The Death Wobble

[Lionswings]

This morning on the way to work I had some wide open road with no traffic so I opened it up. At 131 mph (GPS) it started the death wobble. I backed off and got it under control but that scared the hell out of me! Anyone else have this problem? If so, at what speed? What has been your top speed on the FJR?

I think I'm buying new tires AND undies today!

 

[El Toro Joe]

140...no wobble

 

[Wee Willy]

Go check your front tire: pressure and wear pattern. Mostly wear pattern though. These are first-order players in your adventure.

See anything like this?

After this comes bearings and steering head torque. I'm betting on the tire though.

And no issues like yours at speed here with good rubber on the road.

W2

 

[wheatonFJR]

Do you have a top case?

Are your tires adequately balanced?

ON this closed course I was on last year, I was able to hit speed of 150+ with no hint of instability...so something balance-wise is doing something funky to your bike.

 

[Fred W]

Top case will do this with no passenger to fill the hole between your back and the case.

It isn't really a death wobble, can't recall anyone ever being pitched off the bike due to it. It's just a little unsettling.

 

[canucklehead-biker]

Fastest I've gone is 130-ish... steady as the rock of Gibraltar.

+1 on W2's post. Them triangle tires can be funky.

Hope you sort it out!

Griff

 

[wheatonFJR]

You had your hands on the handlebars, right?

:lol:

 

[Lionswings]

You had your hands on the handlebars, right?
:lol:

Well, No! Guess I spent too much times reading the "No Hands" thread! :yahoo:

 

[Wee Willy]

Top case will do this with no passenger to fill the hole between your back and the case.

At these speeds, the frequency of the event will tell you if it is mechanical or aero-related. If the frequency is relatively low (1-2 hz say) it might be aero related. If it is high then it's most likely mechanical in nature.

Question to Lionswings: how fast was the shimmy? At 130 mph, a wheel-driven shimmy would be in the 5-9 hz range.

1 hz = 1 full cycle per second.

W2

 

[Lionswings]

I am placeing an order for some PR2's from Derby Cycles today. My tire looks just like Wee Willy's picture...I was hoping to get a few more miles out of them but not now.

Thanks Guys! :clapping:

 

[Lionswings]

Top case will do this with no passenger to fill the hole between your back and the case.

At these speeds, the frequency of the event will tell you if it is mechanical or aero-related. If the frequency is relatively low (1-2 hz say) it might be aero related. If it is high then it's most likely mechanical in nature.

Question to Lionswings: how fast was the shimmy? At 130 mph, a wheel-driven shimmy would be in the 5-9 hz range.

1 hz = 1 full cycle per second.

W2

It was pretty fast...maybe around 5 hz. And once it started I couldn't get it stopped completely until I got down to about 70mph. After it was stable I went back up to about 90mph with no issues.

 

[Wee Willy]

Top case will do this with no passenger to fill the hole between your back and the case.

At these speeds, the frequency of the event will tell you if it is mechanical or aero-related. If the frequency is relatively low (1-2 hz say) it might be aero related. If it is high then it's most likely mechanical in nature.

Question to Lionswings: how fast was the shimmy? At 130 mph, a wheel-driven shimmy would be in the 5-9 hz range.

1 hz = 1 full cycle per second.

W2

It was pretty fast...maybe around 5 hz. And once it started I couldn't get it stopped completely until I got down to about 70mph. After it was stable I went back up to about 90mph with no issues.

That's definitely mechanical then. Get that rubber replaced and get back out there. Your next 130 event will be a winner...

Cheers,

W2

 

[Lionswings]

Top case will do this with no passenger to fill the hole between your back and the case.

At these speeds, the frequency of the event will tell you if it is mechanical or aero-related. If the frequency is relatively low (1-2 hz say) it might be aero related. If it is high then it's most likely mechanical in nature.

Question to Lionswings: how fast was the shimmy? At 130 mph, a wheel-driven shimmy would be in the 5-9 hz range.

1 hz = 1 full cycle per second.

W2

It was pretty fast...maybe around 5 hz. And once it started I couldn't get it stopped completely until I got down to about 70mph. After it was stable I went back up to about 90mph with no issues.

That's definitely mechanical then. Get that rubber replaced and get back out there. Your next 130 event will be a winner...

Cheers,

W2

Thanks W2...and everyone else. LOVE this forum! :yahoo:

 

[greywolf]

You may consider adding a fork brace , piece of mind is relatively cheap.

New tire / check all bearings and you should be flying soon.

 

[Patriot]

I assume my lil wiggle at 130+ is because of my Gen I is more manuverable and I have a yammy topcase. Don't know about the flags fly on top as well. Funny, my flags aren't lasting as long as they used to lately...

:yahoo:

 

[HaulinAshe]

I assume my lil wiggle at 130+ is because of my Gen I is more manuverable and I have a yammy topcase. Don't know about the flags fly on top as well. Funny, my flags aren't lasting as long as they used to lately...
:yahoo:

You should switch to a Givi top box. You get more wobble that way. Much more entertainment for the money at triple digits.

 

[ShowMeMo]

I am placeing an order for some PR2's from Derby Cycles today. My tire looks just like Wee Willy's picture...I was hoping to get a few more miles out of them but not now. Thanks Guys! :clapping:

Just ordered some yesterday... ordered the B spec and they are on BO... told them to send the standard spec and they are on the way... just a heads up.

 

[cruppelt]

I've had the death wobble a few weeks back - it was so bad I thought the whole front was going to fall off - and it hit just at about 115mph or so. I immediately backed off and looked at my front tire once I got home. I already knew there was some cupping on there, had been already from the previous owner, but I had not realized how bad it had really gotten until I jacked up the bike and freely rotated the tire. That was eye-opening! Now with a brand new PR2 front, the handle bars feel more stable again. Don't know yet about the wobble - I'll have more info on that by Sunday night... :lol:

 

[wnyfjr]

I am placeing an order for some PR2's from Derby Cycles today. My tire looks just like Wee Willy's picture...I was hoping to get a few more miles out of them but not now. Thanks Guys! :clapping:

Just ordered some yesterday... ordered the B spec and they are on BO... told them to send the standard spec and they are on the way... just a heads up.

Ordered mine today too and found the same about the B spec back order. They called and offered to cancel the order if I wanted, but I don't really need 'em right away, so I told them to send it when they get it. He said maybe late June I think. My front looks a little like Wee Willy's pic but then again, I'm not planning on hitting triple-digit speeds in the near future...