Surferbruce

sorry but i can't buy that at all. a bike should handle well when a rider is in a comfortable biomechanically correct position. weight distribution is a critical part of proper fit and positioning, but a bike needs to perform well when climbing as well as descending. if it were just about position at speed we'd all be on low cg gravity type bikes.

VegaVixen

If all else fails, try some streamers on the handlebars. Helps stablize like a tail on a kite. For real. Serious. But they have to match your bike's color scheme, or else the bike will become more unstable due to NOCP accesorization.

Surferbruce

if this WERE the case, everyone would be setting their fore-aft saddle position for weight distribution rather than pedaling efficiency. likewise, it would be impossible to sit up no hands at high speed, something you see all the time in elite racing.
motorcycles are completely different because they don't have to be propelled by the rider.

pedalgeek

"Is your bike stable at high speed?"

My bike stable is not really at high speed. Unless you count the rotation of the earth or the the earth's orbit around the sun. It's just the corner of the basement.

grahny

I've hit 47mph on my soloist (compact frame) and I get no wobble at all and always have the bike under full control. I've gone over some pretty rough roads at those speeds too with no issue. I sit back off the saddle, head tucked down, right knee touching the top tube and have no issues.

thomspins

who powers the 2 wheeled vehicle doesn't matter..

your position IS for weight dist. Try a hard fast corner where you are on the edge of traction; too far foward like a tt position the and your cornering capabilities are greatly reduced, too far back and you get the same thing.

your position fore aft with your saddle is just moving your center of gravity back and forth to balance you to unweight your arms and even your weight out over front and rear tire; it just so happens that somewhere in a small area you achieve a efficient pedaling stroke . Knee over pedal spindle with a plumb line for pedaling efficiency is bull.. speak with richard sachs about this. Fit and position (sometimes...rarely fork rake) are the only things that result in goofy or great handling

thomspins

buy or check out at a library a book titled

A Twist of the Wrist

a book on motorcycle racing; explaining all the forces acting in turning, your weight distribution, traction, steering... etc.

Will help your cycling alot esp. racing..

I wish that the USCF would require cat 5 racers starting out read this book; everyone would handle much better. I find myself thinking this in every race i'm in... "i wish some of these guys had ridden/raced motorcycles before" it helps alot! It is noticable in every race the people whos bikes don't fit or just have poor position. these are the guys that get all wobbly descending and can't corner fast to save their lives; unfortunately cause most crashes too..

ken cummings

Rock solid at high speed up to 38 MPH so far. But then it is a Bruce Gordon loaded touring design. I had a Miyata 1000 bike with a full touring load reach 45 MPH. Again solid. A fully faired recumbent was not stable. When I got over 65 MPH I started getting lift on the front end due to air getting trapped under the shell.

mtnroads

Both my Bianchi's were twitchy over 35 mph - no amount of relaxing the grip, changing weight distribution, etc made any difference. Very quick steering geometry and scary when descending with cars passing two ft away, or in crosswinds. I didn't like it so I sold them. My Trek 2100 was rock solid, as is the 5200 which replaced it.

Dave Moulton

I wrote at length on the subject in a blog article called Shimmy Re-visited.

dokie

every time i see a post like this i wonder what is wrong with these people. im new to the sport and reach 60+mi on my dawes lightning on every ride. dont every have to worry about wobbles or anything.

messed up my spokes and got a flat trued my wheels myself for the first time then whent down the hill again the next day.i think alot of it might be nerves. put your hands onthe drops, tuck and dont hit gravel.

slowandsteady

What size stem do you have? My bike is downright scary with a 70mm stem, but smooth as silk with a 90mm.

gfrance

When it starts to get scary, get back and low!!! And keep hands and elbows flexy. "Go with the flow".

Ride a mountain bike too to learn these kinds of skills. You'll quickly learn after you do endos enough.

DocRay

not the frame, likely crap wheels.

Quijibo187

i'll let you know if I ever get it going fast.

Dave Moulton

Some bikes shimmy, some don’t. Bikes I built had a little more trail than average and as a rule do not shimmy. Large frames tend to shimmy because they are taller and more flexible. Plus the rider’s weight is more over the center of the back wheel.

It is a combination of rider and bike that causes shimmy. I have seen a video of a motor cycle on the Bonneville Salt Flats than shimmied so violently that the rider was thrown off. Once the rider was gone the bike stopped shimming and carried on in a straight line, on its own, for a considerable distance.

There is a clue here. Try not to hold the bars too tightly and gripping the top tube between your knees will dampen the shimmy without you actually being attached to the frame. Having the bike shake is bad enough but if you are attached to the bike so firmly that your body shakes also you are adding to the shaking mass, and a crash will probably ensue.

Once again here is the link to the full article I wrote on the subject.

sjumper

A couple of years ago, I had some serious speed wobble problems one of my bikes. Here was the initial setup:

- 2003 Fuji Team Issue alum frame and carbon fork
- Easton Circuit wheelset
- Specialized Turbo tubes
- Specialized Mondo Pro tires 700x23

I listed the wheelset/tubes/tires because that was the cause of the problem. The wobbles (a couple of times I thought I was going to kiss the road) would start at relatively low speed, at around 30mph going down a hill. I tried everything to solve it - different riding positions, grip, etc. The only thing that seemed to make a difference was reducing the tire pressure to around 90psi or lower. This seemed to push the speed up where the wobbles would start.

It was driving me nuts so I started swapping out parts with my other bikes. Eventually, I tried a different wheelset (Mavic Cosmic Elite with some no name tubes and crappy tires) and no wobbles whatsoever. I wasn't quite satisfied so I put the Easton Circuits back on but with different tires (Conti GP 3000, same size) and tubes (generic no name). Surprisingly, no wobbles. Then I acquired a set of Supergo Korso wheels and put the Specialized tubes and tires on them and again no wobbles.

My conclusion was that the combination of the frame, those tubes and tires produced the wobbles. Fortunately, I had the parts to try different combos or I still wouldn't know what to do.

G_Sup

Thanks for the tips folks. I have had this happen to me on my Orbea Onix and it freaked me out. I thought my front tire was coming off the fork so I feather braked to slow down. Really freaked the $%# out of me. I'll try bring my knees to the toptube and see if that helps.

alanfleisig

Might be the wheels, not the frame.

curiouskid55

Its the weight. Lighter bikes are not as stable as slightly heavier models. My Roubaix started vibrating on a 50 mph descent with a high cross wind. Just about everybody else had the same problem except the guys on steel, solid as a rock. A big heavy rock made out of steel.

Sirrobinofcoxly

My Orca flexes a bit at 80km/h down hill, but no chattering or speed wobble

GuitarWizard

Is 17 pounds heavy? Because I've approached 50 mph on my 5200 and it's completely stable.

Gee3

I have a Allez Elite (compact geometry) with Mavic Equipes w/ bladed spokes and I hit a little over 44mph on a descent this weekend. It felt pretty solid with no wobbles. I stay low in the drops, arms tucked in, with my head down, butt up and back some on the seat and don't have a death grip on the handlebars. (I learned to not hold with a deathgrip from racing cars.) Not sure if that position is correct as I don't race but it seems to work so far. I never felt I was gonna lose the bike under me.

Im taking a descending and climbing clinic this weekend so hopefully they'll show me the proper way to position myself on the bike.

curiouskid55

Congratulations.

patentcad

Cannondale Six13. Very stable, no problems @ speeds up to 45+mph.