DESTRUCTIVE AGENTS. Water. Water is the natural enemy of good earth roads. The chief object of maintenance should be to keep the surface smooth and properly crowned so that rain will be shed into the side ditches. These should be kept open so that the water may be carried entirely away from the road. This subject is fully considered in § 194.
"The matter of width of tires has been a subject of much remark. There has, indeed, been no end of idle talk concerning this matter, much of it directed to the point that our American wagon-builders have shown a lack of judgment in building with narrow tires, while they should provide their vehicles with broad treads such as are in use in Europe. The fact is that in this, as in many other ways in which our people have departed from ancient and old-world cus toms, they have been led by wisdom and not by folly. This will on a little consideration be made evident. Where there is no definite pavement, as in ninety-nine hundredths of the mileage of American roads, the wheels have in muddy weather to descend into the earth until they find a firm foundation on which to rest. In so doing they have to cleave sticky mud which often has a depth of a foot or more. If these wheels were broad-tired, the spokes would also have to be thick and the felloes wide, so that the aggregate holding power of the mud upon the vehicle would be perhaps twice what it is at pres ent. It is useless to talk about the advantages of a broader tread to the wheels of our wagons until we have a thoroughly good system of roads which they are intended to traverse. Any laws looking to this end would be disobeyed because of private needs so general that they would amount to a public necessity. When the roads of a district are made good only as to the main lines of communication, the side roads and the farms still demand the peculiar advantages afforded by the narrow tire." * Tables 4 and 5, pages 24 and 25, show that under some condi tions the narrower tire requires less tractive power than the wider tire, which supports the claim in the above quotation.
Although there is not much difference between the tractive power of broad and narrow tires, the latter are much more destruc tive on any road, particularly on an earth one; hut in deciding upon the proper width of tire, there are other factors besides the road that must be considered. If wagons were employed only upon the public highway, it might be wise to use wide tires and sacrifice some trac tive power for the benefit of the roads. Other things being equal, a wagon with broad tires is not so easily managed as one with nar row tires. To be equally easy to turn, the broad-tired wagon should have the narrower bed, or the longer front axle, or the smaller front wheel. In Europe it is customary to adopt the smaller front wheel, which is very destructive of the broken-stone roads so common in that country. Increasing the length of axle interferes with getting the wagon up to cribs, warehouses, etc., and increases the difficulty in going through gates, passing buildings, and the like, and hence it is not clear that laws should be passed regu lating the width of tires, many claims to the contrary notwithstand ing.
"The best argument against the enactment of laws concerning broad tires is found in the fact that the numerous and long-enforced English statutes on this matter have of late years been abrogated, a century of experience having shown that they are difficult to administer and generally disadvantageous." * The Massachusetts Highway Commission, after an elaborate discussion of the subject,t says: "It is a matter of doubtful expediency to endeavor, in the present state of our highways, by general legislation to control the width of tires or the diameter of wheels." It is probably best to leave the matter to private individuals and the enterprise of manufacturers. The matter should at least be left to local authorities to pass regulations which shall be suited to their particular conditions. Several states and cities have laws regulating the width of tires, but it does not appear that broad tires are any more common there than in localities where no such laws exist.