My bike has seen a lot of modifications since it first left its boxy womb. I think it has about 3 stock parts left, if you count the frame and fork. I thought it would be fun to chronicle a bit of it since I’m a weight weenie and spend far too much time lurking web sights looking for light ideas. I should point out this is my race bike. A lot of this stuff is pretty durable, but most of the choices I make regarding what I use are based on weight reduction more than the need for long-term durability. Having said that, racing is hard on parts and I want them to work flawlessly during a race, but I don’t buy lightweight race tires and expect to get a year’s worth of riding out of them.
It’s really cool that a guy can go to his local shop and buy a mountain bike off the floor that weighs under 20lbs stock. Frankly, that’s a pretty big deal. However, I like personalizing my bikes and one of the best ways to do that is to buy a new bike and switch out a bunch of the parts before my wife realizes what I’ve gone and done…
I suppose this post will… be just fine. ahem.
Gordon at B&L Bikes had some great ideas and was instrumental with my project and really helped dial it all in. Dude’s a master at tickling out those hidden grams. I like light, but my shits gotta work, too, and he had it nailed. Thanks! If you’ve been riding a while, a lot of this stuff you can probably already do, either by cannibalizing a current bike or digging through your bike box with a bit of imagination.
Starting with a Stumpjumper Expert Carbon 29 in size XL ringing in at about 24.6 lbs, we cut some big weight just by pulling the tubes and swapping the heavy stock cassette for an XT 9spd I had lying around. Switching to a carbon bar and lighter stem also helped.
One of the biggest places I saved weight was by switching to the S-Works double crank.
Though I suppose that crank might not be lying around in your bike box… I really think this crank played a big roll in how my bike eventually got to the state it’s in now. Once I felt the awesome potential of the double up front, I became more motivated to adapt my entire drivetrain to match. But at this point I think my bike was hovering around the 23-23.5lb mark with pedals.
That was a pretty good weight and it stayed like that for a while. I made some more mods, but they were more about improving shifting performance in the front than losing weight. I put XX rings up front and ended up putting a XX frnt der on as well which gave me super reliable front shifting. The only problem was I had to use an old twist shifter to work the front der properly. It worked fine, but I’m a trigger guy.
Especially with Thomson Ti hardware:
And my bike was sitting happily at just under 23. At that weight, my bike was really feeling fast. A little weight reduction makes a huge difference. So much of mountain biking is breaking and turning and climbing and accelerating and lifting and hopping. Every time you do any of those, a few grams here and a few grams there are working against you, even if just a tiny bit. But you add all those small changes in movement together over your ride; it accumulates into hundreds if not thousands of additive repetitions wearing you out. Sure, if you take 30g off your bike, your not gonna feel a thing, but if you do that in ten different places, it makes a difference.
And wheel mass is the most critical mass to lose. For simplicity, just think of it like this:
I = mr2
where the objects resistance to change (accelerating your wheel) is equal to the mass of its outermost weight (your rim and tire) multiplied by the radius of your wheel squared (yep, squared!). For a 29er, that can really add up. So of course, you need light rims and tires.
I chose Stans new Crest rims and had them built up with an old set of American Classic hubs to get me a 1507 g wheelset. Not ridiculously light, but strength and durability were also an important consideration since I plan to race Breck Epic with them. Even so, I saved almost an entire pound by switching to the new wheels. And that is something I can absolutely feel every time I turn my cranks.
Other fun weight weeny activities which weren’t remarkably expensive include:
Ashima rotors are a bit lighter than stock. Not as light as alloy, but a fraction of the price. Add some Ti hardware and your good to go. I should mention I prefer the performance of the Avid rotors but for two-hour Kenda Cup races, they are fine.
Gold alloy bolts for all the brake connections saves some weight on the race bike and looks sweet, taboot.
Alloy bolts for my levers, too. Ti bolts for the stem. The ESI grips are light, comfortable, and come in my favorite color. The Campy top cap is one of my favs.
So what with the wheels and all my sparkly bolts, my bike was down to 21.89 with pedals and bottle cage.
At this point, I was pretty much done.
Until I held this…
The XX cassette. Once I put that in my hand, I was a goner. That thing is light!
I had planned to upgrade to a 10spd drivetrain eventually, but my 9spd was working so well, I really hadn’t planned to do it so soon. But, well, you know… Breck epic is coming and I just need that 36 tooth in the back.
Which, with pedals and cage, has my bike down to this
Whoa Nelly! Pretty good for an XL 29er. Sweet, especially since the Conti Race King tires on there are 70g heavier ea compared to Specialized Fastrak LK S works tires.
Well at this point my bike is pretty sick. Without question the best mtb I’ve ever owned, and most of the parts are durable, real-world parts.