Engines and MPG

[Trundler]

I was browsing the 'Fuel costs Germany trip' thread in the Syncro 25 years anniversary forum and found a wealth of info there about the MPG and pence per mile a Syncro achieves on a long continental journey with a range of engines and on petrol, LPG and Diesel. There's so much info in the thread that I thought it deserved a higher profile, so here's a link:

https://club8090.co.uk/forum/viewtopic.php?f=33&t=68319" onclick="window.open(this.href);return false;

[Trundler]

Another question which could be covered in this thread is how much do aggressive off-road tyres affect the fuel consumption? On the other thread (link above) Aidan reckons it's as much as 30% !

I currently have Matador Izzarda in 205/70/15. They have been great (no complaints about grip, wear or noise) but are only a mild all-terrain pattern. I don't do serious off-roading but I quite fancy some much more aggressive Maxxis Trepadors which are more of a mud terrain tyre. ..For the gnarly looks more than anything, I have to admit .

Anyone have experience of AT and MT tyres and the pros and cons for mostly road use?

[KarlT]

What would be really nice, would be a graph showing that German/mpg trip.
As far as tyres go, I've had many different types/makes over the years, but I don't think BFG's can be beaten, some budget makes may be 30/40% cheaper but wear out 50/60% quicker.

[Trundler]

When you say BFGs do you use All Terrains or Mud Terrains? The MTs have the look I'm looking for, the ATs are a bit too mild.

As regards longevity, I'm very satisfied with the cost/longevity ratio of my Matador Izzardas. I can't recall what I paid for them now, but they are still available for around £65 each and at that price they seem to be a fantastic bargain - they have already done well over 30,000 miles (perhaps close to 35,000) and still have a bit of life left in them. One more wheel rotation and then they will be done, call it 36,000. That's about 9p per mile for a set of 5, which seems pretty good.

I haven't priced BFG's yet but I suspect they will have to last an extraordinary mileage to be as cost effective as the Matadors.

Good sense says I should just get another set of Izzardas but I'm a bit of a tyre fetishist (!) and do like a change...

[KarlT]

All good points, (although my Falken AT ones were looking tired after only 12K) but do they say "Baja Champion" on them?

[syncropaddy]

I used to have BFG M/T's on mine. I took them off and sold them because they were noisy, heavy and had a huge effect on MPG. They looked good though.
I use an M&S tyre from Continental now whenever I do actually drive it!

[..lee..]

Mt will make less mpg. 30% I can believe although I've not done the maths. Width also effects mpg. It's all a compromise between form and function. I think I have reasonable looks with reasonable traction and reasonable mpg with the camper. The panel van I'm going for economy. I've even had thoughts on a 1600tdi ??

Lee

[lloydy]

I'm tempted to stick road tyres on the alloys, and put the AT's back on the steels. Could be worth it for long drives

[tforturton]

A 30% decrease in MPG is a pretty massive drop, especially when the MPG figures aren't that great to start with.

[v-lux]

I'm not entirely sure that 30% is accurate really.

I used to run BFG MT's on my van the whole time and i havn't noticed there being all that much difference in fuel consumption since swapping to AT's.
Don't get me wrong, i'm sure there is a difference, but i just don't think its as large as that.

MT's are certainly noisier, and maybe a bit less sure footed on tarmac but as an all round tyre, AT's are hard to beat. The only time they let you down is sticky/slippy mud, they just turn into slick, MT's are definitely superior in these conditions. But muddy slippy conditions are probably only 1-2% of most peoples driving so its hard to warrant using MT's continuously.

[Allanw]

A good chunk of the consumption increase might be from going taller ratios - you can easily eat another 30% if you go too tall! The engine ends up struggling too much - less revs doesn't always mean less consumption (quite often doesn't, actually!)

[HarryMann]

Yes, the lowest engine consumption typically occurs at the peak of the torque curve, which for a diesel is fairly flat . Though a much narrower overall band than a petrol (say 2500 to 3500). The prevalance of 5 and 6 speed gearboxes on modern diesels points to that the optimum range is smaller, so despite their reputation for lugging well, hints at a fuel penalty. OTOH, indirect injection TDs definitely degrade badly when cruised at hign revs, despite them spinning up there much more happily than Tdis.

MTs can be dreadful fuel guzzlers around town, as they don't float from tread block to tread block until a certain speed, mine are not only noisiest at 12 to 15 mph, but from there on down literally act as brakes, being able to feel the van stop in a rut eventually, between the blocks.
Anyway, 30% seems high but perhaps the comparison should be between them and road tyres, even ATs and road tyres probably somewhere approaching 5 to 10% ??

[lloydy]

couple of tyres here i'm looking at, this one is band B on fuel and only 70dB
http://www.camskill.co.uk/m91b0s523p105 ... se%3A_70dB" onclick="window.open(this.href);return false;
this one is a C on fuel and 72dB
http://www.camskill.co.uk/m91b0s523p983 ... se%3A_72dB" onclick="window.open(this.href);return false;
compared to that, my existing tyres are G on fuel and 73dB. So there has to be a decent saving on fuel there?
http://www.camskill.co.uk/m64b0s233p992 ... se%3A_73dB" onclick="window.open(this.href);return false;