Officially this is the Fox Racing Shox 34 Float 29 and the Float RP23 rear shock. I've run this suspension on a Transition Bandit 29er (previewed for MTBR here) and now had over 50 rides on the bike. I've run Kashima coated forks for over 100 rides on my personal bikes and therefore feel comfortable speaking to the coating's longevity.

As an aside, it never ceases to amaze me when a review in mid-year is already dated. The Fox website is loudly proclaiming its 2013 lineup on the homepage but for the sake of posterity, here in June 2012 is the Fox 2012 Fork lineup. I'll make no excuses for taking my time to vet a product and give impressions based on more than cursory use. First I'll briefly describe technical details. Then I'll relate impressions.

random places in Mount Seymour trails in North Vancouver where I found terrifically flat "old-school" drops. A fantastic place to test the ability of front and rear suspension. And yes...I had a lot of fun making this video

Lee Lau's biases

I am 160 lbs and 5'11" and have had over 15 years experience riding bikes in North Vancouver, Squamish, Whistler, the Chilcotins and many other areas in B.C. and Alberta. I've also made many bike trips to Switzerland, Utah, Washington, Oregon, California and the Yukon (for example) so I've had some experience biking in a variety of terrain. My bias is towards pedalling up and unlike many people who learned to ride bikes on North Shore trails, I actually enjoy riding (and sometimes bushwhacking) uphill.

My personal bikes are a Santa Cruz Tallboy, Pivot Mach 5, and a Specialized Demo 7. As previously mentioned, I had this front and rear suspension on a Transition Bandit 29er. I also have Kashima-coated Fox front and rear suspension on the Pivot and the Tallboy so have had over 100 days on Kashima coated suspension.



Fox 34 Float 29er Technical Details

This fork is part of the family of Fox's ubiquitous FIT-cartridge equipped front suspension found throughout its lineup. New for this year are 34mm stanchions and 29er specific arches (more room for the bigger wheels). I tested the Float version which was a fixed 140mm travel (travel can be adjusted down with internal spacers but it's not adjustable on the fly). From the website here are other details
  • OEM colour is black. Aftermarket colour is white
  • The quick release is Fox/Shimano's 15mm through-axle
  • Claimed weight is 4.32lb/1.96kg with (1.5" tapered steerer). I neglected to check weights on my tapered version till I cut the steerer to 7". Even then it weighed in at 4.01lbs. I had no idea that 1.5 steerers were that heavy
  • Travel is 140mm/5.5"
  • Post-style mounts for disc brakes
  • Suspension is an air spring (found in the left leg). Adjustments are low-speed compression and a lockout flip switch on the top of the right leg. Rebound adjustments are on the lower right leg
  • Axle to crown measurement is 552.8mm (520mm for the Fox F29 120mm if you're curious - more measurements for different forks are here)
  • There's no official tire size limit I could find stated. This may be academic as 29er tires haven't got to ridiculous sizes yet. I fit a 2.5 WTB 29er tire in this fork without issue.
The F34 Float's FIT technology is old news so I'll waste only a few words on it. Basically FIT (or Fox Isolation Technology) incorporates a bladder system to keep oil and air separate presumably giving a more consistent shock feel over the course of a long downhill. It replaced Fox's old open bath designs which were a bit heavier (more oil was necessary). Finally service intervals should be longer as the damping oil in the cartridge no longer also serves as lubricating oil - thus theoretically reducing wear and tear.

Kashima coating applied to the F34's stanchion is also old news. It's an anodizing process applied on the upper tubes of the fork (and the body of the RP23 rear shock). The claimed effect is to reduce friction and increase reliability by increasing surface hardness of the aluminium. Borrowed from motorcycle technology, Kashima coat is impregnated molybdenum sulphide deposited on micropores on the surface of hard-anodized aluminum. Since 2009 when it was first introduced into the international mountain bike racing circuit, the distinctive gold colored Kashima coated stanchions have been reported to offer better lubrication characteristics, attain a level of hardness and abrasion resistance four times tougher than standard hard-anodized aluminum in lighter weight package. Tech weenie details aside Kashima is gold - coloured and everyone knows that gold coloured parts are 3.141529x stiffer, stronger, faster ...

SKF Seals are new for Fox forks in 2012.Popular in motocross industries they are purportedly lower friction and seal better (which kind of begs the question why it took Fox so long to start using them - but maybe I'm just cynical). If you have a 2012 fork you'll have those seals. It's worth noting that you can purchase them aftermarket from Fox direct and install them.



Fox Float RP23 Technical Details

The RP23 really needs no introduction. It's become the standard for rear shocks and, with Kashima coat in 2012, is now the gold standard. Otherwise it's unchanged from previous variants. Technical details follow
  • Claimed weight of 0.46lbs for the 6.5x1.5 size (no reducers)
  • Lots of different sizes from 5.50 x 1.00 all the way to 8.5 x 2.5
  • Adjustments feature rebound, propedal on/off, compression adjustment and air spring via a schrader valve
Three key technologies bear highlighting. Kashima is already explained above. The others are Boost Valve which is an actual valve in the rear shock (pictures, video and more tech speak here). The RP23 (and RP2) have always been velocity sensitive in that the air spring activates differently depending on whether an impact is high or low speed. Boost valve is position sensitive; activating to increase compression damping at the bottom part of stroke ie when the shock is deeper in its travel. The theory is that the rear shock preserves plushness and small bump sensitivity in smaller hits but ramps up during bigger hits that use up all of the stroke.

Adaptive Logic is a fancy name for re-arranging the Propedal lever so it can thoroughly confuse riders who were used to the old lever. Basically now you set a preferred level of open compression (0 to 2 with 0 being wide open) and then flick a switch to go from "climbing mode" (or compression level 3) to the open compression with one flick of the switch. Mild complaints aside once you learn the new habit it's pretty easy to remember which way to turn the lever of the RP23.



Fox 34 Float 29er Impressions

Suspensionwerx of North Vancouver helped me set up the fork. Initial settings for sag of 25% were 60 PSI, LSC 4 clicks in. I'd have to conclude that Fox's recommended settings were a tad high (my recommended setting is 75psi) but its pretty easy to check for yourself. Here's some observations on performance:
  • The F34 feels decently smooth out of the box. As does most suspension, it does need some break-in so check your air pressure against your sag after say six or so rides. I couldn't say whether the fork was smoother after it broke in - all I can say is that I added a bit more air (5psi) to get the fork to stay at 25% sag so it must have overcome some initial pre-breakin stiction.
  • I took the fork apart when it arrived and it came with the correct amount of oil in the lowers so QC from my single sample size passes. After approximately 50 rides I took the lowers off again, checked oil and noted no discolouration characteristic of contamination. I'd have to conclude that the SKF seals are doing their job of keeping out mud and muck
  • Further to that note, the Kashima coating is undamaged and still looks beeeyooutiful. I'll note that my older Kashima coated Fox forks with 100+ rides also look pristine so longevity of the coating also gets a pass.
  • The FIT cartridge damping on the F34 chassis is much improved over the lamentably underdamped 2011 Fox FIT which blew through travel mid-stroke (my experiences were with the 2011 F32 Talas 150 and F36 Talas 160). With the 2012 FIT, it's possible to set up the F34 Float so that travel is as it should be; supple at the start of the stroke and progressively more supportive towards the middle and end of the stroke.
  • Having said that, low-speed compression settings don't seem to do too much. My preference is to run as wide open as possible with just a touch of low speed compression. To achieve this I have to wind in halfway through the LSC dials. I'll contrast this (unfavourably) with almost all other brands where the compression settings generally make meaningful differences.
The last comment is to fork stiffness and is a point which has been interminably debated on MTBR .On this topic, TO ME (emphasis deliberate) the F34 is not noticeably -significantly- stiffer than the F32. By this I mean that the F32 I have on the Tallboy feels nicely stiff but so does the F34 that I have on the Bandit 29. Neither fork feels remarkably stiff in the same way that say a Fox 36 160 with 20mm thru-axle feels.

Note that I am 160lbs. Heavier riders have different opinions. I have no doubt that other riders who are the same weight as myself may feel that the F34 is stiffer than the F32. This comment then segues into another point which will be more than a little bit of rambling. WHY OH WHY FOX DID YOU NOT PUT A 20MM THROUGH-AXLE ON THIS FORK?

Deep breath and let me explain further. The F34 is the long-awaited long travel 29er fork from one of the major bicycle fork companies on the planet built for a category of bikes (long-travel 29ers) that is still small. These bikes should be ridden hard. They should not be poncy little weight-weenie gram-shaving bikes and if they are the owners perhaps should explain themselves. Where I am coming from is that it would have been nice (and IMO logical) of Fox to spec the F34 with a 20mm Maxle front end to take the stiffness of the fork to its logical conclusion. Not the 15mm thru-axle which allows for radial slop between axle and sliders (the axle just applies a strong clamping force so there's always some play). Maxle not only applies axle clamping force but also expands radially between the sliders so movement is minimal. While I'm on my Gedankenexperiment rant why didn't Fox also spec 36mm lowers on this fork. Just how much weight would have it added anyway? Why not go with Maxle and 36 and shoot for the moon with this long-travel 29er fork. Why go halfway?

At this point I am probably inviting (and probably deserve) rebuttals that this fork is plenty stiff and that I am just indulging in useless speculation and that if I didn't notice the stiffness difference between a F34 with 15mm thru-axle and equivalent F32 then how on earth would I notice the difference with my hypothetical uber-fork (read this fascinating piece on Weber's Law of Just Noticeable Differences for more on whether bike components are all in the head) I leave you with the thought that I really really like the Fox F34 Float 29 FIT RLC; am.a Fox fanboy and own a ton of Fox suspension on my bikes. The fork performs well, it can be tuned, and its spring rate is nicely progressive but I can't help wanting for more. I wanted to be blown away, like I was the first time I rode a bike with a Fox fork with 36mm stanchions and the 20mm axle and beefy crown. The F34 29er is like vanilla ice-cream without dark chocolate sprinkles and topping - oh so close but just those few vital bits missing.



Fox Float RP23 Impressions

I set the RP23 at body weight for the Bandit 29er and either ran the Propedal wide open or engaged if I was climbing (note that rear shock settings may be different for different bikes). There's really not that much to say about the RP23 except that it quite boringly and seamlessly works. It works well uphill. It works well downhill. It works well on the flats. As with the front suspension I notice compression adjustments with the Propedal switch only when making big changes (eg flipping the lever from climb mode to wide open mode) but perhaps that is just me.

I have one minor nitpick but this relates more to the fact that I am able to bottom out the rear shock on the Bandit 29er when I drop to flat from anywhere more than 3 feet (approx 1 meter). One might reasonably note that drops to flat are passe and that I should quit doing that. One might more reasonably note that the Bandit 29er's suspension is of the type that requires a bit more support at the end of the stroke (perhaps a custom tune or Boost Valve pressure?). To do so one must avail themselves of the services of a suspension tuner; the Float RP23's settings are relatively fixed to ranges of tune. I have Suspensionwerx in my neighbourhood but not everyone is so fortunate and may have to mail in their suspension to PUSH or to FOX itself. It would be nice if the RP23 was user-tuneable to a greater degree..

Finally, because this is comically quasi-scientific data but ultimately useless I'll throw up some random data points. Suspensionwerx's sample size is approx 350+ people over a year who came in with RP23s to service and tune. They checked through logs to whittle this down to riders who were switching from non-Kashima to Kashima-coated RP23s. Being pretty busy at this time of the year I didn't press them for exact numbers of this sample size but I am told it was probably around a hundred.

Of this hundred approximately 70% of riders added pressure to Kashima-coated rear shocks to achieve desired sag as compared their non-Kashima shocks. Riders added 5 to 10 PSI (ranges varied). Assuming that the RP23s were set up for body weight and assuming a 180lb rider this is between 2.7 to 5.4% more air pressure. Now this is hardly experimentation of the German Bike magazine standard. Error sources include, without limitation:
  • the fact that many of these riders were coming in to get suspension tuneups so their older suspension might not have been set up correctly
  • the fact that the riders were also coming in to get old suspension worked on so the old suspension might have been performing sub-par
  • the fact that some riders were changing bikes of different designs and thus the rear shock pressures could have varied due to the different design
Unfortunately my data point therefore has a ton of caveats and is unfortunately basically useless. It also ignores the question of whether or not riders would have even noticed if they had not added more pressure to their new Kashima shocks (as compared to their non-Kashima shocks); accordingly had more sag and then noticed whether or not they had more sag! Another data point is that I played around a bit with an empty RP23 upper shell and moved a Kashima coated lower shaft and non-Kashima coated lower shaft up and down the upper shell; the Kashima coated shaft felt smoother. This also ignores whether or not I would notice the difference in smoothness when riding (see treatise on the psychophysics of Just Noticeable Differences above)

In conclusion, there's really not much to say or find fault about the RP23. It does the job without fuss. It's a part that rarely fails and works without getting in the way. All bike parts should be this good.

Fox 34 Float 29 & Float RP23 Gallery