Dear Sir,
Is there anyone know which is faster, SC9 w/o draft box2
or w/draft box2. I will race 40 miles (bike) at triathlon. It's not necessary to bring a replacement tubular and Co2 cartridge due to a fair road surface.

The draft box has been described by Trek as being "aero neutral", meaning that the aerodynamics are neither better or worse with it attached.

If you don't need it, then I would advise that you leave it off of the bike for your race.
Having it attached is just one more thing that could possibly go wrong somehow.

Dear Liaman,
The "aero neutral" is impressing word. No wonder I saw SC9 w/o draft box2 running at TT. Thanks a lots.

Our testing in the tunnel indicated the box was neutral...I believe Jim@EROsports has found on more than one occasion that during track testing it is an aero benefit (here is one such instance)...as he often says, results are individual.

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Carl Matson

Never quite understood this from the second gen SC white paper. On page 27 it shows the draftbox as slightly beneficial at low yaw with the OLD SC, particular a wide variant. And yet, on page 28 when that design is used with the NEW SC it shows no benefit. It may well be that the scale of the diagram on page 28 is such that any gain is hard to see though.

page 27: R&D shapes on the old bike
page 28: production version (based on one of the R&D shapes, but not the same) on the new bike

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Carl Matson

Yup, can see that, but if you'd taken the most promising design from page 27 and then put that into production with the new SC you'd expect the diagram on page 28 to look a little different. The assumption here is that the new frame works in the same way as the old one in conjunction with the wide draft box. Like I say the drag/yaw diag on page 28 is slightly harder to read but it doesn't appear to show the same saving as that on page 27.

those were shapes...not designs...design involves more than shape (my industrial design friends would be so proud of me for saying that).

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Carl Matson

Wondering if anyone has seen this kind of failure on an SC or is a known issue? My steerer stub failed during my ride earlier, it happened while I was braking for a stop light. Both bolts on the steerer stub snapped leaving no secure attachment to the fork and also caused some significant scrapping of paint on the frame behind the fork. Thankfully it snapped at the end of the stop or potentially would have caused a crash. While the local Trek dealer is taking care of me for a warranty case, it's unnerving to see both bolts of the steerer stub sheer off and worried that it might happen again.

So I asked a month or so back if an internal Di2 battery will fit in the aluminum seat post. I couldn't find this info on the web so I wanted to make a note for anyone that is searching in the future. It does in fact fit. The fit was tight enough that I feel the friction will hold my battery in the tube on it's own, but not so much that you can't pull it back out. We'll see over time, I have not ridden it yet as I'm still awaiting a tool set to finish up the install of the groupset (first build so I don't have anything past allen keys and basic hand tools).

Yes, whn I first got mine the handle bars started rocking around something chronic. I took it back to the shop which found that one bolt had snapped - they then blamed me for it. I contacted trek Australia durectky to complain - they engaged me for a few emails regarding the issue and my bike then just stopped responding. While Carl in here is brilliant, sadly that level of service was not reflected by the people I delt with.

Carl,

What size SC would you recommend for these fit coordinates? Looking at the fit charts I seem to be on the outer reaches.

Pad stack 596
Pad reach 490 to back of pad so probably about 510-520 to middle
Saddle height 779
Saddle setback 55

Thanks, I appreciate your input.
Gareth

definitely an interesting set of coordinates. Large & low-far makes the most sense for the pad reach and saddle height, but it can't go that low (minimum 605)...which leaves a Medium with same stem, and technically that can hit all your coordinates but it puts your pads pretty far forward relative to the front wheel. how tall are you and are you evenly proportioned?

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Carl Matson

I'm 6' with a 33" in seam.

Was in the same boat re: pad stack and reach.

My reach points to a large, my stack can't be hit on a large.

Ended up with the medium low far and plug in mono (where the pads needed to be made any of the standard monos not realistic when I put my hands on the end)

Did you get to resolve it? Without a replacement fork, I doubt that you can since it's impossible to take out the broken bolt from the fork.

Actually you go me thinking - the bolts weren't broken. I couldn't quiet remember last night. They were missing. So yes it got fixed. The bike shop blamed me for removing them, I'd never even seen them! I contacted Trek to try and get the bike independently checked to ensure it had been put together correctly. When it came down to doing something, they didn't.

Holy crap batman. I hope this issue isn't widespread like shiv issue was...

reinforces my previous thoughts...medium can hit your position, but I don't think it's the right fit . if a large went that low it would be the better bike for you IMO. zachboring would be a better resource than me at this point re: how a medium is working for coordinates like yours.

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Carl Matson

Ok, thanks, I appreciate the info. That was kind of where I was after looking at the fit chart.

One more question, do the pads effectively tilt down some if you tilt the extensions up? I guess it would depend on where the pads are mounted relative to the pivot point?

Zach, how did you find the ride of the medium set up that way?

Thanks,
Gareth

extensions and pads tilt together...meaning the position of the pads relative to the extensions doesn't change as you tilt...so yes, the pivot point will determine if the pads move down relative to the rest of the cockpit, but they stay level to the extensions no matter where the extensions go.

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Carl Matson

Honestly I can't tell much of a difference in handling compared to an optimal as I use the long reach to put my upper arm angle past 90.

Bike handles great and I haven't had any issues with me feeling like I am too far over the front wheel. Been riding the setup for almost a month now with some moderate descending (where I think you would feel this affect the most)

you have the right idea on the pads re: up/down with tilt. However, on a medium with your reach they will definitely add stack with the mono is tilted up.

So did this issue get satisfactorily resolved as a one-off incident? I was fully expecting this issue to provoke a lot of discussion on here. I have a new SC7.0 with conventional stem and haven't had any issues. I wanted to sell my my old SC7.2 frame but am not going to do this until there is some sort of closure on the above incident. I think it needs some sort of statement here.

Edit: I misread the conversation. Not resolved

Phew! (Thanks)