МТБ групсеты: всё, что нужно знать

Итак, групсет, реже группа – это набор навесного оборудования для велосипеда, в который входят: шатуны, передние звезды, кассета, цепь, педали, каретка, тормоза, тормозные роторы, передняя и задняя втулки, переключатели и манетки. Список нарисовался довольно широкий, и он справедлив только для компании Shimano.

Подход Американской SRAM в значительной степени упрощен, в ее групсеты зачастую входят только манетки, переключатели, шатуны со звездами, цепь и кассета. Тормозные системы выпускаются посредствам суббренда, втулки под брендом SRAM, но в групсет их включать исторически не принято, педалей своих они не делают. Получается, что в этом случае групсет как бы неполный, но вполне способный обеспечить велосипед движением, пусть и в паре с компонентами сторонних производителей. При подстановке к слову групсет дополнения в виде “МТБ” или “шоссейный” суть никак не меняется, компоненты будут те же, хоть и видоизменены.

Мы же, в рамках статьи, ограничимся необходимым минимумом и рассматривать японскую комплектацию в полном формате не будем.

Cranks for MTB groupset

A quick look at all cranksets divides them into single, double, and triple. The name refers to the number of chainrings, called front chainrings. The appropriate solution is selected depending on the bike's intended use and discipline. For high-speed cross-country racing, the largest chainrings and the greatest number of them (up to three) are used to allow the rider to reach high speeds. In recent years, single-chainring cranksets have become the most popular.

You can learn more about MTB cranksets by following this link , where the topic is covered in more detail.
 

Carriages for MTB

Какие бы крутые и дорогие шатуны не были, они нуждаются в кареточном узле с подшипниками, чтобы выполнять свой функционал. Разделение здесь происходит по способу закрепления – резьбовые или PressFit. Последние славятся не самой высокой надежностью, так как частенько усилия запрессовки бывает недостаточно для надежной фиксации, из-за чего вскоре появляются скрипы, щелчки и хрусты. Появление шумов, как итог, неминуемо приведет к выходу подшипников из строя, ведь они будут работать с перекосами из-за смещения самой каретки. Хотя, сказать плохо о всех запрессовываемых каретках невозможно, есть приличные. Основные аргументы, которые производители используют для оправдания их применения – повышение жесткости кареточного узла и снижение веса. Однако для их обслуживания требуется дорогостоящий инструмент – пресс. Нет, конечно, можно запрессовывать шпилькой с гайками, но так далеко не уедешь – малейший перекос – треснувшая каретка, раздавленное место посадки в раме… оно вам надо?
Резьбовые каретки применяются производителями чаще, они намного лучше фиксируются в раме велосипеда и лишены “шумных” недостатков. Хотя и жесткости раме не придают.
В отдельной статье мы рассматривали разнообразные стандарты кареток и их особенности.

Кассеты для МТБ

В зависимости от предполагаемого стиля езды, кассеты комплектуются разными по размеру звездами. Обычно называется количество зубьев на самой малой и на самой большой кассете. Например, кассета на 11-32 зуба подойдет для кантрийного применения, где предполагаются . сравнительно высокие скорости, а кассета 11-50 подойдет для более агрессивного применения с большими апхиллами. Количество звезд может колебаться от 7 до 12 – этот параметр часто напрямую зависит от степени профессиональности велосипеда, чем меньше звезд, тем ближе к любительским моделям. Хотя в даунхиле, самой экстремальной дисциплине, 7 скоростные кассеты также встречаются. А вот 8 звезд ставятся на дешевые велосипеды, 9-скоростные почти вымерли, 10-ки стоят дороже и стали уже стандартом для среднего уровня. Встречаются кассеты с соотношением 11-51 или 52 зуба (SRAM), всё ради повышения диапазона и перехода на системы с одной звездой спереди.

Цепи для МТБ

Количество передач на велосипеде определяет параметры цепи. Самые широкие – на 7 скоростей, самые тонкие предназначены для 12 скоростей. Речь идет о реальной ширине звеньев. Дело в том, что на семерках расстояние между звездами кассеты, например, составляет 5 мм, а на 12-скоростной уже не более 3-х (значения примерные, для понимания разницы). Разумеется, для корректной работы трансмиссии требуется, чтобы цепь была тоньше этого промежутка.

They are also categorized by price. The most expensive models feature hollow pins and links with cut-out windows for lighter weight. While they do reduce weight, the downside is that these chains don't last very long. For long-term performance, it's best to choose a mid-price range chain without the lightweighting but with corrosion-resistant coatings.
Rarely, there are models with single-sided mounting. These chains feature the traditional link shape only at the bottom, while the top remains straight. The increased metal content makes the product heavier, but this design also lasts longer, as the chain resists stretching better—a major cause of wear.
 

MTB gear shifters

The design of front and rear derailleurs may vary depending on the manufacturer. While the principle is generally the same, it can be quite difficult for a beginner to spot the differences visually. Budget models are very simple in design and contain a lot of play, which is factored in during the design stage. The fit of the components often leaves much to be desired. However, this is sufficient for proper transmission operation.
Slightly above-midrange and high-end models are often made from lightweight materials, which significantly impacts the weight of the entire assembly and, ultimately, the cost. Special limited-slip clutches are also included in the design. Their function is to apply strong tension to the chain with the derailleur cage, preventing it from slipping during rough riding.
Of course, electronic shifters on mountain bikes also exist and are widely used.

For a more detailed overview, we recommend checking out our articles on all Shimano MTB groupsets . We also have an article covering all SRAM MTB groupsets.

MTB shifters

The aforementioned shifters are operated by shifters (or shift levers). Their internal design varies, but their appearance is often very similar. SRAM, among others, offers specialized GripShift shifters. They work by twisting part of the handlebar to change gears. They're not particularly popular, despite being a breakthrough in their day.
Other models feature a dual-lever design, designed for the thumb and index finger, for budget-friendly options. High-end models are controlled entirely by the thumb. This allows you to keep your index finger on the brake lever and always be ready. For the convenience of quickly finding the right gear, multiple gear changes are possible with a single pull of the lever.

How to Choose an MTB Groupset: Cost vs. Performance?

Weight

The main factor driving up the cost of a groupset is almost always weight reduction . Historically, lightest weight is a key consideration in professional sports. The race for grams is driven by the belief that a lighter bike accelerates more easily, brakes more easily, and climbs more easily.

Weight reduction isn't achieved by shaving metal off lower-end groupsets. Instead, titanium, lightweight aluminum, carbon fiber, ceramic bearings, and modified manufacturing processes are used, significantly increasing the complexity. This approach results in precise component fit, increased system precision, and low weight. The latter, as we've already established, directly impacts performance. Of course, adding top-end components to a heavy frame and wheels is practically pointless; it's crucial to build the bike entirely from lightweight components. The price of such a rocket ship will, of course, be high, but the performance will be top-notch.

In terms of weight, the top-end Shimano XTR is almost 300 grams lighter than the pre-top Shimano XT. American SRAM XX1 Eagle and X01, meanwhile, differ by just 46 grams. And that's without considering the brake systems and bottom brackets. In other words, performance always correlates with groupset weight. Reducing weight automatically increases performance, and consequently, price.

Durability

When cyclists shell out hefty sums for top-of-the-line components, they expect them to last longer than budget-priced options. In reality, this isn't quite the case.

Lightweight components are manufactured to the ultimate in strength. That is, they withstand the minimum loads necessary to reach the finish line of a race, and then "let the grass grow." Groupsets one level lower, as strange as it may seem, last much longer without failure. The reason is that the technologies used are the same, the materials are almost the same, but their quantity increases. In other words, the thickness of the metal or carbon increases, which adds weight, but also increases strength, and therefore the durability of the groupset.

Budget series don't last long due to low-quality raw materials and poor manufacturing practices. Incidentally, the situation with cassettes and chains is almost the same. Mid-price components are made of hardened steel, while expensive racing components are made of aluminum or carbon, which has little correlation with durability. This means that the highest-performance chain and the same cassette will last a very short time compared to their more modestly priced counterparts.

Performance

In addition to weight reduction, the higher the price of a groupset, the more precise, smooth, and fast the shifting becomes. Lever effort is reduced, and the stroke is shorter. Electronic components require minimal effort, as shifting is lightning fast with a button and incredible precision. It's all about performance. Yes, electronic groupsets are heavier, but this is often overlooked because the rider gains an advantage in shift speed and precision, which is crucial in competitions. Psychological comfort is also a factor in bike performance. Unfortunately, only Shimano (Di2) and SRAM (AXS) make electronic groupsets for mountain bikes.

More expensive braking systems often feature cooled multi-layer rotors and four-piston calipers. The latter is especially true for downhill racing, where high braking power is essential.

Another striking example of improved performance lies in cranksets. Without increasing weight, engineers are increasing the complexity of the design, which reduces deformation, which in turn increases the amount of energy transferred to the bicycle wheel. In other words, the energy previously spent on elastic deformation of the metal is now channeled into acceleration.

If you think these energy savings are insignificant, you're very much mistaken. Using road bikes as an example, even a 4-watt savings difference is clearly noticeable. The thing is, measurements are taken over a 40-kilometer distance, and over that distance, savings can add up to tens of seconds—an eternity in sports!

Additional features

The most common option on expensive mountain bike groupsets is a "limited-slip clutch." Shimano implements this clutch using increased friction and a stronger spring (called Shadow Plus). The Americans have taken a slightly different approach, but the principle remains the same: the chain is tightened further, resulting in a smoother, quieter drivetrain and eliminating the risk of chain drop on uneven surfaces.

Another interesting fact is that high-end groupsets don't have gear shift indicators. The idea is that professional riders can easily tell what gear they're currently in even without indicators. There's a theory that this also means less weight... and that's true, but indicators are sometimes removable (for example, Shimano SLX or XT; the XTR series doesn't have indicators by default), and they weigh only a couple of grams.