The classic bicycle rim is gradually replaced by new modifications with cast discs, which are a one-piece design with 5-4 blades produced by the mold casting method and further heat treatment to improve the mechanical properties.
Cast bicycle disks are made mainly of aluminum alloy with the addition of magnesium and carbon. The composition of the alloy can be carbon or of heat-resistant fiberglass, but at the same time the cost of disks will increase exponentially, since their price is excessively high, and demand for this product is extremely rare.
Difference of cast disks from wheels with spokes
1. The first difference is the design approach: a bike with cast disks looks unusual and presentable;
2. If you compare the weight of a bicycle wheels with cast disks with a spoke wheel, the cast alloy wheel is heavier than usual, this does not add comfort to long trips;
3. The aerodynamic characteristics of the cast bicycle disk are much higher than usual; flat cavities create less resistance and therefore in sports bikes, mainly cast wheels are installed;
4. For an extreme trip on mountain tracks, they do not fit, since they spring much less than the usual wheel.
5. The bicycle disk does not lose its durability to its similar model;
6. Maintenance does not require special skills and adaptations: wide varnish surfaces are easily wiped with a normal napkin;
7. To break a cast disc is extremely difficult, but with the condition that this is a high-quality original detail and not a fake.
8. The load maintained by the cast wheel can be much higher than normal. But if the disk does break down, it can not be repaired, unlike the classical model.
Features of fixation
The selection of bolts is one of the main tasks when installing cast discs; such models are more voluminous, and longer nuts are used to attach them.
Universal models of bolts are not suitable; they will cling to the thread and tear off or twist off when rotating. If the bolts are longer than expected, they will touch the immovable parts of the mechanism, in particular the braking system.
Manufacturers can produce an original bike wheel with a cast disk and special fixation; this set includes: a wheel, a chamber, tires, fixtures and protective caps, but their cost significantly exceeds the retail purchase of individual parts.
Also, one of the main parameters of the wheel with the cast disks is the radius; it is usually marked as ET; before you buy and install the disk, you need to check whether the radius of selected parts for the bike wheels fits. The parameter is always indicated on the wheel, package, label or other related documents.
How to calculate the required parameters of a cast bicycle disk
The width of the cast bicycle wheel is calculated in inches (1 inch – 1.54 cm); this parameter is measured by the width of the wheel itself and is converted to inches.