RST SDK Aerosa BAS Forks

Initial thoughts as I removed the forks from the delivery box – these are the wrong forks, I’ve been sent some Marzocchis to try out! These forks are nice and chunky at first glance.

On closer inspection I noticed some very nice one-piece lower legs – rather than the 3-piece bonded at the cantis affair of latter days, these are now a full one-piece lower leg set-up, the major bonus is a stiffer fork as there are less places for the fork to flex. The lower legs are a very large diameter and the brace is plenty thick enough. The fork crown is also of reasonable thickness and diameter to visibly instill confidence in the fork, the upper legs weren’t finished as evenly as say an Rock Shox Sid as some of the coating appears to be thinner in places. The steerer tube is nice and long and leaves bags of room for stem adjustment before finally chopping the excess off – my only suggestion here is to leave plenty of room in the steerer in case you ever need to adjust your stem height – use 2-4 spacers.

Doing the floor-pushing test, the forks seemed very soft and I think they needed some more air in them before riding them. I then decided out of curiosity to find out how much they weighed – I was very surprised to discover they were over 3 lbs (3.1lbs), these forks feel much lighter than 3lbs but it is reassuring to know that the weight is there and therefore the strength is to.

Once you have the fork in your hand, you can’t help but have a closer look at the finish – in stunning white (perhaps Arctic White?), the lower legs are a one-piece assembly with very smooth lines. The top crown looks and feels suitably beefy but the underside of the crown isn’t as well finished as the rest of the fork.

The upper legs are finished in a standard look similar to Manitous and Rock Shox legs, but I did notice that the right leg didn’t have such an even finish as the left leg – time will tell if they wear at an even rate.

The brake bosses are nicely sculpted into the rest of the fork so instead of them looking like add-ons, they blend very well into the whole finish of the fork. The disc mounts are also an excellent thought-out area, with a gusset added to the left leg to support the additional forces a disc brake brings with it, this appears to be a new addition from the 2000 range.

The valve covers are nicely shaped and almost mimic the lightening bolts found on Hopes DH4 rotors, nice touch as it looks more attractive than standard valve caps. These caps simply screw off to reveal a schraeder valve in each leg for adjusting the air pressure in each leg – be careful though, I overtightened the valves by accident and ended up removing the shraeder valve and some air!

These forks seem to have a lot of upper fork leg exposed, with full compression you get 75mm however if the forks use maximum overlap then the actual travel is almost 150mm. Obviously maximum overlap is advantageous as they make the fork stiffer, but this fork is beefy enough to not have to worry about lateral flex until the going gets real tough! The only other thing I did notice was that compared to my Pace RC-36 forks, these forks raised the front-end of my bike by about another 2cms.

I was pleasantly surprised with these forks, my only other experience with RSTs was a few years ago and it was terrible, the wheel flopped about; it couldn’t keep a line; the flex was unbelievable and the travel was either on or off – these forks were a complete revelation, very smooth operation, tracked very well (perhaps even better than my Pace EVO IIIs!), felt very stiff and didn’t feel much different from the extra height. The other bonus was that my DH4 Pro disc simply slid straight on without any spacers and worked right from the beginning!

The first few rides were over general trails and the forks responded very well, not much vibration came through the bars and the steering remained positive. The next few rides were over the clifftops in North Third where the knocks tended to be slightly bigger and more often, again the control was spot on, and the steering remained precise. I did notice through these sections that the forks were working very well as the ride ‘felt’ far smoother than other excursions down the same tracks.

So far so good with these forks, they clean up very well indeed, they don’t appear to be affected by weather or by riding conditions. The only problem I have had with these forks was the right leg discharging the air while cycling over Stirling Bridge – no serious effort as there are a couple thousand cars driving over that bridge daily. I heard a sound like riding over broken glass and the forks sagged.

I’m still unsure what caused the discharge but a quick pump with the fork pump (rather nice piece of kit as well), and the forks returned to normal. I’m running them with 6p.s.i. in each leg so I don’t think it was due to excessive pressure.

In conclusion, I’d be happy to ride these forks, I’m not 100% sure of the price of them, but I believe they are in the region of £200-£300 (pretty broad price band I know!). If I was in the market for a new pair of forks, these would definitely get a look-in – they are very stiff, reasonably light (3.1lbs – not THAT light for an air fork, but they are strong), track very well and feel very strong.

The only other compalint I have about them (alongside the discharge – which so far has been a one-off) is that the hose guide for the disc isn’t slotted – you’d have to actually remove the hose from the brake and thread it through – not a huge hassle if you are servicing your brakes when changing forks but a small pain in the backside if the brakes are working.

I hate giving things top marks simply because I believe everything can be improved, so these forks will get a 4.5 out of 5 overall, they are very good performers and seem to be holding up to the weather and conditions they have been subjected to so far – the seals seem to be pretty good as I ended up jet-washing the bike due to tiredness/laziness after a particluarly muddy ride – jumped on the bike and they still felt plush!