Save Petrol - Buy Tyres!

tomstickland

If you can have a free run then I've discovered that the time of the journey scales with the inverse of the speed. It's almost as if time is distance over speed.

Anyway, I know what you mean. Power consumption increases with speed cubed, mpg will scale with speed squared. Braking is throwing energy away.

I find it hard to believe that a pair of tyres increased the mpg by 20%. Was the tracking also sorted?

It's always worth checking mytyres.net, I pay £45 per 15" Goodyear F1 fitted inc VAT and these are in the top 3 of performance tyres.

Gorgeous_George

Little_John wrote:

Driving at increased speeds on motorways doesnt actually reduce the journey time by much anyway,

I beg to differ. By choosing my journey start time carefully I can travel the 329 to my parents in 5 hours if I stick to 80-ish on the motorway. Slowing to 65 would definately increase the journey time, probably to six or seven hours and I'd need an extra break.

On shorter journeys, I'd agree 100%.

If you want to increase mpg even more, remove amy unnecessary weight from the car AND the driver/passengers. Use quality fuel, keep tyres at the correct pressure (were the OP's old tyres at the correct pressure and the wheels correctly aligned BEFORE the new tyres were fitted?).

Don't overfill your tank. Petrol/Diesel is heavy.

EDIT: Crossed with Tom's post - I type slower than I drive. 56mph is just a speed set by the Government so that comparisons can be made



GG

tomstickland

Weight has a minimal effect if you are not accelerating hard. I'd be surprised if you could remove 5% from a modern (ie: overweight) car. Rolling resistance is small compared to aerodynamic drag.

withabix

Just to add to the mix...

I used to run my Galaxy on the recommended Dunlop SP2020E tyres. These cost a princely £85-£110 each typically and I achieved a long term average (from trip computer) of 32 mpg (diesel). Life of front tyres typically 17000 miles (down to the TWI).

I now run on Alpha Accelera directional tyres, costing £52 fitted. I get a better ride, more than 20000 miles on the fronts and 35mpg long term average!

Note that I drive typically 40,000 miles per year, so have quite a bit of comparative data!

tomstickland

Grip, drag and wear rate all going to be trade offs.

Quinny_2

A friend of mine works in the local tyre house,and he tells me that people buy big brand tyres,just because of the name.

A lot of economy tyres made nowadays,are just as effective as the big guns,due to the advances in technology,but cost a lot less. (His words,not mine.)

I've just gone for 4 new economy brand directional tyres for my 406 HDi,and so far,they are a lot quiter than the Michelin/Dunlops,that they've just replaced.

Cost? £150 all in.

Ken.

tomstickland

Depends on what you want really. There's a lot of budget names that are pretty good nowadays. There's also some real crap out there. If anyone ever tries to convince you that Regal Sports are good tyres then they're wrong!

Seeing how I can have top 3 performance tyres fitted for less than £50 per wheel then I'm going to stick with them. I want grip and predictable performance when loading them up. In exchange I only manage about 10,000 miles per tyre.

Cumbrian_Male

tomstickland wrote:

It's always worth checking mytyres.net, I pay £45 per 15" Goodyear F1 fitted inc VAT and these are in the top 3 of performance tyres.

Mytyres quote £43.00 for Falken ZE-512 205 55 r16.

I paid £41.50 each fully fitted at my local place, also a fitting centre for these online dealers.

What size are your Goodyears at that price?

Little_John

Gorgeous_George wrote:

I beg to differ. By choosing my journey start time carefully I can travel the 329 to my parents in 5 hours if I stick to 80-ish on the motorway. Slowing to 65 would definately increase the journey time, probably to six or seven hours and I'd need an extra break.

If driving at constant speed you should be able to cover the 329 miles in just over 5 hours at 65 mph

Increasing your speed by 15 mph to 80 again at constant speeds should save you about 40 minutes getting it down to 4 hours 15 minutes ish.

The problem is that it isnt possible to drive at those speeds all the way. you have trafic lights to stop at, acceleration time, deceletation time and traffic jams other people driving at 65mph to save fuel all these add on time to the journey and are variables. ohh and you cant forget your breaks.

gtone28

albertross wrote:

Surely the increase in mpg is down to your reducing your speed, rather than the tyres..?

I agree if you lower your speed to 55mph and 60mph you will see a difference in mpg plus if you drive slower and brake less harsh you will see a difference, only problem with continentals is they wear down very quickly and they can be expensive