Mounting Tire And Tube On

Steel rear wheel rims should be barbed. If not, add barbs to inner wall of bead using a cold chisel. Locate the barbs in three groups, one group symmetrical about valve stem hole, and two additional groups located approximately 120° either way from valve stem hole as shown in Fig. 2C-19B. Each group should include 16 barbs, 8 barbs to a side, with 4 barbs facing opposite the other four. Barbs should extend approximately 1/32 in. to 1/16 in. in height from surface of rim.

Carefully remove all dust and dirt, particularly hard particles from tire which might chafe an inflated tube. Wipe tube and inside of tire thoroughly with clean, dry cloth. If rim is dirty or rusty, clean it with a stiff wire brush. Be sure to examine a used tire caremlly for fabric injuries which if neglected will damage tube.

Position rubber rim strip (for front wheel only) in rim-well with valve holes correctly registered. Swab thoroughly all around base of tube, between tube and side walls of tire with tire mounting compound. Place valve at tire balance mark, and inflate tube just enough to round it out. A tube flap (for rear wheel only) should be inserted between the tube and tire beads as shown in figure 2C-20. Install tube flap with hole over valve stem first. Tuck in remainder of flap carefully underneath tire beads all the way around both sides of tires. DO NOT ALLOW ANY FOLDS IN FLAP AND BE VERY CARE FUL TO SEE THAT POSITION OF FLAP IS NOT DISTURBED WHEN INSTALLING TIRE ON RIM AS FOLLOWS: With wheel lying flat, place tire on rim and align valve with hole in rim. Push bottom bead into rim-well near valve, and hold in well while forcing remaining portion of bead over rim flange with a tire tool. Spread tire and insert valve through hole in rim. Force upper bead over rim flange and into well at point opposite valve. Stand or kneel at this point to hold bead in well and pry remaining portion of tire over rim flange. While forcing bead over rim flange, keep as much bead as possible in rim-well. Be careful not to damage beads or pinch tube.

Inflate tire to recommended pressure and reinstall bead anchor screws in rim sides (if used). Then, completely deflate tire to smooth out any wrinkles in tube and allow tube to find its place, free from strain or stress. Again, inflate to recommended pressure and check valve for leak. See "Specifications," Section 1 A, for correct tire pressure.

Figure 2C-19B. Rear (Steel) Wheel Barbs Revised: 5-68

Figure 2C-20. Rear Wheel Tire Flap Installation


Check runout by turning wheel on axle, measuring amount of sideways displacement from a fixed point near the tire (see Fig. 2C-20A).

Figure 2C-20A. Checking Tire Lateral Runout

Tire tread runout should be no more than 3/64 in. If tire tread runout is more than 3/64", remove tire from rim and check rim bead side runout to see if rim is at fault (see "Truing Wheel").

If rim side runout is less than 1/32", tire is at fault and should be replaced. If rim side runout is more than 1/32", correct by tightening selected spoke nipples as outlined previously, reinstall old tire and recheck tire tread lateral runout.


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