After extensive trail checking over the past months we happy to announce some course changes for BUTM for 2025. These are partly introduced because part of our previous courses have become increasingly sealed, partly to shake up the courses a bit and give repeat runners some new trail experiences. We have found some spectacular new trails and are working on trying to incorporate them into the courses. Some of these are rather remote with some steep sections and drop-offs that would require additional work from a safety perspective before becoming part of the courses. At this time we have several course amendments that have already been incorporated as briefly outlined below - and we are working on possible further amendments. Full maps and descriptions will be provided in due time before the race. 

The base concept with a central start and finish at Kiulu Riverside, and a "Figure 8" out from here for the 100 km route with the 50k halfway station and dropbag back in the Dewan at Kiulu remains as this works very well and makes logistics easy for runners with own transport. 

The 100k will see some course amendments between start and W1 and between W5 and W6. The biggest change is currently an entirely new trail between W9 and W10 where the track/road has been exchanged for a trail section. The new trail has a relatively steep initial climb, but this is generally covered and well shaded compared to the old exposed climb. This is followed by a long gradual descent, eventually following and crossing a couple of streams several times - offering a welcome opportunity to cool down in hot conditions. In dry conditions, which is the norm at the time of the BUTM, these streams can generally be crossed without getting wet shoes. We have an alternative "high route" in place for safety for the river section in case of heavy rains and risks of flooding of the streams. 

View over Kiulu Valley from new trail section

Sample stream crossing on new trail

 For the 50k route, we are after two years of following "the first loop" of the 100 km trail reverting to the "second loop". This means that the 50k competitors will also be using the new trail section, and for those who have not joined the 50 or 100 km BUTM trails prior to 2023, this will be a very new experience compared to the 50k route over the past 2 years.

The 30 km course will also see significant changes. The 30 km course will now start with a shorter (though still significant) climb at the beginning, followed by a more direct route to W8 at Kitapol which will be the first aid station for the 30k. The traverse of the ridge from W8 at Kitapol to W9 at Namadan will still be part of the course, then followed by the new trail section to W10 at Rangalau, which the 30k did not previously visit.

The 30k will be slightly longer, but with less elevation gain, and is considered to be similar or slightly easier than the previous route. The 50k and 100k routes will as it stands at the moment be slightly shorter. The ITRA / UTMB rankings will be similar and we maintain the generous cutoff times with the intent to let as many as possible complete the courses.