# XTR vs XT weight?



## jaxson (Mar 7, 2006)

Not including wheelsets or cassettes, what's the approx weight difference? I'm considering the purchase of the shifters, brakes, and front and rear derailleur only.

Thanks!


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## Ilikemtb999 (Oct 8, 2010)

http://www.bikescale.com/index.php?d=index&mar=14


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## jaxson (Mar 7, 2006)

Thanks for the link. Looking for current product on their listings.


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## Thatshowiroll (Jan 30, 2009)

Ilikebmx999 said:


> Bike Scale


What a great website. :thumbsup:


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## Falcon2000 (Sep 13, 2008)

Very cool thanks for the link.


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## texasnavy05 (Sep 9, 2010)

Everything I see in the link is 2008 or older.

edit: nvm, there is some newer stuff, just looking at brakes in general there is alot of old stuff.


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## lazarus2405 (Jul 16, 2011)

I just was working on this question tonight, using the data from bikescale. Comparing a complete XT kit to XTR, you'd save about a pound (.92lbs, 418g by my math). Half of that weight savings is in the shifters and brakes alone - and they're a lot less than half the price difference. Rear derailleur will save you a little bit, and the front almost nothing.

*Edit: I wrote the above with some faulty math. I was comparing two XTR "race" front brakes to two XT front brakes with Ice-Tech pads. This has been corrected and the listings are both now for a front/rear combo with Ice-Tech pads. Furthermore, the shifter comparison is between XTR SL-M980-I and XT SL-M780 with the optical indicators - I can't find weights for I-Spec XT shifters.

Both errors served to unfairly tilt things in favor of brakes and shifters, and undercut the advice I first gave. :madman:*

My data (forgive the messed up columns):

xt weight	xtr wt	xt price	xtr price	delta-w	delta-$	dw/d$
brakes	586	510	298.8	514.8	-76	216	-0.351851852
shifters	277	220	142.11	226.332	-57	84.222	-0.676782788
front der	153	145	53.298	106.596	-8	53.298	-0.150099441
rear der	246	208	124.344	239.832	-38	115.488	-0.329038515
crank	779	691	302.004	577.368	-88	275.364	-0.319576996
cassette	339	271	82.674	263.052	-68	180.378	-0.376986107
10 chain	275	268	41.328	60.12	-7	18.792	-0.372498936
totals	2655	2313	1044.558	1988.1	-342	943.542	-0.362463992

All weights are in grams. Prices are approximate computer garbage, but roughly in line with MSRP. Most parts are Mx80. "Brakes" are a complete pair, "trail", rotors not included. Cranks are trail triple, rear derailleur is Mx86-GS Shadow+.

I can't find weight differences between chainrings, unfortunately. I suspect a large fraction of the weight reduction in the XTR cranks lies in the chainrings.


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## steiny (Jul 8, 2004)

lazarus2405 said:


> I can't find weight differences between chainrings, unfortunately. I suspect a large fraction of the weight reduction in the XTR cranks lies in the chainrings.


I have a brand new, completely disassembled 2012 FC-M780 170mm silver sitting in front of me. My Weigh 7001DX

42t = 77g
32t = 56g
24t = 25g
granny bolts = 12g
outer bolts/nuts = 8g
BB = 87g
spacer 2.5mm = 1g (all 3 spacers = 4g)
end cap = 4g
ND arm 170mm, silver = 219g
DS arm/spindle, 170mm, silver = 365g

Total = 766g (all parts minus BB and spacers)

Edit: OK, figured it out. That 779g looks correct for a 175mm FC-M780. Mine is 170mm. I initially didn't notice the 779g was excluding the BB and spacers. Duh!


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## AC/BC (Jun 22, 2006)

There is something wrong here.
https://www.bikescale.com/index.php?d=artykul&kat=54&art=3413


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## lazarus2405 (Jul 16, 2011)

steiny said:


> Total = 854g (all parts on scale at same time except only (1) 2.5mm spacer)
> 
> Edit: I just looked at the weight you listed of 779g for XT cranks and have to conclude you're looking at FC-M785 (2-ring) cranks to get that kind of weight difference and not M780 (3-ring). Oh well, maybe this will help someone anyway.


Thanks for your weight breakdowns. That's pretty nifty. You'd pretty much negate the weight difference between XT and XTR cranks if your riding allowed you to simply discard your big ring and save a few hundred dollars. I'd certainly underestimated that.

As for the weights, I compared this: XT FC-M780 - Cranksets - Bike Scale
to this: XTR FC-M980 - Cranksets - Bike Scale

Both are most certainly FC-Mx80 42/32/24 triples. It seems that BikeScale did the measurement _without_ the bottom brackets. Without your BB, you'd get a weight of 767g, right?

It would also seem reasonable that they would have measured a 175mm crank by default (though I have no way of determining that). I'd estimate that the difference between that and a 170mm crank is maybe 10g-15g. Extrapolating from your non-drive arm: 2*219*(175mm-170mm)/170mm=12.9g.

Add in the difference and you're at about 780g compared to the 779g they listed? So that would put your crank (without BB) in pretty good agreement with the measured weights at BikeScale. I don't think there's anything fishing going on.

Edit: I did catch a couple of apples-to-apples mistakes in my earlier math, namely comparing i-spec XTR shifters to non-ispec XT, and not making sure the brake pairs were front/rear. I can't find weights for XT SL-M780-I shifters. I updated it above.


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## steiny (Jul 8, 2004)

lazarus2405 said:


> Thanks for your weight breakdowns. That's pretty nifty. You'd pretty much negate the weight difference between XT and XTR cranks if your riding allowed you to simply discard your big ring and save a few hundred dollars. I'd certainly underestimated that.
> 
> As for the weights, I compared this: XT FC-M780 - Cranksets - Bike Scale
> to this: XTR FC-M980 - Cranksets - Bike Scale
> ...


While I was re-weighing the parts and writing up the edit to my post you must have posted and I didn't see your response. Looks like we're pretty much in agreement on everything. Cheers!


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## TigWorld (Feb 8, 2010)

If you're comparing XT and XTR cranks you should also consider the SLX which people claim is stiffer than the XT yet the crankarms are lighter - http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/cinfirmed-slx-arms-lighter-than-xt-580071.html


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## wannabeRacer (Feb 9, 2004)

my 2012 FC-M780 170mm double chainrings 38T/26T weight 720g with BB 820g


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