Ducati Monster Motorcycle Forum banner

1 - 9 of 9 Posts
Q

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I thought it might be interesting to hear from victims of tank slappers regarding their bike set-ups with the intention of identifying commonalities.
Info along the lines of suspension type (adjustable or not) and modifications/condition, handlebar types, rear sets or not; number of miles, road type/condition and bike operation details at time of event, etc., yada yada, like that.

This is seemingly not an isolated phenomenon though certainly not epidemic.

Just wondering if certain planets need to be in alignment or what.
 
M

·
Guest
Joined
·
0 Posts
Discussion Starter #2
you will probably find a convergence of factors rather than any individual isolated fault

my recent one was attributable to primarily me and.....bad road surface + old tired
 
Q

·
Guest
Joined
·
0 Posts
Discussion Starter #3
Thanks MR!
I'm just trying to shed some light on a problem with potentially serious results ( don't cringe...I'm no safety freak ;) ).

Over the years I've experienced more than a few slappers on bikes you'd never expect in a million years to give trouble, yet each one finally gave up it's secrets even if they were bike if not model specific.

If no interest however I'll stick to turn signals and tail chops :-X
 

·
Registered
Joined
·
45,105 Posts
since i have only experienced notable headshake twice, but never a tankslapper (hope i never do!) i have nothing to contribute.

i would like this thread to continue.
 

·
Banned
Joined
·
3,931 Posts
Okay, here's a reference point for your study:

Rear suspension 100% stock, with the sag set correctly by a suspension expert. Front suspension at stock height, but with slightly stiffer than stock springs, and sag set correctly by a (different) suspension professional. (I weigh just over 200 pounds in full riding gear, so stock springs are too soft.) Bars were stock. Tires had good tread, no cupping or anything, and were inflated to 33/35 front/rear. Bridgestone BT-020 front and rear.

The forks had recently been revalved and springs stiffened, but that clearly fixed several other handling problems that it had had before then. Previously, braking into a bumpy turn could cause it to ride like a jackhammer until the brakes were released. It was tracking better than ever with the modification. I can't blame the forks directly.

Tank slapper was caused by crossing a cattle guard at 40-50 mph on an uphill section. Bike was probably in 4th gear and speed was either steady or very slight acceleration. The road was almost straight, but not quite.

I'm guessing the cattle guard caused the front wheel to bounce off of the pavement slightly and come back down less than perfectly straight. The bike seemed to instantly go to full lock, oscillating 5-10 times, then tossed me off and began sliding on down the road. There was no warning that it might do something like that and only about a second to "enjoy the ride".

I've had dozens of experiences with headshake while accelerating out of bumpy corners or landing wheelies a little off and the bike had always settled right down. There had never been a scary moment before this incident.

I'm pretty sure that a steering damper would have saved me.
 
O

·
Guest
Joined
·
0 Posts
Discussion Starter #6
had a suzuki tm 100 spit me off a couple times with very violent tank slappers. nothing i could do.
riding along minding my own buisness as usual. high speed for the bike, realatively smooth terrain, slight turn.. hit small bump. next thing you.. laying there looking at the sky.
 
Q

·
Guest
Joined
·
0 Posts
Discussion Starter #7
Howie, please, yours could be most interesting!

Scott, though a slapper is like getting sucker-punched in a crowded gin mill so details are sketchy, I'm sure you've gone over it a thousand times to try to recall details. Is that cattle guard so constructed that when the front end returned to the pavement could the tire have touched down behind the normal contact patch?

Ditto, OT; CBR1000, 50mph, straight flat road...bars shook right out of my hands and spit me off with out so much as a "by your leave?".
Steering head bearings on that one. Changed from loose ball to tapered rollers and not another problem. ???
 
O

·
Guest
Joined
·
0 Posts
Discussion Starter #9
Ditto, OT; CBR1000, 50mph, straight flat road...bars shook right out of my hands and spit me off with out so much as a "by your leave?".
Steering head bearings on that one. Changed from loose ball to tapered rollers and not another problem. ???
did not have a clue about bike set up at the time. 15 yrs old second bike.. i'm 40 now cnnot count the bikes.. six bikes in the garage now
 
1 - 9 of 9 Posts
Top