Two questions, not one
The access question splits in two, and most people answer only the half a tape measure reaches. The first half is geometry: will the vehicle pass the gate, the lane and the overhead, and can it turn into the yard and stand where the concrete has to go. That is answerable today against a dimensioned drawing, and a failure announces itself harmlessly — the vehicle stops at the entrance and nothing is broken. The second half is bearing: will the surface and whatever lies under it carry the wheel loads without rutting, cracking, sinking into soft ground, or dropping a wheel through a drain cover, a septic lid or a soakaway. That one cannot be measured from the driving seat, the answer depends on ground nobody can see, and the failure arrives after the vehicle is already standing on it. Grass, a lawn crossed to reach a back garden and an unmade rural track are the sharpest form of it, because there is no specification on any machine that answers them: the bearing question there is settled by the person standing on the ground, after the weather that ground has just had, and by nobody else.
The two halves also fail differently once you try to solve them. A gateway that is too narrow is solved by a smaller machine, and width is the dimension we can document: ten of our sixteen self-loading mixer records carry measured overall dimensions, and across those ten the machines run from 1.60 to 2.30 metres wide. A surface that will not carry the load is solved only by a lighter machine, which means knowing what the lighter machine weighs, and that record is far thinner. The order matters too. Geometry is cheap to check and its answer holds all year, while bearing moves with the weather, and ground that carried a load in the dry season may not carry it in the wet. Neither half is answered by a brochure photograph of a machine standing on a flat yard. Read what follows as an inventory rather than a reassurance.
Source: the plants' dimension records, ten of our sixteen self-loading mixers measured; the split into two classes of constraint is reasoning rather than measurement, and every figure supporting it is sourced in the section where it appears.
What a loaded ready-mix truck weighs
Plan the ground against 9.51 tonnes on one axle, not against 32 tonnes spread over a lorry. The British Ready-Mixed Concrete Association and the Mineral Products Association, in their practical guide for site personnel, open the delivery chapter by telling the contractor to ensure suitable, stable and safe access for the ready-mixed concrete truck, "the largest of which may be up to 10.5 metres long, 2.6 metres wide and 3.8 metres high and weigh 32 tonnes when fully loaded". That is a ceiling for the largest truck in general use, not a description of every delivery that will arrive at your gate. The word carrying this page is stable. The figure printed beside that sentence gives the axle weights of a typical truck as 7.1, 7.1, 9.51 and 9.51 tonnes. A surface fails under a wheel rather than under an average, so the number that decides a driveway is the largest of those four, applied twice.
Two of those figures do not reconcile, and smoothing them over would be the wrong service. The four axle weights sum to 33.22 tonnes against a stated 32 tonnes fully loaded; the text describes the largest truck in general use while the figure is captioned as a typical one, so the two are not necessarily the same vehicle and should not be averaged into a single number. Both are quoted here as printed, and the heavier reading is the one to plan against. The same section states the consequence of getting it wrong, which is not only a broken surface: where the truck cannot discharge directly into the works, transport has to be provided to move the concrete to the pour, by front shovel, by dumper, or for larger volumes by a hired pump. A delivery that stops short does not get cheaper. It acquires a second machine and another pair of hands.
Source: British Ready-Mixed Concrete Association and Mineral Products Association, "Ready-Mixed Concrete — Practical guide for site personnel", first published 2017, updated June 2020, section 3.1 on site preparation and the truck figure printed with it, at https://brmca.org.uk/documents/BRMCA_Ready_Mixed_Concrete_Practical_guide_July_2020.pdf — quoted as printed and not converted. The 33.22 tonne total is the four declared axle weights added here.
What we can tell you about ours
Three of the sixteen self-loading mixer records carry an operating weight confirmed in writing by the plant: 5,800 kg, 8,500 kg and 8,500 kg. The lightest of the three belongs to the SLM-18, the one model whose specification set is complete enough for us to attribute figures to it by name. The other two are larger machines in the same range, and one of those is a variant we do not publish at all. What the plant does not state is what the figure covers — whether fuel, water or an operator sit inside it — and we have not asked, so we do not gloss it. What is certain is that it is not a laden weight. What any of these machines weighs with a full drum is recorded nowhere, for any model, and we will not produce that number by multiplying a drum volume by a concrete density we have not sourced.
Five more machines on this site do carry a written weight, and they belong here because they hold the one number this page most wants. The five crawler dozers are recorded at 17,000 to 24,540 kg, and each of them has a declared ground pressure, from 28.4 to 76 kPa; the lowest of those belongs to the one running wide low-ground-pressure tracks. They are a different category of machine doing a different job — tracks rather than tyres, a blade rather than a drum — so their weights are not a comparison with the mixers and are not offered as one. The contrast is what earns them a mention on this page. Ground pressure is a specification plants do publish for tracked machines, and for our wheeled mixers not one of them has published it.
One load figure does exist on the mixer side, and it is worth stating precisely. The SLM-18's tyres are declared as 20.5-16PR with a maximum tyre load of 2,840 kg. Four of them give 11,360 kg of tyre capacity, multiplied out here. That is a ceiling the tyres are rated to carry — not a weight the machine reaches, not a permitted gross weight, and not a statement about what lies underneath them. It is the only load-carrying number anywhere in the mixer records, and it belongs to one machine out of sixteen. The comparison a contractor actually wants is per wheel and laden on both sides. The association gives an axle split for the truck and no wheel split; the plants give neither for the machines. Its honest form is this: a machine the plant records at 5,800 kg against a truck the association caps at 32 tonnes is a difference in kind, and the size of that difference on any one wheel is not a number either of us has.
Source: plant specifications as supplied to us. Three of the sixteen self-loading mixer records state an operating weight; the other thirteen are recorded as unconfirmed and no estimate is substituted for them. The weights and ground pressures of the five crawler dozers are the plants' declared figures, as published on their model pages here. The tyre rating is the plant's figure for the SLM-18, and the four-tyre total is multiplied out here — it is a rating, not a weight.
Tyres and ground
Fifteen of the sixteen mixer records carry a tyre designation, and the designations divide the range more sharply than the drum sizes do, which is why they are worth reading before the capacity column. One mixer record has the field blank; the five crawler dozers have no tyre field at all, because they run on tracks. Three mixers are on 12R-22.5 steel-belted tubeless, a 22.5 inch rim of the kind a road truck wears. Nine of the other twelve sit on 16 and 20 inch rims with much wider sections: three on 20.5-16 in various grades, one of them the SLM-18; three on 23.5/70-16 heavy-duty; one each on 16/70-20 heavy, 15/70-20 heavy on eight wheels, and 1670-20. Two are narrower than the road-truck tyre rather than wider: a 10.5/46-16 off-road and a 1000-16 semi-solid. The twelfth states only a heavy-duty mountain type with eight wheels, and no size designation at all.
What that tells you about the nine wide-section machines is a direction, legible without help from us: a wide low-pressure section on a small rim puts a given load over more ground than a tall truck tyre does. The two narrower designations do not follow that direction and do not inherit it, and one of those two is declared semi-solid, which is not a low-pressure tyre. Two of the tyre entries specify eight wheels rather than four, and a third record declares an eight-wheel-drive chassis in its equipment list, all three on machines we do not publish. What none of it tells you is the size of the effect, which would be a ground pressure in kilopascals, and no mixer record carries one. Inflation pressure, load index and contact area are missing on every mixer as well. A designation identifies a tyre. It does not tell you what your slab feels, and nobody should convert the one into the other on your behalf.
Source: the tyre row of the plants' specification tables, quoted as designated, with the English renderings as they appear in the model tables on this site. Fifteen of the sixteen self-loading mixer records carry a designation and one is blank; the five crawler dozers carry none, because they run on tracks. No mixer record carries a ground pressure, an inflation pressure, a load index or a contact area.
If the truck cannot come in
The reason to put a self-loading mixer on a tight or soft site is not, first of all, that it is lighter. It is that it removes the journey: the machine that reaches the form is the machine that made the concrete, so there is no transfer from a delivery vehicle to the pour — provided the machine reaches the form, which is the question the rest of this page exists to qualify. All sixteen mixer records carry an equipment list, and that is the evidence for what the machine does unaided. A drum that raises and slews through 270 degrees appears on seven. A water-fill system appears on fifteen, so the machine takes on its own water rather than waiting for a plumbed supply, and an external suction pump on seven of those lets it draw from a drum or an open tank. Six records steer by articulation.
This page will not convert any of that into output. No figure for cubic metres a day, loads per shift, cycle time or fuel consumption exists in any document we hold, and one assembled from a drum volume and an assumed cycle would be the most quotable and least true sentence on the site. The cycle itself is documented and you can work it against your own crew: load with the machine's own bucket, take on water, mix while travelling, discharge at the form. How many of those your site needs in a day is your arithmetic, and it will beat ours. Three of the sixteen records declare one more detail that belongs on a page about broken ground — a rear axle that swings through 28 degrees on a swinging frame, which keeps wheels on the surface as it changes. That is a mechanism, not a measurement.
Source: the standard-equipment lists in the plants' specifications, which are declarations rather than measurements; all sixteen self-loading mixer records carry one, and each count above is a count of records carrying that item. The rear-axle swing is a declared figure on three of those records. No output, cycle-time or fuel-consumption figure exists in any document we hold, which is why none appears here.
The honest gap
Thirteen of the sixteen mixer records have no operating weight confirmed in writing, and four of the six mixers published on this site are among them: the SLM-10, SLM-24, SLM-35 and SLM-45. That list contains the machine a reader with a difficult driveway would ask about first. The narrowest machine we publish is given by its plant as 4.35 by 1.60 by 2.45 metres, and it is the only one of the eleven machines on this site that goes through a 40 ft high-cube door whole, as the container guide sets out. Its weight column is empty. On that machine we can answer the geometry question to the centimetre and cannot answer the ground question at all. Publishing that on a page about ground is uncomfortable, and it is still better than a plausible figure, because a plausible figure is the one a reader would pour a slab against.
The missing items, named rather than gestured at: a laden weight, on every mixer; axle or wheel loads, on every mixer, and the tracked machines have neither by construction; a ground pressure, on every mixer; a turning radius, on every mixer, so the turn into a yard is the question these dimensions cannot settle, though two of the tracked machines do carry one; and gradeability, which would decide a steep ramp and is recorded for no mixer. The first two are what we ask a plant for in writing, alongside the dimensioned drawing, before a quotation goes out rather than after. Until they arrive, the sentence that belongs on a quotation is the one on this page: here is the confirmed weight where it exists, and here is where it does not. The laden figure is not ours to invent, and a quotation that invents it is the one to be careful of.
Source: the plants' specification records — three of the sixteen self-loading mixers with a confirmed operating weight, thirteen recorded as unconfirmed. No laden weight, axle load or gradeability figure appears on any mixer record; a ground pressure appears on all five crawler dozer records and a turning radius on two of them, and on no mixer record at all. The overall dimensions quoted are the plant's own figures and the plant does not state the posture they were taken in. The container-door verdict is the calculation already published in the shipping guide, not a new claim here.