A few months ago I fitted 17x7 wheels and 205/40R17 tyres in place of the 14in steel rims on my Easy TA manual.
They fit perfectly and ride quality isn't bad. I admit I cheated a bit by setting tyre pressures at 28psi in the hope that made the tyres more compliant. Yesterday I stopped after an hour of 110km/h driving to inflate them to 38psi. The tyres were not hot to touch and were showing 31psi, so that's only +3psi over cold pressure.
First thing that I noticed that seemed strange since fitting the new wheels a few months ago was the average fuel consumption on the trip computer was showing 16.2L/100km around town. This was with a number of short trips (2km or less) over about 80km total. The worst I've seen before under such conditions was about 9-10L/110km.
Then I went on a 600km highway round trip yesterday. Over 250km the car used 19.8 litres of fuel. The trip computer showed 8.3L/100km. Actual was this probably more like 7.9L/100km. On the way back, I achieved 6.8L/100km indicated.
Performance seemed blunted too. Before on the highway I could squeeze the throttle in 5th and speed would increase quickly from 110km/h to 130km/h - up a hill. Yesterday it was struggling up some of the long hills to maintain 115km/h, foot planted to the floor. It has never been like that before.
Okay, so the tyres are not an exactly replacement in terms of rolling radius; they are a few percent taller according to the tyre size charts I've looked at. I bought them as they are a much more common tyre size than closer size replacements.
The GPS shows 107km/h at speedo reading of 110km/h. This is +3km/h over the original wheels (104km/h at 110km/h indicated).
I checked the trip meter against roadside kilometre makings yesterday and it is spot-on.
I suspect the heavier, wider and slightly taller wheels/tyres are playing havoc with this little car. It could well be something else, but I am going to change wheels back to the originals for a while to see what happens. A bugger if it is the new wheels, because it looks so much better and lateral grip is really impressive...
They fit perfectly and ride quality isn't bad. I admit I cheated a bit by setting tyre pressures at 28psi in the hope that made the tyres more compliant. Yesterday I stopped after an hour of 110km/h driving to inflate them to 38psi. The tyres were not hot to touch and were showing 31psi, so that's only +3psi over cold pressure.
First thing that I noticed that seemed strange since fitting the new wheels a few months ago was the average fuel consumption on the trip computer was showing 16.2L/100km around town. This was with a number of short trips (2km or less) over about 80km total. The worst I've seen before under such conditions was about 9-10L/110km.
Then I went on a 600km highway round trip yesterday. Over 250km the car used 19.8 litres of fuel. The trip computer showed 8.3L/100km. Actual was this probably more like 7.9L/100km. On the way back, I achieved 6.8L/100km indicated.
Performance seemed blunted too. Before on the highway I could squeeze the throttle in 5th and speed would increase quickly from 110km/h to 130km/h - up a hill. Yesterday it was struggling up some of the long hills to maintain 115km/h, foot planted to the floor. It has never been like that before.
Okay, so the tyres are not an exactly replacement in terms of rolling radius; they are a few percent taller according to the tyre size charts I've looked at. I bought them as they are a much more common tyre size than closer size replacements.
The GPS shows 107km/h at speedo reading of 110km/h. This is +3km/h over the original wheels (104km/h at 110km/h indicated).
I checked the trip meter against roadside kilometre makings yesterday and it is spot-on.
I suspect the heavier, wider and slightly taller wheels/tyres are playing havoc with this little car. It could well be something else, but I am going to change wheels back to the originals for a while to see what happens. A bugger if it is the new wheels, because it looks so much better and lateral grip is really impressive...