Cycle days. Not a day without a bike!
Bicycle cassette and ratchet
A cassette is a unit that is a set of rear sprockets in the transmission of a modern bicycle. Installed on the rear bushing free wheel drum with a splined fit and secured with a lockring. Provides a change in the transmission gear range.
Do not confuse a cassette with a ratchet. they are incompatible with each other, the ratchet is used only on old and / or very cheap bicycles. A cassette has a minimum chainring of 11 or 12T, a ratchet. at least 14T.
Bicycle ratchet (eng.freewheel). a part of the bicycle transmission, which is a few driven sprockets combined with a freewheel hub (ratchet).
At the moment, the ratchet is found only in cheap bicycles, in more advanced ones it has been replaced by a cassette. The main disadvantage of the ratchet is poor compatibility with eccentric wheel mounts, since the nature of the load distribution often leads to breakage of the hollow axle.
Ratchets differ in the number of stars (from 4 to 8) and the number of teeth on them. One of the most common types has 6 sprockets from 14 to 28 teeth, designated as “14-28T”. The 7-star Shimano Megarange 14-34T is also quite popular. The ratchet is screwed onto a compatible rear wheel hub and requires a dedicated ratchet puller to replace. On the inner sleeve there are pawls of the freewheel mechanism, an outer sleeve is installed on it, between them there are two loose bearings, about 35 balls each. The outer hub has asymmetrical splines, thanks to which the sprockets can only be positioned in a certain way (which is important for good gear shifting). The role of the nut holding the stars is often played by the lesser of them.
Bicycle cassette designation
Usually cassettes are marked with a range and number of stars, for example 11-36T 10-speed. Road bike cassettes can be compatible with one of the following systems: Shimano or Campagnolo. third-party models are labeled accordingly.
Classification of cassettes
Cassettes are available in 7 to 11 cassettes. Generally, modern rear hubs are compatible with 8-10 cassettes. 11-star cassettes are available only for the Campagnolo system and are only compatible with the corresponding hubs.
By bike type
- Mountain bike: star ranges from 11-28T to 11-36T, usually 8-10 stars.
- Road bike: sprocket ranges from 11 (12).22T to 11 (12).27T, usually 8-11 stars. The 12-27T cassette is considered a transition from highway to mountain.
Road cassettes (except Campagnolo) are fully compatible with mountain cassettes with the corresponding number of stars.
On a few spiders
Typical cassette designs are listed in order of increasing price and decreasing weight:
- Dismountable. individual stars are fastened with rivets or screws. The heaviest and cheapest design, prone to dirt, theoretically allows for replacement of individual worn stars.
- On a spider. 2-6 large stars (the larger, the more expensive and lighter the cassette) are fastened into a non-separable unit using an alloy spider, which reduces weight and tendency to get dirty.
- On several spiders. the stars are fastened by 2-3 pieces, which theoretically allows you to change the most worn groups without replacing the entire cassette.
- OpenGlide is a SRAM technology used only on road cassettes. The entire cassette is a monolithic structure in the form of a hollow truncated cone with teeth, closed by an aluminum “cover”. Contact with the bushing freewheel drum occurs in only two places (the top of the cone and the hole in the “cover”).
- X-Dome. SRAM technology, used on SRAM XX cassette, provides significant weight savings and increases in price. The large sprocket is made of aluminum and has slots for mounting on the drum. 7-8 middle stars are carved from a bar of chromium-molybdenum steel and represent a truncated cone fixed on the small and large stars. The small sprocket also has splines for mounting on the drum. Contact with the bushing freewheel drum also occurs in only two places.
According to the material of the stars
- Steel (chrome-plated, nickel-plated or otherwise coated) is inexpensive, durable and the most common material. Cheap cassettes naturally serve less expensive ones.
- Titanium alloy. used in top cassettes (sometimes only on large stars), very high price, low weight. There is no consensus on the durability of titanium stars versus good steel stars.
- Aluminum Alloy (Anodized). Used in Weitwinner cassettes. Very low weight, high price, low resource (may be at the level of a bad steel cassette).
How to remove a cassette from a bike
You have to remove the cassette, firstly, to adjust the bearings of the rear hub (in principle, you can not remove it, but with the cassette removed, it is more convenient to adjust the hub), or to replace the sprockets themselves. If during a trip you have to replace the rear wheel spoke on the right side, then the cassette will also need to be removed.
Naturally, in order to remove the cassette, you must first remove the rear wheel.
Well, after you disassemble it, do you need to assemble the cassette? 🙂 Therefore, a video to help you on how to assemble a cassette on a bicycle:
Differences between a ratchet and a cassette on a bicycle. What’s better?
Sooner or later, many bicycle lovers face this question. Someone asks this question in advance, even before buying their new “war” horse, and someone later, in order to understand how to maintain and care for him. Regardless of which category you belong to, soon the veil of this mystery will open for you once and for all.
Ratchet or cassette?
Let’s start with the simplest. why is this interesting attribute needed at all.
What is the difference between a ratchet and a cassette? The cassette, in turn, at first glance, is very similar to a ratchet, but has its own characteristic differences.
The difference between cassette and ratchet
The ratchet is different:
- The presence of small round openings on the outside, which serve to remove the cover, under which the bearings themselves are hidden;
- The presence of a thread for fastening to the sleeve on the inside.
The cassette is different:
- The presence of a flat nut with slots on the outside, which presses all the stars to the drum itself;
- On the inside, there are slots for the hub drum.
If you are still in doubt, then for complete confidence you can count the number of stars (how many rings there are). If there are no more than seven of them, then with almost complete certainty we can say that this is a rattle. If there are more than seven, then you have a cassette. If there are exactly seven of them, then it is best to still find the visual differences described above, since sometimes seven stars can be found on both the ratchet and the cassette.
Another way. count the number of teeth on the smallest sprocket. if there are eleven or twelve. it’s a cassette, if there are thirteen or fourteen. then it’s a rattle.
If you have only a bushing or a wheel in front of you and you need to understand what part you have, then this is easy and simple to do. A characteristic feature of the ratchet bushings. the presence of a thread onto which the ratchet itself is screwed with stars. At the cassette bushings you can see the drum on which the cassette is put on.
How to extend the life of a ratchet or cassette
During the operation of your two-wheeled friend, dirt, grass and sand get into the sprocket teeth, which can cause an early possible malfunction of this component. To avoid this, you need to take care of this part. disassemble, clean and lubricate with oil. Sometimes possible wear and tear will require a complete replacement, as in the case of erasing the teeth on the sprockets themselves.
Removing the ratchet
In order to remove the ratchet, you need a special puller. They may look different, but the essence and principle are the same. Without it, you will not be able to remove the ratchet from the bike.
Removing the cassette
You will need two tools to remove the cassette. In addition to a special cassette puller, you will also need a whip key. If this is your first time, the process will seem complicated to you. We highly recommend stocking up on paper towels and rags so you don’t have to mess around in the oil.
Which is better cassette or ratchet?
From a financial point of view, you will have to pay extra for all the advantages of the cassette. Therefore, it is worth considering how often you are going to ride? If once a year, is there any point in overpaying.
In addition, it is also worth considering the style and manner of riding, as well as the type of coverage. If you ride aggressively, you like jumping, and rough terrain is your favorite trail. then of course it is worth giving preference to the cassette. If you like measured walks on smooth and asphalt surfaces. ratchet, not a bad combination.
What is a ratchet and what is a cassette?
Topic: In this article, we will briefly discuss the difference between a ratchet and a cassette. We will also tell you what is better and when is better.
Who the article is for: The article is intended for those who want to assemble a high-quality bike just for their parameters, no more and no less.
Conclusion: Both threaded chainrings and cassettes are suitable for cycling. It all depends on the size of your wallet. But it is important to know the features of each type of structure in order to avoid unpleasant situations.
In this article, you will learn:
Ratchets are too easy, but you need to know how to unscrew and tighten them correctly.
Cassettes are even simpler than ratchets. But you need to know how to choose them correctly.
A ratchet is a ratchet and sprocket mechanism that transfers torque from the chainrings to the rear wheel. Ratchets are both threaded and slotted. Very often the word “ratchet” means a threaded ratchet. Such a “thing” was installed on top bicycles of the mid-20th century and on the simplest bicycles of our times.
Why Threaded Ratchet? It turns out that in the threaded ratchet the ratchet is mounted outside the sleeve. Such a system is unreliable and outdated. At the same time, ratchets are the simplest and cheapest. The cost of a ratchet that can roll over 3 thousand km. no problem. about 10 dollars, which is very nice for the
In practice, it is worth noting that the stars then wear out faster than the ratchet mechanism itself, and the disadvantage of such a mechanism is the impossibility of replacing individual stars. Although, it is very convenient and cheap, when you constantly ride a 5-6 star, it has worn out and instead of replacing the cassette, you only change one or two stars. The disadvantages of ratchets include a small number of stars. Ratchets have 5 to 7 stars as standard. Some unique threaded ratchets have 8 stars.
Their cost is high, and is justified only in one case. This case is something like this: you have an expensive wheelset with a threaded sleeve, and to increase the number of sprockets you simply have to buy such a ratchet.
And we have not yet indicated all the disadvantages of ratchets. We would like to warn you that most of the disadvantages will only be noticeable to experienced cyclists, so you should read carefully.
As the pedals are rotated, the ratchet spins onto the thread of the sleeve each time. stronger and stronger. Sometimes, then unscrewing the ratchet is almost impossible! There are two ways to unscrew the ratchet.
The first is a wrench slotted bushing. This bushing is inserted into the splines inside the ratchet, and unscrewed with a wrench. In practice, there are several broken spokes, and sometimes the splines are torn off. We know a unique method for unscrewing the ratchet with such a puller. Soon, we will post a video where the principle of removal will be shown, but for now we will describe in words. We need the puller itself and a vise securely attached to the table. The splined part of the puller is inserted into the ratchet, and the hexagonal part of the puller is clamped in a vice. As a result, the wheel takes a horizontal position, it looks like a steering wheel. Next, we take the tire with both hands on the edge of the wheel and unscrew the wheel. It is because of the large lever and two-handed grip that the knitting needles remain safe and sound.
The second method is with a handle-shaped puller and pieces of chain. Please look at the photo. Of course, the price of such a puller leaves much to be desired.
But when installing the ratchet, the main thing is to get on the thread. After all, the thread pitch is small, and the probability of damage to the thread is high. The most important thing is that you will only notice it when you screw it to the end and you will see the skew of the ratchet. Be careful, and smoothly wind the stars.
We see no point in disassembling the internal ratchet mechanism. It’s not worth it, and then collecting is problematic. We advise you to sprinkle a little WD-40 grease into the ratchet, and then pour silicone grease, this will be quite enough.
Cassettes not for a tape recorder
The cassette has the same ratchet and stars, the difference is that the mechanism is moved to the hub. Cassettes are designed for spline-mounted bushings, are a negative factor, since when switching to a larger number of stars, the bushing must also be changed, from threaded to spline. But cassettes, or drums (as they are also called) have a huge number of advantages and, in our opinion, there is only one drawback. the price.
Cassettes have the following advantages:
By the way, we see no point in describing the problematic removal of cassettes, since these are isolated cases. But we will be happy to answer in a comment to someone who is really interested in this question.
The clamping nut ensures reliable fastening of the cassette to the splines of the bushing. In quality bicycles, this nut is lubricated with a special thread sealant to prevent self-loosening. That is why we recommend heating the nut with an industrial hair dryer before unscrewing it. Also, when removing, it will be necessary to fix the stars so that they do not scroll. This is possible thanks to a special whip.
Here we come to the end of the article. Today the velo-travel team decided not to overload you with a large amount of information. After all, everything is simple. What to choose for your bike? It’s up to you to decide. If you are not an avid cyclist and use a bike without too much stress. the threaded ratchet is enough for you! It is reasonable to purchase cassette cassettes only for constant participation in competitions, or for serious hikes.
Thank you all for your attention, and may your bike horse never let you down!