Does Gen 2 alloy seat post from a SC 7.5 accept carbon rail seat posts (the oval style rails)?

No, but you can get new seat clamps, probably the 7x9 version... depending on the seat.

https://www.trekbikes.com/...-clamp-ears/p/25893/

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What's your CdA?

Anyone know where I could get a Gen 2 Draft Box shipped to Canada? The Trek Website says to contact my local Trek dealer, but they're fresh out.

I don't even need the draft box itself, just the piece of plastic that attaches to the frame, which broke off with the bolts still attached.

Failing that, has anyone macgyvered a solution to fix the plastic piece that attaches to the frame?

Does the Gen 2 Speed Concept have some sort of magnet or steering centering mechanism? I can't find anything online about it or in the service manual...

On the one I just bought (2015), there is definitely something that keeps the steering straight but I find it kind of sketchy in variable.cross winds and wondering if it's some that can be deleted.

No. There’s nothing that can be adjusted.

https://retailerassetsprd.blob.core.windows.net/...ZzABYHTFInUlT%2Fo%3D

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So they all have that feature? Manual doesn't say anything about it.

If yes, how is the centering achieved?

The stem isn’t your traditional stem that mounts to the steerer tube and you have to align it with the front wheel to ensure it’s centered.

The stem mounts around the steering axel via a pinch bolt but it also mounts via 2 screws into the fork (fork has threaded inserts). Look at page 7 of the manual and the stem attachment bolts. That’s how everything gets centered and there’s only one way it can be mounted. The base bar, mono spacer, and aerobars then mount on top of the stem aligning with the stem and fork.

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I think we may be talking about different things.

What I am wondering is whether the SC has some sort of centering feature that keeps the fork and front wheel straight after everything is assembled. On the bike that I have, the fork and wheel want to stay dead straight and it takes a bit of force to get it to come of center/straight.
It's almost like two magnets...one on the actual head tube of the frame and another on the fork that keep it straight. It is nice on a calm day on a dead straight ride, but on gusty cross winds it lets loose and a small adjustment to accommodate ends up being bigger than needed.

Maybe I'll get used to it but just wondering if it's normal. I've got tons of experience and time on bikes and wrenching; but TT/tri bikes is the one category I've not. Curious if it's a standard feature or something that was added after the fact.

I haven’t wrenched on the 2nd Gen SC. But have extensively on the 1st and 3rd Gen SC. When what you are describing occurred with the 1st Gen SC it was due to the fork steerer bearings corroding. Often from trainer use in the straight ahead position. On 1st Gen SC, the upper steerer bearing was very small and it didn’t take a lot of corrosion to cause an issue. I got in the habit of over-greasing the upper bearing to reduce the issue. Sealed cartridge bearing so this shouldn’t be necessary. But that location just seemed to trap a lot of moisture and fail quickly.

Ahh now I understand… my apologies. No there is nothing that keeps it straight. That’s completely controlled by rider input. The fork and bars should rotate freely. The headset bearings could be worn if it’s requiring force for the fork and bars to rotate. But it’s probably you just not being used to a tt/tri bike. It handles much different than a road bike and you have a lot more weight on the front end. A little cross wind can make the front end a bit twitchy but it takes some time to get used to. Try to stay relaxed in your upper body and steer with your hips.

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Ok that helps gang. Appreciate the feedback and help. Might replace the bearings and see.

I thought if it was the bearings it'd be a bit more of a grinding feel. This feels like it's supposed to be there. It's very smooth, but obvious in both directions. There's no noticeable signs of rust or sweat, but it could be a worn or deformed bearing. Was hoping it wouldn't be too hard and require a year down of the front end. I just put di2 on and that was a lot more involved than what I would have thought with all of the integration in the whole system.

I just started doing some shorter tris mix things up. Needing to break up my exercise routine due to back injury and have enjoyed it the variance during a race. Definitely not a comfortable bike (when comparing to the bike universe)! Lol. Very different than my Pivot MTBs.

It could also be the brake cable housing being too short. If the cable housing doesn’t have enough slack in the basebar and stem, it can cause some issues with the steering.

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Definitely not too short...had to finagle it in because it was too long. Also did it when I had all of the cables out so gotta be something in the headset area. Got the bearings ordered so will give it a shot.

Just bought a new Gen 3 SC. How are people mounting their Varia tail lights? The 'aero' rubber insert doesn't fit great, and the 'D-shape' and 'round' are worse.

Definitely headset bearing are shot. I've had this several times.
The behavior you described I have every time the bearings are worn out. I assumed that hitting road surface defects while going straight (the most common position of the steering) creates indentations of the bearing balls into the race, creating that indentation feeling. The upper bearing is ridiculously small and therefore not very durable.

It is wearing to that point especially fast if there is too much torque used when tightening the steering bolt during install.
For a while I had to change the bearing a few times per year until I learned to be really gentle w the preload on that bolt. Now it's been a few years since I had to change those bearings on both my SC's.

Change the headset bearings and you'll have smooth steering again. I agree w you, feels dangerous when it wants to stick in one position, as if something falls into a notch.

Some install instructions posted here by the previous Trek resource that was posting here (Carl); the preload torque is very small for that big bolt:

with the bearing preload nut just finger tight you install the stem to the fork and torque those three bolts down first
then set the preload (it's not much...2-3Nm if memory serves)
then tighten the stem pinch bolt to lock in the preload
as a final check, before you put the stem cover on, try turning the preload nut...if you can, and the pinch bolt is torqued to spec, you may need a replacement preload nut w315072.

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T. Guertin / Spocket

It's funny you mention this. I checked the torque on it yesterday and it was way higher than 2Nm. I took it apart and put it back together and torqued to spec. Definitely much better but still there. I have bearings on order and will replace. Thanks for the info!

Wondering if some of the fit gurus on here could give me some guidance.

I have Gen 2 Medium SC. I bought it very reasonably priced and am still working on getting comfortable. Finding myself pushing the far limits of the stack and reach. I come from more MTB XC racing but am enjoying some shorter tris. I'm 6'0" with 32" inseam with fairly proportional build.

Ideally I think I'd be on a L frame, but I found an XL frame at a very good price and could just swap all of my comments over.

My current stack is 655 and I think getting to about 670 and reach a touch longer (I'm currently maxed out which works...but I find myself slid g forward) would help me get my hip angle open a touch closer to what I'm used to on my MTB and thus generate more power.

Is going to an XL stupid? Should I just wait and find a LG?

No way you can get to a 570mm stack on the L frame, think the lowest is about 600mm with the low stem. So forget about the bigger frames I would say. Maybe get the Mono extension plugin and standard 22mm extension to achieve more reach.

My bad...I typed 5xx...meant 655 and 670mm. Was distracted when sending this and didn't proof read.

Damn...555...that's touching my toes.

That makes a lot more sense :-) I am same height as you and riding a size large SC. Think you should be okay with that as well, probably need a medium stem.

Is this steerer stub still available? Can't find one online..

Part 438987

Hi all, great thread been stalking here for a while getting info and got a question.

Got a new to me 2016 Speed Concept, and i want to change out the stem and spacer. After reading about the older bolts for the monobar slider i want to know if it is best to change them out or if they should be ok if installed correctly.

Looking at it, if i want to change the bolts i need:
New Mono Bar-$170
6mm bolt kit-$70
New Slider (cant find only the Madone Speed slider)-$13

This is on top of the new cables, stem and spacer i want/need to change :)

Did you find it?

I have both options:
- Brand new draft box never opened (the std black with metallic grey accent) - including the mounting plate.

- I also have just the plastic mounting plate (no screws, or at least I would need to go through my pile of ziplock bags of SC bits and pieces to locate them).

PM me if you still need something :)

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T. Guertin / Spocket

Tridude93...so not sure if you ever got a reply to this one but.....they are not the same, or at least the one i just got is not. I couldn't find the Speed Concept version for sale in the US, so i got the Madone version and the new bolts do not fit in....not sure how this works but they are too big to even thread in.


Not sure if i am going to order one and wait to get it shipped or try to drill this one out a bit.

Since not everyone checks the classified.. I am in a bit of a bind.


Need to locate a High/Far stem for the Gen 2 speed concept...
Anyone has one of these laying around?


- Speed Concept Gen 2 High/Far stem part #436150
- Also the corresponding stem cover part # W326774

Selling my Gen 2 and potential buyer would need that.. trying to make the deal happen - PM me or reply here if you have something - thanks!

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T. Guertin / Spocket