what could be causing slight fishtail sensation?

Discussion in 'Road Bikes' started by lakawak, Apr 29, 2015.

  1. lakawak

    lakawak Member

    Toward the middle of my ride today I felt what seems like a slight fishtail when cornering. I was careful the rest of the ride not to corner too fast, figuring I may have popped a spoke or something, but when I got home, I found nothing. The spokes are all fine. There is no wobble whatsoever from the wheel. And the tires were inflated to the middle of the recommended range right before the ride. And it happened enough times (or seemed to) that I can't imagine it was sand on the roads, although after a tough winter, that IS a problem so far.)

    Is there anything else that could be causing it? It wasn't horrible. And quite frankly, I am starting to wonder if I was imagining it, but that seems unlikely since I stated noticing it halfway through the ride and then it seemed like it happened a few times after that.

    Could worn tires cause it? I admit my back tire is a little more worn than I'd like, but a friend and I are replacing my drive train this weekend, so I figured I would wait until then to put new tires on so I can start the new season totally fresh, and basically consider these sporadic warm April days as a bonus pre-season. (And I accidentally ordered blue side walls to go with my green bike so I sort of want to put them on when I will wear them out quicker.) And the tire isn't terrible. Definitely worn, but not thread bare or anything. And I would think that if they were that worn, I would feel other problems with them, but I didn't.

    I am not one to take tight corners too fast to begin with, but I definitely want to make sure nothing is wrong, so is there something else I can check.

    FRISKY Maturity Challenged

    Check spoke tension and bearing play in the hub. Also check to see if the brakes or frame are making contact during wheel flex. A worn or over-inflated tire can get loose pretty easy.

  3. biglou630

    biglou630 Active Member

    I agree with Frisky!

    I have noticed that exact feeling myself in the past, and the time I noticed it my tire was under inflated. I know you inflated to the middle of the suggested range but is it possible when removing the pump more than usual air escaped?
  4. lakawak

    lakawak Member

    I checked each spoke pretty thoroughly, an they all seem fine. I also keep my brakes pretty tight, so if there was any wobble at all, it would rub and it doesn't. The eyeball test suggests it is straight as an arrow. So even if my eyes are off a bit, I can't imagine it being so far off to cause that without me seeing something. The hub seems OK too, but I am not comfortable enough with my knowledge on that to say for sure.

    I put my pump back on to check the gauge and it is still within specs, though it was lower than when I pumped it. I've definitely ridden on less with no sensation.

    I really am baffled. I hope when I go out tomorrow, I can forget about it so I am not exaggerating any tiny movement in my mind to be a fishtail. That way, I will only notice it if it is really happening.

    I DID just notice this...If I loosely hold my frame, and spin the back tire, the bike slightly moves side to side. Maybe a half centimeter total. Now...that is the entire bike...not the wheel which is perfectly fine. But since the tire is the only thing moving, and as far as I know, my hand is steady enough to not move back and forth involuntarily, I would think that has to be causing it. But how could that be if the tire itself is not wobbling at all? Even if when I gave the tire a spin I also put a little lateral force into the frame, I wouldn't think it would oscillate.
  5. kneedrachen

    kneedrachen Moderator Mod Team Tavern Member

    A couple of things spring to mind and all from experience not in expertise from mechanics.

    Frame: I had a Raleigh steel touring bike that would do this when cranked over in a turn or when climbing. It turned out it was just normal frame flex from riding. Using a lower gear when climbing and weighting the outside pedal more helped.

    Wheels: Checl to make sure they are completely seated in the dropouts. I had a rear wheel not set in prefectly (out the by tiniest amount) and it created the fishtail/flat rear tire feeling

    Hubs: As noted previously, check for play/slop

    Headset: Check for tightness, I had a loose headset on the CX bike and felt it as rear slop.

    bottom bracket: same as above.
  6. qmsdc15

    qmsdc15 Well-Known Member

  7. warren128

    warren128 New Member

    That's the first thing that came to mind after OP described how the wheels checked out okay. You should inspect the frame carefully for cracks.
  8. lakawak

    lakawak Member

    No cracks in the frame. Nothing else that I could find that could be causing it. But now with my dented rim, I can't really test things to see if I was just imagining it. In the 2 1/5 miles before I hit the damn pothole, I didn't notice any real fishtailing, but I never really got p to a fast speed. I guess since I will have to take it to an LBS since I am not comfortable building a new wheel on my own, I may as well have them look at it. I'm just mad all this didn't happen on my first couple rides when I had a week or more in between with bad weather
  9. Sneakers

    Sneakers Senior Member

    Only way a worn tire would do that is if the tire is worn to the carcass which I doubt yours is.

    The only other odd thing, which I would try first, is to clean the tire really well with a degreaser, you may have gotten oil or wax etc on the tire, clean it and ride it again. Check to make sure the skewer is still holding the wheel properly, some of the lighter "racing" skewers tend to stretch over time and thus won't hold tight any more, take a skewer from another bike and try it out on a test ride. For that matter take a rear wheel from another bike (yours or a friends) and test ride to see if you get that sensation.

    However if the above doesn't work then I too suspect a crack in a chain stay. Is this a carbon fiber bike? If so cracks aren't always visible because the problem is happening on the inside. Take a coin and tap along the entire length of each chain stay, if you can't hear anything different then remove the wheel and see if you can squeeze the chainstays together with your hands by placing them between your hands and squeeze, don't use your feet or tools or place one side on the floor and push down on the opposite side, kind of like the famous thighmaster work out toy but use your hands instead of your knees, as you squeeze see if you notice one chainstay moving more than the other.

    I doubt if it's anything happening on the front end, like headset etc since the feeling is in the rear, but for giggles make sure the headset is adjusted right and make sure the wheel's spokes are adjusted correctly and that the skewer is tightened properly.

    If you still can't figure it out then take it to an LBS and have them look at it.
    Last edited: May 7, 2015
  10. davereo

    davereo Well-Known Member Tavern Member

    Are you hitting your brakes in the turn?