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Keeping the rear solid on landing

2K views 26 replies 10 participants last post by  Reactor 
#1 ·
Here is a question for the experienced.

I have lifted off both wheels while on track. It seems every time it happens, the rear gets squirly on landing? What gives? Suspension set, bike performs well the only thing is I am not running a damper. Is that what I need to keep the bike settled when coming down? The rear normally touches first, it happens so fast I can't tell if it starts before or after the front touches down.
 
#2 ·
Other times both seem to touchdown at the same time. My thinking is that the rear doesn't get silly until the front touches and the wheels are not aligned for whatever reason (normally me). And yes, I get bad head shake too. I know I need a damper just for that reason alone.
 
#3 ·
throttle input is what's gonna make the back loose on landing. either too much or too little. input on the bars is what gets you headshake. it's difficult to lift the front and stay neutral on the bars, tho. a damper will help that, but i think it's important to understand why the bike does what it does before you mask it with parts...


s3aturnr
 
#5 ·
So you have a track were you get air born? Try to land both at the same time or rear slightly first. Stay on the throttle.
 
#6 ·
Yea but you really have to try to do it or be crazy aggressive on the gas. The crest at the exit of turn 10a at Mid-Ohio will send you airborn if you have little regard for the slight right turn at the bottom of the crest. But is repeatable.

I am still trying to wrap my head around it. I can keep it on the ground by putting more body weight forward and/or a slight roll off pre crest or by simply going slower or even being in a higher gear. Since going slower isn't really an option right now and a higher gear feels sluggish, I am looking at rider error first and other stuff second.
 
#8 ·
I would bet it is similar to that, front up higher than the rear. Rear really a few inches off the ground with a wiggle on landing.

Now let me look at this differently, how do the fast guys carry speed over crests? I see other riders go over that crest without leaving the ground going faster than me. Why do I jump and they don't?
 
#14 ·
I know you said that you had your suspension set but it really sounds like your rebound damping needs another look. Im sure you already know that traction and the "feeling" of traction are not the same thing when tuning. With minimum rebound, the shock could rebound and extend too far moving the chassis upward and possibly in your case pushing the wheel off the ground.

However on the opposite end of the spectrum with maximum rebound, the shock may not respond fast enough and "pack" which possibly in your case is holding the wheel off the ground.

I would take a close look at the atop fork screw adjustment and the rear shock shaft eyelet before any purchases. Also remember that if you've had a change in rider weight it will effect settings.

Lastly, someone already mentioned it but throttle control is key. So just remember that due to torque reaction, suspension rises in acceleration, if it rises enough, you'll be leaving the "sweet spot" in your suspension before you even hit the bump!
 
#9 ·
Try keeping steady throttle over the crest. Not accelerating but not slowing down either.
 
#10 ·
not sure how serious of a question this is to be honest, but possibly try rear brake over the crest.. stay on the gas, but a little rear brake keeps the front down. some have to do the same out of the bowl at turn 4 homestead, and exiting the chicane at Daytona, and cresting turn 4 at Barber..
mostly just keep loose on the bars too. let the bike drift a bit, especially up the big hill of turn 4 at Barber. You know in your head the track turns right at the crest, so you instinctively wanna push the right bar to go right, well, if the front is light as you crest the hill and ya are pushing, the wheel wont' be straight. You get all kinds of wobble, and you grip the bike even harder, which compounds the problem putting those forces through your body into the REST of the bike. There is tons of room to the left of t4 there, just let the bike run wide with little bar input and steady throttle.

I give that as an example as i don't race roadA. but principles may be the same. there are lots of things to work on to go faster.
 
#22 ·
mostly just keep loose on the bars too.
This was my first thought, too. It's easy to grab the grips too tightly because of the pucker-factor of going airborne. :nocontrol
 
#11 ·
You will pretty much always experience a little wobbly/slide when landing.... the only way to have a 100% smooth landing is to have the tire rotation speed match the forward movement speed..... which is nearly impossible.

Rear brake will help, and being relaxed... but you'll never be 100% solid when landing. Because there is no ground traction/friction when airborne, you will need less throttle input to generate the same wheel speed as if you were grounded.

If you're wheel speed is 100km/h on asphalt, once you're airborn that wheel speed will increase to say, 120km/h because the ground traction is removed if you're maintaining your throttle input. There are so many variables to consider.

All of the above will "help" get a smoother landing, but you'll never be totally solid when you do unless you're god-like at riding.
 
#12 ·
Yes, this is a serious question! I am going to eat shit hard if I don't get a handle on this. It wasn't a problem last year, my pace simply wasn't fast enough. I either need to keep the wheels on the ground or figure out a rider/bike setup that keeps me in control when it happens.

Thanks for you input thus far. Churning it all in my head while reviewing my videos.
 
#13 ·
Find some ppl faster than you in that section and ask them what they do
 
#17 ·
No one has caught it on vid yet :(. They will next time though, I asked then to watch out in case I bite it and not take them out and so I can see what is going on back there.

My rear suspension is set pretty hard. Sag was set, my preload is at max and the suspension guy asked me a bunch of questions to fine tune the rest so not sure on those settings. Adjustments could be made I guess based on a faster pace since my last adjustments.

I am average weight I guess, 190lbs with gear with no recent changes in weight.
 
#23 ·
Static Sag is a separate variable in the suspension equation and is determind by spring rate and preload ONLY. Rebound damping is what I mentioned earlier as a possible cause for your "air time". Damping doesnt affect static sag at all. However, if your preload is at max you may want to use a fork with higher spring rate and less preload. Without some vids its a little hard to tell but I'm still puting money on rebound damping and throttle control.
 
#20 ·
lol, It's not because I am doing it right believe me, it don't happen every time either. It's definitely not my smoothest riding and I feel I am charging the corners (told by a control rider) with a very aggressive throttle, where everyone else is smooth and floats right over. I think if I smooth out my lines and pace throughout straights and corners, I won't have to get on the throttle so aggressively. I will start with a few laps with control rider, then have my suspension checked again based on a faster pace.

I am interested in a faster lap times and I would rather keep the wheels down but if it happens, I don't wanna wad it up either.
 
#21 ·
i would forget about that air-time issues for now and work on getting smooth. by your own admission, and from what you say other c.r. are telling you, that is something to start with.
 
#24 ·
My guess is that the faster guys are turning later and apex at a different point in the turn, thereby reducing the " jump potential ". Being airborn mid turn is not fun and there is probably no right or wrong way to deal with it.

I would not use the rear brake. I would shoot to stay on the gas more than anything. If you do have the incident I would also shoot to get the rear tire down first. It seems to me that it would be easier to deal with the wobble without the front tire in the equation. Watch the moto cross guys for example. You can come out of a turn with the front tire in the air and if the rear slips out it is easy to work with it. When the front is down the sudden loss of rear traction transfers weight on the front and can maker the bike buck even more.

Using the rear brake like that mid turn and then suddenly getting airborn is a quick way to lock the rear tire up while in the air. When it comes back down the tire speed VS. road speed will be incompatible. This could lead to an instant loss of traction and a big slide. I would follow the rule " once you get on the gas in a turn, you will continue to stay on the gas, or accelerate throughout the rest of the turn" .
 
#25 ·
an apex for a faster rider is the same apex for the slower rider. it is the point in the turn that makes for the fastest way through the corner when using all the track as needed. THat is not to say that 2 riders of vastly different ability will apex at the same point, but they should..

you won't be standing on the rear brake pedal, it actually takes some effort to lock the rear brake in most cases. And in any event, a 350+ lb motorcycle with a rider will get the wheel quickly spinning again once it touches down. A hot sticky rear tire is gonna grab the pavement and roll. I understand where you are coming from with the word of caution though.
 
#26 ·
From chatting with two AMA racers specifically about that area of the track. Here is the response.

The initial setup to that turn is critical and I have only seen someone like Pinson do an amazing job at the entry to that turn. You need to exit turn 9 under load and upshift a gear if gearing is correct. However, that causes the bike to want to continue it's pointed direction. Meaning, you NEED to get the bike flicked and out wide before turning in to 10a from 9. Again, Pinson does this better than anyone I have seen. I cannot get the bike switched as well as he can, but our lines end up the same.

You need to hug that curbing all the way up the hill. The crest will obviously lighten the front, but shouldn't be a huge issue unless you are carrying serious speed up the hill. If you stay far left up the hill, you can throttle manage or LIGHTLY press the rear brake and be totally fine. When you crest, too often, people are aiming for the curbing and the grass inside on 10b. You should apex this curbing of course, but instead of aiming inside, aim outside for the grass between 10b and 11. This will carry you wide and allow a solid drive down the hill and through 10b.

I see guys rolling out too much in 10b which allows for a great passing area. They will apex and roll off and go wide left to setup for 11. This is where being left up the hill has an advantage. You can swing down and be driving while they roll off and pass under or right of them between 10b and 11 all while carrying speed at the crest of 11.

That turn is a drive corner for sure! Under load, the front will be light and in race pace mode, you will lift the front there. Most often, you will get a slight wiggle, but carry the drive all the way to the yellow curbing on exit.
So it looks as if my first initial thought was somewhat in the right direction. The fast guys shift between 9 and 10. I don't... and as I said before, if I shift a gear the problem goes away but I don't feel as much drive. I guess I will have to be less of a sissy and go even faster but in a higher gear. My lap times are around 1:40 give or take on a good tow or traffic. I am trying to get into the 1:30's

More practice..... Thanks again for everyone's insight.
 
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