It's gotten squirrely. . .

[Bud]

I'm not sure if I spelled squirrely correctly, but you get the idea. Anyway, something has changed with me and/or my position on the bike. Lately, it seems pretty loose in the back end, mostly when descending at high speeds.

Some background: The bike is a steel Fierte that I've had for almost 1 year. I was fit (by WRC) on it when I bought it. Since that time, I've become stronger and faster on the bike, and I've also made a couple of changes along the way:

1. I replaced the original Terry saddle with my Specialized BG that I had on the old bike. It fits me much better.

2. I replaced the original setback seatpost with a Thomson Elite zero setback. I really only moved the saddle forward by about 2 mm, but it made a big difference in comfort on the bike.

3. I replaced the original Specialized stem with an Oval Concepts (much stiffer) stem of the same length (120)

4. I've lowered the stem/bars by about 1.5 cm over the last couple of months.

I know that's a lot of changes, and I'm not sure than any or all of those are the cause of this change in handling. It could be more due to my body. I've been less flexible lately. However, the change in handling is noticeable while coasting down the descents, which leads me to think that it's something about my weight distribution on the bike.

Any ideas on where to start the diagnosis? Should I go see a fitter again? Could it be something mechanical? Wheels? Any advice is welcomed. This is frustrating me.

[CNY rider]

Have you checked mechanicals, particularly looking for a loose headset, and alignment of the wheels in the dropouts?

[bigdeal]

sounds to me like, between the lowered stem/bar and the forward seatpost (assuming you didn't slam the saddle back), you moved forward on the bike a couple of centimeters, relative to the frame. This would put more weight on the front, and less on the back.......

[Bud]

CNY: Headset is fine- I thought that might be it.

Bigdeal: I was thinking that I might be a bit too far forward. Is there some way I can tell (ie- a measurement)? I guess I could slide the saddle back a few mm and experiment.

[dgauthier]

It sounds trivial, but make sure you close the quick releases with the bike upright, while applying light pressure downward on the frame. This ensures that the wheel axles are completely seated in the dropouts before the qr's clamp them in place.

Though I'm not a fitter, I would expect a weight shift forward to make your bike *less* squirrely, not more. Unexplained changes in handling make me nervous. Check your bike (maybe take it to your LBS) for failing components: cracked rims, bent axles, cracked carbon, etc.

[Sandy]

bigdeal makes a lot of sense to me. Saddle may be forward too much, causing too much weight on the front and not enough on the rear, making the rear too light.


Saddle Serotta Sandy

[Bud]

The wheels/QR's are fine, as far as I can tell.

I moved the saddle back by a magic number (3 mm). A quick spin around the neighborhood yielded inconclusive results. It definitely feels a bit different, but I won't be able to tell for sure until I go for a longer ride and do some descending.

I still don't understand why I didn't notice this earlier when I replaced the seatpost (~2 months ago). Only recently (within the past couple of weeks) have I noticed a change in the handling. Maybe there's something else going on too. I'm taking notes as I make adjustments, anticipating that there will be more experimenting.

[RPS]

I would first check the frame, fork, wheels, etc… for anything that doesn’t look or feel right.

The changes you described above (moving saddle 2 MM forward and lowering the bar), if accurate, should make less difference in weight distribution than placing an extra water bottle in a jersey rear pocket; which I wouldn’t expect to affect handling or high-speed stability. Since most road bikes have wheelbases in the range of 1000 MM, even if you moved the entire center of gravity 2 MM, the weight distribution would not be affected significantly.

[Richard]

How old is the tire in the rear? If it has "squared off" it will cause all kinds of issues.

[stevep]

is the stem angle different?
is it 15 degrees up now? instead of flat?
i have found this can dramatically affect the front end of a bike in a negative way.

[Bud]

STem angle is the same.

RPS- I agree that these minscule movements of the saddle wouldn't seem to affect my weight distribution that much. I think there are other issues at work.

Richard- you may be onto something with the rear tire. I had never given it that much thought, but it is getting squared off a bit. I've been meaning to change it out. We'll see if that was it. I dunno.

Thanks for all of the suggestions.