How to reduce weight of your mtb!

Specific ways to reduce bike weight
Tires
Unless you like tasting the dirt, I’d highly suggest focusing on function over weight when you pick your tires. First, you need to find tires with widths and tread that work well with your riding style and on the terrain that you visit often. After you’ve done that, start checking out the weights of the tires you’ve identified as suitable and try new ones until you find a good mix of performance and light weight.
Shiggy’s MTB tire site is a good place to start when comparing tire specifications. Typically, tires come in wire beads and kevlar beads, with the kevlar being significantly lighter. Kenda tires seem to have a good WW reputation but, personally, I use IRC Seracs and Mythos XC because they are cheap (under $25) and widely available.
You also need to be careful when selecting tires because, if you aren’t, you can easily drop $70 on tires in a hurry.
Tubes
Typical bicycle tubes are made of heavy butyl rubber but there are lightweight tubes that are made out of light rubber or latex. Personally, I’ve had nothing but bad luck with the lightweight tubes so I can’t recommend them for the average cyclist — they seem to pinch flat or puncture with thorns more frequently than regular tubes and they cost a lot more.
One thing you can do is to go to drop weight from your tubes is to run a narrower width tube (1.5″) — it will just expand to fill the volume of your favorite weight weenie tire.
Tubeless conversions
I am a big fan of tubeless conversion systems that use regular non-UST tires. I use non-UST tires with these systems because UST tires are significantly heavier than normal tires (they have thicker sidewalls than ‘normal’ tires). I’ve been using the Stan’s NoTubes system for a year and have been really happy with the overall performance. If you’re going to follow this path, read my tutorial and then decide out if you have the right kind of mentality for Stan’s. While the system isn’t without problems, you can get some great weight savings in addition to getting better traction from running lower tire pressures.
There are other commercial tubeless systems out there, as well as several DIY setups if you’re the adventurous type.
Wheels
A light set of wheels can make a big difference on how a bike feels but you need to be careful that you don’t go lighter than your weight, riding style, and terrain require. While there are so many complete wheel systems out there that it truly is mind boggling, I prefer the more straightforward wheelsets that either you or your local shop can build and fix without ordering in special parts.
That being said, I did spend a fair amout of time on some Cane Creek wheels and can vouch for how stiff they are and how fast they do accelerate. These wheels are a good example of how rotational weight can be felt much more than static weight. These wheels are not considered super light in terms of pure weight but, since the spoke nipples are placed at the hub as opposed to the rim, their rotational weight is lower and they do ’spin up’ very well.
Hubs

There are several names that come up when you talk WW hubs. Boutique makers like Tune and Soul, as well as larger manufacturers like Dt-Swiss and American Classic make some seriously light hubs.
American Classic has some OEM hubs that are available as part of WTB’s Laser Disc Lite wheelsets. In my opinion, these things have to be the best bang for the buck disc hubs on the market.
Note: American Classic / WTB rear hubs had some durability issues and pre-2005 hubs had some suspect parts in the freewheel, but there is an upgrade kit that is easy to install and it seems to do the job once properly installed.
For non-disc hubs there are a couple of budget WW hubs that come to mind. You can usually find the Sun-Ringle SOB for under $40. There’s also the GT-Hadley rear hub and, while it isn’t made anymore, you can find it on ebay fairly often. These hubs are pretty light and are well made but you need to make sure you get the three pawl version, flush the original grease from the freehub body, and replace it with a light grease or light lube. And, if you pick up one of these things, you’ll have to perform preventative maintenance at least once a year.
Rims

Mavic X517 rims are a good standard for lightweight rims but they aren’t made anymore. You can still find them if you look carefully but, if you can’t, the DT Swiss XR4.1 is widely considered to be the best widely available xc rim out there in terms of weight, durability, and overall quality.
When it comes to disc-specific rims, there is one king out there and that king is Stan’s Olympic Rim. I run these things myself and, while I did dent mine on the first ride, it bent back easily and I haven’t had any other problems since then.
Custom wheels
There are some great wheel builders out there like Mike at Odds and Endos and Speed Dream that can make you the lightest wheelset that fits your budget, weight, riding style and terrain.
Pedals
Pedals are rotating weight so they should be fairly high on your priority list when it comes to paring weight from your ride. That being said, pedal choice seem to be very personal. A lot of people love the Crank Bros. Eggbeater pedals but when I tried them, I ended up going back to my Shimano spuds.
Like tires and frame types, this is one of those things where I think that it’s better to worry first about feel, functionality and personal preference and then to focus on weight reduction.
Shoes
A lot of people forget about shoes when they WW their bike. Like pedals and wheels, shoes can also be considered rotational weight, and turning over a heavy pair of dogs for 70-100rpm for 4 hours can add up to a lot of wasted energy. Carbon soled shoes are an option for dropping some weight as they are lighter and stiffer than shoes that use more traditional materials, but they also cost a lot more.
Again, when it comes to shoes, go for comfort and fit before absolute weight reduction.
Grips
Foam grips are one of the best bang-for-the buck items in WW circles but you should make sure you like how they feel before you start riding with them regularly.
Bolt-on skewers
Bolt-ons can save a lot of static weight over standard steel quick releases. However, you have to keep in mind that you need an allen wrench to open them up. This feature can lose you a bunch of time if you need to change a flat in the middle of a race and can be a pain if you rack your bike by the front wheel on your car. I had some of these things but changed back to regular quick releases because it was just too much of a hassle to mount my bike on my car’s roof rack.
Seatposts
I have a history of breaking everything associated with my behind: saddles, seatposts, and seat tubes on frames. Hence, I gravitated to the Thomson seat post — and even though it is not considered a super light post, it isn’t super heavy and it’s really tough.
Note: One free WW thing you can do is trim off excess seatpost that is below the minimum insertion length of your post. Note that running a seatpost that is too short will most likely void the warranty and make it harder to resell your bike.
Handlebars
There are lots of choices for carbon bars out there and there are some very light aluminum bars on the market. While flat bars tend to be much lighter than riser bars, you need to consider body positioning when choosing your bar setup. For example, you can get flat bars to sit as ‘tall’ as riser bars by running spacers underneath your stem, but a longer steerer tube might offset the weight savings from the flat bar. But you can cut flat bars much narrower than riser bars because your levers position isn’t constrained by any bends in the bar.
Stems
Two names that often come up when discussing WW stems are the Ritchey WCS and Syntace F99. There is a recall on older Styntace F99 stems so it’s probably a good idea to avoid picking up a used one unless you’re prepared to play with fire.
Another WW jewel is the budget-conscious Pazzaz stem. It’s reasonably light and very cheap.
Bottom brackets
Square taper bottom brackets seem to be ligher than ISIS and Octalink bottom brackets but they are becoming harder and harder to find as manufacturers move to newer technologies. Of course, this makes the cranks that go with them harder to find as well.
Older Race Face turbine and turbine LP cranks mated to Sugino Supershifter rings are a great budget setup IF you can find the parts. Action Tec and American Classic still make titanium square taper BBs if you’re stuck for something along these lines.
Other drivetrain parts
X0 twist shifters and X0 rear derailleurs are super light although you actually have to like twist shifters to really benefit from these parts. Hollowpin chains are also good options for cutting a bit of weight from your drivetrain. Also, there are some aftermarket cassettes that are designed to be lighter than mass-produced models, but your shifting may not be as smooth as when using a major manufacturer.
There are extra light cable housings on the market that are expensive and difficult to install, but hey, lighter is lighter.
Brakes
For disc brakes the Magura Marta Sl is the WW standard. I did own a set of these brakes but I traded them out for heavier Avid Juicy 7 because of the ability to dial in lever contact position. What can I say, I’m very finicky when it comes to stoppers.
If you’re looking for lightweight v-brakes, try to find the Vuelta Magnesiums. Koski makes a budget V-brake that is decently light although the Avid mag, ti, or Ultimate brakes are probably more realistic targets, in terms of availability.
V brakes levers
Sram 7.0 levers or the original 9.0 with the fake composite are cheap, light and strong levers.
Note: There is a red plastic thing inside these levers that can adjust the braking force. Take it out completely for super strong levers.
Rotors
Stan’s makes some lightweight replacement rotors for disc brakes but they are pretty expensive. However, being rotational weight, the weight savings you make here will make more of a difference than other parts.
Other things
Don’t forget to consider the weight of things like multi tools and hydration paks, as they can add weight to you and your ride pretty quickly, and there are a bunch of lightweight options out there for you to choose from.
Frames
For hardtail frames there are lots of lightweight choices in titanium, carbon, and Scandium aluminum. If you hang with the “steel is real” crowd, you can get steel frames down into the 3.5lb range but, to get there, your best bet is to go with a custom frame builder. It should go without saying that the fit of a frame is much more important than weight. Also keep in mind that the super fast, aggressive geometry that often goes along with lightweight race-oriented frames may not make the most comfortable bike for just cruising around — a super light bike often requires a lot of skill and attention to ‘details’ on technical terrain.
For lightweight full suspension frames Titus and Specialized lead the pack, although there are a couple of full Scandium frame manufacturers out there (Kona and Salsa come to mind).
I do think that a heavier full suspension frame that has a more efficient suspension system is going to feel faster than a lighter fully that uses a less efficient suspension system. Take the time to find the suspension system that works best for your pedaling style and terrain before you make a decision based on weight alone. I already made that mistake and ended up trading out a full scandium frame for another that weighed a pound more but has, in my humble opinion, better rear suspension system.
The next level
Once you exhaust the avenues outlined above, you can continue your quest by doing things like bolt tuning. With bolt tuning you replace stock hardware with lighter weight alternatives made from alloy or titanium. Structurally important bolts (ie. stem bolts) should be replaced with titanium, and non-critical bolts (ie. waterbottle cage bolts) can be replaced with alloy ones. If you use anything made of titanium, be sure to use Ti-prep (an anti-sieze compound) on the threads so you don’t curse yourself down the road.
Feel free to do a bunch of searches at the online forums to get lots more information on bolt tuning and, once you start to look for replacement bolts, a good source for titanium parts is Redmist Motorsports.
For the truly out of control
Three things you’ll need: drill press, dremel tool, a good life insurance policy. That’s all of the advice I’ll give for those of you who are at this stage.
Conclusion
Weight weenism should be one of those things that has a 12 step withdrawal process — for many cyclists, it’s an addictive habit and needs careful monitoring so it doesn’t get out of control.
In the end, whether or not extreme bike weight loss makes a significant difference in performance is still up for debate, but there can be no denying the fun in it or the potential for placebo effect it has on getting cyclists riding better (and faster). There also can be no denying that lighterweight parts are less durable and are going to break easier and will need replacement sooner.
So keep all of this in mind when trying to get your full suspension racer below 25lbs or your hardtail under 22lbs. And, most importantly, enjoy the entire process — for most of us, this is a hobby and it should be something that is fun to think about, play around with, and talk about with friends.