Tarmac SL4/Supersix - how are the stock builds so heavy?

Discuss light weight issues concerning road bikes & parts.
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alex1987
Posts: 6
Joined: Tue Aug 14, 2018 4:03 pm

by alex1987

Hi all, read up on the forum for some time and been pondering on a couple of questions as of late, as I start looking into getting myself a new, much lighter road bike to step up from my alloy Synapse.

With my budget not being the biggest and my weight ambitions not being as high as those of some others (something around the 7kg mark would please me, +/- a few undred grams as budget and reality allow) I've narrowed it down to Supersix (non Hi-Mod) and Tarmac SL4 (Elite/Fact9r) bulds.

Now, looking at stock builds from Cannondale and Specialized, every bike is sold weighing in at over 8kg but as I do some basic maths taking account of frame and component weights, even rounding up high very generously (by a few hundred grams, pluss adding a couple hundred on top for good measure), using ok but not class-topping components (largely 105 components, 275gr or so handlebars, wheels that are sub 1.5kg but not by much, ~200g saddle etc) I find it hard to get the sum to creep towards the 7kg mark.

While I appreciate stock builds often save on components (especially wheels which can be close to 2kg a pair even on carbon frames like those I'm looking at) it feels somewhat hard to push the total weight towards and definitely past the 8kg mark. While this sounds all well and good I wonder - am I missing something really big?

by Weenie


WorkonSunday
Posts: 40
Joined: Tue Jan 16, 2018 4:39 pm

by WorkonSunday

typical differences:
200g frame (top carbon vs second tier carbon)
500g wheels (stock wheel vs something like fulcrum racing 5)
200g tyres (some heavy stock training 25mm vs lightweight 23mm)
100g stem/handlebar (probably can go for more if paying top dollar)
400g drive train (you seen the maths yourself)
100g saddle (typical race saddle around 270, lightweight padded carbon pushing below 170g)

so straight away from a 7kg bike, you are looking at 8.5kg. or looking it from other way, if your bike started with 9kg, you probably wont get it near 7kg any time soon.

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themidge
Posts: 893
Joined: Fri Jan 13, 2017 4:19 pm
Location: yer ma

by themidge

alex1987 wrote:
Tue Aug 14, 2018 4:26 pm
largely 105 components, 275gr or so handlebars, wheels that are sub 1.5kg but not by much, ~200g saddle etc
I feel like this is the problem, the stuff you describe is fairly lightweight, but 'largely 105 components' really just means shifters and derailleurs to the manufacturers. And it might be wishful thinking to believe that the handlebars are less than 300g, or that the saddle is closer to 200 than 300 :? . Other heavy things (especially on a 105 level bike) will be bar tape, seatpost, cranks, expander, fork (std. Mod forks are often surprisingly heavy), stem, non-series brakes, all the hardware on the frame will be less 'optimised' than it might be on the higher end models.

FWIW, my Cannondale (top end frame, but 10yrs old so heavy) has the opposite of what stock 105 level bike have these days: 105 shifters and derailleurs but higher end everything else, and it's still 7.3kg.

rlpaul
Posts: 147
Joined: Thu Oct 30, 2008 9:25 pm

by rlpaul

Some bike weights include reflectors, some don't. So there's some potential weight in the listing as well.

Some of the cheap alloy parts are actually quite heavy. 300+ gram bars aren't uncommon. I have a Cannondale C5 stem somewhere, and it's quite heavy.

Are Cannondales still coming with Ksyrium SLs? They're actually closer to 1800 grams, not 1500.

AJS914
Posts: 2366
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

Don't forget things like cables in your calculations. Advertised frame weights also don't include hardware, headset, and sometimes even paint.

alex1987
Posts: 6
Joined: Tue Aug 14, 2018 4:03 pm

by alex1987

AJS914 wrote:
Tue Aug 14, 2018 5:09 pm
Don't forget things like cables in your calculations. Advertised frame weights also don't include hardware, headset, and sometimes even paint.
No paint? Sneaky!

I've been throwing in about 350g for cabling on top of my generous rounding up, am I being too optimistic?

dondemola
Posts: 1
Joined: Sun Aug 19, 2018 8:33 pm

by dondemola

Interesting as I just registered in the forum to ask something in the line... (hi everyone by the way)

I'm in the same situation as you, wanting a new bike and can't figure out the difference in weight between, in my case, a Synapse 105 2018 at 9.7kg and a Canyon CF SL 7.0 at 8.2kg. Both have a rather similar frame weight (1040gr for Canyon and approx 1100gr for the synapse), the groupset is the same (105) so no differences here and the wheels (1577gr for the canyon and approx, say, 2000gr for the Synapse) show a good advantage for the canyon, however...

The penalty in weight for the Synapse is so far 483gr, but there is still 1000gr for justify and I´m just left with the handlebar, stem, seatpost and saddle (and maybe fork but probably weight is very similar). Is it really possible to find a 1kg difference in those elements?

by Weenie


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