Tyres Different Treads

kipthomaskip

I’ve read it’s not a good idea to have different makes of tyres or treads on the same axle. My rear tyres are identical makes with a speed rating of 89w, front axel different makes, different treads with a speed rating of 93v, is having a different speed rating also an issue.

It is a small SUV front wheel drive. I’ve had the car three weeks from main dealership, it’s a 19 plate. Sadly not getting advertised mpg of 46, getting around 26mpg, wondering if tyres are an issue, obviously checked psi and tyre pressures etc. Was never expecting 46mpg given it’s an automatic, but above 33mpg would be nice. Passed last service and MOT with no issues.

Any advice?

k3lvc

The best time to have checked was before you bought it - you could then have asked for the tyres to be matched (which they may or may not have agreed to) and you could have checked the MPG based on your driving style.

Assuming you've checked tyre pressures then MPG is much more likely to be about driving style than anything else - how does it compare with previous vehicle ?

And 'small SUV car' covers a multitude of sins - there are plenty of 200bhp + models where 26mpg could easily be the norm given the right (or wrong) usage

Ebe_Scrooge

Ideally you'd have the same make of tyre on each wheel on the same axle, but it's not really the end of the world unless you're doing very fast, high-performance driving.  The only thing you mustn't do is mix cross-ply and radials on the same axle.

Speed ratings, similarly, not particularly an issue, so long as they all meet or exceed the stated minimum for the car.

Correct tyre pressure will contribute to fuel efficiency, but it'll not make a big difference.  Driving style, as mentioned by the previous poster, will have a far greater impact.  Also, do remember that the quoted MPG in all the adverts is achieved under "ideal" and "laboratory" conditions.  It's never intended to reflect real-world MPG, it just allows you to compare one car against another since they're all tested under the same closely-controlled conditions.

Flight3287462

What car make, model, engine size, fuel and gearbox?

Herzlos

https://www.honestjohn.co.uk/real-mpg/ will give you an idea of what fuel economy you can actually expect based on reports by other drivers. I generally figure you'll get somewhere near the urban figure quoted.

Driving style also makes a huge impact. My latest car will do about 60mpg around town at 20mph but only barely 40mpg at 30mph.

You're probably fine with mismatched tyres on an axle, assuming they are suitably rated and not anything fancy like snow tyres.
But then compared to the cost of the car a new set of tyres is fairly small change so might be worth replacing the fronts (or all 4) for peace of mind.

What tread depth are all 4 tyres?

diystarter7

Ebe_Scrooge said:

Speed ratings, similarly, not particularly an issue, so long as they all meet or exceed the stated minimum for the car.

Correct tyre pressure will contribute to fuel efficiency, but it'll not make a big difference.  Driving style, as mentioned by the previous poster, will have a far greater impact.  Also, do remember that the quoted MPG in all the adverts is achieved under "ideal" and "laboratory" conditions.  It's never intended to reflect real-world MPG, it just allows you to compare one car against another since they're all tested under the same closely-controlled conditions.

Agree with all of but a note re speed rating. You can have lower speed rating tyres for winter ie winter tyres are often lower banding and on one of our rear wheel drive cars we had H speed tyres on ie lower than the spec for genral tyres but ok for winter - but you need to tell your insurance to ok this but I've never had a problem and do tell them as if you are in an accident they may invalidate your car insurance/not pay out, part pay etc.

kipthomaskip

It’s a Ford EcoSport 1.0 EcoBoost 125 Auto.

Urban driving day to day. Style of driving, I’m an advanced driver so feel my driving is very good.

All tyres are in excellent condition and plenty of tread depth, well above legal limit, I’d say the rear axle are brand new tyres. Front axle probably been on less than 12 months.

Did not really consider front axle tyres being different, first car purchase but that is no excuse. Sales advert said 46mpg, but I knew being an automatic I would perhaps be getting more like 35mpg with day to day driving.

Prior to this I was driving a new 1 litre 120bhp auto Hyundai for three weeks which was giving approx 42mpg by the time it was handed back, although that was a mild hybrid.

Prior to that Seat Areca but that was a diesel, so around 58mpg

And prior to that a Ford Kuga 1.5 Ecoboost AWD which had a rubbish mpg of around 26mpg for three years, and was blamed on being an AWD, compared to a neighbour who had a 2 litre diesel Kuga giving over 50mpg.

On-the-coast

It’s a Ford EcoSport 1.0 EcoBoost 125 Auto.

I just drove that same model as a hire car for almost 1000 miles and got a lot better mpg.  At least 40.  

How are you calculating mpg? By measuring how far you go between refills? Or just looking at the instantaneous gauge.  Only the first is really accurate. 

I personally wouldn’t worry about the tyres. 

Oh and btw I’ve found that modern auto gearboxes can be more efficient than me in an equivalent manual (if driven reasonably gently)

Ectophile

On the speed rating, W is up to 168 MPH, whereas V is only 149 MPH.  So if you're planning on doing 150 MPH on your next motorway trip, you really need to get those tyres changed.

Realistically, mis-matched tyres are generally legal.  Unless they are hopelessly mis-matched, it's not really a problem.  I have driven cars with 3 different brands of tyre on, and nothing bad happened.

Goudy

The mpg you quote is a claim figure under the worldwide harmonised light vehicle testing procedure.
It is meant to be more accurate than the old NEDC system as it based on real driving data rather than theoretical data.

The figure is based of four different test procedures, low, medium, high and extra high speed, which are then averaged.

As you aren't the tester and aren't solely driving under the same conditions as the test, you will obviously get a different result.

Also, most modern cars tend to have "Eco" buttons or settings, these are used in the tests to help improve the results, most owners tend to disable them as the car really does under perform with them switched on, on the test they don't care about that.

I am surprised the Ecosport tested average was so high in the first place.
It isn't the most aerodymanic of cars and small turbo engines do then to suffer reduced mpg if only slightly worked a little harder.

There are plenty of owners bemoaning this. Perhaps you might have considered a Mazda, their Skyactiv program bucked the turbo downsizing trend and produced very efficient larger, non turbo engines with the same sort of power with similar mpg claims that are a bit more easily realised.

Your tyre brands won't make much of a difference.
It's recommended that you stick with the same tyre brand/type on the same axle, but if they are similar types and ratings (summers on both) and not mixed (summer on one and a winter on the other) then it shouldn't make any noticable difference with mpg or handling really.

Your 26 mpg suggests you are doing a lot of stop start town driving. I get something similar on my local commute through central London in a similarly powered (small turbo'd) dual clutch automatic. Out on a steady 70 mph cruise I can nudge 58 mpg. 

If this isn't the case and you're getting this after hours of steady motorway cruising, them you perhaps have a problem with something else on the car.






 

Herzlos

Ectophile said:

Grey_Critic said:

****I’m an advanced driver so feel my driving is very good.****

That's your problem.

Every driver feels like their driving is very good.  In one study, of people who were in hospital as a result of a single-vehicle accident, those people still thought that their driving was above average.

There's been various studies showing that over 80% of drivers feel they are above average in terms of ability, so I can believe that even crashing drivers feel they are.

Anecdotally, the people who I know who claim to be the best drivers are also the most terrifying to witness driving.

Not to say the OP isn't a good driver, or hasn't done the IAM course, but I'm not entirely sure how much difference that'd have on fuel economy.