Тормозные барабаны. Чугун или алюминий? На чём остановиться?

Good afternoon. Today we'll talk about brake drums. We'll compare drums made of different materials, aluminum and cast iron, discuss their advantages and disadvantages, and examine them all using VAZ "eighth" family parts as an example. Immediately recall Jeremy Clarkson's remark about the "cheesy properties" of aluminum drums, which is fundamentally incorrect, as the working surface of an aluminum drum is made of cast iron. More on this later... First, let's unpack the aluminum drums. Manufactured by PAO AvtoVAZ Lada Image, Tolyatti, Russia. https://goo.su/2QKz The package is marked "volatile corrosion inhibitor." Catalog number and marking of the cast aluminum alloy "AL35" The interior is machined similarly to the exterior. Metal burrs are minimal. The cast iron insert is machined with a completely different tool. The edge is completely free of casting and machining burrs. The drum weight is 2,390 grams. Next, NPO BelMag, Magnitogorsk, Russia. https://goo.su/2ql The package is simple: the drum comes in a branded package. Catalog number and country of manufacture. Drum parameters and the "STR" certification mark in the Russian Federation technical regulations. The working surface of the liner is almost polished. The drum weight is 2,486 grams. Let's compare the two manufacturers. The material is the same, but the casting is somehow different. This is most noticeable on the outer part of the AvtoVAZ drum. It can be assumed that this is due to either a reduced cooling rate during casting or an improper silumin modification technology. The wheel fit is smooth, but Belmag, for some reason, additionally chamfered the edges. The machining inside the rims is more or less the same. The working surface finish is different; how important this is is up to you to decide, as After a hundred kilometers, the surface will become uniform. The stiffening ribs, also known as cooling ribs, are thicker on the AvtoVAZ. The post-processing is almost identical. Cast iron solutions. Manufacturer: AvtoReal Russia LLC, Miass. https://goo.su/2qL The set includes two drums in oiled paper. Cast iron grade: SCH-25. Review of this drum set: https://goo.su/2qkz The manufacturer is currently painting the product with heat-resistant paint. Drum weight: 3616 grams. Let's look at a product from the Melitopol Plant of Automotive and Tractor Parts, Ukraine, Obilnoye village. https://goo.su/2Ql Cast iron grade: gray cast iron SCH-20 Painting the drum requires intervention. It's painted on both sides, and there are also questions about the coating inside. Drum parameters: The holes are chamfered, there are no metal burrs, and the milling is excellent. Unlike the cast iron insert in aluminum drums, the working surface is machined directly on the cast iron drum blank. By the way, it's not very successful. The manufacturer's solution is to oil the work surface. There's nothing to worry about, but don't forget to degrease the surface before installation. Let's compare cast iron drums. The casting quality is indistinguishable at first glance. The roughness is the same, but the MZATZ drum will definitely need painting. Don't forget that the paint needs to be heat-resistant. Link: https://goo.su/2qKz Both manufacturers use CNC milling. The interior of the Avtoreal drum is flawless, but the Melitopol plant needs to pay attention to the metal burrs and paint. The Avtoreal drum's work surface is cleaner due to the oil film on the Melitopol drum. Now we come to the main topic of this video: the pros and cons of drums made of different materials. Perhaps, aluminum drums are a good start. Pros: Weight. 1 kg unsprung = 40 kg sprung. Aluminum is almost twice as light. 1200 grams. Cooling. Aluminum is an excellent conductor of heat, meaning it heats up and cools down quickly, but this can also be a disadvantage, more on that later. Corrosion and aesthetics. Aluminum doesn't rust or darken. This is practical, requiring no maintenance or touch-ups. Cons: Prone to strong adhesion to the mounting point. Fragile, highly prone to breakage during disassembly. Temperature conditions: changes geometry during rapid cooling; for example, if heated strongly, it can get stuck in a puddle. In most cases, after this, replacement is the only option. The following advantages of cast iron can be noted: Strength and wear resistance; on average, they last 25-30% longer. Very low adhesion to the hub. Very low risk of deformation during rapid cooling. Weaknesses of a cast iron drum: Heavy, They create excess axle load, which can be mitigated by installing alloy wheels. They take longer to cool down, reducing braking performance, but in cold weather, this feature prevents the pads from freezing to the drum. They corrode, requiring touch-up paint on the outside, which will be unsightly. Ultimately, the decision to install them on your car is yours alone. Purposefully replacing aluminum drums with cast iron ones doesn't make sense. However, if you're replacing a part...