4
27
Dualed wheels,
stud located, ball
seat mounting
(continued)
NOTICE: Do not exceed
maximum wheel load.
Customer must compare
OEM vehicle load rating
to maximum wheel
load rating.
Refer to tire manufacturer’s
recommendation for proper
tire pressure. Before
mounting the tire perform
a wheel fitment check
to insure proper clearance
from any obstructions.
Most vehicles have standard length studs (1.31" [1-5/16"] to 1.44" [1-7/16"] stud standout).
Some vehicles use studs longer than standard (up to 1.88" [1-7/8"] standout).
When changing types of brake drums be sure to check for excessive stud standout
(greater than 1.88" [1-7/8"]). Excessive stud standout may cause the inner cap nut
to bottom out on the longer stud preventing proper seating of the wheel.
Each outer dual wheel is attached by 10 single cap nuts which thread on the inner cap
nuts. Use Alcoa outer cap nuts, Part Nos. 5996R, 5996L or equivalents. Match mounted
dual wheels should be put on the vehicles with the valve stems180° apart.
DiscMate wheel spacers are recommended for use with Alcoa Dura-Bright
®
surface
treated wheels to protect the wheel contact surfaces from marring. DiscMate wheel
spacers are placed between the contact surfaces of the Dura-Bright
®
wheel and the
brake drum and between the dual aluminum wheels as shown below.
On occasion Alcoa aluminum truck wheels are operated dualed with a steel inner wheel.
In the event a steel inner wheel is used, extreme care must be exercised to properly seat
it to the hub or drum prior to mounting the outer aluminum wheel. Selection of an inner
cap nut capable of fixing the steel inner wheel and providing adequate external thread
length to secure the outer aluminum dualed wheel is critical to a safe assembly. Alcoa
recommends the use of inner cap nuts 7896R and L (Grade 8), or equivalent, for this purpose.
Alcoa Aluminum Wheels
Drum
3/4” Stud
Hub
Outer Cap Nut
P/N 5996R or L
(See 4-2, page 24)
1.31” to 1.88”
Correct mounting for dual aluminum, stud located, ball seat mount, wheels.
WARNING
Incorrect inner cap nuts used with dualed aluminum wheels
can bottom out on the unthreaded portion of the stud before the wheels
are properly seated.
Improperly seated wheels can run loose, cause stud breakage and disengage
from the vehicle which can cause serious injury or death. Loose running
wheels can lead to stud breakage.
Use only cap nut 5978R or L, 5988R or L, or their equivalent when mounting
dual aluminum wheels.
Inner Cap Nut
P/N 5978R or L
or P/N 5988R or L
(See 4-2, page 24)
WARNING
DiscMate (when used)