Rear tire slip - help!

[kawa64]

Going around a long left-hand turn...

Entrance is about 150kph, exit is fully open throttle;- my rear tire keeps slipping and I don't know why.

During races, others manage to make up some time on me here because of this.

Rear also spins when rolling on a gear up.

Dry track very sunny, very hot, tires warmers than Satan's asshole.

I am using Bridgestone R11 tires, they have a small amount of tread but are very sticky, basically soft-medium slicks in heat. (Tire pressure is good, great grip everywhere else.)

I've messed with both suspension damping, I've also messed with wheel weights and adding weights to the left side of the rear wheel.

I am as low to the ground as possible with my elbows digging into the ground and the bike is as straight up as possible around the bend.

Why the hell does the rear keep slipping.

[ellipsis]

...something to do with the throttle and its tenuous link to the brain I'd say...

[dave100]

Are you tailbraking through there, maybe ur front wheel is being pushed down

[kawa64]

Are you tailbraking through there, maybe ur front wheel is being pushed down

Off the front brake before on throttle

[Kickaha]

Going around a long left-hand turn...

Entrance is about 150kph, exit is fully open throttle;- my rear tire keeps slipping and I don't know why.

During races, others manage to make up some time on me here because of this.

Rear also spins when rolling on a gear up.

Dry track very sunny, very hot, tires warmers than Satan's asshole.

What corner on what track?

[buggerit]

What corner on what track?

Top of ton straight, coro

[Grumph]

Going around a long left-hand turn...

Entrance is about 150kph, exit is fully open throttle;- my rear tire keeps slipping and I don't know why.

During races, others manage to make up some time on me here because of this.

Rear also spins when rolling on a gear up.

Dry track very sunny, very hot, tires warmers than Satan's asshole.

I am using Bridgestone R11 tires, they have a small amount of tread but are very sticky, basically soft-medium slicks in heat. (Tire pressure is good, great grip everywhere else.)

I've messed with both suspension damping, I've also messed with wheel weights and adding weights to the left side of the rear wheel.

I am as low to the ground as possible with my elbows digging into the ground and the bike is as straight up as possible around the bend.

Why the hell does the rear keep slipping.

What do you weigh ? - and what is the bike ?

[kawa64]

What do you weigh ? - and what is the bike ?

I am 75kg, the bike is 185-195kg.

The bike is a 2014 fireblade

Currently running carbon fibre front wheel, alloy rear wheel, Ohlins ttx gp suspension, stock swingarm, stock chasis and frame; but a bit of the rear frame has been cut to improve handling.

[riffer]

Where's all your weight as you accelerate - inside or outside peg?

D'oh - just realised, if you're leaning as far as you can out there's no weight on the outside peg hardly.

Maybe you've actually got too much weight off the bike - perhaps being a bit closer to the bike could help get more weight on the tyre. Or maybe its something more like how hard you're holding on to the handlebars is causing some imbalance in the suspension causing the bike to struggle.

[riffer]

I know bugger all about how those Ohlins rear shocks work through their travel but maybe it's just not working enough at the start of the travel.

[malcy25]

Could be any number of things. I'd check....as a starting point
Too much compression or Spring rate or preload which is not allowing it to ride over bumps,
Too much rebound so not extending off the backside if bumps
Chain Too tight
Swing arm spindle not free
Too much tyre pressure - what gain are you seeing cold to hot?
How old is the tyre
Is there anything odd with your rear geometry
Some one changed the linkage

[Reckless]

Going around a long left-hand turn...During races, others manage to make up some time on me here because of this.

Or maybe its something more like how hard you're holding on to the handlebars is causing some imbalance in the suspension causing the bike to struggle.

Exactly the scenario put to us at Superbike school, grip with the lower body, relax the arms, feed the throttle and let the bike have its way.

I am by far no expert, others may have much better advice but as soon as I read it, it rang a bell to our lesson
Great question, Interested to keep following and see what others have to say
Make sure you post your outcome

[kawa64]

Could be any number of things. I'd check....as a starting point
Too much compression or Spring rate or preload which is not allowing it to ride over bumps,
Too much rebound so not extending off the backside if bumps
Chain Too tight
Swing arm spindle not free
Too much tyre pressure - what gain are you seeing cold to hot?
How old is the tyre
Is there anything odd with your rear geometry
Some one changed the linkage

I have messed around with swingarm malleability, but because of the "low quality," of my stock swingarm, there isn't much to play with.

I don't know much about hot graining or cold tearing, but I always make sure my tire is at a reasonable temperature, the tire pressure seems to be the best grip wise I have evern riden with.

Chain, links is all good.

There aren't any bumps, it's all smooth and no curve on the track surface at that point.

I certainly don't feel there is anything wrong with my rear geometry but I'd have to recheck that from a third person view.

I'll double check with all the info you gave, thanks mate.

[kawa64]

Exactly the scenario put to us at Superbike school, grip with the lower body, relax the arms, feed the throttle and let the bike have its way.

I am by far no expert, others may have much better advice but as soon as I read it, it rang a bell to our lesson
Great question, Interested to keep following and see what others have to say
Make sure you post your outcome

Might have to join one of those. Most useful thing you learned?

[Grumph]

Could be any number of things. I'd check....as a starting point
Too much compression or Spring rate or preload which is not allowing it to ride over bumps,
Too much rebound so not extending off the backside if bumps
Chain Too tight
Swing arm spindle not free
Too much tyre pressure - what gain are you seeing cold to hot?
How old is the tyre
Is there anything odd with your rear geometry
Some one changed the linkage

You seem to think as I do - that it's a setup problem at the rear. I don't like to hear that he's messed around with swingarm "malleability" as errors here can be terminal...