hi all.hope this is in the right slot.im trying to find out what advantages are and savings etc on limiting your truck to 52 mph.is there a link to find out info etc.im travelling all over and pulling 44t most of the time.is there issues with automatic gearing wear and tear etc,the vehicle in question is a daff xf 460.any help would be great.this is against running at 55 mph
i was running an 04 plate XF530, if i ran at 56 all the time, it used to average 7.5 (ish) over the week, i knocked it back to 52 (on the cruise control, not by having the limiter reset), it was then averaging 9+ regularly
i have currently got a couple of MAN TGA’s, a 430 euro3 XLX and a 440 Euro4 XXL
the 430 when ran at 56 managed 8.6 (by a driver that is a member on here), but, now at 52, on the last check, it achieved 9.84 over the week
shuttlespanker:
i was running an 04 plate XF530, if i ran at 56 all the time, it used to average 7.5 (ish) over the week, i knocked it back to 52 (on the cruise control, not by having the limiter reset), it was then averaging 9+ regularlyi have currently got a couple of MAN TGA’s, a 430 euro3 XLX and a 440 Euro4 XXL
the 430 when ran at 56 managed 8.6 (by a driver that is a member on here), but, now at 52, on the last check, it achieved 9.84 over the week
As above driving a daf auto if i drive 56 usually get 8 ish but when i go 52 usually average 9–9.2
Have any of you tried it@ 50mph IE like Tesco wagons 
At speeds above 55mph you lose 0.1mpg for every 1mph increase in speed. Above 55mph aerodynamics are the major factor, under 55mph the biggest impact on fuel economy is rolling resistance, so the better the rolling resistance figures on the tyres, the better the improvements will be. Gearing will also play a part, as will sweet spots in the engine, but speed always triumphs everything, it is the number one factor in fuel use (in 99.9999%) of cases 
newmercman:
At speeds above 55mph you lose 0.1mpg for every 1mph increase in speed. Above 55mph aerodynamics are the major factor, under 55mph the biggest impact on fuel economy is rolling resistance, so the better the rolling resistance figures on the tyres, the better the improvements will be. Gearing will also play a part, as will sweet spots in the engine, but speed always triumphs everything, it is the number one factor in fuel use (in 99.9999%) of cases
Theres new eu tyre labeling regulations coming that include rolling resistance
Denis F:
newmercman:
At speeds above 55mph you lose 0.1mpg for every 1mph increase in speed. Above 55mph aerodynamics are the major factor, under 55mph the biggest impact on fuel economy is rolling resistance, so the better the rolling resistance figures on the tyres, the better the improvements will be. Gearing will also play a part, as will sweet spots in the engine, but speed always triumphs everything, it is the number one factor in fuel use (in 99.9999%) of casesTheres new eu tyre labeling regulations coming that include rolling resistance
Finally, I’ve been saying it for years, tyre choice can have the single biggest influence on fuel economy, the difference between a bad set and a good set can be more than 1mpg and there is nothing else on earth that can (edit-that you can buy) make a full mpg improvement in economy 
Well other than the weight of the boot on the peddle.
too much use of the brakes and stopping and starting must have a major effect too
Foxstein:
too much use of the brakes and stopping and starting must have a major effect too
Not at all, braking uses absolutely zero fuel, it is the bit before and after the braking that affects mpg, if the driver is all throttle and brake, then fuel economy will suffer, if they use the momentum of the vehicle as much as possible and stay off the loud pedal unless they’re actually going to get somewhere by using it, they can make a huge difference, as much as 30% and that saving is 100% profit and it costs you SFA
Reducing 56 to 52 without doubt saves money.
I have done this on a fleet of around 50 artics - we have seen anything from 0.5mpg to 2mpg improvement and only a couple got worse. These two that got worse were premiums that wouldn’t then select top gear - all the driver needed to do was manually make it have it and it was OK. We have two identical Actros. One is at 56 and one at 52. On average each week the difference is 2mpg. The slower vehicle also has Michelin energy saving tyres which I reckon is giving an extra 0.5mpg. Some of this vast difference is the driver which will be the next issue to be addressed.
Yes there is a time difference. Now the drivers have got over the moaning about the speed most admit it makes hardly any difference and at most 20 minutes on a day. The savings outweigh any time factors. Some drivers prefer the slower speed.
Surely any saving is worth making?
shep532:
Reducing 56 to 52 without doubt saves money.I have done this on a fleet of around 50 artics - we have seen anything from 0.5mpg to 2mpg improvement and only a couple got worse. These two that got worse were premiums that wouldn’t then select top gear - all the driver needed to do was manually make it have it and it was OK. We have two identical Actros. One is at 56 and one at 52. On average each week the difference is 2mpg. The slower vehicle also has Michelin energy saving tyres which I reckon is giving an extra 0.5mpg. Some of this vast difference is the driver which will be the next issue to be addressed.
Yes there is a time difference. Now the drivers have got over the moaning about the speed most admit it makes hardly any difference and at most 20 minutes on a day. The savings outweigh any time factors. Some drivers prefer the slower speed.
Surely any saving is worth making?
I find setting the cruise control on my Premium at 53 is better, although there are days that don’t have a spare 20 minutes so having the option to run at 56 is a necessary thing
Denis F:
I find setting the cruise control on my Premium at 53 is better, although there are days that don’t have a spare 20 minutes so having the option to run at 56 is a necessary thing
Being able to run at 56 when needed is an excellent option - but most drivers will simply sit at 56 because it will … we did try just asking the drivers first 
I run a 6x2 actross and never go over 50mph and I have improved my mpg significantly I’m a lot more relaxed driving and the time factor is barley noticiable,I don’t get stuck tailgating the lorry in front either, it’s my own moter so every penny counts, take an average trip say Kent to poole Dorset I regular run I do about 140 miles about 110 are moter way miles taking traffic hills etc into account let’s just say you could avg max speed for 100 miles lorry a sat at 50 would cover the 100 miles in two hours lorry b would take 1 hour 48 a saving of twelve mins which is negotiable where not delivering human organs so what’s twelve mins on a avg journey equivalent to a ■■■■ stop/ diesal stop just because the trucks limited to 56 doesn’t mean u have to to do 56 all the time
I always found that driving at 52mph reduced stress & road rage immensely.
Every time the fool pulls in front of you leaving a 2 foot gap, he starts to move away instantly, giving you your braking distance back.
You use less fuel, arrive a lot calmer, the motor takes less abuse and the time cost is negligible
Just had a new Actros 2546 for the week running on Bridgestones normally not a fan of anything non Michelin but ive run this truck 3200km s this week and the average was 10.7mpg just by running at 50-52 mph, ive never had figures like that in my driving life, my old range rover didnt do that!!!