Dogsled

I had an older Trek aluminun bike that was stable as ever at high speed. My Carbon S-Works Roubaix is not. On decents, all can be doing ok and then all of a sudden it feels like I am getting a front flat and I have to slow down. I have experienced 1 episode of hspd wobble that was pretty spooky. I met a guy with a Roubaix and he said his bike does it all the time. Anyone have the same problem? Could the compact frame design be more prone to this? For those who have light weight bikes with bladed spoke wheels, is your bike rock solid at high speed and what bike is it? Thanks

the beef

Not due to compact frame design.

Instead, don't put so much of your weight far forward. Shifting weight aft tends to alleviate some of the front-end wobble, which admittedly can be scary. Don't lock your arms; keep em loose.

I've experienced it once or twice, but never on a regular basis. However, my old Bianchi Veloce was pretty chattery at high speeds. Cables clanging around on the frame, water bottle cages oscillating, headset shaking. Pretty annoying.

jschen

2006 Cervelo R3 (lightweight carbon bike) with Rolf Prima Elan Aero (mildly bladed spoke wheels, 24 mm rim depth), rock solid at speed unless I hit big crosswinds, which will make me have trouble holding a line on any bike since I'm so light. Hit 56 MPH. Also stable at speed with Easton Circuit (round spokes, 31 mm rim depth, comparable downhill coasting speed), generally used as my rain wheelset. Hit 48 MPH on a damp road.

2004 Specialized Roubaix Comp (not nearly as light carbon bike) with Mavic Equipe (round spokes), routinely got minor but non-frightening speed wobbles above 40 MPH. Hit 50 MPH on that bike.

2005 Specialized Allez Sport (by far the heaviest) with Alex wheelset of some sort (round spokes), rock solid at speed as long as the road surface is good. Not as compliant, so not as confident on rougher roads. No cyclocomputer, but I've probably exceeded 45 MPH on that bike.

EventServices

All are stable. All different types. Too many to name.

Likely you're holding on with a death grip. Relax. Try to be supple.

scottmorrison99

My bike is fine, but I am Unsafe at any speed!

Cypress

Yeah, I'm pretty fast.

CerveloNW

Cervelo Soloist Carbon (compact geometry) with Rolf Prima Vigor wheelset; went + 42 mph downhill today and it was as stable and as smooth as could be. I did not feel unsafe at all.

I also have a Specialized Roubaix Comp, and agree that it doesn't feel quite as stable at high speeds, but a lot depends on the wheelset and rider position.

Lecterman

They're great

johnny99

42mph is not fast. This is fast: https://www.wired.com/culture/lifesty...ikerecord_0330

operator

Pfft 81mph is not fast. This is fast: https://www.youtube.com/watch?v=ZNwmp...elated&search=

WishYouWasMe

I have a Tanzer Rhino I bought from Toys R US a few years ago(I cant find the bike specs online)

but anyway...everytime I go down a hill it wobbles and shakes ESP if its a dirt rd....

Oddly enough I noticed my mountain bike which was not intended for off road didnt move AT ALL when I tried to ride it over the the subdivision construction sites.

nobrainer440

I've hit 45mph on my allez before. Solid as a rock.

rruff

It has nothing to do with the compact frame. I ride a flexy (compact) Ti frame down a hill at 50mph every day (I live at the top of an 8% grade), and have never experienced it. I have light wheels with bladed spokes, too... but they aren't *fat* bladed spokes.

A speed wobble is caused by the system hitting a resonant frequency. It is tricky to diagnose this, but some things you might want to look at are your headset adjustment, wheel bearing adjustment, wheel trueness, and how you grip the bars... if your body is tense, I think this is more likely to occur. A flexy seatpost might be a contributing factor. Actually, if that is it then the compact frame *is* a contributing factor, but you could fix it by getting a stiffer post.

bccycleguy

My Lemond Sarthe (steel frame with Bontrager race Lites) is more stable the faster it goes, at least up to 74 km/hr, which is the fastest I ridden on it.

brundle_fly

My bike is very stable,but the rider is a bit mentally unstable

Will G

I've heard, but haven't had the opportunity to try it, that bringing your knees in to the top tube will solve or reduce a high speed wobble.

Carbonfiberboy 

May be due to your compact frame, depending on sizing. Can you grip the top tube securely between your knees? If so, do it. If not, problem.

Put more of your weight forward. In particular, weight the pedals and unweight your butt. Pedals horizontal. Hold the bars firmly, but not death grip and try to relax your arms. Grip that top tube (the most important thing) if you can.

Trek 5200 with Rolfs - bladed of course. No wobble. 55 has been max.

GuitarWizard

I don't recall ever owning a bike that was "unstable" at high speeds - relax, ease up the grip on the bars, look far ahead for any road obstructions, and keep a neutral weight balance.....if you're cornering at speed, put weight on your outside foot and shift your weight forward a bit to get maximum grip on the front tire.

Either that or something may not be adjusted right on your bike, or it's out of alignment.

SDRider

Nope, I've had it up to 50mph with no wobble.

jschen

Yes, doing that will change the resonance frequency of your frame and dampen the existing vibrations, so if you're hitting road imperfections at your frame's resonance frequency, briefly bringing your knees to the top tube can help. A brief touch of the knees always did the trick for me whenever slight speed wobbles affected my Roubaix.

Surferbruce

according to an article by framebuilder craig calfee a common cause of high speed instability (shimmy/speed wobble) is fork alignment. specifically it is the symmetrical position of the fork dropouts in relation to the steering axis. he found that forks more than 1.8mm out of alignment caused instability at speeds over 30 mph.
the problem is many manufacturers don't check this after the forks come out of the molds (cf forks). traditionally steel forks can be cold set after welding/brazing and master framebuilders can get forks to within .5 mm of alignment. carbon fiber forks cannot be cold set so therefore the molds must be as close to symmetrical as possible. slight assymetry can be corrected when dropouts are bonded but it must be checked, and guess what, most manufacturers don't do that. one would think companies would put effort into insuring symmetrical molds,but according to his tests several manufacturers were off by more than the 1.8mm number.
other things can contribute; loose headsets, out of true wheels, unaligned frames, poor design- but assymetrical fork blades can almost guarantee a problem at speed.
interesting article , among others he's written. the guy knows his stuff.
you can send him a fork to be tested for a nominal fee if you're curious.

Dogsled

This problem is not all high speed wobble, although that did happen 1 time. I do try the knees to the top tube and the loose grip on decents to try to prevent this, (I'll call instability). It just feels like I am getting a flat and maybe hspd wobble IS what is starting to happen but with the prevention methods like "knees in" it doesn't get into it but I always have to slow down grrrrrrr. Like I said, the old aluminum Trek was rock solid the only thing that changed was the bike. It's a sad day when your group rides away on a decent. I do notice, in a pack I can hit 30+ and the bike feels pretty good, so, that's in a wind protected environment hmmm (wheels) and it's not 40mph. I just don't know.

DiscoStu

New Tarmac feels better than the old Allez Elite. I don't think I'm gripping as tight because the bike handles that much better.

Another point is that my old bike had crap Alex wheels on it and the rear was WAY out of ballance (light on the stem side as usual). I put a couple valve nuts on to help balance it (weight trade-off), but it still caused vibrations. The back end felt jittery.

thomspins

it's not the bike; any instability at speed and in cornering is due to a poor position.

If position is set up for racing it'll be wayy more stable on higher speeds and hard cornering but not as comfy on long group rides; if set up for touring and screwing around... it'll be the inverse..

same as racing motorcycles

biker7

Not necessarily. I have descended at speed approaching 80 mph with gail force side winds when standing one legged on the saddle riding no hands and my bike tracks dead solid. I believe it is a combination of how the rider is on the bike and the bike itself.
George