Ducati.ms - The Ultimate Ducati Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
985 Posts
Discussion Starter #1
Esteemed Moderator Don posted this (in part) in another thread:

. . . OK, lets talk about the somewhat controversial whys of "headshake" and why some folks experience it and others do not. . .

. . . The fact that the front suspension is less than ideal increases this liveliness. Poor compliance means that the various loads fed from the contact patch up into the steering head are in constant flux. . . .

-don

I experienced my first and only instance of "headshake" shortly after buying the GT. It was a real tank slapper, which almost threw me off of the bike. Scary! I rolled off the throttle and gave a quick jab to the rear brake, which calmed things down. A Storz Performance steering damper cured the problem, but at the cost of the bikes otherwise light handling.

A few months later, I replaced the heavy OEM steel wheels with nearly-new light alloy units from a Paul Smart. I immediately noticed that the bike's suspension was now more compliant, and the ride quality better.

This evening, I'll remove the steering damper to see if the new wheels cured the headshaking problem. I'll post the results here.

Has anyone else here noticed improvement in this phenomonon after modding the wheels and/or suspension?
 

·
Registered
Joined
·
421 Posts
Personally, I'm convinced that the 'headshake' that some have experienced on the GT is all about weight transfer, or weight bias if you will. It's simply a matter of not having your weight forward.

Notice that it's always when 'on the gas', and stops when you let off the throttle? Have you ever ridden a bike that was the opposite- one that shook violently when you let off? Now that's scary. I'm thinking of a Yamaha XS650 in the early 80's. Scared the crap out of me, and the only way to get it to stop wagging it's head was to roll the throttle back on.

Lighter wheels help the suspension cope with road irregularities, but they also have less centrifugal force. I don't know if the net result would be to help or make a headshake worse.

I do have adjustable Showa forks on my bike, but I can't say it's made any change to a headshake problem, because I've only had it shake a few times, and that's been when at WOT, power shifting to the next gear with my weight too far back, unloading the front. Either pushing myself farther forward or simply chopping the gas fixes it.

I think the reason we don't hear so much about the Sport 1000 or Sport 1000 S having a headshake is more about the riding position putting more weight forward, and less about the lighter wheels.
 

·
Registered
Joined
·
2,321 Posts
The problem here is that you may not get any warning before you crash! (see Major Softie's experience, and others on this forum). I have never had any headshake on my GT, but after reading the threads here, I fitted a damper for peace of mind.
 

·
Registered
Joined
·
1,071 Posts
Esteemed Moderator Don posted this (in part) in another thread:




I experienced my first and only instance of "headshake" shortly after buying the GT. It was a real tank slapper, which almost threw me off of the bike. Scary! I rolled off the throttle and gave a quick jab to the rear brake, which calmed things down. A Storz Performance steering damper cured the problem, but at the cost of the bikes otherwise light handling.

A few months later, I replaced the heavy OEM steel wheels with nearly-new light alloy units from a Paul Smart. I immediately noticed that the bike's suspension was now more compliant, and the ride quality better.

This evening, I'll remove the steering damper to see if the new wheels cured the headshaking problem. I'll post the results here.

Has anyone else here noticed improvement in this phenomonon after modding the wheels and/or suspension?

Yes, very much improved handling on my Sport since changing to Ohlins, alloy tubeless wheels and a Speedy Moto triple clamp (extends the forks an extra 1/2" or so). Not sure if any one of those changes fixed it, but all together, they seemed to have cured the headshake problem (knock on wood) among other handling problems (forks bottoming out, etc.) without going to a steering damper.

No expert here, but what I've read here seems to point to the greater unsprung weight of the stock wheels with tubes being the main culprit for headshake. I'm sure the less-than-adequate stock forks don't help -- the only times I've experienced headshake are after hitting a sizable bump with the stock wheels, forks & tubes.

Seems like I've also read here that those with the high rise handlebars on the GT are getting more tankslappers than with the standard bars for some reason.
 

·
Registered
Joined
·
126 Posts
Personally, I'm convinced that the 'headshake' that some have experienced on the GT is all about weight transfer, or weight bias if you will. It's simply a matter of not having your weight forward.

Notice that it's always when 'on the gas', and stops when you let off the throttle? Have you ever ridden a bike that was the opposite- one that shook violently when you let off? Now that's scary. I'm thinking of a Yamaha XS650 in the early 80's. Scared the crap out of me, and the only way to get it to stop wagging it's head was to roll the throttle back on.

Lighter wheels help the suspension cope with road irregularities, but they also have less centrifugal force. I don't know if the net result would be to help or make a headshake worse.

I do have adjustable Showa forks on my bike, but I can't say it's made any change to a headshake problem, because I've only had it shake a few times, and that's been when at WOT, power shifting to the next gear with my weight too far back, unloading the front. Either pushing myself farther forward or simply chopping the gas fixes it.

I think the reason we don't hear so much about the Sport 1000 or Sport 1000 S having a headshake is more about the riding position putting more weight forward, and less about the lighter wheels.

Rossi....not to shift gears (excuse the pun) but I was wondering what model Showa forks did you put on your GT and where did you find them? Also if you don't mind...how much did they cost? For the life of me I can't find anything on Showa as a replacement on the GT. Did it require any special modifications and/or new parts for the front end?
 

·
Registered
Joined
·
421 Posts
Seems like I've also read here that those with the high rise handlebars on the GT are getting more tankslappers than with the standard bars for some reason.
Again, I'm sure this is because higher bars put your weight farther back. For what it's worth, my bars are about 1" lower than stock, which I think lessens the tendency for headshake.
 

·
Registered
Joined
·
421 Posts
Rossi....not to shift gears (excuse the pun) but I was wondering what model Showa forks did you put on your GT and where did you find them? Also if you don't mind...how much did they cost? For the life of me I can't find anything on Showa as a replacement on the GT. Did it require any special modifications and/or new parts for the front end?
Mine are off an '06 Monster S2R 1000. Direct bolt on, though slightly longer (about 10mm more travel?). Monster S4R forks work as well, as do ST3/4 I believe.

I bought them from a forum member who was selling his bike stock and selling the add-ons separate. EBay is also a good source. Cost can be $300-600, more for the higher end titanium nitride coated versions.
 

·
Registered
Joined
·
126 Posts
Mine are off an '06 Monster S2R 1000. Direct bolt on, though slightly longer (about 10mm more travel?). Monster S4R forks work as well, as do ST3/4 I believe.

I bought them from a forum member who was selling his bike stock and selling the add-ons separate. EBay is also a good source. Cost can be $300-600, more for the higher end titanium nitride coated versions.
Thanks Rossa (sorry for the mispelling of your name earlier...in a rush). I am searching for an alternative to the stock setup on my GT. I like the idea of adjustability in preload, compression dampening and rebound dampening to customize for my ride.
 

·
Registered
Joined
·
421 Posts
...see Major Softie's experience, and others on this forum...
I believe Major Softie's bike has lighter wheels, but I can't recall for sure. I know he has SS 1000 Showa forks, and since they are quite a bit longer and stick up past the triple farther he made extensions for the handlebar risers, making the bars higher than stock.

I'd have to find the thread again, but wasn't there some question about whether his crash was due to some failure of some kind?

Major- you out there?
 

·
Registered
Joined
·
188 Posts
Feel more secure now, but can't confirm which of my mods helped most to solve the headshake.

I bet that Showa adjustable fork and a lower handlebar (more weight front) where the principal aids, and light wheels where just helping the handling and the suspension work on bad surfaces.

I'm not completly sure I'll not get a steering damper... have to test/ride more.
 

·
Registered
Joined
·
1,109 Posts
I've been running CF wheels for six days and am on my second tank of gas with them and have had *no* headshake since making the change. It is so noticeable that I am considering removing the ohlins steering damper altogether.

FWIW I'm also running hyperpro springs, ohlins forks and with the wheel changes put on Michelin Pilot 2c's.
 

·
Registered
Joined
·
128 Posts
I would keep the damper on....... I put one on my sport and I am convinced it has saved my life (or at least my skin) like a gogolplex times.....

I keep it on the lightest setting and thats all it needs. Now I can monster-truck through off camber, bumpy, potholed hilly corners on the throttle all day long without a care in the world.

Yup-
 
1 - 12 of 12 Posts
Top