June 2nd, Thunderhill Raceway Park
Ambient 90F and track temp 106F
2013 RSV4R SE
Fork height +10mm, preload 6 turns in, rebound 16 clicks out, compression 8 clicks out
Shock height +4mm, preload 5 threads showing, compression 5 clicks out, rebound 8 clicks out
Electronics: sport mode, ATC (traction) 3, AWC (wheelie) 2, ALC (launch) 2, ABS 1
Tire warmers on high for 30 minutes reading 150F, 32psi hot and 26psi hot off the warmers
"The all new V02 slicks with MotoGP carcass innovation (advanced belt
construction technology) looks immediately different to the V01 in roll
profile. The feel of the carcass is also completely different on the
grip surface of the tire compared to the V01 in regards to flex and to
me it felt slightly stiffer but more importantly slower to react to
pressure/weight changes from my hand pushing on the center and sides of
the tire. Always good to feel a tire before it gets mounted! This
resistance indicated to me that the tire shape would not instantly
deform under hard acceleration and that should equate to 2 things:-
excellent drive grip and accurate corner exits.
V02 soft front and V02 medium rear.
I had R10′s on the RSV4R Factory from the last track day for chassis
dial in and used them to get the geometry I was looking for at Laguna
Seca. With a different track, that geometry would be wrong so with new
tires and completely different circumferences may as well get a 2 for 1.
The initial scrub in laps gave a very different feel indeed from the
R10′s in terms of tire peak feel, turn initiation, side contact patch
and side to side transitions. Geometry was close but not right, but I
needed to really get to know these tires first before making any
decisions on chassis changes.
The one thing that stuck out in my mind immediately was the ease in
getting to the edge of the tire and the secure feeling it gave me.
Normally on warm up/scrub laps I’ll explore lean angles but in this case
there was no desire to do so. I went straight to my knee right away.
Tire Temps: 165F front (35psi hot) and 175F rear (26psi hot)
The tire temps gave me a hint that all was not well as Session 2 was
going to be about trail braking and driving hard out of corners. I was
concerned that the rear was under inflated and the front over inflated
BUT that was just an educated guess. Again, no chassis changes until the
tires requested that be done from wear patterns.
Session 2 was used to get more familiarization with the roll profile
of the tires in turn initiation, line correction and acceleration with
ever quicker lap times. My brain needed the time to recalibrate as the
R10 is a much softer carcass. Entry speed rose and it was very apparent
that the initiation of a turn was certainly a little more controlled
than the R10, and that is something I like. The roll to the edge of the
tire was very easy indeed and there was no acceleration from the profile
in getting to the edge of the tire. That gives a very secure feeling
for me (versus the 125 V profile tire that gets to the edge very
quickly). A little more bar pressure and the turn in sped up so there’s a
nice blend here between the V and more round front tires that
Bridgestone offer. Bad line selection? The bike responded immediately
and with calmness which inspires confidence. Drive grip? Oh my, there’s
an absurd amount of drive grip between this tire and the R10 with the
RSV4 ejecting from the corner into the fast sections of the track.
Tire Temps: 165F front and 190F rear
The goal of Session 3 was to explore feel on the edge of the tires. I
chose Turn 2 and Turn 14 for heavy trail braking and drive grip in
Turns 6, 8 and 12. Tires were again 150F when I took the warmers off and
the first few laps were dedicated in focus to trail braking. As the
entry speed into the corners was raised, I could feel the edge of the
tire gripping the track but not overly deforming sending me off line
from an excessive profile degradation. That encouraged me to enter
faster and brake harder. In so doing the Aprilia held its line and
didn’t over or under steer at all. I was charging Turns 2 and 14 so that
gave me all the information I needed to know. Switch to corner exit –
this should be fun!
Turn 6 leads into the fastest section of track so turn in and apex
point are critical to get the exit defined. Careful approaches and
throttle timing gave me some lessons until I had the line set and then I
could get to the throttle. In turn 6 the tire slid, gripped and flew
off the corner. Turn 8 no slip, turn 12 not slip. I put that down to the
chassis being already loaded from earlier acceleration/apex speed and
lean so the carcass is already compressed into the track. No point
staying out when you are getting slides, so back into the pit.
Tire Temps: 165F front and 211F rear
front tire showed the faintest of geometry tears so I added 4.5 turns
of preload and set fork compression to 5 clicks out. The carcass was
still effectively cold so I took 1psi out on the warmers (34psi hot)
just before heading onto the track. The rear was clearly under inflated
so I brought the hot pressure up to 27.5psi off the warmers from 26.
The good thing about slicks is you can see the rubber ball size
(should be 2-3mm) and rubber aggregation on the edge of the tire.
Classic visual that the tire is too hot with the rubber stringing itself
together and lots of rubber balls 3-5mm in diameter.
With the revised tire pressure and fork settings I went back out on
the track, tires again at 150F off the warmers. The front felt stiff,
non compliant and introduced chatter on heavy trail braking which
removed confidence. Change geometry not settings! The front tire
couldn’t care less and gripped the same as before and wear improved with
the faint geometry tear gone. The rear was initially frightening out of
Turn 6 as there was no slip at all and the bike drove so hard at Turn 7
that I couldn’t get my timing right for that corner. Yes, I’m glad I’m
in Sport mode……..
Tire Temps: 175F front and 188F rear
So, reset fork settings to get the plushness and feel back in the
forks and raise the front by 3mm to reset geometry. Drive grip was mind
boggling to me so the math in the rear end and shock settings aligned to
hot pressures is dead on for now. I’m new to this Aprilia and
calibration is taking me a while with this level of power in getting my
brain comfortable with acceleration and speed over distance to trust
where I am in time and space. Once that gets settled down I can move
back to peripheral vision and start relaxing again." - Dave Moss