[DarkHorse]

First trackday?

I wouldn't touch it if it's your first time on track even though rebound is a bit slow

Thank you good sir.

I'll post more pics after track day.

 

[DanQ]

You sir are correct. Reason why I asked was because of the service. You got one rebound reading correct, but missed the other. Two different grooves, two different readings.

Yes.

Examples of where we see this are:

1. Shock out of nitrogen (service issue)
2. Shock oil wore out (service issue)
3. Shock spring too stiff/too light for valving curve (needs a revalve)

That's why Marcelo asked immediately about the service on the shock. We've seen this before a time or 20.

 

[timdingo]

Yes.

Examples of where we see this are:

1. Shock out of nitrogen (service issue)
2. Shock oil wore out (service issue)
3. Shock spring too stiff/too light for valving curve (needs a revalve)

That's why Marcelo asked immediately about the service on the shock. We've seen this before a time or 20.

Very impressive!
That's the thing I'd like to learn; it may be obvious to you, but could you share how on earth you actually see that by looking at the tire?
I mean, I knew something was off when I couldn't get the rear to behave just right: my tire kept losing grip for a fraction of a second under heavy acceleration out of the slowest corners like the tire wore off, nothing serious or unmanageable though, but there was no problem at all in the medium speed corners nor on straights, and it kept feeling like the shock was behaving as it should, even though I knew something was wrong, does that make sense at all?

 

[Ckempf]

Mine from last weekend

 

[MaRce1o]

Very impressive!

That's the thing I'd like to learn; it may be obvious to you, but could you share how on earth you actually see that by looking at the tire?

I mean, I knew something was off when I couldn't get the rear to behave just right: my tire kept losing grip for a fraction of a second under heavy acceleration out of the slowest corners like the tire wore off, nothing serious or unmanageable though, but there was no problem at all in the medium speed corners nor on straights, and it kept feeling like the shock was behaving as it should, even though I knew something was wrong, does that make sense at all?

There was one raised groove and one in groove, the in groove is slow rebound, the raised is fast rebound. Since you can't have both on the same tire, tells us the shock is a bit "lost" on what it is doing

 

[MaRce1o]

Mine from last weekend
View attachment 743018

You sir most likely need to adjust your tire pressure. What were you running starting and off track?

I bet that was very slippery

 

[timdingo]

There was one raised groove and one in groove, the in groove is slow rebound, the raised is fast rebound. Since you can't have both on the same tire, tells us the shock is a bit "lost" on what it is doing

makes perfect sense, thanks!

 

[MaRce1o]

makes perfect sense, thanks!

:thumbup

 

[Shifu]

You sir are correct. Reason why I asked was because of the service. You got one rebound reading correct, but missed the other. Two different grooves, two different readings.

What do you make of this? It is a Dunlop Q2 after one session at Philip Island. Track temp 38deg, 23 psi hot.

 

[DanQ]

There was one raised groove and one in groove, the in groove is slow rebound, the raised is fast rebound. Since you can't have both on the same tire, tells us the shock is a bit "lost" on what it is doing

On point as usual :bow You've come a long way.

And thanks for explaining. Between meetings and my WiFi hotspot not wanting to cooperate, I could not get a reply down range.

What do you make of this? It is a Dunlop Q2 after one session at Philip Island. Track temp 38deg, 23 psi hot.

Looks like a compound separation line.

Have to watch the pressures on the Q2/Q3 (unless they are race tires on your side of the pond). They should NOT be running the tire pressures of the GP/GPa/other race tires. I've seen many a new rider turn those tires into grease balls running track pressures on a street tire and overheating them to no end. One guy I saw started at 22 cold and ended up at 42 hot, and he DECREASED the starting pressure :scared! Needless to say he changed tires after the next session :eek5:.

 

[Shifu]

Looks like a compound separation line.

.

Well done Dan:thumbup

That was indeed a tire delamination problem. We had a bad batch of tyres from Dunlop at the track. The rubber was just flaking off like a pages of the book. The fast group riders were coming into the pits just after 2 laps.
Needless to say we all got brand new replacements.
I find Dunlops the easiest to ride. Once you get your pressure right, they are very consistent though I can't say they last very long.

 

[MaRce1o]

On point as usual :bow You've come a long way.

And thanks for explaining. Between meetings and my WiFi hotspot not wanting to cooperate, I could not get a reply down range.



Looks like a compound separation line.

Have to watch the pressures on the Q2/Q3 (unless they are race tires on your side of the pond). They should NOT be running the tire pressures of the GP/GPa/other race tires. I've seen many a new rider turn those tires into grease balls running track pressures on a street tire and overheating them to no end. One guy I saw started at 22 cold and ended up at 42 hot, and he DECREASED the starting pressure :scared! Needless to say he changed tires after the next session :eek5:.

I learn from the best :bow

 

[DanQ]

Well done Dan:thumbup

That was indeed a tire delamination problem. We had a bad batch of tyres from Dunlop at the track. The rubber was just flaking off like a pages of the book. The fast group riders were coming into the pits just after 2 laps.
Needless to say we all got brand new replacements.
I find Dunlops the easiest to ride. Once you get your pressure right, they are very consistent though I can't say they last very long.

We've been seeing pretty decent life out of the tires. And yeah, the tire pressures are the life of the party. I saw Dave M. posting up about the Driven Mantis. I may read up on them, because with the new tire I know we've seen .5 psi adjustments, and I could swear the math was telling me .25 psi. Drive me crazy sometimes, but the guys racing them do great things and love them.

I learn from the best :bow

Nah. I learn from the best (Dave gets tire pictures whenever I'm surprised... he's seen naughty pics of your tires :fact). You're just stuck with my interpretations :lol

 

[jrcidr6]

1st time running R10's .... Awesome track tires !!!!:thumbup::thumbup:

And also Dave Moss Setup

 

[Shifu]

1st time running R10's .... Awesome track tires !!!!:thumbup::thumbup:

And also Dave Moss Setup

The picture is a bit fuzzy but that is not a great looking wear pattern. The rebound definitely needs attention (smooth triangular areas at he ends of the sipes) He needs to finish that setup.

 

[jrcidr6]

The picture is a bit fuzzy but that is not a great looking wear pattern. The rebound definitely needs attention (smooth triangular areas at he ends of the sipes) He needs to finish that setup.

Here is another shot not the best picture but maybe u can see better ... the center marks on it are from the trailer ..tire was hot when I loaded the bike so gets stuck to it .

 

[MaRce1o]

We've been seeing pretty decent life out of the tires. And yeah, the tire pressures are the life of the party. I saw Dave M. posting up about the Driven Mantis. I may read up on them, because with the new tire I know we've seen .5 psi adjustments, and I could swear the math was telling me .25 psi. Drive me crazy sometimes, but the guys racing them do great things and love them.



Nah. I learn from the best (Dave gets tire pictures whenever I'm surprised... he's seen naughty pics of your tires :fact). You're just stuck with my interpretations :lol

Thats fine with me...and soon well need a tire pressure gauge that reads 1/4psi :lol

1st time running R10's .... Awesome track tires !!!!:thumbup::thumbup:

And also Dave Moss Setup

The picture is a bit fuzzy but that is not a great looking wear pattern. The rebound definitely needs attention (smooth triangular areas at he ends of the sipes) He needs to finish that setup.

That unworn edge is suggesting something different, i do think compression is one of the issues here. But i dont think its being caused by the shock.

Any guesses on what i would check first?

 

[Shifu]

That unworn edge is suggesting something different, i do think compression is one of the issues here. But i dont think its being caused by the shock.

Any guesses on what i would check first?

The sag & spring rate

 

[DanQ]

Thats fine with me...and soon well need a tire pressure gauge that reads 1/4psi :lol

I think most would be fine accurate to .5 psi. But I know you had to use more skill than traction a few times last year. That's going to happen, but I'd rather it be last lap going for a position than every lap trying to keep the bike out of the grass.

Not that I like you or anything like that. I'm concerned about your forks and shock :lol

That unworn edge is suggesting something different, i do think compression is one of the issues here. But i dont think its being caused by the shock.

Any guesses on what i would check first?

To be fair, the tire is showing a couple of issues. I don't think this year's group has seen the issue you are talking about. Might want to elaborate.

 

[DanQ]

To be fair, the tire is showing a couple of issues. I don't think this year's group has seen the issue you are talking about. Might want to elaborate.

Ok, Marcelo texted me and said he's not available to respond right now. And although I try to let him provide the explanations, we don't want to leave anyone hanging.

Any guesses on what i would check first?

The sag & spring rate

Good start, depending on what steps you have included with checking the sag. I've been burnt several times with something that nearly 100% of the time will cause this pattern and make setting accurate sag near impossible.

What is it?

Chain slack. Always begin by checking chain slack. If it's too tight you won't get full articulation of the swingarm. It can make sag measurement wrong if it stops the swingarm and I've seen it cause those triangular patches many times.

Too much spring can cause that wear pattern, as well as too much compression damping. But those will take a little more to diagnose and resolve. Always check the chain tension when making chassis adjustments; it can save you time and tires.

The tire also looks to be overheating a little. This could be a function of tire pressure, but also the compression issue that is causing the triangular wear patterns. All other considerations aside I would increase the starting pressure. But in the "make one change at a time" approach I would see if I could address what is causing the triangles first (while double checking starting pressure) and go from there. I suspect the tire was a lb or so low on starting, but unless it was a race weekend I would only make one adjustment.

I can't see the rain sipes well enough to see if there are any rebound issues, but I'm a firm believe that whenever you make any other chassis changes you always must double check rebound. It's the force that keeps the tire in contact with the pavement; so always double check.

jrcidr6: If you have the opportunity to show the wear to Dave, I'm sure he fine tune all of that in a matter of minutes. If not, the above information can help you improve your wear/traction.