Gravity Point 3 Frame and fork |

I tallied up the components and weights in five groups:
- Frame
- Front End
- Drive Train
- Front Wheel
- Rear Wheel
I'm sure it could be argued to divvy the components up separately but, I did it this way so to section off areas of the bike to see where I might be able to shave some weight.
A critical decision point, value versus cost. Race bikes usually are not intended to be super durable as the team sponsor has the dough to replace parts as needed. The primary focus of most race bikes is to make the bike light as possible and handle extremely well for the rider and that bike is tuned to the rider. Of course the bike must hold up to a number of races in succession but, how many Clydesdales race in comparison to a normal racer on a circuit. I would be afraid to ride a bike that costs 8k as I could not afford to fix the stuff I broke as a weekend warrior I'm 5' 10" @ 220lbs.
Analysis
Frame

Had I known then what I know now I would have likely purchased a Sette Razzo 29er Alloy Hard-tail Frame @ $199.00 and weighing in at 3.5 lbs saving a 1/2 pound however, the chain-stay is .20" longer than the Gravity.
Front End
Wow, I could not believe that the front end less wheel and brake accounted for 22.66% of the bikes total weight @ 6.69 lbs. The over weight component here is the Fork when combined with the front wheel and etc. it would account for nearly 40.28% of the total bike weight at 11.89 lbs. The recon weighs in at a hefty 4.8 lbs. For 270.00 this shock performs flawlessly. I could shave 1 lb by changing to a Recon Gold tk for another $100.00. I would have to sell my recon silver first and likely would end getting maybe $150.00 for it on eBay. So in reality it would cost another $219.00 to loose a pound.Drive Train
This is a hard area to cut weight first off I could go with clip-less pedals but, then I would need to purchase clip-less shoes which ups the cost to save the maybe 1/4 pound weight the shoes and egg beaters are considered in weight versus cost. For me that is not worth it. I could switch out the current FSA Crank-set for a Shimano SLX M665 Crankset w/ Bash Guard 8/9 Speed and save a 1/2 lb for around $200.00Front Wheel
Right off I could replace out the slime tubes and go tubeless and loose nearly a pound for each wheel (14.4 ounces). If I did the ghetto setup it would barely cost anything other than gorilla tape and a used 26er presta tube and slime in a bottle. If I used Stans tubeless kit for $65.00 it would relate to shaving nearly two pounds of rotational weight for front and rear. If I were to change out my Easton EA70XC wheelset for Stans ZTR Arch EX 29 Black the new purchase price would be $595.00 plus shipping and tax. I could save nearly a 1/2 pound. The Easton wheel-set would need to be sold on eBay maybe getting $175 - 200.00 meaning I would still need to come up with nearly $400.00 not worth it to me at least now. I could shave a bit of weight with the Hayes brakes but, they perform flawlessly and are not part of the rotational weight of the wheel. When looking at weights of brake sets you are talking about ounces and grams in my opinion if you have a good brake set why change it for a few grams?
Rear Wheel
Basically the same story as the front wheel with exception to the cassette. Right now I run the 29er specific cassette which is already lightened up quit a bit plus has a 36 tooth cog. Here is another spot where there is very little difference in terms of weight unless you have the bottom of the barrel cassette. The SLX derailleur works flawlessly to save a few ounces/grams to go to XT does not interest me at least yet. Where else can I shave rotational weight? Tires. Over the current tires I have now I could shave 50-150 grams per tire.If I wanted to spend $65-85.00 per tire. Does this make sense for a weekend warrior who never races? To ride on a tire that has no protection flimsy sidewalls and little to no tread? Not worth it to me.
Summary

- Lighter Frame save 1/2 lb - $200.00 and up
- Lighter Fork save 1 lb - $219.00 and up
- Lighter Drive Train 1/2 lb - $199.00 and up
- Tubeless 1.8 lbs front and rear - $ 65.00
- Lighter Wheel-set - 1/2 lb - $400.00 and up
I think I will do the tubeless hack! and ride more to lose the fat on me.
29er
build spec's
| ||||
Type
|
Brand
|
Model
|
Weight
|
pct.
Of weight
|
Frame
| ||||
Frame
|
Gravity
|
Point
3
|
4.18
|
14.16%
|
Water
bottle holder
|
Black
Burn
|
competition
|
0.1
|
0.34%
|
Seatpost
|
Easton
|
XA70
|
0.6
|
2.03%
|
Saddle
|
WTB
|
Speed
V
|
0.8
|
2.71%
|
Headset
|
Crane
Creek
|
10
ZS
|
0.15
|
0.51%
|
Frame
etc. total
|
5.83
|
19.75%
| ||
Front
End
| ||||
Fork
|
Rock
shox
|
Recon
Silver TK 29er 100mm
|
4.8
|
16.26%
|
Stem
|
Truvativ
|
Hussefelt
60mm stem
|
0.7
|
2.37%
|
Handlebar
|
Crank
bro
|
Cobalt
3
|
0.5
|
1.69%
|
Grips
|
ODI
|
TLD
Lock on
|
0.25
|
0.85%
|
Shift
Levers
|
Shimano
|
Deore
|
0.2
|
0.68%
|
Bar
ends
|
Titec
|
Shorties
|
0.24
|
0.81%
|
Front
end etc. total
|
6.69
|
22.66%
| ||
Drive
Train
| ||||
Pedals
|
Wellgo
|
LU-A52
|
1
|
3.39%
|
Chain
|
Sram
|
PC
951
|
0.7
|
2.37%
|
Chainrings
|
RaceFace
|
Single
Speed 34t
|
0.1
|
0.34%
|
Bottom
Bracket
|
FSA
|
Mega
XO
|
0
|
0.00%
|
Crankset
|
FSA
|
Gravity
|
2.9
|
9.82%
|
Drive
Train etc. total
|
4.7
|
15.92%
| ||
Front
Wheel
| ||||
Front
Tire
|
Continental
|
XKING
2.4
|
1.5
|
5.08%
|
Tube
frt
|
Slime
|
29
x 2.2
|
0.9
|
3.05%
|
Front
Brake
|
Hayes
|
Stroker
Trail
|
0.9
|
3.05%
|
Front
Wheel
|
Easton
|
EA70XC
|
1.9
|
6.44%
|
Front
wheel etc. total
|
5.2
|
17.62%
| ||
Rear
Wheel
| ||||
Rear
Tire
|
Continental
|
RKING
|
1.6
|
5.42%
|
Tubes
rr
|
Slime
|
29
x 2.2
|
0.9
|
3.05%
|
Cassette
|
Shimano
|
SLX
CS-HG-61 29er Cassette
|
0.7
|
2.37%
|
Rear
Brake
|
Hayes
|
Stroker
Trail
|
0.9
|
3.05%
|
Rear
Wheel
|
Easton
|
EA70XC
|
2.4
|
8.13%
|
Rear
Derailleur
|
Shimano
|
SLX
|
0.6
|
2.03%
|
Rear end etc. total |
7.1
|
24.05%
| ||
Total
|
29.52
|
100.00%
|
4 comments:
Nice breakdown of weights on this build! I just finished mine and weighted out at 29.5 pounds as well. I am a little disappointed with the amount of tire clearance in the rear. I may try re-dishing the rear wheel and see if I can get a little larger tire on there. It's currently much tighter clearance on the non-drive side than the drive side. Do you have this same experience?
Here's my link to my build... it's the last on the page at the moment.
http://forums.mtbr.com/motobecane/unbranded-gravity-29-point-5-a-707668-2.html
JF thanks for the comment. I have two wheelsets that I use. The Eastons have a 19mm internal rim and I run the conti X front and conti race king rear. They are pretty wide at MFG claimed 2.2 My other wheelset is a Mavic with internal rim width at 17mm I run the conti mountain kings 2.4 that is a pretty fat tire. I have maybe 3mm clearance on either side of chainstay for those tires.I looked at your post on MTBR looks good! BTW I went ghetto tubeless and down now to just under 29 lbs.
Joe,
Could you measure the distance between the chainstays and post some pictures of how a 2.4 tire looks in the back of the BikeIsland Unbranded 29er alloy frame?
I know its been a few years, so hopefully you still have the bike!
Sorry Paul I do not have the bike anymore. I do re-call that the rear chainstays with a 2.4 (continental MKII more true size to a 2.2) had minimal clearance maybe 2-3mm on either side. An Ardent 2.4 would never fit. a Kenda 2.35 might.
Good luck!
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