How to find out the size of a fork on a bike

Choice of budget plugs ZOOM, RST, Suntour

UPD: Learn about the construction of various types of forks. you can in this article.

When faced with the purchase of a bicycle of low and medium price categories, we come not only to the choice of the bicycle by color, but also to compare the components of each of them separately. When evaluating most hardtails, a component list is drawn up. And which components are considered important and which ones. not? We usually compare forks, frames, maybe. transmission. If everything is simple with frames. each bike has its own frame design and it is generally visible to the eye, but the forks differ quite seriously and you will not see this difference from the photo.

It is important to immediately divide such a list by price category: Zoom occupies the most budgetary niche, RST. medium, Sr Suntour. middle price segment. Hence the differences in the modifications of each of the forks follow. RockShox, FOX, Manitou forks. elite manufacturers of plugs and put on fairly professional models. Shock absorption brands like DVO, Ohlins, Elka Suspension, BOS are even more rare and expensive guests on bicycles.

The list contains 5 forks, all spring or spring elastomer forks, without any dampers.

  • The 327 model is the simplest, spring-loaded fork available on the most budget-friendly bikes;
  • At the same time, the similar 327E is already equipped with a rebound elastomer on the fork. Both forks have a 1 ”stem. Fits on the most budgetary bike models, 50 mm travel;
  • The 381 has a 1 ”stem but has more travel. 60mm;
  • Model 327 and 381 have crown-legs-stock. Reliable but tough;
  • But the 386 stock is already standard, aluminum, straight, 1, ⅛ ”, which allows you not to look for special steering. The travel of this fork is 60mm. Forks of the following modifications differ in travel, stem diameters and crown materials.

Here everything is also generally clear: the forks are spring-elastomeric, the differences are only in the weight and strength of the models (depending on the purpose).

  • Blaze is the simplest modification of a spring-elastomer fork that includes only spring stiffness adjustment.
  • The Dirt modification offers a reinforced, spring-elastomeric fork, more suited for small jumps, as indicated by the name Dirt (earthen springboard).
  • RST Gila ML Coil. cross country fork, spring, ML marking. indicates a mechanical blockage.

Although they are positioned as a more expensive segment of forks, they also have the simplest models in the lineup. SR Suntour M3010AL (spring fork designed for non-extreme riding, only rim brakes can be put on it), and the M3030 model is already a spring-elastomer fork with adjustable stiffness. this model is higher in class, respectively, and its reliability is higher.

Here we will take a look at the entire list of Suntour forks. we will see two subcategories:

  • forks for hybrids or city bikes: NEX4110, NEX HLO, NCX;
  • for mountain bike: XST, XCM, XCR.

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Model NEX4110. city ​​bike forks: for 28 ”wheels, with spring in one leg and without any damper. Small fork travel indicates urban destination.

NEX HLO. by analogy is a fork for city or touring bikes, with the possibility of hydraulic locking.

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SR Suntour NCX fork. opens a niche of quality forks for city bikes, for 700c wheels. In addition, it uses aluminum and magnesium alloy in its design, which helps to reduce weight. And the spring rate adjustment and hydraulic interlock complete the picture nicely. The letter D in the marking means a thru-axle mount for increased rigidity and clarity of control.

The XCT model represents the niche of budget forks for everyday non-extreme riding. Fork construction includes reinforced dropouts, tough pants, aluminum crown, 28mm legs. all this adds strength and reliability to the fork, in comparison with the younger models. This model in the Suntour line comes with forks suitable for moderately aggressive riding, unlike the M3010 and M3030 models.

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XCM model group. forks of the middle price range, with a steel spring in various modifications, are suitable for moderately aggressive riding, in terms of technology they are higher than the T models: 30-mm legs add rigidity and improve control over the bike.

XCR. spring-oil or air-oil forks. Models are more focused on aggressive riding. Also differ in a set of options.

For the entire line of XCs are relevant general option markings, eg:

  • HLO. hydraulic blocking;
  • LO. mechanical blocking;
  • LO-R. spring fork with lock cartridge, steering wheel control;
  • LO-R AIR air fork with handlebar lock;
  • RL. rebound cartridge.

Raidon models. quality semi-professional forks, but significantly cheaper than analogues from the RockShox / FOX segment. Air spring forks, RL-R. the fork has a rebound cartridge and steering lock. HLO-R. the same hydraulic steering lock.

The abundance of options is dizzy, but important to understand. whether you need this or that option. For example, buying a walking bike for trips to the park 1-2 times a month, the consumer will hardly need a hydraulic blocking of the course. But for the active skating amateur who sometimes goes to the races. this option will be useful for saving energy during long training sessions or racing.

12 years in mountain biking, tried all types of bicycles and their harnesses. from regular XC models to heavy downhill bikes. A true fan of his hobby. Able to select a comfortable steering wheel height within 1.5 months.

Additional tips for choosing a frame

find, size, fork, bike

An important factor in choosing a frame is also your personal riding style. If you are a fan of extreme riding in difficult terrain, then it is recommended to choose a frame that is one size smaller than your norm. This way you will feel more confident on difficult terrain and under heavy loads. And the bike in this case will be much more maneuverable, which is important. But if you prefer a calm and measured ride on a regular road, then it is quite possible to accurately navigate according to the table.

Choosing the right stem is just as important. There are really a lot of them, so we strongly recommend that you spend some time choosing so that later you do not feel discomfort while driving.

Always consider your own physique. And it’s not so much about the load on the frame as about ride comfort. If you are thin or have a standard physique, then you can easily choose a large size bike. For overweight people, it is recommended to take one size smaller. It is easier to drive, get on and off the bike.

Remember that you can adjust the saddle position and stem at any time (but not on all bikes). In many mountain bike models, the stem cannot be adjusted, but the saddle can be raised and lowered quite perceptibly. If you see that the handlebars are not adjustable, do not rush to refuse such a bike. This is made in accordance with the safety standards for bikes designed for extreme riding.

How to choose a bicycle wheel size (diameter) for height?

The table shows popular bike wheel sizes and heights for adults and kids bikes. Large bicycles in one wheel size are available in several sizes. The table shows the average value, you can choose the diameter of the wheel individually according to your height.

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When driving in the city, it is better to choose a bike with an average wheel size of 24 or 26 inches. When driving on highways, asphalt roads and rough terrain, you should choose wheels 26, 28, 29 inches. Large bicycle wheels reduce energy consumption at high speeds and transmit less vibration to the handlebars and saddle. Recommendation: For a height of about 150 cm or less, limit the choice of a bicycle with wheels of 24 “for city riding and 26” for riding on asphalt and unpaved roads. Bicycles with a wheel size of 20 inches are easy to store and transport, but less convenient to ride. With a large frame size (16 inches and above. adult models), these models with small wheels are less stable on uneven roads when driving. The position of the center of mass and the distribution of the rider’s weight depends on the size of the bicycle wheels and the frame design. During the ride, there is a constant transfer of the cyclist’s weight between the handlebars, saddle and pedals. On bicycles with contact pedals (hooks or tour clips), the leg force is applied to both pedals at the same time. To reduce fatigue and stress on the knee joint, select a smaller frame size or a specially designed frame. On a bike with a regular frame, it may be necessary to change the height, shape and stem. The height and width of the bicycle seat is selected individually.

Another calculation formula for men

Using a tape measure and all the same board or book, measure the distance from the floor to the crotch, and not to the top of the head. Multiply the resulting value by 0.57. for mountain bikes (including full suspension). For track bikes, a factor of 0.63 is used. When choosing a road model, the multiplier is 0.66. A touring bike has a multiplier for the size of the frame. 0.61, if a shock absorber seatpost is used. another 5 cm is subtracted from this value.To convert the result to inches, divide the result by 2.54.

Base table

Universal values ​​that can be used for initial estimates.


Of course, it doesn’t matter to a child what size of the frame, and on any frame it will be inconvenient for him in six months, but buying bicycles “for growth” is still not worth it if the health of the baby’s joints is expensive.

How to choose the right bike frame size?

Many people choose a bike by the size of the wheels, some by the color. The main thing, of course, is the convenience of the athlete, and this is achieved by the following key elements:

  • Bike frame size and configuration.
  • Saddle comfort.
  • Drive quality.

In fact, only the frame and handlebars seriously affect the rider’s position and can either create ideal conditions for pedaling or seriously spoil the ride pleasure. Most importantly, an incorrectly selected frame can damage the cyclist, as serious loads will fall on areas of the body that are not prepared for this, such as the wrists or knees.

But if the load on the knees or feet can be compensated for by adjusting the seat tube or pedals, then the tilt of the body over the bike is very rarely amenable to change. Therefore, in order to maintain health and get real pleasure from riding, you should know how to determine the size of the bike frame.

How to determine the size of the bike frame?

A bicycle frame is something without which the rest of the bike components would not contact, would not interact with each other. Without a frame, a bicycle would not be a single whole, it would be impossible to ride on it even to the next block, not to mention long trips and bike trips.

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How to choose the size of the bike frame for height?

The size of the frame in terms of height must be selected from the size of the wheel: the larger the wheel, the smaller the size. The popular Stealth Navigator 500 series bike is available with three wheel diameters and 3-4 frame sizes. Let’s look at the height of 175-180 cm which frame is suitable for growth (table).

Scientific approach

A more accurate and reasonable calculation will allow you to get the maximum comfort from riding the bike you choose.

It is not only the size of the frame that is important here, but also its effective length, or the ETT value.

The ETT is based on the length of the cutter line parallel to the road surface. This line starts at the center of the head tube (front end of the frame) and ends at the point where the seat tube extends. The beginning and end of this mowing line are aligned with the center of the section of both pipes. The following ranges of values ​​allow choosing the most comfortable bike according to the rule using ETT values.

The latter are for racing, sports bikes.

How do I know what forks fit my bike?

This approach is used in conjunction with the previous one. That is, together with the size, it is recommended to check the value of the effective bicycle length. Choosing a model that is too short will not allow you to keep your back straight while riding. A bike that is too long will also stretch your joints and back muscles.

For non-sporting (e.g. urban, road models), 5% is subtracted from the above ETT values.

Universal rule

The general rule of thumb is to test any bike before moving on to testing different types of fit. The same rule will help you quickly choose the size of the frame.

So, you should stand over the bike frame so that the saddle rests on your back, and relax. At this point, the distance between the top tube of the frame and the crotch should be between 5 and 15 centimeters.

Too much distance will reduce the stability of the bike on the track and most likely corresponds to a too short base, and too little will create inconvenience and a greater likelihood of injury.

Choosing a bike frame is about sizing. Size is the most important for those who ride a lot, but should not be forgotten by other cyclists, because the most valuable thing depends on the configuration and size of the frame. human health.

Size charts

Each size table below will help you determine the range of models you are interested in, but the main thing to know is that no size can be determined accurately. 18 or 24 inches is the manufacturer’s estimate of a very specific distance. for example, the length of the seat tube, or the distance from the center of the carriage to the junction of the extensions of the upper tube and the steering column. there can be many measurements!

Therefore, it is very dangerous to buy a bike via the Internet or “by eye”. any bike should be tested in practice, sit on it, feel the maximum distance from the seat to the pedals.