PUSH ACS-3 Conversion by Craig Richards

Push have made quite a name for themselves over the last few years in the suspension game by offering custom tunes and parts for bicycle suspension fork and shocks. Their range is growing and one of their latest offerings is the ACS3 Fox 36 conversion kit which promises a significant step up in performance on the standard F0X 36 Float. The ACS3 kit replaces the standard air spring found in the Float with a hybrid coil and air spring – a coil handling the first two thirds of its travel and a combination of air and coil for the last third of its travel. This way you get the advantage of both spring platforms rolled into one – the initial and mid-stroke performance of a coil combined with the progressive nature of an air spring. This should give you excellent small bump performance – giving you improved traction and stability over chatter – and excellent big hit performance and tune ability. The kit does add a little bit of weight to the fork as a metal spring is heavier than air but with the addition of between 210 and 285 grams, depending on the spring selected. I am not going to go into detail about how the Push ACS3 works – but if you would like more information on the inner workings you can visit the Push website.

I got a new bike a few months ago fitted with a Fox 36 Float, and sported the now-discontinued 36 Vanilla coil fork on my previous bike. Moving to the Float, it definitely was not as plush as my old Vanilla, but didn’t dive as much under braking and felt far sturdier when cornering and hitting things hard. A Fox 36 equipped with the ACS3 conversion kit promises to turn the already exceptional Fox 36 into an unrivalled trail weapon by combining what was so good about the old Vanilla with the pros of the newer Fox models – reduced weight, improved damping and bottom out control and a stiffer chassis – something which should get any rider who leans towards the gravity side of mountain biking sitting a little more upright in their chair. 

I thought I wouldn’t do too much setting up to start with, just ride it a few times and start tweaking it from there. I started out on 50 psi in the air spring and kept my rebound settings as they were and went riding. My first ride was just on the mountain side of 3 Rivers, which is mostly fast, gently graded trail but has enough rough stuff to get a feel for the fork. At the start of the descent is Red Rocks which is littered with rocks (fancy that) - ideal terrain to test the small bump performance of the ACS3 conversion. I didn’t really push things first time round but tried to hit any rocks which were within reasonable distance from the main line. The fork definitely felt far more composed than it did previously on the small chatter and I was also quite surprised by how much more traction I felt I had when cornering – the wheels stick the ground far better than with the old air spring which equates to more grip.

Another of my rides was at the Garden Route Trail Park which I was pretty excited about – I had seen lots of videos and it looked pretty cool – the fact that I had a new toy to test out on the trails only added to the excitement. While riding we bumped into Robbie and because I was only using about two thirds of my 160 mm travel on the fork, we dropped the pressure in the air spring to 10 PSI. This helped but was still not really getting close to using all of the available travel. I then did a few rides at home and tried to get my bottom-out settings tuned over a small drop with a flattish landing. After going off it a few times it became obvious that I was not going to get close to bottoming out and also while cornering I felt the bike’s front end was bit high. So, to get the setup dialled before writing a proper review I decided to order a new spring as my kit came with the black spring which is designed for riders 15 kg heavier than myself (At the time I got this conversion to test out – Robbie only had the black spring available). This process highlights one of the disadvantages of a coil - to change your spring rate you need to change your coil, or alternatively in my situation, eat nothing but pies and ice cream every meal and wash it down with a 6-pack for three weeks straight. As tempting as that sounds I opted for a new spring.  In all honesty though it is very easy to avoid this mistake – Push have an excellent coil selection chart and with a front fork leverage ratios do not come into play meaning it is very difficult to go wrong. 

I am really looking forward to the new coil arriving and getting back out onto the trail – even with a spring that was too stiff for me, the fork still felt better over chatter than the standard air spring – so hopefully with the right coil and getting the setup dialled I’ll be floating over those roots and rocks on a magic carpet while still been able to soak up any big hit situation I find myself in.