Northern Auto Tech - ECU and Blue & Me Repairs

General Small wheels, big difference?

Currently reading:
General Small wheels, big difference?

PandaLounge

PandaLounge

500 fan
Parked in the garage
Joined
Aug 4, 2008
Messages
435
Points
169
Location
Newcastle-under-Lyme
Hi guys

My 500 is currently in the dealers with a few niggles and I've been given a base spec 1.2 Pop, which is a charming little car.

So charming in fact that with only 800 more miles on the clock than my car it a vastly more responsive and a damned site more economical!

On the same run as my car, same fuel, same amount of fuel and same driving style I am averaging 55.5mpg. My 500 Lounge only manages a mere 42 at a push!

Therefore I have a couple of questions. Do small wheels really make a great deal of difference to economy? My 500 has the 16" alloys, whereas the little entry level scamp has 14" steels. Also I have A/C (which I have only used properly a handful of times) whereas this one does not and any other standard Lounge parts which I assume all add weight???

I find it odd that the same car, only 2 months older and with 800 miles more on the clock can be such a different beast to drive and re-fuel.
Also has the fact that this car won't have been "run-in" (I know, not necessary in this day-and-age) and driven like a hire car from day one had an affect on the engine? More supple, loosened up? etc?
Whereas I have tended to tread carefully (although not driven like an OAP) and given it plenty of time to bed-in over the first 1,000 miles.

Anyhow if this is how a standard Pop drives and runs I might forget the Lounge extras and enjoy the Pop factor and frugality next time.

Steve
 
Last edited:
Yes, tyres make a huge difference. On my narrow winter tyres I was getting mid 50's in terms of mpg and now with the 16" summer wheels on it's struggling to do 50 mpg indicated. This is purely down to tyres/wheels. I wouldn't get a pop, you're better off getting a lounge and selling the standard wheels and getting steelies.
 
Also the type of tyre and the correct inflation pressure. Running overinflated will save some fuel but will also wear the tyres much quicker (in the middle) and increase braking distances.

FWIW On a long run at 60mph I get over 70mpg running on 16" multispokes with Eagle F1s - book is 78mpg extraurban and 67mpg combined (1.3MJ).
 
Do bear in mind also that the accuracy of the odometer will be affected any time you change the rolling diameter of the wheels, so making mpg comparisons between tyres isn't necessarily as straightforward as just swapping them over & monitoring the mpg figure. Just measuring the tyres isn't enough, either, as the rolling diameter depends on how the tyre deforms under load, which is in turn affected by tyre pressure, etc.
 
jrkitching said:
Do bear in mind also that the accuracy of the odometer will be affected any time you change the rolling diameter of the wheels, so making mpg comparisons between tyres isn't necessarily as straightforward as just swapping them over & monitoring the mpg figure. Just measuring the tyres isn't enough, either, as the rolling diameter depends on how the tyre deforms under load, which is in turn affected by tyre pressure, etc.
Click to expand...

It is pretty much as simple as that though!

The tyres with the smallest rolling circumference are the 195/45 r16 and the biggest rolling circumference is on the 185/55 R15's. The difference is only about half a percent between the two. Sure tyre deformation may change things slightly but it's reasonable to assume that the tyres will deform a similar amount to each other.

My last couple of tanks on the 500 showed indicated consumption of between 56-60 mpg and the 500 is now showing consumption of 50mpg so the difference is a big one.

There are three main things to consider.

Aerodynamic drag, it may seem silly but the extra width of the tyre does cause extra drag
Rolling resistance - That extra 12% of width has an impact on rolling resistance
The extra weight of alloy wheels - I wish I had scales, because I'd have weighed my summer wheels last weekend and compared them to the weight of the winter wheels. I can comfortably carry one winter wheel in each hand, but if I try the same with summer wheels it feels like I'm going to dislocate both elbows :p This extra weight takes power to be accelerated up to speed.

My best tank with winter wheels on is 56.6mpg and the best with summer tyres on (bearing in mind I've done more tanks with summer tyres) is 51 and this was of course done in warmer weather than the 56.6 mpg tank ;).
 
The way you drive makes more of a difference, even if you think you are driving the same, you probably aren't. Even your mood can alter your economy. I've had 17" wheels on my Abarth 500 from day one, sometimes i get 23 MPG, other times i get 51.5 MPG.

Not to say that smaller wheels don't make any difference of course, i'm just saying driving style is the biggest contributing factor to good or bad MPG's :)
 
DraigFlag87 said:
The way you drive makes more of a difference, even if you think you are driving the same, you probably aren't. Even your mood can alter your economy. I've had 17" wheels on my Abarth 500 from day one, sometimes i get 23 MPG, other times i get 51.5 MPG.

Not to say that smaller wheels don't make any difference of course, i'm just saying driving style is the biggest contributing factor to good or bad MPG's :)
Click to expand...

Of course, but you're more or less teaching people how to suck eggs :p Everyone knows that how you drive affects economy ;)

Also, I don't see any 51.5 mpg's here ;)
http://www.fuelly.com/driver/draigflag/500

Indicated MPG's over small distances are more or less worthless as a measure of anything. The other week on the way back from work after someone's leaving party I fuelled up 10 miles from work and because the engine was up to temperature, the roads were clearof traffic and it was more or less downhill all the way I was able to get just over 70mpg on the trip home, by the end of the tank it was saying 60mpg on TripB. Like I said, indicated mpg's over small distances mean nothing.....
 
Wherever possible, I tend to go with steel wheels / no aircon option.

Seems to work well for economy combined with driving style, of course.
It is nice to see shiny, stunning alloys but they are bound to affect fuel economy
for the reasons discussed in the posts above - rolling resistance from big fat tyres
being the main factor.
 
Last edited:
Interesting post. I phoned a very reputable dealer this week for a price on a basic 1.2 pop (only 13-14 weeks left now for the scrappage) and when he was pricing the car up - he said - you will have to have the alloy wheels which are only €450 because if you don't the car will look like a Nissan Micra. On the 1.4 sport model that I had I didn't really care about the economy impact on the car because it was a 'pretend' performance car. Looking at a secondhand Abarth I'm specifically looking for the 16 inchs because they're lighter than the 17inchs and are much cheaper to buy tyres for. But the 1.2 pop - I would seriously struggle to resort to putting steelies on unless it was for a winter tyre - because it would damage to 'look' of the car. A compromise might be to opt for the 15 inchs although I still love the look of the 16s. And if you really worried about the mpg over inflate for the long journeys which you are supposed to do if you're on an autoban
icon7.gif
. But I take you point about the 5mpg impact for the look.
 
zanes said:
:eek: How hard are you driving the thing???
Click to expand...

Well his car only arrived in late November just before all the weather and it has 16 alloys so not the best combination of factors. Come summer it'll push up closer to 50 no doubt.
 
TechHouseC said:
Hi guys

My 500 is currently in the dealers with a few niggles and I've been given a base spec 1.2 Pop, which is a charming little car.

So charming in fact that with only 800 more miles on the clock than my car it a vastly more responsive and a damned site more economical!

On the same run as my car, same fuel, same amount of fuel and same driving style I am averaging 55.5mpg. My 500 Lounge only manages a mere 42 at a push!

Therefore I have a couple of questions. Do small wheels really make a great deal of difference to economy? My 500 has the 16" alloys, whereas the little entry level scamp has 14" steels. Also I have A/C (which I have only used properly a handful of times) whereas this one does not and any other standard Lounge parts which I assume all add weight???

I find it odd that the same car, only 2 months older and with 800 miles more on the clock can be such a different beast to drive and re-fuel.
Also has the fact that this car won't have been "run-in" (I know, not necessary in this day-and-age) and driven like a hire car from day one had an affect on the engine? More supple, loosened up? etc?
Whereas I have tended to tread carefully (although not driven like an OAP) and given it plenty of time to bed-in over the first 1,000 miles.

Anyhow if this is how a standard Pop drives and runs I might forget the Lounge extras and enjoy the Pop factor and frugality next time.

Steve
Click to expand...

Steve, your first 500 was a Pop but with the 16" wheels so was that one more economical than the Lounge with 16" wheels?
 
mjsmke said:
The only downside to narrower tyres is less traction/longer braking distance.
Click to expand...

Only when you're actually braking hard...... if you're only braking as normal then there's no difference. The only two things that limit the effectiveness of the brakes are of course the amount of braking force the pads and discs can apply at any given moment and the amount of braking torque the tyre can handle.
 
I noticed a difference in braking going from a 1998 punto to my old 2005 punto with wider tyres (same engine and brakes). Mostly in the wet or when someone cuts across you and you hit the brakes.
 
mjsmke said:
I noticed a difference in braking going from a 1998 punto to my old 2005 punto with wider tyres (same engine and brakes). Mostly in the wet or when someone cuts across you and you hit the brakes.
Click to expand...
Which is precisely what I was saying....
 
i have ocd when it comes to wheel weights and size, never been much of a scene queen, i ticked the 16" multispoke option as the design at the lip makes them look bigger than they are, maybe i should have had my economy head on more

not much experience on the economy front but last year swapped from oem rims to some motorsport spec pro race 1.2s for everday use, the reducion on unsprung mass (3kg per wheel) made notible differences to ride quality and turn in

i also noticed some positives in terms of braking performance mainly due to the design meant they brakes got a lot more cooling so i got less faid

interesting dilema is when i am on the hunt for some winter wheels to i go oem 15, or 16 or throw on a set of lightweight pro race 1.2s
 
wigit said:
i have ocd when it comes to wheel weights and size, never been much of a scene queen, i ticked the 16" multispoke option as the design at the lip makes them look bigger than they are, maybe i should have had my economy head on more

not much experience on the economy front but last year swapped from oem rims to some motorsport spec pro race 1.2s for everday use, the reducion on unsprung mass (3kg per wheel) made notible differences to ride quality and turn in

i also noticed some positives in terms of braking performance mainly due to the design meant they brakes got a lot more cooling so i got less faid

interesting dilema is when i am on the hunt for some winter wheels to i go oem 15, or 16 or throw on a set of lightweight pro race 1.2s
Click to expand...

Well I'm thinking of getting rid of my steelies for winter wheels as I don't like the car looking like a pop. That said I don't think I'll be going for a lightweight wheel like the pro race, I think I might go for some speedline 2118's like the ones we have on our Subaru. Still lighter than Fiat wheels I'm sure, but more likely to damage potholes than vice versa and I think that's important especially for winter wheels.
 
Thanks everyone who has replied so far. As lame as it may sound I have never really placed much thought into wheel size/weight affecting the overall economy.

Off all three of my 500's each one has had 16" wheels. I've never driven one with small wheels and that, of course, led me to this post.

Went to Liverpool today. Mostly motorways and dual carriageways. Sticking to a reasonable 60-65mph we managed 60.4mpg. It is very pleasing to drive a car that delivers near textbook figures. And like as been said here already I purely had the 16" wheels because I think they look better. However my longterm wallet much prefers the fuel saving rather than the eye catching benefits.
 
You must log in or register to reply here.

Similar threads

carpetmankent
Technical Large Wheel Gap Difference between near and offside rear
2 3
Replies
46
Views
2K
Derbyfella
D
Jodsclass
Technical Oil from small pipe/grommet of cam cover
Replies
1
Views
103
steveras57
S
D
General locking wheel nut thread different
2
Replies
25
Views
1K
John202020
John202020
GettinBetter
Technical engine differences fiat 199B6.000 vs fiat 312A2.000
Replies
1
Views
210
The Panda Nut
The Panda Nut
GettinBetter
Technical Different Socket Head Cap Screw
Replies
10
Views
618
chris3234
C
Back
Top