jdtschida

Hello everyone! Wasn't sure exactly where to post this, but figured fellow roadies might be able to help the best.


Long story short, I'm nearly done converting my Trek Y-Foil 77 '99 frameset into a triathlon / tt bike. Now I'm working out seat position and stem length to get it more aero and better riding. Photos below are of me on my trainer after riding the bike about 16 miles. Comments are included with each set about how it felt, etc.

My goal here is to get my position adjusted better on the bike. Ideally a 78ish degree seat position (which may not happen because of weight positioning on the bike) and also a flatter more horizontal back when on the aero bars. Many of my plans come from reading this web site

On with the show!
Notes: Ignore the PFD holding up the front wheel, I just got the trainer and don't have a stand yet for the front end. Also, I'm so fast that the camera just can't keep up! Sorry for the blurry legs...

These first two photos are of me extended on the aero bars. In this position while on the road, I don't feel like I have great control of the bike. The areo bars need to be moved closer together because my hands feel like they are being pulled out to the sides too much. I also feel a little too extended and when I push hard with my legs the bike goes side to side a little bit. Harder to keep going in a perfect line.






The next two photos are of me holding the aero bars about two inches closer, as can be seen in the pics. My goal was to feel less extended, but also have more control. While riding on the road, there was a big difference in this position. The pads were under my forearms, which was no good, but at least I could tell that when I pushed harder I didn't pull side to side anymore, and I also just felt good. After this test, it just makes me think that I really do need to shorten the stem and possibly get a no-setback seatpost, or maybe even a forward post if it needs that much of a move.






Finally I want to include a couple photos of me holding the base bar. I'm not out on the ends at the brake levers, more back near the bend. These bars are 42cm, and I normally ride 44cm. Reason I have the narrower ones is because they are used and I got a good deal so I figured I'd give them a try. For now, they work OK, just not used to them yet.







So, after all that, here are my thoughts on what I think should be done to improve my fit, aerodynamics, control and comfort. If anyone disagrees with my ideas, or thinks of a better one, please let me know. That's why I'm posting all this anyway.

1. Seatpost and seat position. Currently I have the seat as far forward as it will go. This might be visible in the photos. I am thinking that a zero-setback post might be a great idea to move the seat a couple CM forward. Combined with a shorter stem, this should help with the over-extension problem. It also should bring me closer to the magical 78 degree seatpost mark without putting too much weight on the front of the bike. I've thought about a "fast forward" post, but am concerned it would put way too much weight on the front and cause the bike to be twitchy, which I want to avoid.

2. Stem length. I've always known that this frame was a touch long for me, but hey, that's what you live with when wanting to ride a Y-Foil. So I'm thinking to help bring the bars closer, a 90mm stem should be used. Currently I have a 110mm.

3. Bar height. I'd like to have my back more horizontal, and since I can't raise the seat more than maybe half a cm, I'll need to lower the bars. The ICON Graphite stem that I have sets really high, as can be seen in the photos. I think it should be able to go in another cm or so, but it hits the star nut inside before that point. Another option is to find a stem that doesn't come up quite as high.

Grasschopper

Not to be an ass but why not post this in the Tri forum?

That said if you want a more forward saddle position then think about maybe a Profile Design Fast Forward seatpost.

I agree that you probably want to lower your front but can't get a good view of your stem steyup...it sort of looks like you are using quill stem? Can you do a closeup of the stem, headtube, bar area of the bike?

jdtschida

It's always something. I chose the road forum because the Tri forum isn't super active, and most of those folks also read/post here like I do.

The Profile seatpost, from what I've read, moves the seat about 5cm forward. I'm concerned that it would put too much weight up front and cause the bike to be twitchy.

I forgot to say that it is a quill stem. Here's a better photo, grainey because of the camera settings at the time...

Grasschopper

I thought that looked like a quill stem. Well it looks like you can go a little lower (well maybe as much as 3/4"?) just with the stem but that headset looks odd. Is the fork too long so you had to use spacers to raise the nut? This IS a threaded fork and not some sort of adapter right?

Really looks like you could lower your bars nearly 2" with some changes in that area.

jdtschida

Ya, it is funny. The fork is a touch long, and there is a spacer in there. That could be shortened and removed. The stem itself should go in further, but the star nut (i think) inside is jammed in a bit high. Basically the stem is in as far as it'll go right now. I'm not sure at the moment if/how I can get the stem to go in further like it should. I'll have to take it apart to find out. You are right though, I should be able to lower it with those two changes.

BikeWNC

You might have seen this site, but if not it's worth checking out.

https://www.slowtwitch.com/mainheadin...r/bikefit.html

jdtschida

Ya, there is a link to it buried in my original posting.

Grasschopper

Was that headset/stem on the bike when you bought it? I am asking this because I am wondering if it has a threadless to threaded adapter which could be the issue here...the star nut comment adds to this, if it was a threaded setup there shouldn't be a star nut. I think you need a new THREALESS stem, probably a top cap unless you have one floating around, and you should ditch the conversion to threaded and the stem that is on there.

The setup looks similar to this one where the seller claims it has a threadless setup but as you can see has a quill stem and a big stack of spacers. https://cgi.ebay.com/ws/eBayISAPI.dll...ayphotohosting

jdtschida

Sorry for the confusion Grasschopper. It is a threaded setup, no adapter. "star nut" is probably the wrong term for the part I'm talking about. It's the nut inside the steerer tube that the bolt through the quill stem screws into.

I bought the frame about 4 years ago, came with the headset setup like that, and it worked fine for me so I left it be.

Grasschopper

See that is what I am saying. A quill stem doesn't have a star nut for the bolt to thread into, the bolt pulls on an expander wedge at the bottom of the stem and it snugs tight against the inside of the steerer tube. It would look like this:



You can see how your setup looks like the one in the eBay add which that guy says is threadless but is clearly using a quill stem. If you bought your bike used it could very well have been a threadless setup that the PO converted to a threaded setup, thus the stack and the star nut. The way you describe what is limiting your lowering of the stem it DOES sound like there is a star nut in there which if it was originally a threaded setup it wouldn't have.

Your just going to have to pull that thing apart.

jdtschida

My stem is like that, but there is a star nut inside. I just did a search to make sure I wasn't making things up, and here is what I see down in there.




Could be that you are right, maybe the nut was in there mistakenly and I never realized it... When I built the bike, I was a newbie, now I'm smarter, but still no expert. The frame was purchased as brand new, never built. And based on what I received, it was never built. Not a scratch on it. I didn't get it from Trek though, this was just after they stopped making Y-Foils, and there was a guy selling a large stock of them on EBay. That's how I got it. Seems funny that it would have been setup with a star nut down in there though. I know I didn't put it in.

Maybe I'll dig that sucker out tonight and see what happens.

Grasschopper

Yea if you have a star nut in there I think (please someone correct me if I am wrong here) you should get it out. I just did some looking around and the Y Foil did come with a threaded setup and the stack height is pretty tall on the stock setup. That said I saw at least one photo with the stem lower than yours.

jdtschida

The second photo does look to be lower into the steerer tube, but still has a black spacer in it. There's a Yahoo Yfoil user group that I've asked in for some more advice, will see what they have to say as well.

I also went through the groups photo album to see how other people setup their bikes. Looks like anyone still using the threaded stem setup have them set pretty high, most appear to still have the original spacer in there. Those that switched to a threadless setup are all over the place, some really low like I might want, others with spacers, and still others with no spacers but a stem angled up. Kinda all over the place.