New Specialized SHIV Disc

Discuss light weight issues concerning road bikes & parts.
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LeDuke
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Location: Front Range, CO

by LeDuke

I’m guessing adding rim brakes to the new front end would create far more drag than a disc rotor would.


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Hexsense
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by Hexsense

The current argument for disc is more aero is that adding brake caliper make fork and front end busier and less aero than disc caliper+ rotor.

However, that doesn't apply to top tier TT bike where their rim brake is essentially hidden away somewhere in the bike, rather than slap in front of the fork.

Also, Some company also account for thru-axle is more aero than quick release lever, which actually nothing stop you from using bolts rather than quick release lever.

by Weenie


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LeDuke
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by LeDuke

Please tell me where on THAT front end a rim brake would not add a lot of drag.

The fork is set super wide for a reason, I’d guess. To isolate the fork and wheel from each other as much as possible.


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dcorn
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Location: NoVA

by dcorn

Calnago wrote:
Tue Oct 09, 2018 11:30 pm
spdntrxi wrote:
Tue Oct 09, 2018 9:31 pm
a few companies have stated their disc bikes to be more "aero" then the rim brake versions.. it's rarely apples to apples but look at the new madone. If trek can....the bigS can too.. bmc, cervelo, you get the ideal. Why the hard headiness Calnago?
Fair question, the hard headedness isnt' directed so much at the disc brakes themselves, as much as it's directed at the marketing spin that gets more out of control by the day. There are places, and I would hazard a guess, that Kona Ironman is one race where discs are just not needed and, with any crosswinds, are less aero (due to the rotors) than say, a well hidden rim brake. Yet, discs are being pushed at every level no matter the appropriateness. So why, in the one event where aero matters above all else, with no UCI Rule constraints, do they put disc rotors on bikes if it isn't for marketing purposes. And yes, the tri world is the perfect place to sell this, cuz they'll buy anything. Hope that answers your question a bit better.

To the poster that supposes that common sense is not worth anything, I submit that if I have a 6 inch disc in my hand and hold it flat side facing a fan, that I will feel more pressure than if I turn the disc on it's side so that only the edge is facing the fan. This, you do not need a degree in aerodynamics to understand. Or even really much intelligence, for it is easy to feel.

Carry on... I'm sure the bike is very aero, and I suspect it could be ever so slightly more aero, if they really chose to make it so.
Dude. We get it, you want the bike to have rim brakes. Too bad. Nothing you say will change the fact that this bike and many other bikes can actually be MORE aero with disc brakes than with insanely complicated rim brakes. Your fan analogy clearly shows your knowledge on aerodynamics.

mag
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Joined: Thu Mar 16, 2017 12:23 pm

by mag

Actually the new Madone with disc brakes is slightly slower (aerodynamics-wise) than the old rim brake model (according to Trek). The difference is very small, but it's still there. No idea how the new rim brake model compares with these, but I doubt it's slower than or equal to the disc brake one, it's likey slightly faster as well. When you invest some time and effort into fully integrating and hiding them (rim brakes) like they've done at the Madone, they'll outperform disc brakes aerodynamically. Sure the difference might be minimal, but then they've been selling you just marginally faster frame and other components for quite some time and screaming about it loud. And now you're giving up some of that and nobody says anything. Maybe it's that "sometimes you have to take a step back to move forward" thing. :-D

spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

^ I get yeah... the marketing push is very hard no doubt. If your top end bike as not disc brake ...you are leaving something on the table is the general feeling. The Kona route is not particular curvy (good for Tribike) and not overly climb heavy as well (~2500ft or so) But if they get someone on the podium (which they will likely do) even if it's the women it will be job done, marketing done. Dentists will order the other 494 Shivs. :)

TobinHatesYou
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by TobinHatesYou

mag, the new Madone is probably slower because it was compared to an H1 rim-brake model. The H1.5 Madone SLR has a not-insignificant height/frontal-area disadvantage.
Last edited by TobinHatesYou on Wed Oct 10, 2018 2:57 am, edited 1 time in total.

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kkibbler
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by kkibbler

What’s with the base bars do they fold down or something?

*haven’t watched the marketing video not intending to

MoPho
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Joined: Sun Jul 10, 2011 7:48 pm
Location: NorCal/SoCal

by MoPho

There's a big honking sail off the back of the seat post, the frame has thick flat vertical tubing and there are deep rim wheels, but lets whine about the brake rotors being the problem in a crosswind LOL


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hanakuso1
Posts: 43
Joined: Tue Jul 11, 2017 10:44 pm

by hanakuso1

Looks funky/weird in a good way to me. Not sure what they're calling the fin but it reminds of the shark fin in F1

TobinHatesYou
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by TobinHatesYou

hanakuso1 wrote:
Wed Oct 10, 2018 5:48 am
Looks funky/weird in a good way to me. Not sure what they're calling the fin but it reminds of the shark fin in F1
Should call it the Camel Hump since it's a storage bin for a hydration bladder.

pdlpsher1
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Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

This video shows more details of the bike. The hydration feedline is hidden inside the seat tube and down tube. There's also a massive storage area inside the downtube. So no need for a saddle bag. I actually like the fuel cell inside the downtube idea. That box can hold all of my food and gel. Of course I don't do tri or TT but it would be nice to finally put food on the bike instead of in a jersey pocket.

https://www.youtube.com/watch?v=LEpx-qH9-28

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

LeDuke wrote:
Wed Oct 10, 2018 12:57 am
Please tell me where on THAT front end a rim brake would not add a lot of drag.

The fork is set super wide for a reason, I’d guess. To isolate the fork and wheel from each other as much as possible.
That and also...

Conversely, there's a reason why the "headtube" area has such a deep foil/tube shape. The fork design directs/energizes airflow right over that section.

Slack
Posts: 141
Joined: Fri Dec 27, 2013 11:37 pm

by Slack

The new P5 is also disc.
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by Weenie


mag
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by mag

TobinHatesYou wrote:
Wed Oct 10, 2018 2:32 am
mag, the new Madone is probably slower because it was compared to an H1 rim-brake model. The H1.5 Madone SLR has a not-insignificant height/frontal-area disadvantage.
Yes that's very well possible. Unfortunately Trek didn's share details about their testing procedures and how does the disc brake version compare to the new rim brake one. I'd bet the rim brake version will be still marginally faster...

Re that funky sail - well it's a multipurpose bike, you can simply use it on your yacht as an emergency sail. :-D
On a serious note, however funky it looks they added it there on a certain purpose. It's at specific place and has specific shape. With brakes you have to go with limited placements and shapes and integrate them as much as you can.

Still it's true the difference isn't going to be big, but this whole thing shows how much it's marketing driven. Not surprising as I've seen (first hand) similar things being done in another fields. It's going to be be interesting to see what will be the next big thing they'll use to boost their sales.

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