Thanks for all the positive comments on my previous build threads, its great to have been able to contribute something back to the MTB community.
I sold my Specialized s-works Enduro last year after acquiring a 180mm SX Trail. Some of my regular riding mates stepped up to bigger 180 or 200mm bikes and immediately started to pull away from me on rougher sections of trail where the Enduro was starting to feel a bit on the ragged edge and uncomposed. The additional suspension travel and rigidity of the rear end were the most noticeable improvements over the Enduro and gave me the ability to carry more speed through rougher sections of trail and additional confidence to hit bigger drops and gaps. Its been perfect for trail centres like Cwmcarn & Aston Hill and got me out of more trouble than I care to recall.
A year later and Iíve started to ride some different areas and began to feel that the SX Trail may be overkill for some of the tamer trails I ride where the added suspension saps some of the pedaling effort and mutes the Ďfuní of the trail. Earlier this year a friend of mine made me aware of some new hardcore hardtails coming to market which looked a whole lot of fun.....and so the research into a new bike started.
I considered ĎThe Shaní from Production Privee, Production Privee | SHAN 917 // Mountain Biking Videos on MPORA and the BTR Belter, Belter | BTR Fabrications , BTR Fabrications - YouTube both looked like they could be a lot of fun and take some punishment. I also looked at short travel suspension designs like the Transition Double Transition Bikes and Orange Blood Orange Mountain Bikes - 2010 Orange Blood. I even considered having a custom frame produced by a company like Nicolai.
I knew pretty much what I wanted in principle, Iíve ridden enough bikes now to know what I like and what suits my riding style, namely short chain stays, a rigid back end free from flex, a low bottom bracket, slack head angle and a poppy playful suspension system that jumps well.
My research was complete when Specialized announced the Enduro SX earlier this year.
Looking at the data on the frame, it ticked nearly all the boxes...
419mm chainstays, 311mm bottom bracket and a 68 degrees head angle. Perfect for a dedicated 4x or dual slalom bike but not quite what I had in mind but nothing that couldnít be tweaked and addressed later.
I knew I wanted to build this up as a hardcore short travel play bike rather than the outright 4x race bike it was intended to be. I wanted it to be fast but no silly lightweight build as I also wanted it to be capable of hitting jumps and the UKs more popular DH runs.
In my experience, front suspension is critical to a great bike, what the front wheel does dictates to a larg extent how the rest of the bike will follow. Well setup bikes enable the rider to Ďfeelí whats going on at the rubber & ground interface and that builds confidence.
Iím a heavier rider and like hitting stuff fast and hard, I hate flexy stuff, it creates vagaries that mask whats going on at the tyres. Without this critical feedback I start to loose confidence and want to back off. To provide a solid interface, I wanted a 20mm through axle and at least 34mm stantions.
This removed some options straight away like the Fox 831 and Rockshox Pike. Having spent a few years now on Bos suspension, Iíve grown accustomed to its superb performance. Of all the forks Iíve ridden, Bosí offerings constantly impresses me the most. They provide outstanding damping providing unmatched levels of traction and chassis composure as well as being easy to dial in.
Bos donít offer anything with less than 140mm as stock so I set about modifying a set of 170mm Devilles. After analysing the SX frames geometry, suspension dynamics & stack height, I settled on 130mm travel as optimal. I replaced the stock Bos seals with SKF seals which reduce stiction even further than standard and customised the internal air and oil volumes to provide a the desired ramp-up through the travel.
Its pretty obvious that large heavy rotating wheels will have a significant influence on a bikes handling and performance.
Iíve had great results in the past running Easton wheels, both the carbon Havens and the aluminum Havocís which I used on my Enduro and SXTrail. Both of these wheelsets are 20mm/12x142 axle sizes and this frame and fork setup would have allowed me to run these wheels if I wanted. Nothing like a new build though to do some market research and see whats new out there.
I knew I wanted wide rims, I like the tyre profile and stability they provide. I knew I also wanted rims which which could be run tubeless and are ĎUSTí without internal drilling reducing strength and requiring the hassle of needing rim strips to run tubeless.
Iíve used the popular Stans Flows before and had nothing but grief (and associated crashes) with tyres blowing off rims and wouldnít use them again for anything other than XC use. I believe in tubeless but only when done right, and right for me is UST rims with suitable tyres.
I love the rigidity of wheels built on carbon rims as they often use higher spoke tensions which provides a stiffer wheel. I looked at Enveís
but ruled out the AM wheels as they werenít recommended for use in dual slalom or DH use and require rim strips to be run tubeless. I didnít like the idea of the DH models 21mm internal width and so moved on in my search. I may revisit them again in future but Iíd like to try a pair first before committing the spend blind on them.
I noticed a few guys running DT Swiss FX1950s on some DH tracks recently and discovered they were a UST rim with a massive 27mm internal width and using tried and tested DT Swiss 240 hubs.
They use DT Aero Comp spokes laced in an open crowfoot pattern and build up really stiff. I like the fact the hubs are easily converted between standards and the freewheel runs very quietly. A XD driver is available for them too which will be useful for a possible future upgrade.
Iím a big fan of Specialized range of tyres currently, they offer superb tread patterns, a wide range of carcass configurations and rubber durometers. Iíve selected to run Butcher SXís (920g, compound 50a/45a, 60TPI casing) front and rear on the FX1950 for their blend of puncture resistance, carcass stability and ease of rolling. Fitted at 30psi they sit at 57.5mm width block-to-block. I may run a Purgatory GRID rear in the future for a faster rolling tyre but there isnít any inventory available to me currently.
Iíll probably end up running the Carbon Havenís from time to time too. They will be fitted with less burly tyres probably something from Specializedís Control range. They weight in about 500g less than the FX1950ís and with lighter tyres saving a few hundred grammes per wheel should drop over a kg off the final bike weight.
Brakes were quite a tough decision to make for this build. I wanted to run lighter brakes primarily as Iím not planning on using them much. I also wanted to reduce any noise and speed scrubbing associated with pad rubbing.
Shimano XT/XTRís have been getting fabulous reviews over the last couple of years but one of the hardest things I find to adapt to as I swap between bikes are brakes. I decided to stick with Formula brakes as I also run them on my SXTrail. They have been hassle free for me over the last 18 months or so and Iím experienced in bleeding them now to get optimal feel and performance. I also have a fair few service parts lying around which made it a no brainer.
I wanted black and red brakes to match the colour scheme of the frame but after purchasing a set of OEM T1s I found they used a much inferior RX master cylinder. I ended up buying a set of 2013 ROís which came handily in black. The gold accents werenít ideal but I guess they matched with the Kashima shock coating. They come with ECT this year which adds some addition pad rollback for better pad/rotor clearance.
The ROís are the best brakes Iíve had the pleasure of using. Lever feel is awesome and dialing it in to personal preferences is simple due to the TFRA and FCS adjusters. The FCS adjusters also handily compensate for pad wear too so no need to replace pads at 50% wear anymore which was a problem on the older Formula brakes. Power is fantastic as the oval piston is said to perform like with 4-pot levels of power.
I considered running Formulaís R1s but the weight penalty for moving up to ROís seemed pretty insignificant especially when contrast to the additional stoping power offered by the oval pistons in the ROís and hopefully this would compensate for running smaller rotors too.
From the March 2012 Bikeradar brake test (How We Test Hydraulic Disc Brakes - BikeRadar)
Model Weight Piston Power
Formula RO 418g 24mm oval 124Nm
Formula R1 355g 22mm 107Nm
Formula T1 393g 24mm 121Nm
Shimano XTR Trail 407g 22mm 112Nm
Iíve decided to try 160mm rotors, Iím not expecting to be using the brakes for long as most Uk runs are relatively short and I dont think over heating will be a problem. I went with two piece rotors to help keep things silent and also provide maximum heat dissipation. If I donít have enough stopping power or suffer with over heating Iíll step up to 180mm rotors but I think thats probably overkill right now.
Hoses were trimmed to suit and both brakes were bled with fresh Castrol SRF fluid which offers a higher boiling point than the cheaper usual stuff. Having boiled fluid before in the Alps I know I donít want a repeat occurrence.
Potentially an area for further experimentation. I like low bottom brackets but I hate pedal strikes. I wanted to run 165mm cranks as per my SXTrail but didnít want to carry the weight penalty of the stiff and flawless Shimano Saints. Sadly Sram donít offer their carbon crank arms in 170mm and the 165mm version only comes in a 86mm wide DH fit, not suitable for the SXís bottom bracket shell.
Having done some research I discovered all the Sram cranksets use the same arms and figured if they can take the hammering the pro DH guys give them then Iím sure they will cope with what I throw at them. I ended up with a pair of XX1 cranks which came with a 32 & 34T XX1 chainring.
Iíve settled on a 11-25 Dura-ace cassette out back. Iím not planning on riding this bike cross country so didnít want to go with a compromised lower range as you get with 11-36 or 10-42 cassettes. I think the 25 tooth cog should be fine for getting me around between the DH/fun sections of trail.
I had hoped to be able to utilise a lower geared cassette, something like the 9-20 Capreo hybrid or a 10-25 speed X0-DH type. At the moment Iíve not been able to find a way to make a Capreo system work and Sram seem to be missing the point of X0 as a DH groupset as it appears to be become a cheap XX1.
I like to see Sram utilise the XD driver technology and produce a 10-25 speed DH cassette. This would enable running a smaller chainring up front increasing ground clearance of bikes with low bottom brackets. See what Specialized did with the Demo8 team bikes for further info.
Running a KMC x10sl chain with Titanium Nitride coating. Not sure about the gold (except it matches the Kashima shock and now the brakes!) but the one Iíve run on my SXTrail has lasted way beyond anything from Sram or Shimano has ever lasted before. Strength wise Iíve never broken one and the wear rate is positively glacial, even in the sandy mud that the UK can provide. Highly recommended and my go to chain of choice these days.
X0 DH weight
Crank frame clearance - Q168
34T ring weight
To minimize any drivetrain losses from rollers or other such chain retention devices, I considered running without any chain guide which is possible on the XX1 chainring. I settled on using a upper guide only primarily because it weighs very little and as it doesnít touch the chain there is no drag associated with it. The E.thirteen TRS+ guide ( TRS+ Single Guide | the hive ) was perfect as it allowed me to remove the lower pulley, if I plan to ride rougher terrain I can always bolt it back on too so has added flexibility.
As Iím running a tight ratio cassette, I could have run a X0-DH derailleur with the more optimal movement across the cassette but sadly its not available with a clutch mechanism. I wanted to run a TypeII derailleur to avoid having to run a chainguide which increases drag and reduces efficiency. Never had an issue with Sram X0 short cage derailleurs so went with a Type II version this time. Needed to lube the clutch mechanism even from new for it to operate smoothly. It was a fairly simple operation once I figured out what was up.
Shimano SP41 full length outer with sealed ferrules and 1.1mm stainless teflon coated cables ensure smooth shifting through the worse of the British mud.
Shifter cable routing
Had nothing but a great experience running Point1 Podiums. Low platform height helps with ground clearance, wide platform is great to rest my size 11s on and with longer pins, enough grip to ensure my foot stays where its supposed to. To date, Iíve never lost a pedal and therefore loathed to change. Iíve got the bearing replacement tool and a bag of spare bearings so easy to service when needed too. Starting to look well worn in now.
Years on a SDG Ti-Fly have moulded my behind into a SDG Fly shape so sticking with what works although trying a lighter I-beam setup. I like the idea of a single bolt adjuster and the range offered is great than a conventional rail setup which is useful.
The low seat tube means there isnt much room for running a long post, not if you want to drop it down anyway. I have tried the Reverb from my SXTrail and it fits fine. At the bottom of travel it moves the saddle well out the way still and at full extension is high enough to allow the bike to be pedaled easily.
Stem & Bars
Bars are a very subjective point. Iím fairly broad across the chest and I prefer wider bars, I found 780mm to be ideal for me although havent tried 800ís yet. I like the rise & sweep configuration of Renthals bars so stuck with them again for this bike although using a 38mm rise to compensate for the low frame.
I used to run Chromag OSX bars but there is too much flex in them for me, I hated the feeling of the ends moving around as I rode. Renthals weight more but are absolutely rock solid. Iíd be interested to try the Easton 35mm setup at some point, see if this can improve on the feel of the Renthal. I could be tempted to run carbon bars again...I think.
Renthal lock-on grips are finally in the market and about time. Sorry ODI but you are no longer the best! The bonded caps on the Renthals mean you donít get any of that annoying rocking you got with >1 week old ODIís. They are also slimmer, softer & gripper. Pity about the colour though!
Iíve been a fan of shorter stems and longer top tubes for some time now. The Enduro SX has a shorter reach than my Enduro or SXTrail so Iíve gone back to a 50mm stem. Handily the Renthal comes with 10 degrees rise so helps with bar height too. The Renthal stem is also light and solid although a bit more of a faff to fit due to the unconventional mounting system they use to enable further machining of the inside.
Not much of interest here other than I like good quality stainless steel bearings with robust sealing to keep the worst of the British weather out.
Specialized have moved to a integrated setup on the SX which allows the use of internal bearings with tapered forks. Not needing to run a external lower cup allowed me to utilize a 130mm fork rather than 120mm.
Fitting is also easy as the bearings just drop into the frame, no need to press them in. Makes replacement quick and easy when the times comes.
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