OK another of my hypothetical questions with a possible future use, any info shared would be much appreciated.
Looking around at the moment there are loads of 6x2 twin steer units knocking around for not massive money, to my way of thinking taking something like an ex Stobart unit that has only ever done motorway / cruising work and converting it to a rigid might be a better option than trying to find a similar age rigid ready built that hasn’t had a hard life of abuse on sites and rough work.
Let’s take an R420 as an example, cut it in half stretch it to overall chassis length of 12m and fit it with a tag axle. I’d now have an 8x2 with 2 lift axles enabling me to run as a 4, 6, chinese 6 or 8 wheeler which could be handy. Indeed I’ve seen others that have been done this way.
What would be the rough cost of stretching and adapting the chassis to a beavertail and adding a tag axle, £3k, £5k, £10k? I’ve no idea.
Has any one driven one? do they “work” or they more ■■■■■■■■■■ than a conventional 8 wheeler, as the spacing between axles 1 & 2 is quite a bit different.
I had my Daf stretched - by Inter Uk - IIRC cost about £15k to stretch and build a flatbed
Maybe it’s more than I thought but I’ve seen 04 units for £17-18k, a good 8 wheeler if you could find one may cost a fair amount more. Plus you could find a nice powerful unit to chop up.
spoke to someone at euro axles last year they stretched our daf 85 six wheeler from a unit in 2002 said the have problems stretching anything newer than 02 plate due to electrics think they got round it now think cost to stretch and ad axle was around 7k mark
Northwest Commercials from Preston did exactly what you are describing last year to a DAF CF.
They stretched it and added a twin wheel tag axle, but it is still pretty short because it was fitted with 20’ twist locks, no flat just the locks; in fact I saw the vehicle last week around West Brom.
i no a fella who bought a y reg ex stobbies unit had it stretched fitted a tag axle on it with hydraulic ramps at the back which folded right over to make it a flat bed or the ramps would stick up pointin to the sky if he had a machine on etc
not too sure were or how much he paid to get it done but he had a 50tonne crane fitted to it aswell, it stil works today although the turning circle isnt great !
I know it’s possible certainly, there’s a few knocking about in my line of work (plant hire) there’s also a Topline with a yellow 20’ twistlock body running around.
£7k seems to be not too bad, I’d imagine taking an existing 6 wheeler and doing a twin steer conversion would be costly and complicated, much better leave the steering systems alone. I’d imagine the geometry would have to be adjusted to make the 2nd steer turn more otherwise they’d shred the tyres. However the beauty of this system is that you could run as a 4 when empty or 6 when part loaded and only use all 4 axles when fully freighted.
I have stetched a few over the years and the only company I will use is Euroaxle , silverdale road , newcastle under lyme, never had any problems and the price is always right, the second steer is not is not a problem for them, we have had 6 x 2 units converted to tag axle beavertails
8wheels:
I’d imagine taking an existing 6 wheeler and doing a twin steer conversion would be costly and complicated, much better leave the steering systems alone.
Although you saying that, I’d still like to ask have you thought about axle configuration where steering axle is right in front of drive axle(s)? For example this picture shows what I mean (1+3 axles vs. 2+2 axles). I also think that rigid is quite close to 12 metres in length. For this configuration you’d (naturally) need tag axle or double drive rigid or tractor unit. Sure, they’re more likely to have been in harder use than twin steer units, but your question was hypothetical and you just wanted information
That 1+3 axle configuration still is common in Finland in tippers although in last few years 2+2 configuration has got some ground on the tipper market. What I think is that in 12 metre long rigid with 1+3 axle configuration might yields shorter wheelbase and longer rear overhang than 2+2 axle configuration, but that’s just intuitive thought.
It’s an option but it still means that all the weight needs to be kept to the rear, a twin steer can carry weight at the front and the rear making the most of the available load space. My 6 wheeler that I drive needs careful consideration about loading so as not to overload the front axle.
Plus the big draw about stretching a unit is that there are hundreds of twin steers knocking about, double drives and tags are not that common and command a premium price as well as likely having had a harder life pulling over rough ground or tips rather than constant motorway mileage.
I can’t see why we can’t run 2+3 rigids like you get in other places, running at 40t it’d be no different to a short artic.
When you stretch a twin steer you need to move the second steer axle forward ,this will usually remove the capability to lift the axle. Failure to do so will totally bugger up the steering geometry of the truck probably shreading the tyres within a few months.
The other thing to consider is that there are only a few trucks capable of being stretched due to dept of transport type approval issues , I think thats why dafs newer than 2002 had a problem .
My scania was done by a company in Stoke , we payed £11,000 that included
1 stretch chassis to 12 mt
2 move second axle forward (proper scania spec)
3 add a twin wheel rear tag axle .
4 supply and fit drawbar coupling and pipework.
We did get other work done at the same time, ie crane fitted and body built but the bare cost of the stretch was £11,000.
You need to pick carefully who does the work, I recently saw a DAF XF 6x2 that had been streched to make it an eight wheeler, as it turned both front axles were fighting each other as the steering geometry hadn’t been corrected to take account of the drive axle now being further away, the cab was also leaning well back, the cause was revealed on closer inspection as the chassis had bent just behind the second axle, probably where it had been cut and shut, and no doubt caused by the stonking great hiab mounted just in front of the bend. Don’t know how that’ll get through the next test it was’nt pretty
I always felt that the axle configuration of a twin steer couldn’t be 100% for a rigid otherwise why bother making two variants of twin steer, it also figures that there are a good number of normal looking 8 wheelers running about that probably would never have built like that by Scania. Look at Mac’s trucks and they have a shed load of 420 R cab sleepers, pound to a penny they are conversions as they all have brand new bodies but they have the conventional axle spacing.
However there are enough cut and shut conversions about with the wider spacing to lead me to believe that it is workable with some alteration to the 2nd steer when lowered and in operation. I’d be interested to hear of how they handle and whether they do destroy tyres or not.
it was’nt pretty 
