Outer Limits 4x4 Board

I have recently changed from a BFG AT to Silverstone MT117 Sport in the same size. Since doing so I have noticed that my fuel consumption has gone up by 13.25% so now instead of doing 300 km per tank I get 260 per tank.

Rolling resistence and the actual size of the tyre will both impact this, but I was wondering what impact your different tyres (in the reported same size) have had on fuel economy? Particularily interested in MTR's.

TRobbo wrote:I have recently changed from a BFG AT to Silverstone MT117 Sport in the same size. Since doing so I have noticed that my fuel consumption has gone up by 13.25% so now instead of doing 300 km per tank I get 260 per tank.

Rolling resistence and the actual size of the tyre will both impact this, but I was wondering what impact your different tyres (in the reported same size) have had on fuel economy? Particularily interested in MTR's.

I dont know if you saw my dyno sheets testing AT to MTR, but i lost 20kw and 100Nm by going from 265 AT to 285 MTR...

More agressive tires use more fuel.. more resistance, and usually much heavier tires.

dont know if this relates to what your talkin bout but it wont help!

Thanks Bogged, the dyno results are interesting although they are of different sized tyres.

I am hoping to get peoples fuel consumption comparisons using the same sized tyre to help with a decision as to what tyre to run most of the time. The truck is a weekend toy and I get jack of changing tyres between one set or another and for the amount of road kays it does it's usually not worth swapping. Ive got the simex's for serious play but was looking for a tyre I can leave on for 90% of the time that will work well off road and not be as bad on road as the simex's. The 117sports I have seem to fit the bill and are cheap but use what I consider to be a lot more fuel. I was wanting to see whether other muddies have a similiar fuel consumption increase or if I can get a tyre that will work well on and off road but may only use say 5% more fuel. I dont have enough range for touring as it is so dont want to lose a stack of kays because of tyre choice.


so for eg if I were to run an AT, a MTR, a MT117sport and a simex all of the same theoretical size how much extra fuel would you use. I assume that fuel consumption would increase in the order that I have listed the tyres???

Probably the hardest bit will be getting people who swap tyres between At's and MT's etc in the same size.

TRobbo wrote:Thanks Bogged, the dyno results are interesting although they are of different sized tyres.

I am hoping to get peoples fuel consumption comparisons using the same sized tyre to help with a decision as to what tyre to run most of the time. The truck is a weekend toy and I get jack of changing tyres between one set or another and for the amount of road kays it does it's usually not worth swapping. Ive got the simex's for serious play but was looking for a tyre I can leave on for 90% of the time that will work well off road and not be as bad on road as the simex's. The 117sports I have seem to fit the bill and are cheap but use what I consider to be a lot more fuel. I was wanting to see whether other muddies have a similiar fuel consumption increase or if I can get a tyre that will work well on and off road but may only use say 5% more fuel. I dont have enough range for touring as it is so dont want to lose a stack of kays because of tyre choice.


so for eg if I were to run an AT, a MTR, a MT117sport and a simex all of the same theoretical size how much extra fuel would you use. I assume that fuel consumption would increase in the order that I have listed the tyres???

Probably the hardest bit will be getting people who swap tyres between At's and MT's etc in the same size.

yea no stress, I understand what your gettin at.. I think everyone wants those "PERFECT" all round tires, just wonder if they exist in the real world. Some of the kiddies will tell you claws are the perfect road tire and offroad..

When I had my Rodeo I went from near worn out 31in ATs but forget the brand to new 31in MTRs. The fuel consumption increase was quite noticable. Lost maybe 50kms to a tank. So from 450kms to 400kms from about 55L.
Both sets of tyres used the same 15x7 ROH steel rims.

Those figures might not be definately correct but I used more fuel with the MTRs anyway. The MTRs were more aggressive but they were also much heavier.

yeah good point, weight of tyre will impact as well

plus new tyres are effectively bigger than old tyres due to a change in diameter on 15-30mm.

I dunno, I guess I call it a strange kind of logic.

I went from 31" MTR's to the 32" bighorns, and the fuel consumption and apparent loss of power on the road was HUGE.

But the simple thing would have been to put the 31's back on. Nope. Instead I bought a turbo kit, and a bigger tank. The turbo gave me marginally better fuel consumption due to not having to have my foot flat to the floor, and the bigger tank meant I can go further. Still cost $$$ though.

How many people forget to correct the odometer when going to bigger tyres?

KiwiBacon wrote:How many people forget to correct the odometer when going to bigger tyres?

the jump in 1-2 inch tyre size from standed usually makes the speedo spot on! so standed tyre actually get less km then what the trip meter says

my tb45 patrol with 33's reads spot on!(confirmed with GPS)
most factory speedo's under read buy 6-10%..

KiwiBacon wrote:How many people forget to correct the odometer when going to bigger tyres?

The odometer gives an indication of when I need to do a service. I don't use it as a trip meter as I use a GPS on long trips. Around town, who cares?.

As for correcting the speedo, I know it's out, I have a pretty good idea of how far it's out, and I just make allowances for it. A reasonably accurate way of checking how far is by the GPS.

So no, I didn't forget. I simply couldn't be stuffed.

Micky-Lux wrote: the simple thing would have been to put the 31's back on.

Never go back!

Micky-Lux wrote:Nope. Instead I bought a turbo kit, and a bigger tank.

simcoe wrote:

KiwiBacon wrote:How many people forget to correct the odometer when going to bigger tyres?

the jump in 1-2 inch tyre size from standed usually makes the speedo spot on! so standed tyre actually get less km then what the trip meter says

my tb45 patrol with 33's reads spot on!(confirmed with GPS)
most factory speedo's under read buy 6-10%..

The speedo on your average new vehicle reads 5% over at 100km/h (reads 100, you're doing 95), the odometer however is pretty much right.

So if you gain 5% and correct the speedo, then you're losing 5% of your odometer. If you use this to calculate fuel economy then you're alredy 5% behind without any more loss from bigger tyres.