Mountain Biking - Anyone had a speed-wobble on a MTB?

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Pocko
01-15-09, 01:07 AM
I've been reading another thread in the forum about speed-wobbles... all road bikes and road motorcycle accounts.

Road Bike:
http://nz.youtube.com/watch?v=xODNzyUbIHo

Road Motorbike:
http://nz.youtube.com/watch?v=RmtoOmq3ppw

I'm really curious if speed-wobbles ever happen on front or full suspension mountain bikes. Anyone here experienced a speed-wobble on a mountain bike (XC, FR, DH) or a motocross motorcycle?

Cheers!

.


scrublover
01-15-09, 02:44 AM
I hate it when that happens. Makes me drop my beer.

ed
01-15-09, 06:49 AM
I only wobble when I hit the sound barrier.


Totoro
01-15-09, 06:53 AM
It happens to me when I am going down hill at high speed and I have a loaded pannier. I just brake a bit and as soon as it gets under a certain speed (say 50 mph) the wobble goes away. I have started keeping the speed lower on downhills lately anyway. No sense in getting killed.

ed
01-15-09, 07:14 AM
...and I have a loaded pannier...

:lol:

dminor
01-15-09, 09:47 AM
Anyone here experienced a speed-wobble on a mountain bike (XC, FR, DH) or a motocross motorcycle?Never on an MTB; but, oh my lord yes, on a dirt bike. I remember it like it was yesterday. I was about 15 and on a friend's 250 Ossa Stiletto. I rapped it up into 4th on a long straightaway and set up for the corner - - and as soon as I chopped the throttle, it shook so violently it almost ripped the bars out of my hands.

never
01-15-09, 10:01 AM
Never on an MTB

Not right now...I'm at work.

dminor
01-15-09, 10:06 AM
I said Never - - not never . . . ever . . . wherever.

markhr
01-15-09, 10:20 AM
Yes, I had a bike with an old, worn out, headset that speed wobbled the faster I cycled. Fortunately it only really affected hands free riding.

Pocko
01-15-09, 12:17 PM
Through the years I've been involved in the "dirt" side of motorcycling and cycling - and have never known or seen such a thing, until I read about it in a thread in this forum. Never seen it on a DH, or FR or even a BMX bike... or in motocross.

dminor, were you in a dirt track or the road when the 250cc Ossa wobbled?

Totoro, dirt or road downhill? Your MTB has a pannier??


.

dminor
01-15-09, 12:49 PM
dminor, were you in a dirt track or the road when the 250cc Ossa wobbledDirt. Bit of a braking-bump section. Wasn't a full-blown tank-slapper but it's as frighteningly close as I ever came to having one. Found out that Ossas were prone to that; had to learn to roll off the throttle a bit.

ca7erham
01-15-09, 01:33 PM
Almost had one on a high speed run coming down a hill. Some how I grabbed some brake and slowed down, but it was close (plus it was in traffic at fairly high speed).

Lebowski
01-15-09, 04:53 PM
only on the road bike.

on pavement the fat tires seem to soak up any kind of wobble. on the trail i couldn't tell if it was speed wobbling because of how bumpy the ground is.

ghettocruiser
01-15-09, 08:35 PM
I've had this happen repeatedly while riding no-hands on the road. Soon as I grab the bars it stops.

I still don't completely understand how it can occur while holding onto the handlebars.

BenLi
01-15-09, 09:01 PM
On a different (and somewhat related topic...)

I've been running my tires at lower pressures lately, and I've noticed some wobbling with I'm cornering at speed. I'm guessing that the lateral forces are too much, with the tire inflated less than normal.

Terrapin Ben
01-15-09, 11:22 PM
only on the skateboard.

cyclops
01-16-09, 04:13 AM
only on the skateboard.

OOOh! I remember that, I'd was picking scabs for weeks. My Dragstar used to get them pretty bad too, I dont think the cowboy bars really helped.

A mates CX500 (Honda road bike) was so clapped out the front shook like crazy everytime he braked, but none of my bikes ever did

pinkrobe
01-16-09, 08:55 AM
Never on the mtn bike, whether on or off road. On the road, it happens in a pretty narrow range, ~70-80 km/h. Faster or slower than that and I'm fine.

cyclodan
01-16-09, 05:13 PM
Yep, my mid '90s Slingshot will do it. Had it happen while coasting on a paved downhill, sitting up hands free to drink.
Agressive geometry combined with the mid-frame 3M "spring" board.

ca7erham
01-16-09, 05:55 PM
only on the skateboard.

For some reason I'm incapable of lugging on a skateboard. Two of my friends can, though. I think it has to do with weight. I'm probably a good 20 pound heavier than them.