Roller Coaster Wheel Wear & Test Chart 

Early Wear
(Load, Road & Guide)


Wear Patterns: Load (Road) and Guide Wheels typically develop:
Heat bands - darkened bands in contact areas
Concave compression set with depths up to         .12 inches depending on loads.
Heat bands indicate that the material is under cycling load. It is normal for heat bands to occur within the first week of operation.
Compression set with a concave depression is dependent on load factors including vehicle weight, speed and track configuration. This can occur in weeks or months.
Abnormal Wear:
If heat bands occur and are followed by melting of the material, speeds are too high for the load. High loads that exceed the material's limits typically heat the interior of the material or break the bond line, forming bubbles and squeaking wheels which eventually break bond. Maclan can assist you in determining root causes of abnormal wear and recommend solutions.

 Extended Fatigue Life
(Load, Road & Guide)


Wear Patterns: Load (Road) and Guide Wheels typically develop
Discoloration of material as well as lines and heat bands. Multiple tiny lines can also forn on the non-running surfaces. The lines also darken due to common dust and dirt being pressed into the grooves over time.
When a wheel wears in this manner, with a long life, the material is suited to the application. In situations where this is the typical wear pattern, track and vehicle anomalies should be be examined for the exceptions. Old age and fatigue are the optimum wear patterns for any wheel.
Abnormal wear:
If a wheel develops "old age" symptoms early, material and process should be checked. Some materials begin to get "sticky" indicating reversion of the material back to the liquid state, and if the wheels are not several years old when this occurs Maclan should be consulted.

Abrasion Wear
(Guide Wheels)


Wear patterns:
Abrasion can occur as shown above, as a rough surface, because the wheel is literally subjected to grinding of the material by track or contact elements. Abrasion can also appear as chunking of the material and a crystalline or shiny surface on the material in the abrasion depressions.
Abrasion is typically caused when the guide wheel is fixed on a ride bogie and the track curves up or down. The bigger the angle of the guide wheel rotating axis to the center tube track axis of the ride, the more "scrubbing" you have, just like if your tires are out of alignment. Chunking and crystalline abrasion is caused by sudden impact with loads and speeds that heat the material in addition to the "scrubbing". This effect can also occur on drive wheels that have periodic high speed contact.
Abnormal wear:
When you have old track, where the tube surface has worn into the scale or if you are sandblasting and painting to create rough track surfaces, severe abrasion as seen above can occur. Track replacement is often not an option. Maclan can help you evaluate and mitigate abrasion challenges. 

Abnormal Internal Debond
(Any Wheel)


Abnormal internal debond patterns include:
Edge debonding where powder-like material leaks from the edges at the hub-urethane interface. Load debond where bubbles are formed and cause the wheel to squeak as it turns, and works the de-bond around the wheel. Spot debonding, hard to distinguish from load except by ride analysis.
Edge debonding is typically related to specific materials that must be processed correctly to bond correctly. On rare occasion, edge debond can also be caused by hub design features. Load debond is caused by high loading and the "breaking" of the bond integrity from the heat generated by loads. Typically a urethane wheel that carries 12,000 lbs. should be over 30" in diameter or very wide! Spot debonding is typically bond process related.
Abnormal DeBond Solutions:
Debond of any type is not normal wear. Maclan can work with you to eliminate debond problems. 

Normal Fatigue Life
(Load &Road)


Wear Patterns typically developed by load (road) wheels:
Fatigue lines that in early wear, locally relieve the material and in late life extend to the edges of the wheel material. These lines can also occur around the running surface in early life and begin to connect in late life of the wheel. It is always advisable to change wheels when these lines extend to the edges of the wheel or when they begin to connect around the running surface.
Fatigue causes the material to develop these lines, and if the vehicle has side-to-side movement (runout) on the track, the lines will typically curve outward. If the vehicle is relatively centered, these lines will not curve out toward the edges. Fatigue wear is the most desireable wear pattern, indicating that the material is well suited for the loads and speeds.
Abnormal Wear:
Fatigue wear should be a long-term event. If fatigue wear occurs early, it typically indicates that the material is marginal for the speeds, loads and cycles. Maclan can assist you in the selection of the optimal materials for specific rides. 

Normal Fatigue Life
(Guide Wheels)


Wear Patterns: Guide Wheels typically develop:
Lines that form around the running surface, but that are very shallow depending on the loads of the guide wheel. These lines can meet and join, and depth is the determining factor in wheel change-out. If lines connect and are deepening into the material, a change is in order. Guide wheels should significantly outlast load wheels on most rides.
Guide wheels touch the track in an alternating pattern based on curves. Rides with large track, large radius curves and low loads and speeds have extended guide wheel life. Sudden impact of a guide wheel at full speed or very sharp turns at high speeds (typical of most coasters) causes most normal guide wheel wear.
Abnormal wear:
Guide wheels that wear fast can indicate ride or track anomalies. It is typical for the front left or front right guide wheels to wear faster than wheels in other train locations. On some train-type coasters, this may be true of the second, middle or last vehicle front positions, depending on the loads. Maclan can help you track guide wheel position wear and causes if you have a high usage.

 Abnormal Wear
(Upstop Wheels)


Abnormal Wear Patterns: Upstop wheels typically develop:
Similar wear patterns to load (road wheels, especially on looping rides where they may act as load wheels. Upstops also have the challenges of guide wheels, with periodic high speed, high load impacts. On some rides, upstops are a backup feature and never make contact at all, with aging the only wear. Upstops can also develop impact marks and flats.
See load and guide wheel causes for contact and large upstop wheels. If you have a sudden impact of an upstop with high loads, like a vertical bump in a coaster, the rolling resistance and hub design may cause the upstop to hesitate, leading to a skid that eventually results in the flat spot pictured above. If your upstops are impacted to the hub with small marks, check the chain pawl guide; sometimes the vehicle is "lifted" by the chain pawl and upstops are impacted.
Abnormal Wear Solutions:
Upstops are limited by ride design; however, the larger the upstop (as in any wheel design) the better. Maclan can help you evaluate upstop challenges and suggest possible solutions.