Instant fuel increase

[Ean Austral]

Gday All,


Put some mud tyres on the D3 and the fuel computer went up 2 ltr /100 almost instantly. I expected the economy to suffer but didn't expect the computer to notice it that quickly. I would expect real figures will be worse.


Certainly know they are on the car that's for sure.


Cheers Ean

[Slunnie]

Absolutely. i found the same with the D2. Try Simex and it will do it again over the muds!

[Ean Austral]

Absolutely. i found the same with the D2. Try Simex and it will do it again over the muds!

:eek::eek::eek:

Cheers Ean

[~Rich~]

I can't really say mine changed that much, also you have to factor in what percentage different your tyres are.
Mine are 6.33% larger so when I refill I take note of the Kms and add 6.33% to be more accurate before calculating ltr/100.

[Ean Austral]

I can't really say mine changed that much, also you have to factor in what percentage different your tyres are.
Mine are 6.33% larger so when I refill I take note of the Kms and add 6.33% to be more accurate before calculating ltr/100.



Gday Rich,


Same rolling diameter as the tyres that came off , 265 / 60 / 18 Vs 245 70 17. My computer tells me between 10.8 & 11.2 for as long as I can remember. Its now reading 12.8 & 13.2.


Cheers Ean

[DiscoDB]

Which tyres did you fit?

Sort of supports running sports shoes during the week, and putting on the mud boots for the dirty weekends!

[Ean Austral]

Which tyres did you fit?

Sort of supports running sports shoes during the week, and putting on the mud boots for the dirty weekends!


As much as I hate to admit it... Cooper STT. only because they were on the rims that I bought. They will be coming straight off once we get back from our trip.


Cheers Ean

[Eevo]

extra rolling friction.


also, where you comparing old tyres with new tyres?

[Ean Austral]

extra rolling friction.


also, where you comparing old tyres with new tyres?


Not really , my 18' road tyres have done about 15,000ks and these tyres have been used but still have about 80% compared to new.


I expected a difference just didn't expect the computer to notice it so much.


Cheers Ean

[DiscoDB]

As much as I hate to admit it... Cooper STT. only because they were on the rims that I bought. They will be coming straight off once we get back from our trip.


Cheers Ean

It is interesting the difference. Speaking of "hate to admit", I am running 100% street biased cheap Kuhmo 19inch tyres on my D3, cost less than $200 each but very quiet and I am returning 10.2 l/100km (8.8 on the display). Happy with this, but would not take off road.

Looking to pick up some 17inch rims with better suited off road tyres for the trips away.

[DiscoMick]

Had a similar result when fitted MTRs to the D1. The BIL had a similar effect when fitted Mickey Ts to his 80 series. Braking distances also increased.

Sent from my GT-P5210 using AULRO mobile app

[Ean Austral]

It is interesting the difference. Speaking of "hate to admit", I am running 100% street biased cheap Kuhmo 19inch tyres on my D3, cost less than $200 each but very quiet and I am returning 10.2 l/100km (8.8 on the display). Happy with this, but would not take off road.

Looking to pick up some 17inch rims with better suited off road tyres for the trips away.


I run Dunlops as a daily driver that I bought off a bloke who drove his new prado straight to the tyre shop for a new set of AT's . paid $200 each , but wouldn't take them on anything other than a dirt track.


Bought the 17' rims with the Coopers on them, so will use them for trips away.


Cheers Ean

[scarry]

I went from the OEM 18' scorpions to the BFG A/T 17's,both same diameter,made no difference at all.

Except the A/T's are noisier.:(

[shanegtr]

I noticed the same thing with my old 80 series cruiser. 265/75/16 goodyear MTR's used a bit over 2L/100km more than 265/75/16 Bridgestone AT's.

[jonesy63]

Ean - I have the same experience. 18" Wranglers to 17" BFG KM2 MTs and the economy goes up by about 2L/100km. I think it is not just due to the increase in rolling resistance, but also the increased weight. I weighed them a while ago and 18" std wheels with Wranglers were 28kg, while the 17" factory alloys and KM2 were 36kg! That's 12kg per corner of extra inertia to overcome. BTW, the steel 17" wheels I had on my D3 with KM2s were 42kg each!
Cheers,
Rob

[vbrab]

I run 18" Kumho "Road venture APT and average 10.5k/100L. (less if I reduce my overall speed) The tyres are cheap, V speed and R load rated and are quiet.
After 3 sets (of 6 tyres), I have never had a problem with any of them running at speed in hot remote environment. No separations, no blow outs. and they are cheapish at around $210-225 each.

[Nomad9]

Hi Ean,
I went the other way.........I had GG AT's on the car I picked up a set of the same RRS rims quite cheap that came with some entry level HT tyres on them with 80% tread so I'm just using them, much quieter and I'm getting about 1 ltr / 100 klm better fuel consumption, these new rims just keep on paying for them selves.............. same rolling diameter.

Cheers Marty

[Redback]

I went from 18s to 265/70/17 Khumo ATs never noticed any real difference, then to 245/70/17 BFG KM2s and still didn't notice much difference, our economy has always been around the 11.2L to 12.5L/100ks around town, no matter what tyres are on the car, with 10.3L/100KS, as our best on the highway/freeway with the 265/60/18s on, haven't done a long highway run with the 245/70/17(30.5") KM2s on.

Did you do anything else when you fitted the 17s.

Baz.

[Ean Austral]

I went from 18s to 265/70/17 Khumo ATs never noticed any real difference, then to 245/70/17 BFG KM2s and still didn't notice much difference, our economy has always been around the 11.2L to 12.5L/100ks around town, no matter what tyres are on the car, with 10.3L/100KS, as our best on the highway/freeway with the 265/60/18s on, haven't done a long highway run with the 245/70/17(30.5") KM2s on.

Did you do anything else when you fitted the 17s.

Baz.

Gday Baz,

No took off the 18s with road tyres and put on these cooper stt and the whole car is different. Ever since we have had the car it is consistantly around 10l / 100ks but just done an 800km run and we averaged 13.4 towing camper which is 2.4 up on rvery other trip i have done.
By the way Ron moon is full of **** i have slready changed a tyre due to a slow leak in only 800ks.
Cheers Ean

[Redback]

Gday Baz,

No took off the 18s with road tyres and put on these cooper stt and the whole car is different. Ever since we have had the car it is consistantly around 10l / 100ks but just done an 800km run and we averaged 13.4 towing camper which is 2.4 up on rvery other trip i have done.
By the way Ron moon is full of **** i have slready changed a tyre due to a slow leak in only 800ks.
Cheers Ean

13L/100K towing the camper:eek: I'd be over the moon with those figuers towing, I get between 14.5l/100k to 16l/100k depending on terrain, towing our 1400kg to 1500kg camper and that's with our 265/60/18 D697s ATs and not the KM2 muds:(

I hate you, I hate you, I hate you, did I mention I hate you:angel:

Cooper tyre are crap, had them, never again.

Baz.

[Ean Austral]

13L/100K towing the camper:eek: I'd be over the moon with those figuers towing, I get between 14.5l/100k to 16l/100k depending on terrain, towing our 1400kg to 1500kg camper and that's with our 265/60/18 D697s ATs and not the KM2 muds:(

I hate you, I hate you, I hate you, did I mention I hate you:angel:

Cooper tyre are crap, had them, never again.

Baz.

I dont have a roof rack either so assume that would count for a bit.

I agree about the coopers, only reasoni have them is they came withthe rims. They will be getting sold once im back home.

Cheers Ean

[DiscoMick]

Gday Baz,

No took off the 18s with road tyres and put on these cooper stt and the whole car is different. Ever since we have had the car it is consistantly around 10l / 100ks but just done an 800km run and we averaged 13.4 towing camper which is 2.4 up on rvery other trip i have done.
By the way Ron moon is full of **** i have slready changed a tyre due to a slow leak in only 800ks.
Cheers Ean

Those STTs are big chunky heavy things which might be fine in mud, but are not good on bitumen - noisy, affect fuel consumption and steering feel and lengthen braking distances I would expect, judging from what happened when I put MTRs on our D1.
Most people spend most of their time on bitumen, so why run a tyre which is mainly for something else? That's my theory.
I'm going to stick with ATs.

[Reddahaydn]

hahaha you guys !!!


I used to drive a petrol 80 series with 35" mud tyres.... I was stoked if I got 650km from a 130 litre tank!!!


I get an average of 12.5 with 265/65/18 ATs and a roof rack (not taking into account the difference from the larger rolling dia.)


going to change to 265/70/17 muddies when I get back from Darwin.
will see how that go but same diameter so not expecting too much difference.

[Ean Austral]

Those STTs are big chunky heavy things which might be fine in mud, but are not good on bitumen - noisy, affect fuel consumption and steering feel and lengthen braking distances I would expect, judging from what happened when I put MTRs on our D1.
Most people spend most of their time on bitumen, so why run a tyre which is mainly for something else? That's my theory.
I'm going to stick with ATs.

I agree totally , i only put them on to do 2 weeks offroad in the kimberleys then will put the road tyresback on. Not my preferred choice of tyre even for offroad but the price was right so they are what i have.

Cheers Ean

[RobA]

Gday All,


Put some mud tyres on the D3 and the fuel computer went up 2 ltr /100 almost instantly. I expected the economy to suffer but didn't expect the computer to notice it that quickly. I would expect real figures will be worse.


Certainly know they are on the car that's for sure.


Cheers Ean

Allow me to share some numbers
Average tyre weight for an LT, say 118 up is around >37kg incl. alloy rim. Allow another 7kg for steel. This is an increase over a standard tyre and rim of around 17kg so time five equals +75kg. Now allow for the increased rolling resistance, can be up to +50% and you begin to get my drift

Roof rack with bars adds on average .7 to 1.2l per 100km empty. Fill it and double those figures

Which is one of the many reasons why we ask all our tour clients to weigh their cars, front, all and rear axle weights before a tour so they get an idea if why we have probably asked them to carry and additional 60l of fuel for a Simpson Crossing for example

Hope that helps

Regards

Rob

[Ean Austral]

Well the numbers are in, 1150ks all sealed road was 150ltrs so 13/100ks and 1245ks / 148lts mostly dirt but at a slower speed average of 70ks/hr.

Funnily enough the cars computer was within 0.2ltr both times.

Still up on the H/T tyres but expected it.

Cheers Ean