i've been riding XC for about 7 months and i want to get involved in some racing. i just put together a new bike from new parts and parts left over from my '04 hard rock and i want to get it as light as i can, or at least shed most of the unnecessary pounds. i don't really know what areas are considered "heavy" from those that are fairly light. i was hoping you guys (or gals) could help point out which areas i could improve on as far as weight goes. here is my current setup:

Frame: 2003 Jamis Komodo 21"(4.0lbs)
F. Derailleur: Shimano LX (123 grams)
R. Derailleur: Shimano Deore (300 grams)
Fork: Marzocchi MZ Comp 100mm, steel steerer, elastomer/coil spring
Headset: Cane Creek ZS-2 (117 grams)
Brakes: Tektro IO mechanical disc brakes 6" rotors
Crank: Truvativ ISO Flow, alloy
Chainrings: 42t Cr-Mo x 32t heat-treated Cr-Mo x 22t heat-treated Cr-Mo
Shifter/Brake Levers: Deore Mega 9 (439 grams)
Cassette: 9 speed Shimano XT
Rims: Alex DM-20 (around 600 grams)
Tires: Specialized Enduro Sport, wire bead
Handlebar: Alloy, 38mm rise, 9 degree sweep
Stem: Specialized Mobius, alloy, 10 degree rise
F. Hub: Joy-Tech, double sealed loose ball w/ alloy QR
R. Hub: Joy-Tech, freehub, double sealed loose ball w/ alloy QR
Saddle: Specialized Body Geometry Sport ATB

The first three places to look at when trying to reduce weight would be:

1. Frame - but this probably isn't an option
2. Fork - depends on what kind of riding and travel you're looking for
3. Wheels - always an instant improvement but also depends on how much abuse you want them to withstand and such... includes (hubs, rims, tyres, discs as subcomponents)

Personally I'd start with #3 since it will probably get you the most gain in performance... unless of course your fork sucks horribly for what you're trying to do with the bike.

for losing weight, i'd ditch:
the fork to get an "xc" fork ~.5-1.3lb off
the wheelset ~1.5-2.5lbs off (for nondisc)
the chainrings or possibly even the crankset/bb ~.5lb off
the disc brakes ~1lb off (including the rotors, if switching to v's)
the handlebar/stem combo ~.3lb off
tires too, although i'm not sure about what your current tires weigh, light tires are ~4-600grams IMO.

hmm, maybe you and freerider05 could switch bikes...I just posted in his post...you have a freeride bike that you are using for XC (if I'm thinking of the right year that komodo is pretty burly), and he's got an xc bike that he is using for freeride.

The fork is heavy, go rigid
so is the derailuer, but thats not a biggie
the brakes weigh a lot, and i bet good V's will give just as good stopping power
you can always lose good weight on the wheels
and you can get lighter crank assembly

haha. here's a pic of my bike. the frame is pretty strong, but it's still fairly light for its size (21") IMO.

The best economical and noticible change will be in your rotating mass, i.e. your wheels.

If you have just a little money, start with your tires. If you have more money, switch out your wheels too.

The reduction in rotational mass will make your bike "feel" much lighter than what the scale tells you due to gyroscopic effects while accelerating, turning and climbing.

Your fork is on the heavy side from a purely XC viewpoint. It's a good all around fork, but it's heavy compared to a XC Race fork. Some forks are in the 2.8 lb range. Yours is probably in the 3.5-3.8 lb range. But, this is a very costly upgrade.

After that, I would swap out your cranks/chainrings/bottom bracket. Again, this is rotational mass, and a new crankset will (again) feel lighter because of rotation mass, and another benefit is that it will be stiffer (better quality) and it will shift quicker/crisper due to new and better chainrings.

From there, get rid of generic components such as your stem, handlebar and seatpost/seat. This is where manufacturers save money on the complete bikes.

Upgrading your shifters/levers/derailleurs for weight savings is not smart. The cost to upgrade does not outweight (pun intended) the weight savings. It'll improve shifting, but you'll only be saving grams, not pounds.

Now, switching back to vee brakes will reduce weight, but I'd sacrifice a little more weight and stick with discs.

Now, the thing to consider is budget. If you swap out your wheelset and your fork, you could almost buy a complete newer lighter bike. So upgrade, but don't overspend uneccessarily.

L8R

if you can find a good air fork they're very nice. I replaced my fork awhile back for a better one and this new one is air and i noticed a much lighter feel to the bike. also i just replaced my crankset and BB and noticed a small difference and weight but enough to make it worth it.

it seems like the only xc suspension fork that ive found under 4 pounds is the SID, which is in the 2.6-2.9 range. are there any other xc forks in that weight class that i could check out?

bigchina,

Take a look at the Fox's. (The F80 and the Float forks)

Foxs and Skarebs series. The White Brothers forks have also made an appearance on some high end bikes which is cool. Skarebs are nice and realatively light. The F80s are expensive (650-750) but the Floats are a good deal, especially used.

the SID is the lightest fork out there to my knowledge. manitou's mars series and sx ti were good, lightweight forks as well. anything else, though, and you are at the ~3.5lb range. to get worthwhile weight reduction you have to go SID or manitou mars or total-air a Judy or something.

fox and white bros make good forks but definately will not give you the weight reduction you're looking for. even the skarebs will not give you much reduction from what you currently have.

ditch the discs and get a 1500g wheelset and you will feel the weight difference. for sure.

1500g's total or per wheel?

Just face it, to lose weight on your current rig, is going to cost you money. Items like wheels, tyres are a sensible relatively low cost upgrade, then there are the sensible cost options of bar, stems and crankset, that will lose you weight, but to lose real weight will cost a bit. A 'Downgrade' to 'V' brakes is also very effective, with no loss of performance. Then you have the serious money of forks. And you will still have a heavy frame.
You obviously enjoy racing, so why not carry on with your current setup, but look to a new bike. By that I do not mean a full race spec Specialised or Cannondale or any of the other Arm and Leg Bikes that are around for the full race spec. Look for a frame manufacturer that is into racing. In the UK we have people like Dave Hinde who supply Frames of various specs and weights for racing. They then supply kits to build up into a race bike right from very basic up to the ultimate XTR with ultra light wheels and ancilliaries. In the UK you will be able to get a Race bike from £600 right up to your wallets limit.

This is just another way of Improving your Enjoyment from racing, but perhaps for those of us on a cheaper budget, a bit more economically.

what does the average race bike weigh?

i think under 24lbs is raceable, at least for me. however my bike now weighs like 29lbs, it used to be 26ish before i went disc. the 1500g is for both wheels, like 600g front 900g rear. and contrary to what stapfam said, i believe you have a frame that is decently lightweight for its size.

you can take off 4 lbs by ditching the discs, get a lighter wheelset, getting a sid or total-airs. if you shop around this can be had for $200. take off another 2 lbs by changing cranks/stem/bars, but that's less cost effective.

$200 for all that? im sure thats not what you meant, are you talking about just the air fork?

This might be a dumb question, but how about the possibility of the rider shedding some weight? Will that help? It looks like tons of money are spent on losing an ounce here or there. WHat about the rider if he sheds several lbs?

hahahaha... sorry, i had to laugh. i'm 6'0" 140lbs. if i lose any more weight i would break before my fork even compressed.

I was speaking in general. I know what you are sayin though. I am 6'2" and 152 lbs as of this morning. I was just curious as to the effect of changes in rider weight. I am sure some of the experts can advise.

i've always been the type to find good deals on used components. picked up an s-works wheelset and sid xc fork for 75 and 50 respectively. both were used but in great mechanical condition. mtbr classifieds is also a good source for gear.

Get rid of the wire bead tires and put some lightweight tubes in it. New race wheelset.
The rest of your bike is fine.

yeah, im keepin my eyes out for a lighter wheelset. ill be gettin michelin comp s's soon.. ill see where i am after that