Q3s starting to feel weird.

[BikeSpeedman]

Apologies in advance for not keeping this brief.

Switched from Supercorsas to Q3s a couple of months ago. They felt awful at first. I've ridden brand new Supercorsas 3 times and never felt this but I recalled feeling good on Q3s at CSS so I kept the faith and scrubbed them in. 30 miles on the road and then 3 sessions on the track and they started to feel great.

An AFM racer looked at them at the end of the day and commented that my suspension was setup well bc they looked great.

Went back a few weeks later and they still felt good.

Went back Tuesday and set a PB in my first session. 3 laps into my 2nd session, leaned over and on maintenance throttle before the apex of turn 8 (Thunderhill), the rear started to walk around on me. It felt like the tire was low so I backed off the pace and came in to look. It was 30 psi. That was fresh off the track where it would normally be higher than that. I went looking for the Dunlop trailer (which wasn't there) and talked to a tuning guy. He said the tire was covered with craters and my pressure was fine so it must be the shock was too stiff. He backed it off 2 clicks and went back out. I was nervous and slower this time but I felt it again in turn 6. He backed it off another 1 or 2 clicks.

I found a guy who was there in place of the normal Dunlop guys and asked him about it. He said I should drop it down to 23 psi. That's the recommendation for the D211s, not Q3s. Having gotten Q3 recommendations from Cobie and "the real Dunlop" guy before, I knew he was wrong and ignored him.

After lunch, I borrowed an air tank and got them up to 30r/32f. Went back out and felt good again. Went back to the tuning guy and he said they looked good too. I think I went wrong earlier in the day because I started at 29/31 and then immediately after my session, I bled them down to 30/32. That was my process on the 2 previous track days but today was kinda cool outside and I think they ended up too low. Then I suffered by talking to too many people who know a lot about Dunlop race tires but not so much about Q3s.

I almost didn't bother posting about this because I sorta felt like it was all worked out. But then this morning on the way to work, the rear felt really squishy and unstable. I checked and reset my pressures when I got home. I've been riding at 30/32 on the street too bc my commute is pretty severe canyon carving. Today was the first day they felt squishy and unstable at that pressure. I'll try adding a bit of air tonight but I thought I'd throw this out there and see if anyone else feels this way about Q3s and if it's something I should worry about or just ignore.

 

[Jaybird180]

You said that 3-4 clicks were taken out of the shock. Did he dial out compression damping? Usually tire crater issues (tearing) are corrected with rebound changes. If the compression was opened (less damping) and the rebound is too stiff (too much rebound damping) then it can make the rear end "sack" where it compresses but doesn't want to come back fast enough and can give a squishy or vague feel to the rear end. Have you tried resetting your suspension back to your known good baseline for your commute?

[BikeSpeedman]

I keep forgetting to check my notes. Yeah, he dialed one softer by 4 or 5 clicks and 1 stiffer by 1. I'm sure he did it the correct direction bc he seemed really knowledgeable.

Since having the squirmy feeling on the way to work that one day, I decided to run 34/34 on the street. Some mornings are shockingly cold and might cause my pressure to be lower than expected. They feel better. I also put my shock back to my old settings bc I know I've had good results on the track with those settings. The only known variable between 11 good sessions (2 total track days plus 1st session of the 3rd - which included my PB) and the bad sessions was tire pressure.

When I go back to the track, if I keep my pressures where I trust them and still feel squirmy (or see craters) then I'll go back to Dave Moss's settings.

[Hotfoot]

How many total trackdays and commuting miles do you have on the tires now? And what type of bike are you riding? Riding aggressively on the track on a 1000cc bike, if you have done three track days your rear tire may be done. That could be why it is feeling squirmy. It's pretty common to change the rear tire (on a 1000cc bike) after two track days, and the front after about 3 days. The high horsepower bikes eat rear tires.

[Jaybird180]

He's on a Triumph. I think it's a 675?

[BikeSpeedman]

On 7/11/2017 at 10:13 PM, Hotfoot said:

How many total trackdays and commuting miles do you have on the tires now? And what type of bike are you riding? Riding aggressively on the track on a 1000cc bike, if you have done three track days your rear tire may be done. That could be why it is feeling squirmy. It's pretty common to change the rear tire (on a 1000cc bike) after two track days, and the front after about 3 days. The high horsepower bikes eat rear tires.

Oh no. I just saw this.

It's a 675R.

1st: full track day (4 or 5 sessions)

2nd: I was sick so I did 2 half-sessions and 1 full session and went home.

3rd: It was the 2nd session of the day when I started having the problems.

Commuting distance covered about 500 miles.

I thought the "street" tires like the Q3s would endure more heat cycles than that. Are  you guys swapping out tires every other day at the schools? Yikes.

[Hotfoot]

From what you describe that does sound a bit too early for the tire to be having issues just from usage. Had you put in three full track days, especially if it was very hot or a very abrasive or one-sided track, I'd wonder if the tires were getting worn or profiled.

At the school, yes, depending on the conditions - some tracks are hard on tires and keep in mind we have three groups of riders in a day so the tires get a lot of use in a day! The tires are checked continuously and changed often. 1000cc bikes are hard on tires, especially rear tires!

The mechanic did say the Q3s last longer than the Q2s, and I don't personally have a ton of experience on the Q3s on my own bike. I used to use the Q2s a lot but mostly have been riding on slicks since the Q3s came out. I have ridden on them at the school, though, and I love how they feel, great grip and excellent, predictable handling.

Maybe our tire expert can chime in on how many track days are typical for Q3s for a bike like yours, and/or how much heat cycling they can take before starting to feel different.