Alcoa Wheels that are not properly installed or maintained may not be safe or work properly. Follow Alcoa's proper wheel installation and maintenance practices as described in this article.
Firstly, check for and replace bent, broken, cracked or damaged studs. When replacing broken studs, always replace the studs on each side of the broken stud. If two or more studs are broken, replace all the studs for that wheel position. Check with the stud manufacturer for regular maintenance and stud replacement practices. All wheel fastener hardware should be Grade 8 or metric conversion 10.9. Follow the hardware manufacturer’s recommendations when replacing studs.
NOTICES
• Perform a wheel fitment check to insure proper clearance from any obstructions.
• Do not exceed maximum wheel load. Don't forget to compare OEM vehicle load rating to maximum wheel
load rating.
• Refer to the tyre manufacturer’s recommendation for proper tyre pressure before mounting the tyre.
WHEEL INSTALLATION
1. Make sure all wheel nuts are properly torqued — check them often. If the wheel is loose, the holes will pound out (deform). If some cap nuts are tight and others are loose, the wheel may develop cracks or studs may break. This condition may cause wheels to loosen and disengage from the vehicle. Dirt streaks or rust radiating from stud holes
can indicate loose nuts.
2. Be sure the end of the wheel wrench is smooth or cover the wheel mounting surface with a protective shield prior to tightening the cap nuts. The wrench end will mar the wheel around the cap nuts if it is not smooth.
3. Keep all component contact surfaces smooth and clean. Dirt or projections on mounting surfaces may lead to lose wheels. Remove all projections resulting from burrs, nicks, etc. Be sure that loose dirt does not fall onto mounting surface during assembly.
4. Do not introduce any foreign objects such as spacers or top hats into the contact surface areas of the mounting system unless approved by Alcoa. Do not paint Alcoa forged aluminium wheels.
5. Additional care should be used when mounting Alcoa Dura-Bright® surface treated wheels since minor nicks
and scratches cannot be polished out.
6. DiscMates™ are a protection gasket designed to be placed between the wheels and also between wheels
and hub or brake drum contact surfaces. DiscMates™ are recommended to be replaced when the tyre/wheel assemblies are removed and reinstalled.
NOTICES
• Perform a wheel fitment check to insure proper clearance from any obstructions.
• Do not exceed maximum wheel load. Don't forget to compare OEM vehicle load rating to maximum wheel
load rating.
• Refer to the tyre manufacturer’s recommendation for proper tyre pressure before mounting the tyre.
WHEEL INSTALLATION
1. Make sure all wheel nuts are properly torqued — check them often. If the wheel is loose, the holes will pound out (deform). If some cap nuts are tight and others are loose, the wheel may develop cracks or studs may break. This condition may cause wheels to loosen and disengage from the vehicle. Dirt streaks or rust radiating from stud holes
can indicate loose nuts.
2. Be sure the end of the wheel wrench is smooth or cover the wheel mounting surface with a protective shield prior to tightening the cap nuts. The wrench end will mar the wheel around the cap nuts if it is not smooth.
3. Keep all component contact surfaces smooth and clean. Dirt or projections on mounting surfaces may lead to lose wheels. Remove all projections resulting from burrs, nicks, etc. Be sure that loose dirt does not fall onto mounting surface during assembly.
4. Do not introduce any foreign objects such as spacers or top hats into the contact surface areas of the mounting system unless approved by Alcoa. Do not paint Alcoa forged aluminium wheels.
5. Additional care should be used when mounting Alcoa Dura-Bright® surface treated wheels since minor nicks
and scratches cannot be polished out.
6. DiscMates™ are a protection gasket designed to be placed between the wheels and also between wheels
and hub or brake drum contact surfaces. DiscMates™ are recommended to be replaced when the tyre/wheel assemblies are removed and reinstalled.
HUB CENTERING
All European type Alcoa wheels for heavy duty commercial vehicles are hub centered wheels. European type Alcoa wheels have cylindrical boltholes and are not suitable for bolt centering with conical or spherical nuts: never use any kind of this type of hardware on European type Alcoa heavy duty wheels.
Hubs designed for steel hub piloted wheels may not have enough pilot tab length to locate dualled aluminium wheels. Pay close attention to pilot tab length, particularly when converting from steel to aluminium duals. Make certain the outer wheel is engaged and centered by the hub pilot pads.
Before purchasing Alcoa wheels always consult your truck, trailer or axle OEM: the pilot tab length for sufficient centering must be 5 mm or more for single mounting and 1 x disc thickness + 5mm for dual mounting. In both cases dimensions are excluding bevelled edges. Longer spigots make mounting easier.
Always apply some ALgrease or non-water based lubricant on the spigots to reduce corrosion and make it easier to
remove wheels when replacing tyres or for service.
All European type Alcoa wheels for heavy duty commercial vehicles are hub centered wheels. European type Alcoa wheels have cylindrical boltholes and are not suitable for bolt centering with conical or spherical nuts: never use any kind of this type of hardware on European type Alcoa heavy duty wheels.
Hubs designed for steel hub piloted wheels may not have enough pilot tab length to locate dualled aluminium wheels. Pay close attention to pilot tab length, particularly when converting from steel to aluminium duals. Make certain the outer wheel is engaged and centered by the hub pilot pads.
Before purchasing Alcoa wheels always consult your truck, trailer or axle OEM: the pilot tab length for sufficient centering must be 5 mm or more for single mounting and 1 x disc thickness + 5mm for dual mounting. In both cases dimensions are excluding bevelled edges. Longer spigots make mounting easier.
Always apply some ALgrease or non-water based lubricant on the spigots to reduce corrosion and make it easier to
remove wheels when replacing tyres or for service.
DISC THICKNESS & THREAD ENGAGEMENT
WARNING:
Insufficient engagement of threading between stud and nut may cause cracking or breaking of the stud. Insufficient engagement of threading between stud and nut could cause loss of the wheel. Failure to follow proper wheel installation or maintenance practices may result in injury or death.
The mounting flange of Alcoa wheels is thicker (19.0 to 28.5 mm) than the mounting flange of steel wheels (10 to 13 mm) and therefore requires different mounting hardware.
For correct mounting of Alcoa wheels use:
• Longer (replacement) studs with standard nuts, as described in Section A hereafter, or
• Sleeved nuts (also known as Tube nuts) with standard length studs, as described in Section B hereafter
For reference purposes, download the latest Alcoa Wheel Specification Sheet (*Opens in a new window) with details about: wheel sizes, part numbers, dimensional properties such as disc thickness and applications.
WARNING:
Insufficient engagement of threading between stud and nut may cause cracking or breaking of the stud. Insufficient engagement of threading between stud and nut could cause loss of the wheel. Failure to follow proper wheel installation or maintenance practices may result in injury or death.
The mounting flange of Alcoa wheels is thicker (19.0 to 28.5 mm) than the mounting flange of steel wheels (10 to 13 mm) and therefore requires different mounting hardware.
For correct mounting of Alcoa wheels use:
• Longer (replacement) studs with standard nuts, as described in Section A hereafter, or
• Sleeved nuts (also known as Tube nuts) with standard length studs, as described in Section B hereafter
For reference purposes, download the latest Alcoa Wheel Specification Sheet (*Opens in a new window) with details about: wheel sizes, part numbers, dimensional properties such as disc thickness and applications.
NUTS & STUDS
Section A: Mounting Alcoa wheels with standard nuts & replacing wheel studs
The Alcoa wheel version for this type of mounting requires longer studs than for steel wheels. The stud standout
must be long enough to cover the disc thickness of one or both wheels, the height of the wheel nut and additional
two threads. The stud standout must be checked very carefully. The stud standout is measured from the flat mounting surface of the hub, which is in contact with the disc of the wheel, to the outer end of the stud.
Section A: Mounting Alcoa wheels with standard nuts & replacing wheel studs
The Alcoa wheel version for this type of mounting requires longer studs than for steel wheels. The stud standout
must be long enough to cover the disc thickness of one or both wheels, the height of the wheel nut and additional
two threads. The stud standout must be checked very carefully. The stud standout is measured from the flat mounting surface of the hub, which is in contact with the disc of the wheel, to the outer end of the stud.
For Single Mounting the Minimum Stud Standout required = Disc thickness (Alcoa wheel) + Height of standard nut + 3mm** @ M22, M20 or M18 x 1.5 (**2 full threads in the case of 7/8”-11 BSF or 7/8”-14 UNF)
Example: 1 x 22.5 x 9.00 Alcoa wheel with 22mm disc thickness and a regular 2-piece flange nut (M22 x 1.5) result in a stud standout of 22 + 27 + 3 = 52 mm
For Dual Mounting the Minimum Stud Standout required = 2 x Disc thickness (Alcoa wheel) + Height of standard nut + 3mm** @ M22, M20 or M18 x 1.5 (**2 full threads in the case of 7/8”-11 BSF or 7/8”-14 UNF)
Example: 2 x 22.5 x 9.00 Alcoa wheels with 22 mm disc thickness and a regular 2-piece flange nut (M22 x 1.5)
result in a stud standout of (2 x 22) + 27 + 3 = 74 mm
Example: 1 x 22.5 x 9.00 Alcoa wheel with 22mm disc thickness and a regular 2-piece flange nut (M22 x 1.5) result in a stud standout of 22 + 27 + 3 = 52 mm
For Dual Mounting the Minimum Stud Standout required = 2 x Disc thickness (Alcoa wheel) + Height of standard nut + 3mm** @ M22, M20 or M18 x 1.5 (**2 full threads in the case of 7/8”-11 BSF or 7/8”-14 UNF)
Example: 2 x 22.5 x 9.00 Alcoa wheels with 22 mm disc thickness and a regular 2-piece flange nut (M22 x 1.5)
result in a stud standout of (2 x 22) + 27 + 3 = 74 mm
Section B: Mounting Alcoa wheels with standard studs & sleeved wheel nuts
The standard wheel stud length can accommodate Alcoa wheels with more disc thickness when a special sleeved
nut is used. The shank or sleeve of these nuts extends into the mounting holes and compensates the standard
stud length securing sufficient thread engagement. Only use the Alcoa wheels with an appropriate mounting hole
diameter to allow the sleeve of the nut to easily pass through it.
The standard wheel stud length can accommodate Alcoa wheels with more disc thickness when a special sleeved
nut is used. The shank or sleeve of these nuts extends into the mounting holes and compensates the standard
stud length securing sufficient thread engagement. Only use the Alcoa wheels with an appropriate mounting hole
diameter to allow the sleeve of the nut to easily pass through it.
 | To ensure correct mounting with sleeved nuts there must be enough thread engagement. The recommended length of engagement between the threads of the stud and the sleeved nut is equivalent to 95% or more of the diameter of the stud. The minimum recommended number of thread engagement between stud & nut is: • 14 full turns for M22 x 1.5 (Metric, Volvo 2005 >) • 13 full turns for M20 x 1.5 (Metric) • 12 full turns for M18 x 1.5 (Metric) • 10 full turns for 7/8”-11 BSF (Scania) • 12 full turns for 7/8”-14 UNF (Volvo > 2004) |
How to check sufficient thread engagement
Engage a single wheel or dualled wheels to the hub with at least two nuts securing the wheels. Tighten one nut by
hand and count the number of full turns till the nut sits snugly. Do not center hub piloted type wheels with sleeved nuts.
The sleeves of the nut do NOT center the wheel(s); this mounting system still requires a hub piloting or hub centering axle. The pilot tab length for sufficient centering must be 5 mm or more for single mounting or 1 x disc thickness + 5mm for dual mounting, excluding bevelled edges (both single and dual). The torque to obtain
the correct clamping force is recommended by your truck / trailer or axle manufacturer.
Studs with unthreaded part / bottom out
Studs that have an unthreaded part or exposed shoulder can cause incorrect or no clamping of the wheel(s) at all.
Sleeved nuts may “bottom out” on the stud’s unthreaded part or exposed shoulder even before the wheels are
clamped correctly. Before mounting Alcoa wheels on hubs with such studs the space between the washer and the hubs mounting face must be determined.
Engage a single wheel or dualled wheels to the hub with at least two nuts securing the wheels. Tighten one nut by
hand and count the number of full turns till the nut sits snugly. Do not center hub piloted type wheels with sleeved nuts.
The sleeves of the nut do NOT center the wheel(s); this mounting system still requires a hub piloting or hub centering axle. The pilot tab length for sufficient centering must be 5 mm or more for single mounting or 1 x disc thickness + 5mm for dual mounting, excluding bevelled edges (both single and dual). The torque to obtain
the correct clamping force is recommended by your truck / trailer or axle manufacturer.
Studs with unthreaded part / bottom out
Studs that have an unthreaded part or exposed shoulder can cause incorrect or no clamping of the wheel(s) at all.
Sleeved nuts may “bottom out” on the stud’s unthreaded part or exposed shoulder even before the wheels are
clamped correctly. Before mounting Alcoa wheels on hubs with such studs the space between the washer and the hubs mounting face must be determined.
This article is an excerpt from Section 5 of Alcoa's Wheel Service Manual (Europe) - please click the link to download the latest version (*Opens in a new window).
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