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Discussion Starter · #1 ·
Hi, you probably know Ive just finished my giant glory and I just weighed it and it comes in at 46.3lb's. Is this about correct average for DH? After coming from a light freeride bike to a full DH bike I knew it would be heavier, but it really is quite a lot heavier. I have only used average components, a few really nice parts, but how much weight do you think I could take off by swapping things like:
Bars, stem, cranks, front hub, and rims? Apart from it being expensive to upgrade all this, it will probably be done in a matter of time when stuff breaks. I also thought about going tubless, which must save some weight.
All that said, I don't even know if my bike is above average for a DH'er or not :skep:
Cheers for input :cool:
 

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Yeah....good luck with that. You're pretty much on the heavy side. To build a light DH bike, every part needs to be relatively light while still being a viable for DH.

Right now, go tubeless.
 

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Discussion Starter · #5 ·
was thinking a ti spring or maybe dhx air in the future too. yeh I know it wont be a light bike - the glory frame is heavy anyway, I was just curious to see what could be done to make it a bit lighter. im not a weight weenie but as its my first dh bike i didnt know what could be done etc.
cheers
 

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aka Jesse Palmer
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grahamjtriggs said:
im not a weight weenie
If you want to make any bike lighter you are going to have to spend some time findin the lightest parts that fit your needs, so you are going to become (oh no!) a weight weenie. For example: a lot of downhill bars and seatpost can be be over 400g each, but if you get yourself a nice bar and seatpost down in the 200g range you have saved yourself about a pound of weight right there. However, as long as you don't go drilling holes in your seatpost clamp to save 3 grams I think it'll be all good.
 

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40 to 45 is pritty average for a down hill bike (not pro), alot of the time strength is proportional to weight, so be careful you dont get parts which wont last the distance,

if you are trying to go lighter, dont use 888's they are a great fork but heavy, choose forks like the boxxer wc or Fox 40rc2 which are alot lighter,
 

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aka Jesse Palmer
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XSL_WiLL said:
Rotational mass (wheels/tires/tubes) is where it matters the most.
The whole ratational mass thing is very debatable, even for XC bikes.

Oh ya and here is a good reason not to get carried away with light wheels on a DH bike:



The morewood team decided to go with Industry Nine's aluminum XC spokes and here is the result :eekster:
 

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aka Jesse Palmer
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dhracer1067 said:
Rotational mass is easily the most important thing when dealing with weight. Saving 2 pounds in wheels verses saving 2 pounds on say your bars, stem and seat will make a huge amount more difference.
It will make a slight difference in pedal acceleration, as you will have less rotational inertia to overcome (probably only noticable when sprinting out of the start gate), however the added rotational inertia can maintain speed better. So I'd say that unless you are a really light rider, just be carefull when choosing rims, spokes, and nipples. You probably don't really need the ones that feel like they where made from solid lead, but at the same time brass nipples and decent spokes are your friends.


Go ahead and get the lightest tire/tubes you can run without flatting and feel confident on.
Also your tire's rolling resistance is going to have a much larger effect on your bike feeling "sluggish" than rotational weight.
 

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aka Jesse Palmer
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dbabuser said:
Yeah, maintain inertia better... like when you're trying to stop, or turn? Brilliant!!
you are right, acceleration is the only place that rotational weight has any effect, and looking back at what I've read in about rotational weight on XC bikes, its probably more significat to a DH racer who is constantly braking for turns and accelerating out of them, while an XC racer is usually maintaining a much more constant effort and speed.

From Save Some Weight Forum:
Chester said:
One other point regarding rotational weight. It is WAY over emphasized by most who discuss weight.
If you want it for "flick-a-bility" that is one thing, but other wise unless you are accelerating, it makes NO difference whether its on the wheels or anywhere else on the bike...AND.....though many will argue, most bikers are doing a heck of a lot less significant accelerating than they'd like to believe.

Offer me 150 grams off a saddle versus 100 grams off a wheel, and I'll take the 150 grams off the saddle because I know it will get me up the climb faster.
Remember, the "rotational" weight factor is only in effect when you are accelerating.
This is a endless argument/discussion. The science, when done, shows far less acceleration than is presumed by most riders.
Now, the control and "flickability" issue is another matter
 

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in dh racing your constantly changing direction, so you wouldn't want less rotation weight? also when stopping cause then it's easier to slow down and stop with less rotation weight, isn't that what dh racers look for? i don't DH race so i don't know for sure but i would assume that something heavier would be slightly harder to change it's direction of motion, and i would say the same towards rotational weight of the tires.

i personally would save a pound from the wheelset than save a pound from a new expensive TI coil. cause 1, it's cheaper, and 2 i can pedal around a lot better and be more zippy.
 

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My DH bike weight 39LB...

grahamjtriggs said:
Hi, you probably know Ive just finished my giant glory and I just weighed it and it comes in at 46.3lb's. Is this about correct average for DH? After coming from a light freeride bike to a full DH bike I knew it would be heavier, but it really is quite a lot heavier. I have only used average components, a few really nice parts, but how much weight do you think I could take off by swapping things like:
Bars, stem, cranks, front hub, and rims? Apart from it being expensive to upgrade all this, it will probably be done in a matter of time when stuff breaks. I also thought about going tubless, which must save some weight.
All that said, I don't even know if my bike is above average for a DH'er or not :skep:
Cheers for input :cool:
and I can take it down more.
If you'll write down your components, it will be easier to help you put your bike on diet.
 

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Discussion Starter · #20 ·
cheers guys, I'm going to be getting a pair of rims soonish, so I'll look for tubeless ones so I can get rid of the rotational weight of the tubes.
Good to hear my bike isn't the heaviest, maybe it was just the change coming off a much lighter bike. I'll get used to it though
 
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