OPINIONS FROM OTHERS.
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The Editor invites correspondence on all subjects connected .strith the use of commercial motors. Letters should be on one side of the paper only and typewritten by preference. The right of abbreviation is reserved, and no responsibility for views
expressed is accepted.
Chain Transmission versus Shaft Drive.
The Editor, THE COMMERCIAL MOTOR.
 Sir,—After reading some of the sweeping as,sertions made by your correspondent "A Chain Enthusiast," in the article d.ealing with this subject published in The Commercial Motor for April 14th, I began to wonder how several manufacturers of ihaft-driven vehicles, whose names are itching to stray on to the keyboard of my typewriter as I sit typing this letter, can find money to pay dividends, income tax, and the cost of administration of their businesses.
In answer to this heading, "Will the chain come once more into favour for vehicles designed for lighter loads," I should like to know why, within recent years, two of the most prominent chaindrive. makers have introduced shaft-driven machines for loads around two tons.
With reference to the statement re vehicles for loads over four tons being chain-driven in the majority of cases, as regards petrol-driven ones a study of the advertisements in this journal would prove otherwise, for besides four leading manufac
turers of vehicles up to six tons capacity, even when•the Carrimore attachment is fitted to take loads up
to twelve tons, the drive remains unaltered. [The Statement, of course, embraced steam-driven vehicles as well.—En., CM.] Can "A Chain Enthusiast" mention a maker who has dropped shaft-drive in favour of chain transmission, or tell us why two prominent steam-wagon manufacturers have introduced shaft-driven machines within the past two years I With the increasing demand for pneumatic-tyred vehicles of about 50-cwt. capacity, I have not yet noticed any with chain-drive, and as regards chaindrive being conducive to a lew load line, an advertiser in the same issue mentions a "low-frame-level vehicle," which I have personally examined during the past week, and can assure "A Chain Enthusiast" that, if he would view it with an open mind, it would do his eyesight a power of good. Another factor he omits when speaking of chaindrive is speed. If he will look at the back cover of the issue in which the article appeared he will see particulars of a vehicle specially built in view of new regulations proposed as regards speed for vehicles of this class, hut it is not chain-driven. In conclusion, if the chain-driven lorry is a " goanywhere " vehicle, why did it not meet the requirements of the War Office ?—Yours faithfully, Burnley. G. ii. SEaPsoN.
The Editor, THE COMMERCIAL MOTOR.
[23441 Sir,—I was particularly interested in the article by " A Chain Enthusiast," which appeared in your issue dated April 14th, ind I am prompted to write because I, for one—and I know there are many who think with Me—believe that chain transmission of the final drive will never regain other than a possible transitory popularity; in fact, I very mach doubt if it will ever again come into use to any considerable extent, except for the heaviest classes of transport and, possibly, for lighter types of vehicle where cheapness is of primary importance.
I quite agree that chain drive has certain points in its favour, and that, if thoroughly protected from dirt and water, it has a, long wearing life ; but the experiences of users in the past have Shown that it is a difficult matter to devise a satisfactory case for chains which will at once he noiseless, easy to
remove and replace, and, at the same time, be dirt and water-tight, and the unsatisfactory service ob. tamed in some instances in the past has prejudiced its chances of gaining public favour. Improvements have been made in chain ,drive, but, in my opinion, there have been greater improvements in proportion in the live axle. Eventhe double-reduction type has now, in most cases, been reduced to a reasonable weight combined with neatness and accessibility.
I think there are also considerable possibilities for that type of axle in which the second reduction. is within the driving wheels in the manner exemplified in the 7-ton Renault. This enables the whole Of the gearing to be reduced greatly in weight, and there is not the same concentration of weight at the centre of the axle casing.
The chain-drive vehicle cannot always be considered as the " go-anywhere" vehicle as stated by "A Chain Enthnsiast." In country where deep ruts exist in the road, chains and chain cases easily catch the sides of the ruts, and the clearance is usually considerably less than that afforded by the five axle, particularly if this be of a type in which the final reduction is in the wheels.—Yours faith fully, . LIVE-AXLE ENTHUSIAST. Coventry.
Reducing the Weight of Passenger Vehicles.
The Editor, TICE COMMERCIAL MOTOR.
[23451 Sir,—I am glad to see that the question has been raised in The Commercial Motor as to whether the weight of a passenger vehicle can be reduced. I think that, in most cases, the engineers have been busy more with the production of a, serviceable vehicle than with one of as light a -construction as possible—compatible, of course, with the necessary strength and durability. In the matter of engine design, I feel sure that many of the lighter engines designed for use in pleasure cars would give service equal to that of the very heavy types now considered necessary for use in commercial lorries -and passenger vehicles. A six-cylindered or a highspeed four-cylindered engine would give a more even. torque, which would result in enabling a 'lighter transmission system throughout to be employed. Engines can easily be designed so that the torque declines after a certain speed is reached. Such engines for& in themselves-a governor, and prevent the excessive speed at which many vehicles are driven when not loaded.
There is one part of the vehicle which might, with our present knowledge, be lightened, and that is the road wheels. If the case for aluminium wheels is not already proved up to the hilt, it would be well if more attention were given to this very important feature. The article referred to mentions the ma-pension as being a part of the chassis that might have its weight reduced ; it is a question, however, so long as steel alone is relied upon for springs, whether any weight can be reduced here. Weight might be saved by adopting pneumatic suspension.
I quite agree that we can hardly look for any substantial reduction in the weight of bus bodies, as it would almost seem that more attention has been given to the lightening of the bus body than of the chassis. I certainly think that .the suggested weight of 150 lb. per passenger is quite within the bounds of possibility without in any way sacrificing dura