Hi guys , seeking help here as my last resort .
Recently changed the front tyre(S23) & i notice at high speed corners(180-210kmh) my front end feels light and wobble on the mid of leaning . I frequently take the same road back & used to execute the corner smoothly at same speed & same body position . Pressure were 36/39 cold always . Front wheel bearing looks good torque up to specs , new front tire were install properly with aligned marking , balancing were done twice . Cant really think of an answer . Could it be fork , rear suspension , steering head bearings or steering damper ? Appreciate anyone's help !
The forks and rear suspension Do work together, as in, one does effect the other, however, you say nothing changed but the tire.
Is the air temperature the same as with the previous tire?
Is the ride time before the tire shakes the same? Because not only the temperature of the tires makes a difference, but also the temperature of the fork and shock oil.
Usually 20-30 minutes of average riding, in fair conditions, will warm things up into better handling.
Could you possibly be riding a little faster on new tires?
Even a small amount faster can be enough to lift the tire or upset the front end at speed.
If the tire was not balanced correctly, or was defective, you would have a shake at certain speeds, even on smooth roads.
Steering head bearings should be noticeable if they were they cause, as the bars would rattle or clunk over bumps, but, not impossible, they do wear out(what is the bike's mileage?)
You can easily test the steering bearings.
With the bike in 1st gear, engine running, clutch pulled in, and the front brake firmly held, ease out on the clutch until it begins to engage, then pull the clutch lever back in. Do that a few times.
If the bearings are bad, you will feel, hear, and sometimes even see the frame push and rock the forks and bars.
If you do replace them, as it is basic maintenance eventually, tapered bearings are recommended, vs the stock ball bearings, as the tapered bearings will help the bike track better.
As a for a steering dampner, yes they can help, and are good to have.
They personalize the feel of the bars resistance, and they can calm headshake.
They also will Not prevent a tank slapper, and you need to be sure that your bike's suspension is set up correctly before adding an aftermarket dampner, or at least with it turned to it's least resistance.
A steering dampner can be a nice improvement, and it can mask an incorrectly set suspension.
I would measure the fork height in the triple-clamps to make sure they are both the same, assuming so there is no issue, but their height is adjustable, so you can speed or slow corner tip-in by doing so.
If you are over 200 pounds wearing riding gear, then you are too heavy for the fork springs, and need heavier ones for your weight.
Suspension sag needs to be 30-35mm for aggressive riding, with 35-40mm working well, but the softer ride giving less control at higher speeds under most conditions.
Make sure that the chain is not too tight either, because if it is, it limits the range of travel for the shock, which can make the ride feel rigid or very bumpy.
That is usually felt through the rear of the bike too, but again given that the front and rear suspension Do directly effect one another, under the right conditions, vibrations or harshness from a tight chain could possibly be felt through the front end as well.
If the tire vibrated badly at the same speed on a smooth road, even a high speed(which is not uncommon), that would of course point to the tire or balance.
If the tire itself is not the same make and model, it's weight will not be the same, and can require a suspension adjustment.
The suspension, as it is now, may need slightly less compression or more rebound in the forks regardless.
I would go over the bike with a torque wrench, check your suspension settings, note where they are, and pick One setting at a time to make minor adjustments to.
