Цепь 420 или цепь 40: какую же на самом деле стоит купить?

There is only one core difference between 40 chains and 420 chains: the width of the inner chain links. The inner width of the 420 chain is 1/4 inch, while the 40 chain is 5/16 inch. The pitch (1/2 inch) and the roller diameter (5/16 inch) are exactly the same, and the naked eye can’t see the difference at all. If you buy the wrong size, the transmission system will be stuck, and if you buy the wrong size, the dental tray will be scrapped directly. In the past 10 years, I have modified and repaired countless high-torque karts and cross-country motorcycles. I have seen too many novices pull off the chain directly because of mixing these two specifications. In order to write this article, I specifically tested the extreme pull of these two chains on a 212cc engine. The following is a hard core to help you avoid the pit accurately.

Exclusive 3 Step Decision Method (R.A.P. Matching Matrix)
Don’t rush to place an order, use this set of speed (RPM)-application scenario (Application)-gap tolerance (Pitch Tolerance) “3 step troubleshooting method” to 1 through your car. This is the actual combat framework that I summed up after repairing countless sets of transmission systems. Before buying, I sealed these 3 index cards.

Speed requirements directly determine what material you need alloy. The 420 chain is made of motorcycle grade alloy steel, which is born to resist high-speed operation above 5000 rpm and not to be stretched. The standard 40 chain is made of ANSI industrial grade steel, and its main field is in a low-speed and high-torque environment, such as agricultural machinery or heavy industrial doors.

The usage scenario limits your installation space. The engine box space of off-road motorcycles (Dirt bikes) and mini motorcycles is very compact, and can only be stuffed with narrow 420 chains. However, the installation space of heavy-duty agricultural karts or customized industrial equipment is extremely spacious, which can fully accommodate the thicker standard 40 chains on the lower side plate.

The gap tolerance determines that the two must not be mixed. Put 40 chains hard on the 420 tooth plate, and the extra 1/16 inch gap will cause the chain to jump crazily left and right. On the other hand? The 420 chain can’t fit into the 40-tooth plate at all, and its 1/4-inch narrow mouth can’t fit into the 5/16-inch wide gear teeth anyway.

Mechanical parameter disassembly: don’t be fooled by the same pitch
The feud between 420 and 40 chains is, in the end, the contest between the 1/16 inch internal gap. This tiny size determines whether your car will stick to the ground silky or break the chain halfway. Look directly at the core data.

The pitch of both chains is 1/2 inch (pin center to pin center). It is this parameter that gives too many people the illusion that they can be used interchangeably. In terms of length, they are hung on a 1/2 inch pitch dental tray.

Both roller diameters are 5/16 inch. The degree of tooth depth of the occlusal disc is exactly the same. The depth of the tooth groove on your tooth plate is no different for these two chains.

The inner width is the watershed where they go their separate ways. 420 chain inner width 1/4 inch, 40 chain inner width 5/16 inch. The inside of the 40 chain is wider and must be matched with thicker teeth to work properly.

40 vs. 420 Roller Chain Specifications

Технические характеристики	40 Roller Chain (ANSI Standard)	420 Roller Chain (Powersports)
Pitch	0.500″ (12.70 mm)	0.500″ (12.70 mm)
Диаметр ролика	0.312″ (7.92 mm)	0.312″ (7.92 mm)
Внутренняя ширина	0.312″ (7.95 mm)	0.250″ (6.35 mm)
Typical Tensile Strength	~3,125 – 4,300 lbs (13.9 – 19.1 kN)*	~3,700 – 4,300 lbs (16.4 – 19.1 kN)*

A guide to avoiding pits in actual combat: the deadly “horizontal volume” (Sprocket Slop)
Hanging 40 chains on 420 discs, this “fan operation” will produce severe lateral wear and tear, and you can chew your discs in a few days. Many amateur car repair forums say “40 chains vs 420 doesn’t matter” because wide chains can be put into narrow discs. I call this layman’s error “fatal”.

The extra 1/16 inch of internal space will make the chain swing wildly around when running at high speed. Whenever you jerk the throttle, the chain will whip the sides of the teeth of the tooth plate like a whip. This kind of high-frequency impact will continuously cut the metal chips on the lower tooth plate. Once the load is too large, the chain will be detached immediately.

Hard-fitting 420 chains on a 40-tooth tray simply doesn’t work on a physical level. 420 the 1/4 inch inner width of the chain, hitting the 5/16 inch thick tooth plate is like hitting the south wall. If you have to swing a hammer and hit it hard, you will only bend the side chain plate and the main chain link (magic buckle) will be scrapped on the spot.

Hardcore Test Data: Tensile Strength vs. High Speed Wear
My measured data in the store prove that the standard 420 motorcycle chain far exceeds the standard ANSI 40 industrial chain in dealing with extreme high speed and sudden impact. I installed these two chains on an exploded 12 horsepower 212cc Predator engine until they broke.

The standard 40 chain breaks directly at the moment of rapid acceleration because it does not have a high carbon alloy pin. The tensile strength of ANSI 40 chain is about 3125 pounds, and it is no problem to cope with slow and smooth tension. However, when the clutch was violently engaged in a flash of 3000, this sudden violent pulling took less than 15 hours of track driving and deformed the pin shaft of the 40 chain.

The 420 chain was unscathed in the same track violence test, with zero pin deformation. Manufacturers in the design of the 420 chain is the dynamic movement (Powersports). Its tensile strength is calibrated to close to 3800 pounds, and the pin shaft is quenched with high carbon steel to withstand the instantaneous tearing caused by violent throttle.

(Note: There are indeed heavy 40-hour chains with strength exceeding 420 on the market, but the ordinary 40-hour chains sold by hardware stores must be broken on off-road motorcycles.)

Buying Decision: Which Should You Buy?
The thickness of the existing dental tray in your car has already helped you make your choice. This is not a personal preference choice question; all you have to do now is pick up the caliper and measure the thickness of the back tooth plate, and then buy the corresponding data.

When should I buy a 420 chain?
If your tray is exactly 1/4 inch thick, close your eyes and buy 420 chains. This is the industry standard for 50cc to 125cc cross-country motorcycles, Pit Bike, Honda Grom and lightweight racing karts. If you often run on mud or sand, it is strongly recommended to go directly to the high-end 420 oil seal chain (O-ring) to keep the mud and sand out of the roller.

When should I buy 40 chains?
If your tooth thickness reaches 5/16 inch, take 40 chains directly. Whether you are welding an industrial garage door opener, a heavy-duty agricultural conveyor belt, or repairing an old large skeleton kart with thick tooth plates from the original factory. In addition, if your kart is equipped with a high-torque CVT continuously variable transmission (Torque Converter), remember to upgrade the ordinary 40 chain to a thickened 40H chain.

ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ
Can the main chain link (magic buckle) of 40 be used on 420 chain?
Absolutely not. 40 The pin shaft of the main chain link is too long for the 420 chain. The circlip can’t fit tightly on the narrow side plate at all. As long as you 1 the throttle, the main chain link will fly out directly.

Is 40 chain stronger than 420 chain?
Traditionally, standard 420 chains (about 3800 pounds of tensile strength) are stronger than standard ANSI 40 chains (about 3125 pounds) because 420 are forged from motorcycle grade alloy steel. However, if you buy a specially strengthened heavy-duty 40H chain, its pure tensile data will surpass the ordinary 420 chain.

What is the difference between the pitch of 40 chains and 420 chains?
There is no difference in pitch. The pitch of both is 1/2 inch. The only difference between 40 and 420 is all in the width of the inner rollers.

Can 40 chain be installed on the 420 tray?
In theory, it can be hung up, but never do it in practice. The wide 40 chain will cause serious lateral shaking on the narrow 420 tooth plate, resulting in double wear, abnormal noise, and extremely dangerous high-speed chain dropping.

How can I tell if my mini should use 420 or 40 chains?
Take out a digital caliper, directly measure the thickness of the back dental plate teeth. If the tooth thickness is 1/4 inch, buy 420 chain. If the tooth thickness is 5/16 inch, buy 40 chains. The vast majority of modern mini motorcycles on the market use 420 specifications.