Rear feels like its sliding @ speed

So I'm at the end of my break in period. I've done most of the break in exclusively on back roads so very little highway riding.

Today was the first day I did any extended highway riding at speed. The rear feels like its sliding around, even when riding in a straight line. The bike overall seems more sensitive to wind buffeting than my 999. I can't tell if its my riding , the suspension setting or if its mental. BTW on the twisties it feels totally planted. Its in the flat suspension setting on dynamic mode and I'm running 34 psi F / 35 psi R

Any advice?

I would drop the pressure a bit, does your dtc light up at all?

I think your tyre pressure's too high for hi speed street, I run around
Ft 30-31 Rr 27-28
Look at your sag settings, front end will always feel lively with that amount of power
For most people rear std spring is to stiff

I run 36 rear and 34 front, tc set at 3 and have regular spirited rides with no issues. I run sports mode with engine set in race, it's heaps of fun.

The back end is light on these bike but I highly doubt the rear is sliding around on the street specially with the Supecorsa's on. It takes tremendous amount of speed, torque and lean angle to get the rear end to slide around. I had to get use to the way my 1199 Panigale felt with the rear end being so stiff for the street it felt like it was sliding but actually it was the lack of squat on the rear that gives you the false feeling like its sliding around. My 1299 feels 100% better than my 1199 because the rear is much softer in Dynamic mode. I would soften the rear a bit to get that false sense to go away.

I didn't do a good job describing it but yes it's not so much sliding as much as feeling like I'm being pushed around w/ any turbulence presents itself. When you say "soften" is that a spring change or some change in sag or suspension settings ? Also I'm going to try running about 2 psi lower. I see how less squat would give you that sensation.

@whoopaz dct not going on.

Try soften the compression a click or two also progressive setting will give you a softer ride.

Since you are at the end of the break in period, this would be a good time to set up sag for your weight and get the suspension fine tuned.
I'm with you on the lower tire pressure.

Get some suspension expertise going there and adjust your bike to be more compliant. As far as wind, make sure you tighten up your steering damper! Ask me how I know because you don't want to find out the hard way, haha. Ride safe!

Hmmm yeah I would drop the pressure and soften up the rear. Like scrapper mentione the pirellis have massive amounts of grip.

How much do you weigh?

What Dynamic damping setting are you running? I have done a ton of suspension experimentation and should be able to help. My bike will feel exactly like you described when I run the suspension in Softer mode for my commute...

Thanks everyone for your very informative & thoughtful replies! I definitely need some suspension help, be a shame to own this fine bike and not get the most out if it.

I dropped the rear pressure from 35 to 33 psi, increased the rear sag from 25mm to 30mm, and set the DS one level softer.

I'll give this a go and if it's to squishy, start firming things up.

I've never had this problem before. I'm a good 205 lbs...but then again I've never been on Ohlins either.

80shilling said:

How much do you weigh?

What Dynamic damping setting are you running? I have done a ton of suspension experimentation and should be able to help. My bike will feel exactly like you described when I run the suspension in Softer mode for my commute...

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Hmm...like I said above I'm 205. I had the shock on "default" but was thinking of going one softer. You think I should go the other way? As I said this only is an issue when there is turbulence and/or wind...mostly noticeable above 80.

I can totally relate. I just drove my bike back from its 600 mile service and before and after it I noticed the same exact feeling above 55 mph it feels like the bike is sliding back and forth very slightly when going straight. Never had that sensation on my s1000. I was thinking it was high winds but trees were pretty still. It was worst when I was behind a tractor trailer.

Slowdive2 said:

Thanks everyone for your very informative & thoughtful replies! I definitely need some suspension help, be a shame to own this fine bike and not get the most out if it.

I dropped the rear pressure from 35 to 33 psi, increased the rear sag from 25mm to 30mm, and set the DS one level softer.

I'll give this a go and if it's to squishy, start firming things up.

I've never had this problem before. I'm a good 205 lbs...but then again I've never been on Ohlins either.



Hmm...like I said above I'm 205. I had the shock on "default" but was thinking of going one softer. You think I should go the other way? As I said this only is an issue when there is turbulence and/or wind...mostly noticeable above 80.

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im in the same general weight range as you and my suggestion is to first get the sag set correctly for your weight there's a sticky at the top of the Forum for suspension settings that I started with a couple of good videos and some settings.

The softer your tire is, the more it will move around until it gets up to pressure... In essence it moves around more when the pressure is low and that movement makes the tire heat up quicker, but it does mean the rear will feel unstable until the pressures rise.

Try setting sag and stiffen the REAR dynamic damping to harder and then set rear cold pressure at 38 and see if the problem goes away. If it gets better or goes away, you can start to fine tune the pressures back down for twisties etc.

For my commute, I run 40 psi cold rear and 35 psi cold front, but that's just to get the most mileage out of each tire and I set the pressures to 30 psi rear and 31 psi front for really fast weekend hooning through the twisties.

Basically, experiment by going a LONG way in one direction and see if the issue gets better or worse and that will at least help diagnose the issue.

As far as I'm concerned, once you get the suspension right for your weight and style, the 1299 is the best handling and most stable bike I have ever ridden.

If you were local, I would help you set it up..

Cheers.

I was lighter but im at the 200lb mark and run sport mode in flat with 35f 30r sag.

Tire pressure is important and your to high.

Consensus for years here is roughly 32F and 31R,, Im at 31F and 30R.



My bike feels like part of me and I have no issues at all, and excellent tire wear..

To play devils advocate, street tires aren't meant to run at low pressures like race tires. They have a higher silica content (for quicker heat-up), which means they build heat faster...which means at lower pressures, the tires can get TOO hot and will get greasy and start to move around.

Too many people are quick to say "lower the pressure" thinking that will give more grip. But im many cases, that isn't true...especially when talking about street tires. Not to mention that less psi = less sidewall stability...which can often lead to the feeling of the tire moving around. I personally run a higher psi in the front of my Pirelli race tires than many people do because I want the tire to be stiffer and more stable under hard braking.

I am not saying this directly applies to the OP, I am speaking generally.

And there is no need to be sub 30psi on a street tire. I have seen people running 25-27psi in a street tire and that is just silly. On street tires I run 32-34psi with no problems whatsoever.

When I run 55 degree lean angles on the street I need below 29psi for more traction, golly gee whiz!

I noticed the slipping problem on a highway ride recently. I left all my suspension in default, made the damper stiffer and left my tires at 34 and 37 respectively. It fixed said problem on the 130 mile ride back home with 15mph crosswind. I weigh 220 with gear while constipated.

Chaotic said:

To play devils advocate, street tires aren't meant to run at low pressures like race tires. They have a higher silica content (for quicker heat-up), which means they build heat faster...which means at lower pressures, the tires can get TOO hot and will get greasy and start to move around.

Too many people are quick to say "lower the pressure" thinking that will give more grip. But im many cases, that isn't true...especially when talking about street tires. Not to mention that less psi = less sidewall stability...which can often lead to the feeling of the tire moving around. I personally run a higher psi in the front of my Pirelli race tires than many people do because I want the tire to be stiffer and more stable under hard braking.

I am not saying this directly applies to the OP, I am speaking generally.

And there is no need to be sub 30psi on a street tire. I have seen people running 25-27psi in a street tire and that is just silly. On street tires I run 32-34psi with no problems whatsoever.

Click to expand...

I tend to agree. I run about 33f/ 34.5r for street. And a lower pressure on the track. Keep in mind on the street you are not able to keep the temp in a constant window for optimum performance. With street riding you must contend with stop lights, inconsistent pace due to either traffic or road conditions. These Corsa's for a street tire are amazing to say the least.

Lowering the pressure also increases the size of the contact patch. And yes that typically will create more heat but not too much heat especially on the street. I believe the concern for street riding is ensuring you have the pressure to support the tire carcass. Too little pressure can affect stability and of course wear.

I typically start with 26R / 28F on the track and run 28R / 30F on the street on Supercorsa SP V2. I always check post track session pressures and wear patterns looking for 3-4psi gain and signs of cold or hot tearing and that pressure is a good starting point.

I too feel your tire pressures are on the high side...

Here some good info from Pirelli DIABLO SUPERCORSA SC , Motorcycle Tyres | Pirelli | Pirelli

Tom

Update: Nothing conclusive but I did some experimenting today. I increased sag from 25mm to 28mm (not sure this did much), decreased tire pressure from 34F/35R to 32F/33R, set the dynamic damper setting to harder and the shock setting to softer.

Started w/ 4 miles of twisties, felt great. Wind dead calm, but enough cars & trucks to create some air movement on the highway. Went onto highway and sought out as much turbulence as I could find with as light a grip pressure as possible. Much much better after about 15 miles (out & back) I then changed the shock up two levels to harder (from softer to harder) and did it again. I knew within 2 miles I had just made it worse, so I immediately went back down to softer in the back. By stiffening the steering damper and softening the rear, I perceived that when getting buffeted, it calms down much quicker. It's not perfect, but I had no confidence issues at all which is something I couldn't say yesterday.

Theory: As said above, I don't think the tire was slipping I just perceived it to be. I think maybe the hard tires and the faster shock rebound were causing a countersteering movement that I was perceiving as slippage.