There have been a few photos strategically released from Rock Shox via their Facebook page, showing images of a new suspension fork. The images don’t show a whole fork, but started with a steerer tube, then a crown, and then the seals showing the legs – both upper and lower.
So you’ve all guessed it, it’s an upside down fork, an inverted suspension fork – or a USD for the sake of simplicity from here on in. These aren’t new – companies have been testing and producing USD forks since I started flicking through Mountain Bike Action in the library in the early 90’s. Marzocchi, Maverick, Manitou and numerous other smaller players in the mountain bike suspension market have all tried it, and many continue to do so. X-Fusion are currently working on an all mountain model for 2015.
So why is it the right time for Rock Shox to release something? There are a few things to consider.
The Market
We all like new things. And with the informal 2015 trade show that is Sea Otter looming, Rock Shox now have something exciting to release. An upside down fork, with a product name of RS-1, drawing on the lineage of the brand.
Bike Variability
There are three wheel sizes that are commonly used now. 26″ may not get a lot of high end development in the coming years, but bikes will be around for years to come. Right now, manufacturers are producing in three sizes. 26″, 27’5″ and 29″. And for some products, they need to be Lefty compatible, or for Fat Bikes. An inverted design might allow Rock Shox to combine 26″ and 27.5″ models into the one unit. MRP are already doing this with their forks.
But, with the shift to 29ers, bikes are getting tall. That’s ok for some, but shorter riders on XC and marathon bikes have a lot of trouble getting their bars low enough for their position. Looking at the build of these forks they seem to be aimed at XC/Marathon use. And the one piece carbon crown/steerer/upper (CSU) could be moulded for a lower crown to axle height, with the addition of low weight and increased stiffness.
Component and Material Advancement
Speaking of carbon CSU’s, Rock Shox have been making these for a while. Their R&D in-house and through their BlackBox program no doubt means they know what they can do with carbon technology. A current SID World Cup isn’t a Future Shock from the 90’s.
Disc brakes are just about standard on any mountain bike now, and these are essential for any USD fork design. So there are no design constraints there.
USD forks have often been criticised for stiffness. We haven’t seen the dropouts yet, but a USD fork needs the legs to be held together well. X-Fusion are using a Syntace X12 setup, QR15 could be ok, but maybe a 20mm axle will be used? Without the fork bridge that a traditional mountain bike fork has, the dropouts will need some extra heft. The legs don’t look massive, but depending on the travel the forks will offer, there might be so much overlap that doesn’t matter so much.
USD forks are said to keep the seals better lubricated, although other models past and present have been said to experience seal problems with pressure. Think back ten years or more and a lot of forks ran boots on them. None do anymore. A lot of riders used to fit Enduro seals at the first chance they could, but seal quality is getting a lot better. No doubt Rock Shox believe they have theirs dialled.
The problems
But what about controls? How can we have dials at hands reach, or something remote? Are electronics involved? if QR15 isn’t stiff enough, do XC bikes need to adopt a 20mm standard? What’s the treatment on the legs, is it durable enough to protect from rock strikes? Is the service period shortened? There are still a lot of questions until there’s a full product release. Maybe we will see them launched under Rock Shox sponsored riders at the Cape Epic this weekend?
So a USD fork isn’t new. Not for mountain bikes. Obviously not for motorbikes either. And what’s a Lefty or Headshok anyway save for a USD suspension item? From what can be guessed from what we have seen, Rock Shox have developed a USD fork for the XC/Marathon crowd, something that will get the ride height where people want it, with lower weight and the same or better stiffness than a SID World Cup. Many of the inherent problems stopping a mass adoption of USD forks may well have been solved.
Time will tell, but Rock Shox have a lot of people wondering what exactly the new version of the RS-1 will be.