Thursday, August 27, 2009

Why SRAM Chains Suck

I love SRAM...I use their forks, brakes, cranksets, shifters, and rear derailleur.

But their 9 speed chains suck, and I've dissected them to find out why the break so easily (the only two 9 speed chains I've broken). It comes down to the pins they use. On the SRAM PC 951/971/991 the pin only contacts the plate partially instead of entirely around.
 
The pin actually only contacts the plate on above and below the center ridge...weak. SRAM makes a PC 991 CrossStep that increases the pin strength but its a $45+ chain and it still doesn't completely contact the plate
 
Now compare the KMC and Shimano chains (KMC makes the HG53 and 73 Shimano chains). They use a mushroom center punched pin. You can feel how strong this pin is when your using a chain breaker to size the chain. It takes way more effort to push the pin through. In dissecting KMC X9 and a Shimano HG73, I can feel a distinct ridge around the entire pin. This gives the the KMC and Shimano chains more than 1.75x more pull strength than SRAM
 
  

Wednesday, August 26, 2009

Solid Mid-Level Mountain Bike Parts

I've been working on and riding mountain bikes for over 15 years now. While the glamorous high end stuff like Shimano XTR and SRAM X.O. garners all the headlines, its the mid-level equipment that most riders use. Over the years I have seen what works well and what doesn't. So here is a recommendation for affordable mid-level parts that I have used or use and endorse as being solid, reliable, and perform excellent.

Rock Shox Tora 318 Solo Air (Tora Race)-The motion control damper on this fork works right up there with my all time favorite Manitou TPC+ damper. It is very adjustable and does not suffer from spiking like some other Italian branded fork. The Solo Air cartridge is easy to adjust and is very reliable. The spring curve is just right to have plush at the top of the travel while ramping up at the bottom. The fork is very laterally stiff and easy to service.

SRAM X-7 Shifters and Rear Derailleur-Precise shifting in all weather conditions is this combo's claim to fame. It doesn't seem to matter what you throw at the X-7...it just keeps hitting its shifts perfectly.

Deore Front Derailleur-I love this cheap workhorse derailleur. Its performance is right on par with LX and XT front derailleurs I've owned, no reason to spend more to save a few grams.

Shimano and KMC chains-The Shimano HG73 chain, made by KMC, is another workhorse. Use a SRAM, Connex, or KMC quick link with it and it will not let you down. Another great chain in the same price range is the KMC X9. Both these chains use mushroomed center punched pins that have a pull strength that far exceeds SRAM PC chains.

Shimano HG61 Cassette-Not for use on aluminum freehub bodies (which I would never recommend anyway), reasonable weight and price and very long lasting. When combined with the recommended chains above, it shifts with pure precision. And the satin finish looks damn cool!

Shimano XT M756 Disc Hubs-Ok, you get your XT but at a bargain price. These hubs are absolute winners and reliable as it gets. Say what you will about cup and cone bearing systems, the races are precision ground for smooth as silk rotation. Easy to service, good seals, and reliable hubs...what else could you ask for at the price these run.

Cane Creek S3 Headsets (ZS3 included)-Good seals, light weight, long lasting...oh yea and under $50

WTB SpeedDisc Rims-They use a "shelf" with an extra lip to really lock in the tire bead. WTB refers to this as the International Bead Seat. What this means in real life is these rims are great for running tubeless conversions on with either the Ghetto tube method or the Gorilla Tape method. 9 months and 4 different tire brands and not one burp running tubeless.

Time Alium Pedals-The pedal you just can't kill. Immune to mud and snow, consistent entry and release, bomber construction, and a large platform so you can't miss clipping in.

Monday, August 24, 2009

Dream Bikes

Well, mountain bike trails still closed and I've been sick...blah! I did actually get out for a 29 mile ride Saturday on the Shark and will get another ride today so that's something. Work is especially slow right now (this should be the busy season) so in my bordom today...I used the Wrench Science webpage to build my two dream bikes. One is my mountain bike and one is my road bike, I didn't include a cyclocross bike but I'd probably have one of those two. Both bikes are US made from Titanium alloy and use a lot of SRAM and DT components.

Moots XZ with SRAM XX

Litespeed Archon with SRAM Red

There you go, $18k worth of bikes...better go buy that Mega Millions Ticket, its up to $252 million!

Sunday, August 16, 2009

Gorilla Tape Tubeless Pics

OK, since the trails are going to be closed until probably this fall...and I've been suffering from a chest cold...I got bored. So I decided to put my fall tires on, a pair of Kenda Klaw 29" x 1.95" tires setup with a Gorilla Tape tubeless method. I've already have done this setup with my Tubeless Ready Stans Raven tires, but in the spirit of being "Ghetto" I chose to make my own valve stems instead of using the Mavic ones I have.

First, making the valve stem. I cut a valve stem out of an old regular weight tube.

Notice the locknut...this is a reducing locknut since my rims are drilled for Schrader valves.

Next I tape the rim with one layer of Gorilla Tape 1" wide, overlaping the valve stem hole. Make sure to tape carefully to ensure no air bubbles and the tape is centered. Once taped, press the tape firmly down onto the rim pushing out any air bubbles. You then punch a hole in the tape at the valve stem with an awl. (note, my rim was taped several weeks ago so you'll just have to use your imagination here).



Now take you valve stem and place a little sealant around the base. Install into rim ensuring that the rubber base can sit flush in your rim. Tighten as tight as possible with fingers...no tools needed.




The rest is just like my Ghetto Tubeless pictoral. Soap up the beads and hit the compressor. The Kenda Klaw seated very quickly but had numerous pin holes in the sidewalls that leaked very fast. Once seated, I broke the bead in one spot opposite of the valve and installed sealant. Because these tires leaked so bad, I put in 4 oz of sealant in each (I only used 2oz in the Stans Tires). It took lots of shaking and laying on their sides on a bucket to get these tires to seal but 24 hours later they are holding air. I'd like to get some removable valve core stems or even some bolt on Schrader Valves (update, Schwalbe tubes have bolt schrader valves) but for now this will work. Since I already had my sealant and plenty of dead tubes sitting around...I'm in $2.99 for the Gorilla Tape 1" x 30' roll. Pretty Cheap!

Wednesday, August 12, 2009

Will the rain open the trails

Two days of well needed rain here in the PNW...will it be enough to entice Weyerhauser and Longview Fiber to open public access to their lands? One can only hope. Rode 30 miles in the rain last night, big climb up Headquarters Road. I felt really good, legs were solid on the climb. Only my constantly reoccurring back pain slowed me down a bit. But the back was painless the rest of the ride. However, started to feel a cold coming on last night and this morning it was present. Hopefully I can recover quickly as I have a 49 mile ride Saturday with lots of climbing.