A comprehensive list cannot be given, as there are so many variations in size; the quality of steel also has a great influence. The following are a few customary sizes of trap and cart springs, with the weights they are supposed to be suitable for: -

Size of Spring.

Load Borne by Vehicle.

41 in. x 13. in. x 5 in.

6 cwt.

46 in. x 1 3/4 in. x 5 in.

8 cwt.

48 in. x 2 in. x 5 in.

10 cwt.

48 in. x 2 in. x 6 in.

12 cwt.

48 in. x 2 in. x 7 in.

14 cwt.

48 in. x 2 1/4 in. x 7 in.

17 cwt.

48 in. x 2 1/4 in. x 8 in.

20 cwt.

Ordinary merchant quality springs are made of steel of unguaranteed temper, hence the temper is variable. often resulting in weak, unsatisfactory springs. Buyers of springs should require a guarantee that they are made of guaranteed material with a temper, for heavy cart and waggon work, of not less than 0.40 per cent, of carbon; for light trap and carriage work not less than 0.45 per cent.