finishing 2nd in the Motomuck Junior 90 with just under a four minute gap was Nathan Sharland, KTM 125EXC, followed just seconds later by Cohen Chase, KTM 125SX.
Finishing 1st in the popular novice women class was Taupo’s Samantha Akhtar, Suzuki RM125, with a comfortable 7 minute lead from novice rival Sianella Owen, Gas Gas EC125.
The Motomuck Junior 90 race is no doubt very popular, giving young and novice riders the opportunity to take part in a real endurance race, without the pressure of the big numbers and the gun-ho’s.

Overall Results Acerbis 4 Hour 2012:


Rhys Carter / Jesse Donnelly

Mount Maunganui

Suzuki RMZ250


Mark Penny / Josh Jack

Pirongia / Kaukapakapa

Suzuki RMX450 / Suzuki RMZ250


Reece Burgess / Allan Burgess


Husaberg FE450 / KTM 350SXF


Brad Groombridge


Honda CRF450


Simon Lansdaal / Lance O’Dea

Morrinsville / Opotiki

Husqvarna TC250 / TC450


Adam Reeves / Chris Power

Palmerston North / Paeroa

Yamaha YZ450F / WR450F


Jason Dickey / Matthew Quirke




Callum Birch / Scott Birch


Honda CRF450R


Brendon Imlig / Nathan Tesselaar

Reporoa / Patetonga



Hadleigh Knight / Aaron Wiltshire



2012 Acerbis 4 Hour & Motomuck Junior 90 Results:


2012 Video: 





Riders Feedback 2012:

"Wow"..... what a top show you put on. I must say how all my friends thought the same and how well organised it was. It's a crying shame that track doesn't get used again though.

Thank you for a well run event. I ride most of your events and every weekend. It was the hardest ironman I have done with blisters on both hands and that never happens. I still rode on sunday. You have a great team so thanks from us as old riders.

Thanks, it was a successful event all round. the track was fine, the trees allowed a nice break. my bike was bottoming out into corners in the 2nd half so I dialed it back to where it was safe and steady but that's my choice as I was a tad soft. plenty of good lines around if you were fit enough to enjoy them so no complaints. rough would be an expected comment, not a complaint, that's racing.

the cold beer was a nice touch at the end. 

Thank you guys for holding such a great event, yeah the track didn't really resemble the sneak preview photos by the time I got to it haha, but it was a great test for my Race Tech suspension, that track had every element that a track could have, I thoroughly enjoyed it, and after that race I am a big step closer to perfecting my suspension setup.

Hi guys,
Thanks for putting on an awesome event again.
Thoughly enjoyed it. Bloody sore but all good.

Hi Claire
Thanks for running such a great event!

Just an email to say this is my first 4 hour event and would like to congratulate you on a well run event.I have ridden in all your other events in Taupo and at 66yrs old am having a lot of fun times and will be back next year.Once again well done

It was a great event and it’s a credit to you guys, maybe win it time ,roll on next year!

Hi Guys
WELL DONE we are super proud of you what an amazing effort and event, you have tired Enduro/Cross Country Riders that is for sure!

Hi Claire and Gordon,
Thanks very much for running such a great event. The numbers speak for themselves.

Hey Guys
Just wanted to say thanks for putting on an awesome event Saturday. Ok, carting everything down to the pits and back was a bit of a slog :-) but the track was heaps of fun to ride even when my arms were turning to jelly :-) Look forward to next year!


2013 Acerbis 4 Hour – New Classes, New Venue, New Track

Yes…it’s time to get on the line at Epic Events and enter for year 5 of this famous endurance race taking place on 2nd November 2013. You don’t have to be a legend like Daryl Hurley or rocket ship like Cody Cooper to enter either. Anyone with some reasonable riding skills can give it a go! Choosing the teams option is really fun, and a social way to enjoy the event.

The Four Hour first exploded into the NZ cross country scene in 2009, attracting 350 riders racing as individuals or 2 man teams. This race was won by the green team of Nick Saunders and Rhys Carter who just beat Ironman Sam Greenslade. In 2010 the event gained a new venue, attracting nearly 400 riders, and was won by Suzuki duo Daryl Hurley and Brad Groombridge. The nailbiting finish of the 4 Hour in 2011 created a fantastic atmosphere when the Yamaha lead was stolen by the blistering pace of team Honda, who produced the fastest lap of the day of 29 minutes and 15 seconds. The combined speed of Peter Broxholme and Karl Power was too much for the rest of the field as they guided their CRF250 home for the win.
Of interest is the top 4 placings last year were taken up by small bore bikes, so obviously horsepower was no advantage on the day!

Now the crew at Epic Events are stoking the fire for year 5 – the first big change is the name, with the race proudly called The Acerbis 4 Hour – Acerbis have taken on title sponsorship and are providing some fantastic prizes, many of which are given out at random at prizegiving!

The race organisers are now allowing all teams to choose between either sharing a bike or riding their own – bearing in mind the class they have entered must be that of the greater cc rating of the 2 bikes.

The 2013 event will be held in the south side of Tahorakuri Forest, only 10 minutes from Taupo. The start of this race is always a huge spectacle with over 200 dirt bikes firing into action and tearing down the start, before charging into the bush, then back near the pits and out on another separate loop. At the end of this the riders will have done around 30km of berms and twisting trail, and will have the choice of entering a pit stop to change riders, or bypass the pits if you’re an Ironman and have enough fuel onboard to make it round another lap. Repeat all this 6 times and 4 hours later, and this is the Acerbis 4 Hour 2013!

While this is a national class race, the focus is on everyone having a great time on and off the track. There will be intense rivalry at the sharp end of the field and all the way through with mates racing mates and brand against brand, but at the end of the day everyone ends up having a laugh, maybe a prize or two, and telling all the post event lies about how fast we were…or used to be!

Motomuck Junior 90

First run in 2011, and a huge success, this race is for the young guns AND the novice women, and takes place prior to the main event earlier in the morning. This junior race is a great alternative to motocross for kids who want to race, but don’t want the pressure and close contact involved with MX. It incorporates all the aspects that make up the main race in a compact 90 minute version for 11-16 year olds, and novice women 17 years and above. The Motomuck 90 is for individual riders only, and is run over part of the Acerbis 4 Hour track.

In summary…the Acerbis 4 Hour and Motomuck Junior 90 2013 will be bigger, earlier, better, brighter, funnier and younger than ever….you’d be mad to miss it….. 


The Acerbis 4 hour is a motorcycle endurance race located just 10 minutes from Taupo.  The pine forest/pumice soil track is around 30km long and will feature the berms, hills and fantastic 'flow' that Epic Events is known for.  Riders can enter as individuals or two person teams.  One bike per individual (ironman), or teams can choose to ride two bikes or share one bike. There are heaps of prizes up for grabs.  The event is really social with a great prizegiving at the race venue after the event. For the junior riders we are again running the MOTOMUCK Junior 90(minute) race, and a class for novice women! Highly successful in 2012, so kids you won't want to miss out on this year!

The Acerbis Four hour is New Zealand’s premier off road motorcycle endurance race held in Tahorakuri Forest, SH 5 just 15 minutes from Taupo. 

The 30km track includes jumps, berms and twisting trail amongst the forest on Epic's famous pumice soil. 

Just under 250 riders line up on the start ready to explode into action when the shotgun announces the start.  Most riders take part in teams of 2 swapping every lap.  Special riders called ‘Ironmen’ take on the 4 hours on their own. 

Riders need speed, skills, fitness and determination if they wish to take the take on the Acerbis Four hour with the title going to the absolute strongest and fastest rider.

For the junior riders we are again running the MOTOMUCK Junior 90(minute) race, and a class for novice women! Highly successful in 2012, so kids and ladies, you won't want to miss out on this year!

As a prequel to the main event, this race is held which incorporates all the great aspects that make up the main race in a compact version for 11-16 year olds. Over the same 90 minutes, there is also a novice women’s class. The Motomuck 90 is for individual riders only, and is run over part of the Acerbis 4 Hour track.








Leatt Four Hour ALL LAP TIMES



View results of MOTOMUCK Junior on my laps website http://www.mylaps.com/results/showrun.jsp?id=1933846

View results of LEATT Four Hour on my laps website http://www.mylaps.com/results/showrun.jsp?id=1933847

Four Hour Report

21 June 2011

 Set it off

 Motomuck Junior 90.

 The scaled down version of the Leatt Four hour gave young riders the opportunity to take part in a real endurance race with most of the same event elements as the big race.

 Blasting off at 8:30 into the rain soaked track the 40 odd riders got away cleanly.  Juniors competed on a 13km track (around half the distance of the Seniors which meant that Parents could keep a good eye on the youngsters.  In the end Cameron Vaughan won over Hadleigh Knight in 2nd with Anthony Parker rounding out the top 3.  Sean Clarke’s son Jesse took out 4th to put Dad in a good mood for his race later in the day.

 The event will now build upon this first trial and there should be twice the amount of riders on the Motomuck Junior 90 start line in 2012.

 And now to the big race.

 Four Hour

 The start is always a huge spectacle as over 200 dirt bikes are fired into action.  The start was clean with most riders making it around the first 2km of grass track rubber side down.  After 22km of forest riding Adrian Smith appeared on his Yamaha and must have had about a 30 second lead on 2nd.

 With the lap time taking around 30 minutes even for the fastest riders, it meant a fuel stop was required for most riders every lap.  So the art of a quick (but legal) pit stop was critical.

 The Yamaha lead was stolen by the blistering pace of team Honda who produced the fastest lap of the day of 29 min and 15 seconds.  The combined speed of Peter Broxholme and Karl Power was too much for the rest of the field and they guided their CRF250 home for the win.

 Top 3 results.

  1. Peter Broxholme and Karl Power
  2. Adrian Smith and Callan May
  3. Cameron Negus and Barry Morris

 Of interest is that the top 4 placings were taken up by small bore bikes so obviously huge horsepower was not an advantage on the day.

 Great to see the legendary Sean Clarke taking out First Ironman, First Veteran and 7th overall.

 Another fantastic result was Greg DeLatour and Jono Hill taking out 8th overall and First Junior team.  (Greg, your Dad will be proud).

 Track conditions were described as amazingly dry considering the rain, but very, very bumpy which left most riders pretty drained after 4 hours.  So well done to all those individuals who took on the Ironman option. 


View results in web based format by clicking on this link:


Or check the following results in PDF format


Lap times

Class results


Our man Adam Wallis from event image capture was on site to well obviously capture all the action.  Click here to view over 800 photos that are available to purchase. 


The results are loaded on to www.mylaps.com This is probably the best place to view the results beause the report includes total times.  Or you can click on the links below to view overall and class results.  The 'ALL LAP TIMES' is interesting to read.WWW.MYLAPS.COM