Readers’ Rides # 1

This is the first installment of a new column on nsmb – Readers’ Rides.  Many of you spend ridiculous amounts of time, energy and cash building up new and exotic machines.  Sometimes the goal is low weight, sometimes performance and other times it’s your all-encompassing vision of two-wheeled perfection – right down to the rim strips.  These confessionals are laid down on our Gear board all the time and because many of you are good with words and lenses this equals some lip smacking content.  Ken Perras is first up with his Demo 7 build.  Nothing was left to chance and the result is a shockingly light DH capable ride.  I’ll let Ken tell you the rest.

If you’d like to submit your ride please fire me an email and we’ll talk.
Cam McRae

I’m a bit of a gear freak and a weight weenie. I can admit that without feeling too guilty as I believe that it is one part that makes up the beauty of cycling. As a shop employee at Oak Bay Bikes, I have been privileged to have owned many nice bikes over the years, most of which
I’ve built up starting with just a frame, or heavily customized to suit my preferences – and this build was to be no different. I’ve been a loyal Norco owner for a few years but decided this year that I wanted to break the mold.

 The all-Norco quiver.  There are perks working in a bike shop.

I bought a complete Specialized Demo 7 and stripped the parts off the frame, keeping only a few components like the Sram XO derailleur and the Gamut chain guide. The build occurred quite quickly, but I can assure you that weight weenieism is an addiction that slowly builds up ahead of time.

The Specialized Demo frame is an odd choice for a light build. Extra seatstays and some serious frame beef meant that I was starting with an almost 11 lb frame set with a Fox DHX 5 and steel 500 lb spring.

 Something different for 2009.  A specialized Demo 7.

On the flip side, Specialized has put some weight saving detail into the bike, such as a magnesium linkage plate that saves 200 grams over the aluminum version. Paint adds up to 200 grams so clear/raw anodized ftw. Last, a 135mm rear end with a 73mm BB shell means lighter parts choices.

 A Ti spring will drop another half pound.

The Specialized Chunder tires were a major part of the low weight. ~1085 grams per tire vs. the expected 1250 and 1350 for a pair 60a(rear) and 3C(front)Maxxis minions. I’d say the Chunders have a similar sidewall to the tubeless/UST minion, if not thicker. For those that are interested in using them for UST setups, they haven’t lost any psi since I pumped them up last week which is indicative of a quality sidewall for me.

 The bolted, two piece magnesium link plate, available on top of the line Demo bikes, saves 200 grams over the one piece aluminum version.

Yellow Stans tape that covers the spoke holes finishes the tubeless setup. It keeps the weight low, and I can change tires as often as I please with the same low hassle of using a true tubeless rim. All that rubber clings to a pair of Stan’s Flow rims. These rims are XC light but designed as heavy duty All Mountain or Freeride rims, which for me translates to Downhill. They don’t have any eyelets so it is important to grease the outside of the nipples to reduce friction when building the wheel.

I used DT Swiss Revolution spokes (260mm both sides rear, 258/260 in the front) and black DT Swiss pro-lock brass nipples. Both hubs are Hope Pro IIs. The rear is a 135mm by 10mm and includes bolts instead of using more traditional, but heavier, thru-axle.

I wanted a few things to be custom so I built a different rear wheel setup. I used a Hope Pro II single speed hub with a steel shell. I took a weight penalty (296grams for the regular proII vs. 375grams for the SS) but needed the steel shell to keep the cogs from digging in to the freehub body. The 6spd cassette is an XTR cassette. I removed the top two cogs which share a common carrier, and the 16T cog that was between the 18T and 14T. Using an XTR cassette and getting a consistent decrease in cog size is really only possible with the 12-34 or 12-32 cogsets. The 11-34s have cog combinations that leave you with big gaps in the ratios.

 Count ’em – six cogs!  Welcome to 1990.

Last but not least was the XO short cage derailleur. There are some issues with limiting the derailleur to not shift into the spokes. The design is built around movement for at least a 7 speed drivetrain. I modified the changer by drilling and tapping a diagonal hole and using a slightly longer screw to reach the upper limit surface on the derailleur’s body.

  Modified for a new fangled 6-speed cogset.

I used a Sram hollow-pin chain in lieu of the lighter but more expensive KMC SL 9spd chain. The crankset is the new for 2009 Truvativ Stylo OCTs. They are one of the best price cranksets on the market and only weigh in at 690 grams (no chainring or bachguard) with the GXP Team bottom bracket. That’s only 80 grams heavier than a comparable XTR crankset. The truvativ chainring was used instead of the weight weenie’s preferred E-13 ring because there was only a 1 gram penalty for a free chainring. An alloy bashguard (80 grams versus 115 grams for a older style Gamut polycarbonate bashguard) from an older Stylo crankset and alloy chainring bolts round out the crankset. The finishing touch is the Gamut P-30 chainguide, stock on the bike, which is still the lightest guide on the market.

For front suspension the choice of the Totem was secondary to a 2010 Boxxer Team. However, availability of that fork was too far away and I figured the Solo Air Totem was lighter than a Boxxer so why not keep it? On the bonus side, I didn’t need a brake adapter to fit an 8 inch rotor.

The Totem did incur a weight penalty because it is a 1.5 steerer – which meant I was stuck with a heavier stem and headset. Syncros makes an All Mountain headset that weighs in at 190 grams so that was a logical choice, but not as light as a Hope reducer headset for 1 1/8 (140 grams). The Thomson 1.5 stem hits 180 grams but again not as light as a Sunline integrated stem I could have used with the Boxxer (145 grams).

Black is an easy colour, if a little plain, to work with. So I chose a Chromag OSX bar that had all the right numbers. 760mm wide, 25mm rise, 5 degree upsweep, and 8 degree backsweep. Keeping with the black and weight weenie theme, Avid juicy Ultimates, a Sram XO trigger shifter with a black X9 clamp, and ODI ruffian grips round out the front of the bike.

The Juicy Ultimates were a natural choice for me. I already own one set on my Norco Fluid LT1 and they feel fantastic. The largest rotors available with Ultimates are a 7 inch / 180mm setup so I swapped out the rotors for 180mm rear and 203mm front G3 rotors. Also due to the nature of 7 inch post and IS mount calipers, the front brakeset comes with 4 titamium bolts: two for a 7 inch post-mount setup and 2 for an IS mount setup. I hacked the extra post-mount bolts shorter and used them to mount the rear brake adapter. A final touch was to shorten the brake lines for a clean look.

The remaining pieces in the build are a full length Thomson Masterpiece seatpost, a Selle Italia SLR saddle with titanium rails, and a Hope seat collar that weighs only 22 grams. My feet ride on Wellgo MG-1s, the favuorite choice of many and one of the lightest flat pedals available.

The Excel spreadsheet, if carefully filled with well researched grams and ounces, reveals an accurate weight before the bike is built and before parts are purchased. My favourite site for weight references is Sicklines. It has a relevant weight database of Downhill, Freeride, Dirt Jump and All-Mountain parts that suits my style of bikes. For my build, I had calculated a weight of 35.27 lbs and produced a bike with a final weight of 35.20 lbs. Once I locate a reasonably priced 500lb titanium spring, that weight should jump below 35 lbs.

 A photo of the bike on the scale is mandatory for our Light DH Bike thread…

 and a close up shot helps too.
 
I know that I made several compromises regarding durability or even function with this build. My riding style is typical for BC riders: I ride jumps, rock gardens, steep descents, fast singletrack, sketchy lines, tough climbs, and high speed trails. I don’t usually shy away from any line if I’m having a decent day of riding but I know that coming up short or erring in judgment will cost me dearly. This will be more so with a lighter build but that is the price of being a gear freak and a weight weenie. Happy Trails!

 Ken riding on Whistler’s dark side.

Are you a Weight Weenie?  Do you weigh your shifter cables and brake fluid?  Or do you like things beefy and strong – grams be damned? Confess your sins here…