Tarmac S-Works Disc, how to make it lighter.

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mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

Does anyone have one? I just ordered one in size 52. Was looking to take off a few pounds. Other than the stem, bars and seat.......does anyone know if the brake components can be lightened? Where to get light weight skewers for disc wheels? Please give me your thoughts and ideas...thanks
Last edited by mnmasotto on Mon Feb 09, 2015 4:26 pm, edited 1 time in total.

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Pottsy
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Joined: Mon Dec 08, 2014 11:54 am

by Pottsy

As stock it is a decent weight for a disc bike.
You could change the calipers to XTR race ones.

pushstart
Posts: 461
Joined: Sat Jun 16, 2012 3:12 am

by pushstart

I would imagine the wheels would be good candidates, not sure what their hubs weigh. But be careful; they have that funky rear offset. (Not sure if you can get a different derailleur hanger that would allow standard rear hub?)

If they are QR wheels, the hex bolt skewers are light without necessarily becoming flexy. Cheap steel ones will probably still save you measurable weight. But I really like the DT Swiss skewers; maybe in titanium if you want to shave weight (mine are steel).

Pottsy
Posts: 134
Joined: Mon Dec 08, 2014 11:54 am

by Pottsy

The bike will come with 2 hangers. One for running the Rovals (cassette is spaced to a 130mm hub) & another to run any other 135mm disc hub.

pushstart
Posts: 461
Joined: Sat Jun 16, 2012 3:12 am

by pushstart

Ah, that is great that they provide the hanger needed for running standard rear wheel. My vote would be wheels, then.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

Pottsy wrote:The bike will come with 2 hangers. One for running the Rovals (cassette is spaced to a 130mm hub) & another to run any other 135mm disc hub.


I just spoke to my Specialized Bicycle Dealer....They were not aware on these bikes coming with two rear derailor hangers...Where did you get this info???

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Taking off a few pounds is gonna cost you dearly.

The best way would be to sell all parts and start a new build with the frame alone.

Pottsy
Posts: 134
Joined: Mon Dec 08, 2014 11:54 am

by Pottsy

mnmasotto wrote:Where did you get this info???


I just know these things.

Plus I have built a few of them.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

Got It.......thanks Pottsy
Anything I need to know when ordering the XTR calipers? About how much weight do you think I can save?

MichaelB
Posts: 993
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

@ mnmasotto

What calipers come with the bike ?

R785's or RS785's ? If just the R's, then they have the banjo fitting, and the XTR's should bolt straight on, but if the RS, these have the straight fitting and will need a new set of lines to suit the caliper you are changing to.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

I have the R875 hydraulic calipers. What kind of weight savings are we talking about? Do any of you know the model number for the XTR caliper? Thanks in advance.

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dwaharvey
Posts: 470
Joined: Thu Oct 26, 2006 8:54 pm
Location: USA

by dwaharvey

Changing hydro calipers to me seems like a crazy way to try to save weight. It's going to be expensive, non trivial (you'll need to do a very thorough bleed), unknown savings (at present), and who's to say that the amount of fluid that the road levers push is identical to the XTR mtb levers? Maybe it is, but are you really that eager to find out?

Also, I know that the XTR brakes have changed since this post, but check out the savings between trail and racehere
I suspect that your R785 are similar in design to the XTR trail, and that by changing calipers most of the weight savings you'd see would be just from the elimination of the cooling fins on the pads. I suppose you could instead just get different (lighter) pads for your calipers, but reducing cooling capacity in a disc brake seems a bad way to save weight.

Pottsy
Posts: 134
Joined: Mon Dec 08, 2014 11:54 am

by Pottsy

So here are some things you can do.

swap to XTR calipers. lighter yes. (shimano says you will have less power than the current XT ones)
build some light weight wheels. (chainline will be affected)
get some narrow bars. (you may not like them)

If you bought it as a complete bike it will be a Di2 only frame. So no group set swap, at lease until SRAM wireless gets released.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

First thing I did was exchange the stock skewers for Extralite Strreters. I love these skewers. They weight 28 grams and work very well. I did not weight the stock S-Works skewers as the batteries in my scale are dead. However, I am certain they weight at least 120 grams. I see there are a few large steel bolts on the bike. Namel, the stock brake caliper bolts, seat clamp bolts and the stock seat is not the S-Works variant. Any other ideas???

MichaelB
Posts: 993
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

Pottsy wrote:So here are some things you can do.

swap to XTR calipers. lighter yes. (shimano says you will have less power than the current XT ones)
.....


There will be no difference in power, as the caliper piston sizes are the same (22mm dia - 2 off).

They even take the same pads, so no difference there

by Weenie


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