Fox Float CTD Fork Vs RockShox Revelation

Fox Float CTD

In our last issue we offered some first impressions on the new 150mm travel Fox Float CTD fork. Now we’ve had time to give it a thorough flogging and found it to be a very different beast for 2013.

For us the standout improvement came from their new ‘long travel air spring’, which features on all of their air forks from 130mm of travel and up. With this they’ve made the air volume much bigger, and as a result the spring rate is far more linear. In contrast to previous versions, the fork now uses all of its available travel and does so without running masses of sag or hucking off a small cliff. Around 25% sag now does the trick and the fork wallows and bobs a lot less as a result.

In theory, the linearity of the new design could compromise the small bump performance but Fox has also redesigned the negative spring, making it much longer to ease the fork into its early travel. Their goal was to make it feel more like a coil spring and I feel they’ve done a pretty good job. It uses more travel more of the time, so it really feels like a longer travel fork.

Suspension set-up can be a very individual thing, and some riders may find the new design too linear. Thankfully this is really easy to tune. If you find it bottoming harshly or want a softer initial feel, just add between 2.5ml and 10ml of extra oil to the air chamber. This will make the fork more progressive for those who do lots of jumps and drops.

All was well for the first few weeks, but after that I noticed that the fork was getting sticky and harsh over small bumps. I checked that there was the correct amount of oil in the lower legs but in the end it turned out to be a tolerance issue with the seals. The SKF manufactured seals marked ‘Rev AX’ were a fraction too tight. In most cases this problem has appeared as a squeaking noise but in my case the fork just suffered with excess stiction. With new, looser fitting seals in place (marked Rev BV), the fork was supple once again and stayed that way without the need for constant attention.

After a month of solid riding, I noticed the crown had started to creak under heavy braking. It’s something that I’ve encountered before on Fox forks and I’m told they are working hard to eliminate this issue. While it is annoying, it is not a safety concern; the legs can’t go anywhere. Fox replaces creaky crowns under warranty as long as the fork is being used for its intended purpose (don’t expect a warranty if you’ve been dirt jumping on your XC fork however).

The CTD moniker appears throughout the 2013 Fox range on all their suspension platforms and even their new dropper post (page 46). It describes the three modes on offer; Climb, Trail and Descend. With the longer travel forks, the CTD range is set to be fairly soft—more for trail riding plushness. Climb mode isn’t a full lockout; the fork will still move over a mid-sized bump but it’s definitely firm enough to resist suspension bob. Descend is very active and soft with minimal compression damping for maximum squish. Trail mode will be the go-to setting for most riding situations; it adds a subtle amount of low speed compression damping to reduce bob and brake dive—it doesn’t feel like platform damping and it’s not harsh in any way. The ‘Factory’ level forks come with their ‘Trail Adjust’ feature; this gives you three tuning options within the middle Trail mode. Each of these Trail Adjust options made a subtle change and even the firmest setting didn’t make the fork feel harsh. It’s worth noting that their 100-120mm forks get a firmer CTD tune to please the XC-race crowd.

In the end, the CTD system doesn’t do anything that you couldn’t achieve with their older RLC damper—if anything it limits the ability to make tiny tuning changes. However, it does make the settings easier to comprehend and faster to access on the trail. Overall I think CTD is a positive step. When combined with the new air spring, I think Fox has made a real step forward for 2013.

Sola Sports (02) 9550 1655 / www.foxracingshox.com

RockShox Revelation

Like Fox, RockShox has also introduced a new air spring for 2013 and simplified the tuning options. They used to run ‘Dual Air’; a system that allowed you to adjust the suppleness of the initial travel by changing the pressure in the negative air spring. While it was a good idea that was liked by many, it also confused a good percentage of users too.

Now we have a new version of their Solo-Air spring that’s found throughout the 2013 line—from the XC race-based SID through to the long travel Lyric. With 150mm of travel, the Revelation goes head-to-head with the Fox Float opposite; it’s aimed directly at the long-travel trail bike market.

With the new Solo-Air design, a small dimple on the wall of the inner leg allows air to bleed from the main air spring to the negative spring, automatically balancing the two pressures. While Dual Air allowed for a good deal of flexibility in tuning, most people arrived at fairly evenly matched pressures in the negative and positive chambers. Solo Air does just that with one less valve and no chance of messing anything up.

In recent years RockShox has had a nice linear spring rate on their air forks. Most models use all of their travel with just enough progression and damping to avoid harsh bottoming. Nothing changes on this front for 2013. On our test fork, the auto-setting Solo-Air design works as intended and produced a good neutral feel with just enough initial suppleness. Aside from restricting those who want to get all crazy with their tuning, the only limitation is that you now need to buy a different compression rod if you want to reduce the travel (with Dual Air you only had to add a spacer under the top-out bumper). RockShox still offers their ‘Dual Position’ air spring if you want to vary the travel whilst on the trail.

The RCT3 damper is a relatively new design and it’s now appearing the most commonly spec’d option throughout the Revelation range. While the external adjusters look similar to the longstanding Motion Control system, the dials now have different functions.

RCT3 offers three modes that you can access via the main blue dial; the first is completely open, next is a threshold mode to limit bob whilst still absorbing bumps and the third is a lockout. Where the smaller gold dial used to tune the firmness of the threshold on the older system (it was called the ‘gate’), it’s now marked ‘LS Comp’ and it varies the low speed compression in the fully open setting.

How did it work? Well the locked setting was very firm and close enough to completely rigid. The middle threshold or platform setting has a distinct ‘edge’ to it and it takes a noticeable bump to get the fork moving. It successfully limits bob and pedalling mush but also compromises small-bump compliance. As a 65kg rider, I found the middle setting too firm for all-round riding—it just became a mode for road and smooth fire trail climbing. That said, it might open up and work a little better under a heavier rider or suit someone who wants a firm XC-race feel in the platform mode.

For general trail riding I left the fork in the fully open mode and adjusted the low speed compression – the small gold dial – to fine-tune the firmness. This dial has 12 clicks (three full turns) of adjustment and creates a fairly subtle change to the feel. Get it right and it’ll reduce unwanted fork movement whilst still reacting smoothly to bumps.

Look inside and you’ll find that the new system is very different to the regular Motion Control. Where the RLT was a fairly basic orifice damper, the RCT3 features shim-stacks to control the high-speed compression. The more refined feel is noticeable when riding hard in rough terrain, while the independent low speed compression reduces brake dive.

Whilst there is a learning curve to setting up and using the new RCT3 damper, it is a far more advanced design that provides a smoother action and greater control.

Monza Imports (03) 8327 8080 / www.sram.com

Head to Head

So, how do the latest offerings from Fox and RockShox compare?

Travel Usage

Both forks feature a linear spring rate and willingly used all of their travel in normal trail riding. If you prefer a more progressive fork that better resists bottoming on really big hits, the Fox system is easy to tune by adding oil to the air chamber. Doing so allows a softer initial feel that gets much firmer deeper into the travel. You’d need to make some form of volume reducing spacer or add extra grease to tune the Revelation in the same way, as you can’t add oil to the main air spring. The Fox fork is easier to tune in this regard.

You can change the travel on the Fox fork by placing a spacer under the negative spring, whereas different internals are required with the RockShox system. On the positive side for RockShox, their Solo Air spring is a little lighter and this is reflected in the total fork weights.

Stiffness & Weight

Both brands employ an easy to use 15mm thru-axle (we preferred the Fox system but would be happy with either). Both forks felt very similar in regards to stiffness, if anything the RockShox flexed less in a for-aft direction under heavy braking. Torsional stiffness was a wash, so both forks steered equally and felt similar through ruts and off-camber terrain.

The Fox fork came in at 1,710g with a cut down tapered steerer (without the thru-axle). In the same format, the Revelation was 1,680g, so there’s next to nothing in it. However, if you do have weight weenie tendencies, RockShox also offers their World Cup version. With a one-piece carbon crown and steerer it weighed just 1,530g

Suppleness

While the deep gold Kashima coating on the Fox fork looks impressive, there really wasn’t much between the two forks when it came to their suppleness and ability to track the terrain. If anything the Fox moved a little more smoothly into the initial travel, but this seemed to be more due to their extra-long negative coil spring (with the sticky Rev AX seals the Revelation was a clear winner).

Damper Performance

Whether it’s CTD or RCT3, you’ve got three easy-to-select damper settings. In the stiffest mode, RockShox offers a stiffer lockout than the trail-tuned version of the Fox CTD (the shorter travel Fox models have a stiffer tune in this setting). At the other end, both forks have a very light, active and plush tune in the softest mode. With their new shim-stack equipped damper, RockShox really equals Fox on this front.

You’ll find the biggest variance within the middle damper setting. In this mode, the trail-adjust Fox CTD will appeal to riders who want a really smooth suspension action and are happy to accept a little more fork movement when out of the saddle. The RockShox damper had a harsher feel in the middle mode but better pedalling efficiency. If this harshness isn’t to your liking, you’ll need to leave the RCT3 control open and use the gold ‘LS Comp’ dial to limit bob and dive. While this worked fine, the 12-clicks of adjustment made on the trail fine-tuning less intuitive—you find yourself questioning whether you’d just dialled seven or nine clicks and faffing around more as a result. It ends up being more of a ‘set and forget’ system whilst the Fox CTD encourages you to adjust the low-speed compression damping as you ride.

Value

With a tapered alloy steerer the Revelation sells for $820 versus $1,149 for the Fox. While I personally preferred the feel and usability of the three-mode Fox CTD damper, the Revelation matches it in most performance aspects and is a good deal cheaper. If all-out lightweight is your goal, the Revelation World Cup goes for $1,250 and knocks a good 180g off the weight of the Fox. While the winner will depend a lot on your personal preference, it’s pretty hard to argue with the value offered by the regular Revelation RCT3 fork.