Simon C

Cos on the way home tonight I was following a Somerfields truck and got passed by a wagon and drag unit with a 20 ton cat bulldozer on the back.

When I say passed, I mean with ease, I had to do just under 70 to catch it when I overtook the Somerfields truck. The Somerfields was going 55mph indicated which means 51 mph actual.

bootsy

did it have UK plates on it.as i don't think foreign HGV's are limited

RA Dunk

I was under the impression all HGV's were limited to 56 MPH as well?

Steve vRS

Was it downhill? I think they must dump the clutch to get round the limiter!

Steve

Simon C

Yup, Uk reg'd truck

Simon C

Nope, on the flat leading to a slight incline (up).

nick172sport

iTrader: (6)

ive been driving trucks for 20 yrs too long you can overide limiter but that in itself is illegal ie coasting down a hill with the clutch in its a overspeed which vosa wont take to lightley mine is limited to 54 mph in older wagons and irish waggons they can pull fuses on the limiter which is a jailable offence now

al02uk

iTrader: (1)

might have pulled the limiter fuse?

ALi-B

iTrader: (1)

They are, but I think there are ways of making them go faster.

A Scania R530 V8 would probably do 85mph with ease if it had the right final drive fitted.

GC8

Their speed limit (maximum) is 60mph, which is easily achieved downhill, especially with a little weight behind you. HGVs should be limited, although older vehicles dont have to be - there arent many unlimited vehicles left though.

Bypassing restrictors isnt easy, although they can fail. Different vehicles can sometimes be tricked too - although youll usually lose all electrical functions too (lights indicators etc), making it hard to drive practically. I managed to do 70mph empty on a deserted road once, by finding the right position on the ignition key (electrics off, but fuel still on). Interesting as a one-off for the craic, but hardly worthwhile.

Remember that a 40+ tonne keeps the momentum that it has gathered for a long time; far farther than youre used to driving a car. Perhaps his extra turn of speed was carried over from an incline half to a mile back up the road?

GroupNGC8

iTrader: (1)

All European LGV's are electronically limited to 90km/h (56mph) and are calibrated according to their tyre sizes. so if you calibrate the truck on 295/80 tyres and then fit 315/80 tyres for example without recalibration then the truck will go faster. however the actual limit for an LGV over 7.5ton on british roads is still 60mph!!
A wagon & drag or drawbar combination (rigid truck towing a close coupled trailer) has a maximum weight of 44,000Kgs on 6 axles split as 26t on the truck and 18t on the trailer. I seriously doubt that the CAT bulldozer weighed 20,000Kgs as the truck or trailer axles would have exceeded C&U limits, albeit the haulier could have been breaking the law of course.

GC8

Thats simply a misuse of the term 'drag'.

GC8

This is a 'wagon and drag':

Will

And a 7.5ton can only do 50 on national speed limit (British roads as you say) roads, 60 on dual carriage way and 70 on motor ways

chocolate_o_brian

iTrader: (22)

TonyBurns

iTrader: (3)

Tachometer's also record the speed that the vehicle is doing, hard to unlimit them and get away with it, I have heard a few stories of military trucks doing 80+mph (4 tonne bedfords), some with catastrophic failures when the prop/diff explodes

Tony

john_s

iTrader: (1)

We've just had to have a new limiter fitted to our wagon at work as it had stopped limiting. Cost £500, though the local Iveco dealer wanted £1200 plus fitting to install one of their modules.

billythekid

Ok, so the law in E&W&S&NI says 60mph is the max speed for any vehicle over 7.5 tonnes. (Road Traffic Regulation Act 1984, schedule 6). There are some new laws on 3.5 tonne vans too but I wont confuse this post with that as we are talking about large vehicles here.

Speed limiters are controlled under an EU directive, and in most modern vehicles this is a built in part of the ECU on the wagon and cant be changed from factory default of 90km/h.

VOSA have to ensure as an EU nation that we abide by the EU regs, thus the limiter cuts in at 56mph.

What is more interesting is more vehicles are now coming through with the limiters set at 85km/h.....

In terms of coast down a hill, the limiter wont apply the brakes, the driver has to maintain a speed of 60mph, or less. More than this and s/he can be prosecuted. So its either take a lower gear or use the brakes. Most drivers would do a combination of both if its a long hill as not to run out of air. The M62 at windy hill is a good example of this...

Its also worth taking note that the limiters are checked. Either at MOT time at a VOSA station or at the set calibration / check dates for the tacho which is currently once every 2 years for a check and every 6 years for a calibration.

The vehicle is most often put on a rolling road and tyre size etc is noted.

HTH.

Leslie

I always thought it was a 60mph limit for lorries. Looks like I was right but we are ordered as ever by those other chaps to restrict them to 56.

Stops those fellows in London having to make a decision again then!

Les