Lemond1985

I have Lemond Tourmalet I really like, but it has one problem. If I’m descending, even on a slight grade, with one foot down, and take one hand off the bars to get a drink, the frame goes into a terrifying speed wobble. Frame is 525 Reynolds.





The part of the frame where it originates seems to be the joint between the seat tube and top tube. If I sit on the bike to pull on the bars, they cause the frame to flex about 1/2” both right and left. My CF, aluminum, and stiffer steel bikes do flex some when I do this, but not to this degree. I have discovered the same problem on a Peugeot PH 501.

I guess there’s no solution other than to find a stiffer frame (or lose about 50 lbs). I have to wonder if this is not one of the reasons why pro bikes are typically so stiff, so that a rider taking a drink doesn’t go into a speed wobble and take out the entire peloton.

Anyone else have a wobbly frame, and if so, how do you deal with it? Could it be the wheels be part of the problem, or is this a frame issue?

abshipp 

It's a little strange to hear of a bike that small having excessive frame flex. My Trek is a bit noodly but it's also a 25" frame and I'm about 200lbs so I'm expecting (and hoping for, in a way) the frame to flex. It will shimmy if both of my hands are off the bars and I continue pedaling, but it's easily tamed by either putting a hand back on the bar or if I stop pedaling.

My two suggestions are as follows:

Check your headset preload. An excessively loose headset can exacerbate shimmy/speed wobble, and you may want to try tightening it just a little bit more than optimal to stiffen things up. This will come at the expense of your headset life but it wouldn't hurt to try just for a bit.

Try to get into the habit of every time you take a hand off the bar, press one of your knees into the top tube. This is a well-known method to help calm down a speed wobble. It seems like you don't continue to pedal if you take a hand off the bars so that shouldn't be much of an issue.

Cypress

Try loosening your grip on the bar as well.

Seattle Forrest

I don't think it's frame flex. Any bike can develop a speed wobble, the planets just have to align differently for a different bike. See if touching the top tube with your knee makes it go away. Failing that, have your drink at the bottom.

Lemond1985

Thanks for the replies. I was hoping someone would suggest getting one of the Lemond frames in Reynolds 753 (stiffer?) and see if that fixes the problem. I may still do this if i see a good deal on a used one on CL.

Until then, I will try the leg on the top tube test and see what happens. Either that, or keep the pedals level when I take a drink. But it ain't the same, not being able to have one hand in the drops as I crest the climb and take a big drink as I begin the rapid descent, Tour de France-style.

delbiker1 

I suggest getting a Tourmalet with 853. I have one, 53cm, and it handles and rides terrifically. Never a wobble when descending. I look at Lemonds a lot and have not seen steel Tourmalet in that size, but there are some in other sizes on Ebay.

Lemond1985

Yes, I meant Reynolds 853, thank you. I think i will take your advice and begin the search immediately.

Miele Man

Check the entire frame carefully for minute cracking. Seems that when a pedal is at the 6-o'clock position that it might be a bottom bracket/seatube flexing problem as weight is put onto the pedal subconsciously.

Cheers

canklecat

After inspecting the frame and fork, I'd try a different front tire and see if it helped. Maybe the tread pattern on that Panracer doesn't get along with the pavement pattern and your speed, weight, balance, etc.