Thursday, 12 May 2016

Pressure Test - Pirelli Angel GT

3,500 Kms is distance enough to form an opinion of a Tyre. The boots in question? Pirelli Angel GT.
Scratch that - not an opinion, an informed and measured assessment. Let's do it. 

Tyre pressure is both objective and subjective. 

It is objective in the sense that manufacturer prescribed pressures give a rider a starting point - rightly or wrongly. 

It is subjective in the sense that most riders will disagree with these (usually overly high) prescribed pressures and run their own tyres lower. 

For completeness, both the Yamaha owners' manual and the Pirelli Angel GT specified pressures are Front/Rear (F/R - 36/42)

Where (kgf/cm^2) is the same unit measurement as BAR

Considering the lightweight of the MT-09, F/R 36/42 psi is on the high side, even for Sport Touring tyres such as the Angel GT. 

This will not do. 

I've got a route of approx 250kms planned for a shakedown, a mix of coastal flowing roads into climbing technical with some back road shenanigans peppered throughout. 

Tools for the 'job'
Tools is somewhat of a generous term - all you need is a calibrated Tyre Pressure gauge and a good quality floor pump. I use a Slime digital pressure gauge and my trusty old Lezyne push-bike pump.

Using a digital gauge I can easily calibrate the device as necessary - this however is not essential. If using a mechanical or slide gauge, you may not know its calibration point or accuracy. It may sound strange, but this does not matter too much - as long as you know "F/R 32/34 on my gauge feels right to me" you'll be fine. 

Me? I'm anal retentive and like to know (as much as possible) that my readings have an acceptable error margin and are somewhat close to reality. I setup at F/R 34/36 before hitting the black stuff.

Attitude and performance
Being a Sport Touring tyre - if you're looking for super grippy, soft and sticky boots then you're looking in the wrong place. 

That said, the Angels warm up relatively quickly and offer acceptable grip, albeit with a wooden feel and slow tip in. 

The early morning run along the coast provided a mix of sweepers and tighter cliff-top roads. Conditions were wet and cold, high wind, trivial rain and road spray with some gravel washouts in the corners. 

The Angels gripped well enough, changing direction without duress. On corner exit I was comfortable opening the throttle whilst still pitched over with moderate lean-angle. 

Changing pace I head through back roads on the way to some more technical hills, opportunity enough for wheelies and shenanigans. 

The rear picks up strongly when ripping the throttle to loft the front skyward, the front tyre touching down with immediate grip producing a subtle headshake. No problems here. 

As the roads continue to dry out I push the Angels more - to be fair, dry grip and feel is not great, I would report less feedback and road/rider feel than offered by the Michelin Pilot Road 3s I was running on the Aprilia. Significantly less. 

Climbing into the technical section of the ride, I shift back in the saddle, get my weight over the front, move the balls of my feet to the outside of the pegs, grip the tank with my knees - wrap the throttle - Braaaarp. 

Performing a sighting lap reveals a dry and relatively clean road surface - there are some gravel patches on some of the straight sections but the corners are clear. Game on. 

I get busy running this section of road over the next hour, taking some pressure readings as the tyres warm up. By the end of the 'session' they had picked up ~5+%

Going harder on the Angels is not a linear experience. The attitude of the tyre changes from a slow and neutral tip in,  to a sudden falling into the corners as the front pushes wide. 

On corner exit, the rear does put the Yamaha's power down well and I was relatively confident opening the throttle progressively whilst pitched over. Increase throttle whilst decreasing steering rate.

The Pirelli Angel GTs offer reasonable wet grip and reasonable dry grip. Unfortunately, the amount of dry grip and feel being sacrificed does not legitimise the wet performance on offer. 

During the early components of the test today the roads were wet, but not excessively. The 3,500 kms travelled so far have seen far worse conditions in heavy rain, as such - the wet performance of this tyre has been demonstrated considerably. 

While exploring the available grip, the overall road/rider feel is wooden with minimal feedback. I have had the rear let go on more than one occasion in hot/dry conditions during the previous kilometres travelled. 

That said, I still managed to give them a good flogging today.

It is important to mention that the MT-09 suspension really is not up to the task of the motor and chassis geometry. Some of the shortfalls I have experienced will no doubt be attributed to these lack-lustre chassis dynamics. 

Which delivers a nice segway to this...........

Stay tuned......

How much Angle can the Angel handle? 


  1. Great write-up mate. I had the same feeling with the angels. Absolutely love the Pilot Road 4's though!

    1. Thanks for reading mate.

      Kicking myself a bit as I was very close to choosing the PR4s or Z8s insread. Bah!

  2. After having a decent set of 50/50s on the tard I don't think I'll ever go back to a sport touring tyre.although the milage is a lot lower the grip is that much better for me.especially with the ktms.

    1. After the disappointment and lack lustre feel of the Angels, I don't know what to do.

      My main problem is I also commute....

  3. Nice blog and absolutely outstanding. You can do something much better but i still say this perfect.Keep trying for the best.
    brandon auto repair