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PostPosted: Sun May 12, 2019 5:30 am 

Joined: Sat Mar 31, 2012 7:34 am
Posts: 55
Location: Mount Maunganui, New Zealand
In the thread started by Stephen Allcroft, “LMC Rationalisation, an impossible task?” (viewtopic.php?f=4&t=550#p1292) I said:

9711T wrote:
One might say that Leyland had done a generally good job of integrating and rationalizing the Leyland and Albion medium-weight ranges in 1958-59 but was unlikely to have been able to repeat the performance with the AEC range, even had it had the inclination so to do when going in, so as to speak.

To put a little substance behind the statement about the Leyland-Albion medium-weight rationalization, I thought it would be worthwhile to look at the 1958-59 events in some more detail. What happened is not so difficult to discern, when it happened is generally available information, although there are some gaps, some information as to how it happened is available, but why it happened, at the detail level, is mostly left to inference and deduction.

The first round, in which a whole raft of new or updated Leyland and Albion medium-weight truck and bus chassis were released, appears to have taken place in the 1958 July through 1959 July period. The remainder of this post provides a (mostly) chronological model-by-model precis of the events in this period, I hope with not too many errors and omissions. I make frequent reference to Commercial Motor (CM) articles as my main sources, these being available at the Commercial Motor archive, at:

The first of the revised Leyland-Albion medium weight models was the Albion Chieftain CH3, announced in CM 1958 July 04.

Albion Chieftain CH3 195810 p.01.jpg
Albion Chieftain CH3 195810 p.01.jpg [ 978.96 KiB | Viewed 34 times ]

It was announced as being completely new, which was probably something of an exaggeration, but it was certainly substantially new. It was a replacement for the previous Chieftain FT37 series. It was billed as having a nominal 7-ton payload capacity, with a gvw of 10.2 tons. The latter was the same as the highest gvw variant in the FT37 series.

The chassis had a longer front overhang than hitherto, in order to accommodate the long-door version of the Motor Panels LAD (Leyland-Albion-Dodge) cab. This cab, in short-door form, had made its debut on the new Dodge forward control range announced in CM 1958 March 07. It was “modern” in the context of the time, with a single-piece curved windshield. The long-door version made for easier entry and exit, where such were frequent as on urban delivery work.

As with its predecessor, the Chieftain CH3 was powered by an Albion 4-cylinder engine, the EN289. This was said to be a substantially reworked version of the previous EN287, retaining the same key dimensions.

The clutch was hydraulically operated, whereas that on the FT37 had been mechanically operated. Hydraulically operated clutches were not new to Albion practice though. For example the original Nimbus MR9 underfloor-engined bus chassis of late 1955 had a hydraulically operated clutch. The gearbox was the new GB241 5-speed constant mesh unit intended for group use. It had an optional 6th overdrive speed, and had made its debut at least as early as 1958 March in the Leyland Comet ECO2 and ECOS2 models.

The rear axle was completely new, reflecting a new group standard. It was of the epicyclic hub reduction type, with a spiral bevel centre. It replaced the previous overhead worm type. The brakes were hydraulically operated with vacuum assistance, as before, but a Hydrovac vacuum-suspended remote servo was used in place of the previous air-suspended vacuum master servo. Viewed from the export market perspective the latter was probably well past its “use by” date by 1958. The Hydrovac was not new to Albion practice, though, its use going back at least to the Nimbus MR9 of late 1955.

At the same time as the Chieftain CH3, Albion’s lighter-weight models were also updated. Although somewhat out-of-scope here, they are mentioned mostly because of the engine connection with the medium-weight range. A “new” underfloor-engined Claymore range was announced as the CL3 and CL5 series. These were replacements for the previous MR5 and MR7 models. Evidently at about this time the previous vertical-engined Claymore FT25 series would have been discontinued. The CL3/5 was fitted with the new EN250 engine. This was the 4-cylinder counterpart to the 6-cylinder Leyland O.375, at that time yet to be announced. A David Brown 4-speed constant mesh gearbox replaced the previously used Albion 4-speed synchromesh unit, and a spiral bevel rear axle replaced the previous overhead worm type.

The same changes were made to the Nimbus, with the NS3 replacing the MR9. I don’t have an exact date for the NS3, but sales brochure L688 was issued 1958 September, so logically it was some time between 1958 July and September.

The second stage of the revision was the announcement of the Albion Clydesdale CD21 and the Leyland Super Comet 14SC. Both were 14 tons gvw chassis, the maximum then allowed in the UK for 4-wheeled trucks.

The Super Comet was a new model in the Comet range, and extended this upwards from 12 to 14 tons gvw. The chassis was a strengthened version of the existing Comet ECOS2 forward control unit. It was fitted with the short door version of the LAD cab, as used by Dodge. That was probably close to being a “drop-in” replacement for the Leyland cab used on the ECOS2. Using the long-door LAD cab would have required some chassis modification.

Leyland Super Comet 14SC 195909 p.01.jpg
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The engine was the new O.375, a larger bore derivative of the established O.350. The clutch was hydraulically operated, as compared with the mechanical operation on the ECOS2. This appears to have been Leyland’s first use of a hydraulically operated clutch. The gearbox was the GB241, already in use on the ECO2 and ECOS2. The single-speed axle was of the new hub-reduction type, being a heavier duty version of that used on the Chieftain CH3. The two-speed axle was an Eaton spiral bevel driving head in a one-piece Leyland casing. It was electrically operated whereas that on the ECO2/ECOS2 was vacuum operated. Leyland had first used an electrically operated two-speed axle on the Tiger Cub PSUC1 bus chassis in 1952.

Full air pressure braking was used, with diaphragm-type actuators. Leyland had first used diaphragm actuators on the Tiger Cub in 1952, and these progressively replaced the piston-type throughout the range over a period of about a decade. 10-stud wheels were used. The ECO2/ECOS2 had vacuum assisted hydraulic braking and 8-stud wheels.

The Albion Clydesdale CD21 directly replaced the previous PF101 (6-cylinder) series and indirectly the FT101 (4-cylinder) series, which had no similar counterpart in the new range. The CD21 was a 14 tons gvw chassis, whereas the PF101 had both 12 and 14 tons gvw variants.

Albion Clydesdale CD21 195809 p.01.jpg
Albion Clydesdale CD21 195809 p.01.jpg [ 136.96 KiB | Viewed 34 times ]

Like the Chieftain CH3, the CD21 had a new chassis with a longer front overhang to accommodate the long-door LAD cab. The engine was the new O.375, as was also used in the new Leyland Super Comet. The PF101 had used the Leyland O.350. It had the GB241 gearbox, and the new hub-reduction rear axle, heavier duty than used on the Chieftain CH3. Full air pressure braking was used, with diaphragm-type actuators whereas the PF101 had the vacuum-assisted hydraulic type.

Next for updating was the Albion Victor bus chassis, with the VT15 and VT17 models, announced in CM 1958 November 21, replacing the previous FT39 series. The Victor was, more-or-less, the bus derivative of the Chieftain. The VT15 was fitted with the EN289 4-cylinder engine, as was used in the CH3. The VT17 had the O.350 6-cyliner engine, which option was not available for the CH3. In fact the use of the O.350 in the Victor had started in the FT39 era, as a special variant for Ceylon, recorded in CM 1958 May 30. In other respects the VT15/VT17 followed the CH3, with a hydraulically operated clutch, the GB241 gearbox, the hub reduction rear axle and the Hydrovac assisted hydraulic brakes. Gvw was 8.5 tons. Albion, or perhaps its overseas customers – the Victor was primarily an export model - appeared to have no objection to using the relatively noisy hub reduction rear axle on a passenger chassis, contrary to the Leyland position.

A new model, announced in CM 1959 January 30, was the Victor VT19 bulk load carrier truck chassis, derived from the Victor VT15 bus chassis, and similarly equipped. It had gvw choices of 8.25 or 10.2 tons, the former a little less than the Victor VT15 bus, and the latter the same as the CH3.

Somewhere in this timeframe was introduced the Clydesdale CD23 bus chassis, derived from the CD21, and similarly equipped, although I do not have an exact date for this. It was similarly equipped to the CD21. The CD23 offered a truck-derived bus chassis with longer wheelbases and higher gvw than the Victor VT15/17. Gvw was 11 or 12 tons according to wheelbase.

The Reiver RE27 light six-wheeler was announced in CM 1959 February 20. This was a direct replacement for the previous Reiver PF107 (6-cylinder), and indirectly for the Reiver FT107, the latter having no direct counterpart in the new range. The RE27 had a new chassis with longer front overhand to accommodate the long-door LAD cab, the O.375 engine, a hydraulically operated clutch, the GB241 gearbox and the hub reduction rear axle. It had single-drive, unlike the PF107 which had tandem drive via overhead worm rear axles without an interaxle differential. Rear suspension was by overslung springs with a simple balance beam, of a type that had been used on the PF107. Braking was by an air-actuated hydraulic system (not an air-assisted hydraulic system), similar to that used on the Caledonian 24C light 8-wheeler that had been announced in CM 1957 November 01. The PF107 had had a vacuum-assisted hydraulic braking system. The wheels were 8-stud, as before and gvw was 15.5 tons, whereas the heaviest variant of the PF107 was 15.25 tons.

The Reiver RE25 was announced in CM 1959 May 08. This was the tandem-drive version of the RE27, to which it was otherwise similar. For reasons unknown, Albion reverted to the older, pillow-block form of tandem drive, of which Timken had probably been the best-known exponent. Albion used a frame-mounted torque divider gearbox, the GBA19, which it referred to as a relay gearbox. This was a single-speed unit, analogous to the well-known Timken T50 unit. Albion missed the opportunity to also offer a two-speed version, analogous to the Timken T70, which would have been useful in export markets. The two rear drive axles were of the hub reduction type.

Albion Reiver RE.25, RE.27 195910 p.01.jpg
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Last was the updating of the Leyland Comet forward control truck chassis. I don’t have an exact date for this, but 1959 July is the best estimate for the release of the CS3 model as the replacement for the ECOS2. In this case essentially the same chassis was retained, upon which was mounted the short-door LAD cab, as had been used for the Super Comet. A significant change was that the CS3 was available in left-hand as well as right-hand drive form, whereas the preceding ECOS2 forward control model came only in right-hand drive form. The standard engine was the O.350, with the O.375 optional. The clutch was hydraulically operated in place of the mechanical operation of the ECOS2. The gearbox was the GB241, and the new hub reduction rear axle was standard. The optional two-speed axle, an Eaton driving head in a Leyland single-piece casing, had electric operation in place of the previous vacuum operation. The wheels remained as the 8-stud type, and the gvw stayed at 12 tons. The previous hydraulic braking system, with its single rear axle wheel cylinder, was retained, but with a Hydrovac suspended vacuum servo in place of the previously used air suspended master servo. This appears to have been Leyland’s first use of the Hydrovac. Quite strangely, it made much of this change. Why it did not offer an air pressure option, clearly preferred in many export markets, is unknown. The air actuated hydraulic system used on the Reiver would have been an obvious choice. For example, Dodge offered this as an option on its LAD-cabbed forward control 7-ton model (then 11.6 tons gvw), which could also be had with the Leyland O.350 engine.

Leyland Comet CS3 196001 p.01.jpg
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Thus at the end of this approximately one year period, the rationalized Leyland-Albion medium-weight range was:

Albion Chieftain CH3 truck, 10.2 tons gvw, substantially renewed, still with the 4-cylinder engine.

Leyland Comet CS3 truck, 12 tons gvw, minimum change.

Albion Clydesdale CD21 truck, 14 tons gvw, substantially renewed, only with the 6-cylinder O.375 engine, and with air brakes.

Leyland Super Comet 14SC truck, 14 tons gvw, modest change from the Comet, with air brakes.

Albion Reiver RE25, RE27 truck, 15.5 tons gvw, substantially renewed, only with the 6-cylinder O.375 engine, choice of single or tandem drive, with air actuated hydraulic brakes.

Albion Victor VT19 bulk load truck, new model derived from the VT15, with the 4-cylinder engine.

All of the above had one or other version of the LAD cab.

Albion Victor VT15, VT17 bus, substantially renewed, choice of 4- or 6-cylinder engines.

Albion Clydesdale CD23 bus, new model derived from the CD21.

The following Leyland-Albion medium-weight models all continued largely unaffected by this renewal programme, although were subject to some changes:

Leyland Comet ECO2 normal control truck. This had the GB241 gearbox since at least as early as 1958 March, and electrically operated two-speed axle since no later than 1959 July. It did not get the O.375 engine option.

Leyland Comet ECPO2 bus. This is assumed to have had the GB241 gearbox since at least as early as 1958 March, and electrically operated two-speed axle by 1959 July. It also assumed to have had the O.375 engine option by 1958 December, as did the ECOS2 truck.

Leyland Tiger Cub bus. This gained the option of the O.375 engine in later 1958. Also during 1958, the option of a 4-speed synchromesh gearbox was added, although that was unconnected with the medium-weight renewal programme.

Albion Aberdonian bus. As best I can determine, this was completely unchanged.

It should also be noted that although the Leyland Comet ECOS2 was replaced by the CS3 in 1959 July, the ECOS2 did benefit from the addition of the O.375 engine option by 1958 December.

Clearly, the major beneficiary in all of this change was Albion, who by mid-1959 had substantially renewed versions of the Chieftain, Clydesdale and Reiver. Upgrades to the Leyland Comet range were done mostly on a minimum change basis.

Looking at the truck range as it was by 1959 July, the medium-weight forward control models could be seen as forming a quasi-homologous range, covering the gvw points 10, 12 and 14 tons on two axles, and 15.5 tons on three axles. Above the 12-ton point, either full air or air-actuated hydraulic brakes were used, whereas at and below it, vacuum-assisted hydraulic brakes were used. At the 10-ton point, the Albion Chieftain still used the 4-cylinder engine, without a 6-cylinder option. That made it unusual in its class, but presumably it had a definite following that formed a significant niche. The 4-cylinder engine was no longer available at the 12-ton point and above, where the O.350 and O.375 engines were used exclusively.

At the 14-ton point there were two models, the Albion Clydesdale and the Leyland Super Comet. Presumably the total market was such that its supported production at both Albion and Leyland. There were some differences between the two. With its two-speed axle option, the Super Comet may have been better suited to highway work, particularly in hilly territory, whilst the Clydesdale, with its “easy access” long-door cab, was probably better suited to urban work involving frequent loading and unloading activity.

Added to that group was the special purpose Victor VT19 bulk load carrier. I imagine that this was aimed at operators who might otherwise have considered bus chassis for this purpose. And flanking that range was the normal control Comet ECO2 at the 12-ton point, and essentially an export model.

Amongst the truck-derived medium-weight bus chassis, the Albion Victor VT17/VT17 and Clydesdale CD23 formed a homologous series. The Victor still retained a choice between 4- and 6-cylinder engines. Presumably the former still had a place in some export markets where passenger comfort was but a minor consideration. The Clydesdale added a larger, heavy-duty option with full air brakes, where higher capacity and/or greater ruggedness was required. The Comet ECPO2, at 10.2 tons gvw, fell more-or-less between the two, with the added refinement that it did not have a hub reduction rear axle. The normal control Comet ECO2 Special Passenger version was nominally still available, but as far as I know not actually built during the period at interest.

The LAD-cabbed medium-weight truck range remained at the forefront of Leyland-Albion activities until 1964 September, when the first Ergo-cabbed medium-weight model, the Albion Super Clydesdale CD65, was announced. Thereafter the LAD-cabbed models filled a secondary role in this weight class. Between mid-1959 and late 1964, the medium-weight range was the subject of updating and expansion, as will be covered in a following post.


PostPosted: Mon May 13, 2019 5:07 am 

Joined: Sat Mar 31, 2012 7:34 am
Posts: 55
Location: Mount Maunganui, New Zealand
The first upgrading of the new Leyland-Albion medium weight range came quite early. The Albion Chieftain II CH3A, replacing the CH3, was announced in CM 1959 November 03. The major change was with the 4-cylinder engine, the EN335 replacing the EN289. There were also some minor chassis changes, and the gvw went from 10.2 to 10.75 tons.

Albion Chieftain II CH3A 195910 p.01.jpg
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The EN335 had the same bore and stoke as the EN289, but included some major changes. Amongst these were a nitrided crankshaft and shell-type main bearings. These brought it closer to established Leyland practice. Possibly the use of the EN335 designation, where 335 was the displacement in cubic inches (to the nearest 5) rather than say the next available number above 289 was in recognition of this. One may deduce that Albion saw a strong enough ongoing demand for its 4-cylinder Chieftain, but also that it required modernization to bring the engine closer to contemporary practice. The question could be asked why this was not done with the CH3 in mid-1958, but perhaps more time was needed. That the engine upgrade was implemented just 16 months after the CH3 was released suggests that it was part of the original plan, as a progressive development.

At the same time or soon thereafter the same set of changes were applied to the four-cylinder Victor models, which became the VT15A (bus) and VT19A (bulk load carrier). The chassis changes were also applied to the six-cylinder Victor bus, which became the VT17A.

The next event was also an engine change, with the introduction of the Power-Plus O.400 unit. This had been announced in CM 1960 September 09 as the new powerplant for the Super Comet 14SC. The change was recorded by chassis suffix number in the double-digit 1x series in place of the previous single-digits. The O.400 was part of a new “Power-Plus” series of engines with so-called spheroidal combustion cavities, the other two being the O.600 and O.680 used in the then-new LAD-cabbed heavy-duty truck range. The O.400 was a larger displacement derivative of the O.375, and was intended to be a replacement for the latter, although the changeover was a gradual process, and evidently intended to be so. For example, the O.375 powerplant was used in the new Dodge 8 and 9-tons models announced in CM 19600923, optional for the former and standard for the latter. It would appear that the O.400 was not released for proprietary use until around 1962 September.

Leyland Super Comet 14SC 196309 p.01.jpg
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The adoption of the O.400 engine for the Albion Reiver RE25 and RE27 was announced in CM 1960 September 23, whence they became the RE25A and RE27A respectively. Another, and important change was the adoption of the Leyland non-reactive four-spring rear suspension system. This had been developed for the new Leyland heavy-duty models, Hippo and Octopus, as an alternative to the established two-spring trunnion suspension, and so was logically extended, in lighter form, to the Reiver.

Albion Reiver RE25A, RE27A 196403 p.01.jpg
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The Albion Clydesdale truck was also changed over to the O.400 engine at about this time, as the CD21A. The corresponding change for the Clydesdale bus, as the CD23A, was announced in CM 1960 December 16.

Albion Clydesdale CD21A 196409 p.01.jpg
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Not directly affecting the medium-weight models, but related to the rationalization, at some stage during 1960 the Claymore and Nimbus models gained the GB241 gearbox in place of the previous David Brown unit. In the case of the Nimbus, this happened by 1960 June, when sales brochure L716 for the NS3A model was issued. The Albion Aberdonian bus was discontinued by 1960 September, as recorded in Bus & Coach magazine for that month. This appears to have been the last application for which the GB240 gearbox, the 6-speed overdrive derivative of the GB236, was an option. The latter continued in use as the standard unit on the Tiger Cub bus.

Thus far the changes had been improved engines for some of the existing models. But an additional model, the Albion Super Reiver RE29, was announced in CM 1961 June 09. This was a heavier version of the Reiver RE25A 6x4 model, with a gvw of 17.86 tons. It had the same engine, clutch gearbox and torque divider as the RE25A, and heavier versions of its hub-reduction rear axles. A major change was the use of full air brakes, although the 8-stud wheels were retained. Another change was the use or recirculating ball steering gear, in place of the cam-and-roller type. The Super Reiver provided a Leyland-Albion six-wheeler that was intermediate between the 15.5 ton gvw Reiver and the 20 ton gvw Leyland Hippo.

Another “new” engine arrived with the Power-Plus O.370, announced in CM 1961 August 04. This was the junior partner to the O.400, and replacement for the O.350, that change being implemented progressively. Probably the first application was in the Power-Plus version of the Comet CS3, this change being recorded by chassis suffix number in the double-digit 1x series in place of the previous single-digits. I do not have a release date for the Power-Plus Comet, but I should imagine that it was very soon after the O.370 engine was announced. What may have been the initial sales brochure for this model was #809 of 1961 October. I am of the impression that the O.400 engine was optional for the Power-Plus CS3, but I have not found confirmation of this. Perhaps, as the O.370 matched the O.375 in power output, a larger engine option was not considered necessary. Also, at some stage, perhaps with the change to the Power-Plus CS3, the option of air-assisted hydraulic braking using the Airpak unit was added, but again, documentary evidence is scarce. The Airpak was a remote servo unit, the air-pressure counterpart to the Hydrovac. Although it had originated in the USA during the 1950s, it was not available from UK production until the second half of 1960. The Power-Plus Comet CS3 may have been the only Leyland-Albion application, and that because it was a minimum-change replacement for the Hydrovac. Otherwise, the preference, where the air pressure and hydraulic combination was required, seems to have been for air-actuated hydraulic systems, as on the Reiver.

Leyland Comet CS3 19610 p.01.jpg
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Later in 1961, the six-cylinder Victor bus was changed over to the O.370 engine, whereupon it became the VT17B. This change was announced in CM 1961 November 27. (The 4-cylinder Victors continued as the VT15A (bus) and VT19A (bulk load carrier).

A 4x4 version of the Power-Plus Comet CS3, using some AWD components, was announced in CM 1962 February 09. This was the first 4x4 model in the LAD-cabbed series. It effectively superseded the 4X4 version of the normal-control Comet ECO2, also using AWD components, that had been available since early 1957. The CS3 4x4, like its predecessor, used spiral bevel driving axles, and not the hub reduction type like the regular CS3. It was described in sales brochure #828 of 1962 May. Therein the Airpak brake servo option was mentioned, but not the O.400 engine.

Leyland Comet CS3 4x4 196205 p.01.jpg
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CM 1962 March 09 recorded that the Tiger Cub bus chassis had gained the horizontal version of the O.400 engine, which replaced the previously-used horizontal O.350 and O.375 units.

A significant addition to the model range was the Albion Chieftain Super Six CH13, announced in CM 1962 April 27. At last there was a six-cylinder option for the Chieftain. This had the O.370 engine in place of the 4-cylinder EN335. Gvw was increased to 11.1 tons. Larger brakes were fitted, using an air actuated hydraulic system similar to that on the Reiver. Also, recirculating ball steering was fitted, as had been introduced with the Super Reiver RE29. A reasonable inference is that Albion expected demand to move away from the 4-cylinder to the 6-cylinder engine. For the time being at least, the 4-cylinder Chieftain CH3A remained available.

Albion Chieftain Super Six CH13 196204 p.01.jpg
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In mid-1962, the Comet 12C truck superseded the Comet CS3, as announced in CM 1962 July 06. The major change was the use of full air brakes, most unusual for a 12 ton gvw vehicle, and unusual in combination with 8-stud wheels, although the latter had been presaged by the Albion Super Reiver. Discarding the vacuum-assisted hydraulic braking system was well overdue, and whilst Leyland might have opted for an air actuated hydraulic system as on the Chieftain, it made up for past sins, as it were, by going the extra distance to full air operation, as on the Super Comet. In other respects the 12C was much like the CS3, although it definitely had the O.400 engine as an option to the O.370. At this stage, the Leyland-AWD CS3 4x4 was unaffected, and in fact was continued until 1966, when it was superseded by the Leyland-Scammell 13C 4x4.

The Comet 12C passenger model, also air braked, was announced in CM 1962 October 05. It replaced the ECPO2, and was very similar to the 12C truck, except that the standard single-speed axle was of the spiral; bevel rather than the hub-reduction type. With this change, the Comet bus and truck models became closely aligned again, whereas they had been somewhat separated during the CS3 truck era.

Unless the Comet ECPO2 had been the subject of an engine change late in its life – and there is no data to support this notion – it would have been the last Leyland-Albion model to have specified the older O.350 and O.375 engines.

Also in 1962 October were added a domestic market version of the Albion Victor bus chassis, and a 6x2 version of the Albion Super Reiver. Both were announced in CM 1962 October 26.

The Victor VT21L had the O.370 engine, like the VT17B, but it had a spiral bevel rear axle using an Eaton driving head. It retained the vacuum-assisted hydraulic brakes of the VT17B. Gvw was 9 tons. Presumably this was intended to compete in the same market as the Bedford SB and Ford Thames chassis. But it arrived at the time when longer vehicles (such as the Bedford VAL) and vehicles of the trambus type generally were new interests for that market.

The Albion Super Reiver RE31 6x2 presumably responded to a market demand for single-drive six-wheelers in its weight class, for applications where the extra traction provided by tandem drive was not needed, but the incremental fuel economy provided by single-drive was desired.

Albion Super Reiver RE29, RE31 196507 p.01.jpg
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A year passed before the next set of changes, both announced in CM 1963 November 08.

The Albion Viking VK41L was a new bus chassis of the trambus type, that is with a front vertical engine and sufficient front overhang to allow for an entrance ahead of the front axle. It was an established form in some parts of the world, and had been an export type for some UK builders, notably Guy, for a few years, but was only just becoming of interest in the UK domestic market. It was essentially a derivative of the Chieftain Super Six, and had the same O.370 engine and air-actuated hydraulic brakes and hub reduction rear axle. However, a single-speed spiral bevel axle (with Eaton driving head) was available as an option. Gvw was 9 tons. The VK41L was intended for bodywork in the 30 to 32 ft range. One might say that it presaged the Bedford VAM and Ford R192, both of mid-1965, but then Dodge had gotten there a year or so earlier, with its S307, announced in CM 1962 September 07.

The VK41L was the nominal replacement for the Victor VT15A and VT17B bus chassis, although I am not sure that production of these was stopped right away. The Victor VT21L bus and VT19A load carrier were unaffected by this change.

At some stage a trambus version of the Clydesdale bus was also made available, perhaps as a special model. However, I do not have any details as to when this happened.

The Comet 13C truck replaced the 12C, the key change being an increase in gvw from 12 to 13 tons. The driveline and braking system remained the same. The Comet 13C bus was introduced at about the same, judging by specification #976 which was dated 1963 November. Gvw was 10.2 tons. The 13C bus continued to use a spiral bevel type single speed axle as its standard fitting. This was a Leyland-built unit in a three-piece casing, probably not unlike that used in the Tiger Cub and Leopard underfloor-engines bus chassis. As noted the spiral bevel single-speed unit used in the Albion Victor VT21L and optional in the Viking VK41L models used an Eaton head, so there was not standardization in this regard.

Leyland Comet 13C 196311 p.01.jpg
Leyland Comet 13C 196311 p.01.jpg [ 825.91 KiB | Viewed 29 times ]

During 1964, multispeed versions of the GB241 gearbox were introduced. These followed the pattern of the 1960 Leyland heavy-duty gearbox in having a second pair of layshaft drive gears ahead of the main set, thus providing for a two-speed layshaft drive. In turn this enabled splitting of all of the indirect gears, but not of direct drive (5th). Albion referred to the resultant gearboxes collectively as being of the crawler/splitter type, later as the dual-range type. The crawler version, GB243 then GB247, simply split the existing indirect gears, providing half-gear steps from low 1st to high 4th, but leaving a full step from there to 5th. The splitter version, GB248 had the indirect gears moved up by half a gear, so that there were half-gear steps from low 1st all the way to 5th.

These gearboxes became options on at least the Chieftain Super Six, Reiver, Super Reiver and Clydesdale truck chassis, although in some cases, such as the Chieftain Super Six, only the splitter was offered, perhaps because of rear axle torque capacity limitations.

Not part of the LAD-cabbed series, but as a flanking model, the export-only bonneted (normal control) Leyland Super Comet 14BSC was announced in CM 1964 September 11. Mechanically it was essentially the same as the Power-Plus 14SC, but equipped with what was said to be a new Leyland three-seater cab. The normal control Comet ECO2 had been discontinued earlier. The main range appeared to have gone by 1961, with the 4x4 version apparently lasting until 1962.

In CM 1964 September 18 it was mentioned that the Super Comet had been uprated to 16 tons gvw, as allowed by the incoming UK regulations. These chassis were designated in the 16SC series. Whether they were additional to or in place of the corresponding 14SC models is unknown. The 16SC was an interim model. The Ergomatic cab era arrived, as covered in CM 1964 September 18. At that time, the Leyland heavy-duty models were updated with this cab, and it was used on what was a substantially reworked range of AEC truck chassis. It was also used on a new Albion chassis, the Super Clydesdale CD65. This was a 16 tons gvw model, additional to and not a replacement for the Clydesdale CD21A. However, it did signal the arrival of the Ergo cab in the medium-weight range, after which the LAD cab would play a secondary role.

Fitting the new Ergo cab to chassis that had previously used the long-door version of the LAD cab was probably not so difficult. But those that had used the short-door form, such as the Super Comet, would have required a greater extent of rework to accommodate the longer front overhang. As the AEC model range – including engines - was the prime beneficiary of the LMC 1964 updating programme, it looks as if the rework of the Super Comet was deferred, with the Ergo version, the 16SCT, not appearing until early 1966 (CM 1966 March 11).

Something I am not sure about is when the Albion 4-cylinder models were finally discontinued. I think that it might have been after the end of 1964, though. If that was the case, then one could say that the engines used in the LAD-cabbed medium-weight range at the end of 1964 were the EN335, the O.370, the standard (crossflow) version of the O.400, and the horizontal version of the O.400, with the horizontal EN250 used in the Claymore and Nimbus. The crossflow O.400 was the original version. The reverse-flow version, with left-hand side manifolds, was developed for the Bedford VAL (right-hand drive variant only) and then used for the right-hand drive Ergo-cabbed medium-weight models. (I am not sure about the left-hand drive Ergo variants, but these probably could have used the standard version.) The GB241 gearbox (and its crawler/splitter derivatives) were used across the range with one exception, that being the Tiger Cub bus. This retained the GB236 as standard (evidently the only application for it by then) with 4-speed synchromesh and Pneumocyclic options. Possibly the GB236 was retained because it was a better match to the relatively robust and precise remote shift established on this model than would have been the GB241. As used on the Nimbus, the latter had a simple remote shift that was allegedly quite “loose”. Clutches were hydraulically operated across the range, except for the Tiger Cub, which retained mechanical operation until the end as far as I know.

The hub-reduction type rear axle was the modal type amongst the medium-weights, but there were exceptions. The Leyland Comet 13C bus and Tiger Cub bus both had the Leyland spiral bevel axle, in a three-piece Leyland casing, as standard. Both also had an electrically shifted Eaton two-speed spiral bevel driving head in a Leyland single-piece casing as an option, the same option also being available for the Comet 13C and Super Comet 14SC trucks. The Leyland-AWD Comet CS3 4x4 also had the Leyland spiral bevel rear axle, with a derivative of it used as the front driving axle. The Albion Viking bus had the option of an Eaton single-speed driving head in a single-piece casing in place of the standard hub reduction unit. The Claymore and Nimbus used a lighter spiral bevel axle.

Hydraulic brakes with vacuum assistance using a Hydrovac were used on the 4-cylinder Chieftain and on the Victor models, and on the Claymore and Nimbus, and were standard on the Comet CS3 4x4, the latter also having an air-assisted option with an Airpak. Air actuated hydraulic brakes were used on the 6-cylinder Chieftain, on the Viking and on the Reiver. Full air braking was used on the Comet 13C, both truck and bus, Super Comet, Clydesdale and Super Reiver.

Updating of some of the LAD cabbed models continued in the Ergomatic era, and there were also some new models. But that time period is outside of the scope of this study.


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