From wooden rims to composite construction, the motorcycle wheel has changed considerably over the years.
For the most part, "form follows function" when considering motorcycle wheels. But over the years, many different designs have been tried to reduce weight or to help sell motorcycles by enhancing their looks.
The earliest motorcycle wheels followed the designs of bicycle wheels and were typically made from wood. In the photograph is a 1902 Steffey, with wooden wheels, which is a typical example of a motorized bicycle that carried over the wheel design of the un-motorized cycle.
As engineering methods improved, steel rims were included in motorcycle designs primarily as steel was a much stronger base material and essential for the extra loads a motorized cycle imposed.
A lot of the design changes for motorcycle wheels occurred as a result of the increased performance. For example, the first commercially available motorcycle – the 1894 Hildebrand & Wolfmüller – had a top speed of just 25 mph, but by 1903 Glen Curtis had set a motorcycle land speed record of 136.27 mph!
In addition to the need for stronger wheels due to the power increases from their engines, motorcycle wheels had to cope with an equally dramatic increase in motorcycle braking efficiency. While the early motorized bicycles had no brakes, later machines deployed internal expanding drum brakes, and then later still disc or rotor type brakes—all of which greatly increased the loads wheels were subject to.
Many early engineers realized the importance of the weight a motorcycle wheel had. Besides the fact that keeping the total weight down improved the power to weight ratio of a motorcycle, making heavy wheels change direction was difficult due to the gyroscopic effects.
Early experiments in wheel materials included aluminum casting such as those seen in the photograph of a 1929 Czechoslovakian Böhmerland. However, it was many years before cast aluminum wheels would become the norm for street motorcycles in the 1980s.
The first attempt at reducing the weight of motorcycle wheels came with the introduction of aluminum rims. The primary source of aluminum rims came about in 1922 when Carlo Borrani brought the Rudge-Witworth International Patent to Ugo Bassi Street, Milan, Italy.
The Borrani rims are distinctive in having a pronounced flange around their circumference which added to the rim’s strength without adding much extra weight.
Further developments of the aluminum rim included the types as fitted to most of the Japanese racing machines of the 70s, primarily the TZ Yamahas. Although the original TZs (the 250 and 350 A and B models) had a similar rim to the Borrani, the later C models had a more evenly rounded profile where the circumferential flange had almost been eliminated.
During the 70s a number of wheels came on the market with separate spokes, hubs and rims, all held together by rivets. Honda used a wheel like this on some of their model range (CB250Ts, for example, used these wheels known as Comstar wheels), Ducati fitted some to their sports bikes too. Unfortunately, the cyclic loads (from multiple directions) associated with motorcycle wheels had a tendency to loosen the rivets. Honda's Comstar wheels in particular should be carefully examined by classic buyers to check for loose rivets and occasionally cracks forming around the joints.
One particular company that offered aftermarket wheels, of the riveted together type, that proved very successful (particularly on race machines) was Astralite. The British company produced wheels from 1977 to 1992. Production machines using the company's wheels included Heskeths. (Note: a new company has recently resumed production of the Astralite wheels under license).
Further wheel development was attempted by the Honda GP team when they fitted Freddie Spencer’s 250 machine with a set during practice for the 1984 South African GP at Kyalami. Unfortunately the rear wheel broke at speed eliminating Spencer from the GP. It was decided by many organizing bodies throughout the world to ban Carbon Fibre wheels from racing until the technology was better developed. In essence, the main problem with this material is a phenomenon known as SCF (sudden catastrophic failure); effectively carbon fibre wheels are very strong until failure, which can be sudden.
Note:
1) Due to the obvious safety concerns associated with motorcycle wheels, the buyer of a classic motorcycle should conduct research into the history of the wheel type as fitted to any motorcycle if he or she has any concerns or doubts.
2) It is possible to have aluminum and magnesium wheels checked for cracks with a system known as NDT (non-destructive testing).
1. Motorcycle Wheels
For the most part, "form follows function" when considering motorcycle wheels. But over the years, many different designs have been tried to reduce weight or to help sell motorcycles by enhancing their looks.
The earliest motorcycle wheels followed the designs of bicycle wheels and were typically made from wood. In the photograph is a 1902 Steffey, with wooden wheels, which is a typical example of a motorized bicycle that carried over the wheel design of the un-motorized cycle.
As engineering methods improved, steel rims were included in motorcycle designs primarily as steel was a much stronger base material and essential for the extra loads a motorized cycle imposed.
A lot of the design changes for motorcycle wheels occurred as a result of the increased performance. For example, the first commercially available motorcycle – the 1894 Hildebrand & Wolfmüller – had a top speed of just 25 mph, but by 1903 Glen Curtis had set a motorcycle land speed record of 136.27 mph!
In addition to the need for stronger wheels due to the power increases from their engines, motorcycle wheels had to cope with an equally dramatic increase in motorcycle braking efficiency. While the early motorized bicycles had no brakes, later machines deployed internal expanding drum brakes, and then later still disc or rotor type brakes—all of which greatly increased the loads wheels were subject to.
Many early engineers realized the importance of the weight a motorcycle wheel had. Besides the fact that keeping the total weight down improved the power to weight ratio of a motorcycle, making heavy wheels change direction was difficult due to the gyroscopic effects.
2. Early Cast Wheels
Early experiments in wheel materials included aluminum casting such as those seen in the photograph of a 1929 Czechoslovakian Böhmerland. However, it was many years before cast aluminum wheels would become the norm for street motorcycles in the 1980s.
The first attempt at reducing the weight of motorcycle wheels came with the introduction of aluminum rims. The primary source of aluminum rims came about in 1922 when Carlo Borrani brought the Rudge-Witworth International Patent to Ugo Bassi Street, Milan, Italy.
The Borrani rims are distinctive in having a pronounced flange around their circumference which added to the rim’s strength without adding much extra weight.
3. Japanese Wheels
Further developments of the aluminum rim included the types as fitted to most of the Japanese racing machines of the 70s, primarily the TZ Yamahas. Although the original TZs (the 250 and 350 A and B models) had a similar rim to the Borrani, the later C models had a more evenly rounded profile where the circumferential flange had almost been eliminated.
During the 70s a number of wheels came on the market with separate spokes, hubs and rims, all held together by rivets. Honda used a wheel like this on some of their model range (CB250Ts, for example, used these wheels known as Comstar wheels), Ducati fitted some to their sports bikes too. Unfortunately, the cyclic loads (from multiple directions) associated with motorcycle wheels had a tendency to loosen the rivets. Honda's Comstar wheels in particular should be carefully examined by classic buyers to check for loose rivets and occasionally cracks forming around the joints.
4. Aftermarket Wheels
One particular company that offered aftermarket wheels, of the riveted together type, that proved very successful (particularly on race machines) was Astralite. The British company produced wheels from 1977 to 1992. Production machines using the company's wheels included Heskeths. (Note: a new company has recently resumed production of the Astralite wheels under license).
Further wheel development was attempted by the Honda GP team when they fitted Freddie Spencer’s 250 machine with a set during practice for the 1984 South African GP at Kyalami. Unfortunately the rear wheel broke at speed eliminating Spencer from the GP. It was decided by many organizing bodies throughout the world to ban Carbon Fibre wheels from racing until the technology was better developed. In essence, the main problem with this material is a phenomenon known as SCF (sudden catastrophic failure); effectively carbon fibre wheels are very strong until failure, which can be sudden.
Note:
1) Due to the obvious safety concerns associated with motorcycle wheels, the buyer of a classic motorcycle should conduct research into the history of the wheel type as fitted to any motorcycle if he or she has any concerns or doubts.
2) It is possible to have aluminum and magnesium wheels checked for cracks with a system known as NDT (non-destructive testing).
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