What is the thread on the bicycle axle


Can be 5/16 “, which is very close to M8 (7.9375 mm vs.8 mm). Threads can be UNF 24 (24 threads per inch) or British Cycle Std. At 26 threads per inch. There are even some that are metric in terms of diameter, but use BSC for thread spacing! If it’s 5/16 “at 26 threads per inch, then an M8-1.00 nut might work, since 25.4 dpi is very close to 26 dpi and the 7.9mm diameter is very close to 8mm.


I am trying to mount a front wheel to a bike. the axle of the wheel is tucked in, but I am having trouble figuring out the thread size and which nut might go for that. The thread size on the axle is the same as the 8mm screw, but the standard M8 nut (13mm hex head) is not suitable for it. Bicycles have a special kind of nut.?

If I look at the threads and at the standard M8 screw, the thread on the axle of the bike will be a little tighter than on the screw, but I don’t know about the existence of two types of M8 nuts, so far every M8 nut I saw fits every M8 screw.

Tech Tuesday #36: Pop Quiz. Wheel Wobble


Since the accepted answer only consists of a broken link (which is why the links-only answers are so terrible) and this question is highly rated by Google, here is a late answer.

3/8 “x 24 dpi Some solid axle bikes including 3/8” x 26 dpi coaster brakes Solid rear axle 10mm x 1mm Fastest unlocking rear axles Rear axle 10mm x 26 dpi Fast release, Campganolo / p>

Note that the difference between 24 and 26 dpi is small and can be negligible, which means that if you use a wrench to tighten the nut, you could shatter the nut without even realizing that something is wrong. The symptom is often that the nut strips before it ever becomes difficult. To avoid this, slide the nut on by hand until it is directly over the axle. If it still spins freely, this is the correct thread pitch.

Less commonly, you’ll find 12mm or 14mm axles, often on bicycles with loads, but also on Asian or African bikes and some mountain bikes. But this is pretty obvious. Some older front axles were 9mm or even 8mm and they bent easily. Sometimes it is possible to replace a 9 mm axle with a 10 mm axle, depending on the bearing cups available.

Wheel mounting (axle standards)

Posted on 07/31/2014 by VeloTurist in MODERN BIKE // 0 Комментарии и мнения владельцев

Hubs perform another important task, helping to attach wheels to the dropouts of the forks and rear frame stays. The basis for this is the power element of the bushing. the axle. The axles of the bushings are steel, aluminum and, occasionally, titanium. There are many axle standards: 17, 15, 12, 10.9 mm. For extreme disciplines, front hubs with 20mm axles have long become the standard.

lever, 2. dropout, 3. eccentric body, 4. thread, 5. thrust, 6. dropout with female thread, 7. suspension fork

The hub axle is inserted into the dropout cutout, and on cheap or children’s bicycles it is clamped with nuts. over, such axes are usually solid. Most bicycles now have hollow axle hubs and Quick Release eccentrics. The eccentric rod is inserted into the hub axle, and a special nut is screwed on the reverse side of the rod. Then, by turning the lever, the hub with the wheel is firmly pressed against the dropouts.

In the development of bikes for extreme disciplines, it turned out that conventional hubs lacked strength and rigidity. And bushings with steel axles with a diameter of 20 mm (QR20) appeared. At the same time, it was required to tightly clamp the eccentric tightening nut using keys. They were strong enough. But the weight and the need to carry a tool for installing and removing the wheel were not pleasing either. And in 2005 the lineup is vi

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The Rock Shox lock has been designed for use with Sram’s new MAXLE eccentric. The idea behind the novelty is that there is no lag nut at the opposite end of the eccentric. The thread that holds the axle is cut inside one of the fork dropouts, and the eccentric also has a corresponding thread.

special nut, 5. thread, 6.8. dropouts,

axis, 9. lever, 10. numbering, 11. label

First, the eccentric axis is threaded into one of the dropouts, and then screwed into the dropout with an internal thread, and when the lever is turned to the closed position, the tube-body, cut into four petals, opens and locks tightly inside the dropouts.

A hub with such an extreme 20mm axle (Thru Axle) can

The eccentric axle is inserted into the holes in the dropouts. On the thread with DISC brakes. Ex. axles are screwed on a nut, which is fixed with a locking CЄNTrik of a similar system with a strap and a screw using a 2.5 mm hex key.

Then the eccentric lever closes and clamps the bushing. For razraootan and FOR rear KO. correct installation of the eccentric on the dropout there is a mark,

thread, bicycle, axle

How To Use A Thread Die To Fix A BMX Axle

The woods. IN 2008, NEW YEAR APPEARED, and on the nut there is a numbering, lightened by almost 40% and

a cross-country and marathon version of the Maxle Lite. The weight is reduced due to the thinner wall of the aluminum tube-body, lightening the entire structure of the eccentric with the replacement of some parts with an aluminum alloy. The first RockShox XC fork in the Reba line with Maxle Lite will be released in 2009.

Almost simultaneously with the Maxle Lite, the new E-thru front wheel mount standard was developed jointly by Shimano and Fox. With an axle diameter of 15 mm, they managed to make a lighter and very durable analogue of the known 20 mm axles. The OLD is 100mm long and is designed for All-Mountain, Cross Country and Marathon racing. For now, it is only used in groups XTR and DEORE XT, but the list is likely to be expanded soon. A new standard called 100×15, or 15QR as the Fox manual says, will be open to hub, fork and wheel manufacturers.

4-boot, 5-slotted ratchet drum assembly, 6. locknut,

washer, 8. left bearing of the sleeve, 9. brake disc flange for b bolts,

5b. washer, 5c, 5I. ratchet bearings,

5d. splined drum, 5e. ratchet boot,

5f. spring ring holding the pawls, 5h. two pawls,

There is another rear wheel mounting standard, introduced by Shimano’s SAINT group for a long time. The rear bushing has an insert axle with a hex wrench (left), and on the right it is pulled together by a fixing (clamping) nut, which is integrated into the rear derailleur in place of the mounting bolt. That is, the switch hangs on the axle of the rear hub, although it is usually installed lower. on the cock. The taller derailleur suspension offers many benefits in terms of reliability, durability and less chance of damage while racing. Hubs are available in two sizes: the classic (OLD) 135mm and the fast-growing 150mm with 12mm axle.

Three types of energy sources are used to power the electric circuits of a bicycle: pivot dynamos, batteries, and hub dynamos. The main trouble with swivel dynamos is poor, unreliable contact between the rotor and the bicycle tire. Batteries are quite expensive and use up quickly. In recent years, the expansion of dynamo bushings has been noticeable. They are now standard on many bicycles. The rebirth, or rather the revival of the hub dynamo, was helped by two things. The first is the need, as the poet said, to shine always, to shine everywhere, for example, during 24-hour races or on a long autonomous hike, when the weight of spare batteries rises to the skies. And here there is always a reliable source of electricity under your feet, the weight of which is known and not too great. The second point is the law, which is always the law. Especially in the EU countries, where it has been legally established that any bicycle, as a means of transportation of increased danger, must have lights and dimensions. And the best option for an onboard power plant is a hub dynamo. It is also very convenient for city and road bikes, where comfort and a minimum of maintenance are paramount. He sat down and drove off! Fresh batteries, charged accumulators are just unnecessary troubles, from which a peaceful cyclist should be completely relieved. Sportsmen, amateurs and pros are not forgotten either. For them, super easy-running dynamo bushings with high-level bearings ULTEGRA / XT from SHIMANO have been developed and significantly reduced parasitic magnetic losses at idle. Unfortunately, there is no escaping the magnetic losses; by the way, this is the only disadvantage of the hub dynamo in comparison with the swivel dynamo. It is hardly possible to eliminate this minus, but it can be reduced. The sports super-lightweight dynamo hubs DH-3D71, DH-3N71 have much less parasitic losses at idle than the massive dynamo hubs for comfortable riding of the NEXUS, HB-NX22 / 32 groups. But even here improvements are outlined, according to the principle that the achievements of the upper groups gradually come to the lower groups.

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In addition to parasitic losses, the main disadvantages of dynamo bushings include the dependence of the brightness of the flashlight on the speed of the bike and the lack of light during parking. Both tasks are still in the process of being solved. The hub dynamo generates a power of 2.4-3 W at a voltage of 6 V. This is quite enough for a strong headlight, a couple of good dimensions, an on-board computer and a Cyber ​​NEXUS Di2 SHIMANO gearshift and damping control system.

And the last thing. Receiving 3 watts of electricity, we spend our own strength and energy on it. How to assess whether it is a lot? The high-end pro in an hour-long race develops a power of the order of 450-480 watts. So the additional costs will be only about 0.6%. During normal riding on paved roads, the cyclist’s continuous power is 100-200 watts. And the losses, respectively, will be from 3% to 1.5%, which is quite a bit.

Pedal compatibility

D.: Yesterday we bought a pedal from you, it didn’t fit, you have a receipt, can you change it? P.: not a problem. What’s wrong? D: it does not screw in. Compared with the old, like the thread is the same, but does not fit. P.: There is a left-hand thread on the left pedal, maybe this is the case? D: yes, everything is so, carefully looked. P.: let’s check on your pedal (takes new cranks).

Alternately, easily twists the returned pedal and the old pedal from the D.’s bike, which looks like a HVZ pedal.

P.: screwed in, but if you want to change. you are welcome. D: hmm. But let’s change those over there.

Something like this dialogue. Only, I suspect, replacing the pedal will not help this lady.

This is because there are several threading standards for bicycle pedal axles and cranks. Currently most popular standard: 9/16 “× 20tpi (14.28 × 1.27mm). Used in most modern bicycles.

Old “French” thread standard. M14 × 1.25mm (14mm × 1.25mm). It was this standard that was used in the production of bicycles in the Soviet Union.

Everything you need to know about Thru Axles

Now the most interesting thing: what happens when standards are mixed?

Indeed, 9/16 inches and 1/2 are very close, in fact, like the M14 incl. without proper experience, it is not immediately possible to tell the difference. But when you try to screw it in, everything quickly falls into place.

The 1/2 “pedal can only be screwed into the 1/2” crank arm. In connecting rods of other standards, it will dangle touching only the edges of the thread.

A modern 9/16 “pedal cannot be screwed into the cranks of an old Soviet bicycle (road and road KhVZ, Ukraine, Aist, Ural, Orlyonok, Kama.)! The difference in dimensions seems insignificant: 14.28 x 1.27 mm. 14 mm x 1.25 mm, but already is critical ensuring incompatibility. Plus the difference in thread height. (Generally speaking, with the help of an adjustable wrench, oil and some kind of mother, craftsmen manage to screw, but it is better not to do this. At the same time, the old thread is irrevocably damaged, and the new one turns out to be too thin to it could be considered reliable for no matter how long trips.)

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At the same time, a pedal from a Soviet bicycle can be put into a modern connecting rod without any special consequences. Due to its slightly smaller diameter, there should be no serious problems with twisting, although it will hold on a little worse than the “native” for a modern connecting rod. And cutting a new thread in an aluminum connecting rod is much easier than in an old steel one. Perhaps, for the last few turns, an adjustable wrench is still needed.

Some amendment to this coherent history of standards is introduced by the precision of Chinese manufacture of inexpensive components. That is why they are inexpensive, that there may be chips in the thread, the depth does not correspond to the standard, or there may be some surprise. Also, “branded” manufacturers may well allow production defects. Although the opposite effect is possible. the new Chinese pedals will suddenly fit perfectly into the Soviet connecting rods, or by replacing the old wedge carriage with a new square carriage, you can safely put your old pedals. How lucky.

Front Hub Axle Standards

The large diameter of the hub axle provides for high rigidity and strength of the wheel-to-fork connection, although this increases the weight of the entire hub. The axle wheel is installed and removed longer than usual. Individual hollow axle bushings can be compatible with conventional forks using an adapter.

Bicycle Hub Axle Standards

The hub axle length is determined by the Over. Locknut. Dimension (OLD) parameter. This parameter determines the distance between the outer nuts on the axle. It is equal to the distance between fork dropouts or chainstays of the rear triangle of the frame.

Rear Hub Axle Standards

As a rule, rear hubs are asymmetrical, as there is a cassette or rear sprocket on the right side. Because of this, the right flange of the rear hub is located closer to the middle of the hub, so the spokes on the right side are 1-2 mm shorter than the spokes on the left side.

Also read on this topic:

Bicycle wheel. The bicycle wheel takes on the loads that arise during the operation of this vehicle. The purpose of the wheel is to support the weight of the cyclist and the entire structure of the bicycle and to cope with the shock loads that arise from

Bicycle rims. On different types of bicycles, rims with different designs are installed, but the overwhelming majority are rims of the so-called box section. They are designed for tires with bead edges. In the rim itself

Bicycle wheel size. The overall size of a bicycle wheel is the rim diameter plus the thickness of the bicycle tire. The unit of measurement for the diameter of a bicycle wheel is English inches. There are now six common bicycle wheel sizes

Double-sided bushing. Double-sided hub (Flip-Flop). a hub that is designed to quickly change the type of drive and gear ratio by shifting the bicycle wheel 180 ° along its axis. It has threads on both sides and allows you to install

Bicycle cassette. For mountain bikes, cassettes are made with a set of stars from 11-28T to 11-36T for 8-10 stars. For road racers from 11 (12).22T to 11 (12).27T for 8. 11 stars. Campagnolo mountain cassettes are road compatible with equal number of stars