I have been through all of the generations of Bridgestone with many pairs of BT020 F rated tyres.
We ride two up, fully loaded, not particularly aggressive, but probably a bit harsh with the throttle. 5000 miles has been pretty standard, with the centres wearing before the outsides. Rear faster than front, but I change them both at the same time.
Since the T32 GTs came out I have stuck with them (including the T30 and T31s - all GT spec. They ride beautifully, feel superb on the road and wear well and evenly. Loads of grip and inspire confidence in the twisties. I get a fraction more than the BT020s, but it is not worth mentioning - even though I just have. So 5,000 miles is about what I get.
Many people get more than me - from reading the reports. In fact I don't think I have seen anyone report only 5000 miles for a set of any tyre. I used to get 12,000 miles on my 1100 with the old ply Exedras. It dropped to about 8,000 as soon as I fitted radial BT020s to the 1100. It dropped again with the 1300, quicker turning, more power and acceleration, much more powerful brakes. 5000 miles is still the norm for me through all the 020s and T30-T32, and that rate of wear caught me out a couple of times. The BT021 and 023 were not very impressive and for me wore quickly and unevenly.
I have edited this bit as it is not very often mentioned when comparing tyre wear
Tyre wear is very difficult to compare, unless people can quote their loaded weight, style of riding, type of road, road surface etc etc. Since you say you used BT020, I thought this might be a useful comparison as for me, there is only a marginal improvement in tyre wear for the T32s over the BT020s. For information, the roads that I ride are not smooth. Many miles are done in the Yorkshire Dales, Derbyshire, North Wales and Scotland on the quieter roads - B roads and less used A roads. They don't often have the racetrack tarmac surface that we have on the motorways and main roads. These roads and are often resurfaced with tar and chippings. They have many bends, rises and falls so visibility of the road and traffic ahead is not good which means constant acceleration and deceleration.
Eg- this is a satnav speed profile of a 35 mile section of a ride that I took yesterday.
Variations due to some traffic, speed limits in villages, but mainly due to the shape of the road.
And an elevation profile of the same ride.
The heights of hills is not very much compared to the great continental mountains - but they are relentless - up and down, up and down. For comparison, the Tour de France spent two days in Yorkshire, cycling these roads. I think that the riders underestimated them - I have never seen riders at the end of a tour stage looking so absolutely worn out.
The first 10 miles of this route in the profile above seems to be a fairly level bit of road, just undulating between 500 and 700 feet above sea level. But you keep going up and down and in the 10 miles at the start there is a total of about 700ft of climbing and descent. They tend to be sudden sharp climbs and descents with poor visibility of the road ahead. They often require a bit of grunt or use of the brakes. That has to take its toll on the tread of the tyres when loaded compared to the major roads that I could have taken - where a speed of 50-60mph can be maintained with little use of brakes and throttle.
