420 Chain vs 35 Chain: Which Is Better for Top Speed?

420 chain vs. 35 chain: how to choose if you want to squeeze the limit tail speed?
The conclusion is left here first: if your engine is less than 15 horsepower, as long as the goal is to pursue the extreme speed, then the 35-size chain is the absolute winner no matter from the theoretical calculation or the actual measurement on the track. Hard-fitting an original or lightly modified machine with a thick and heavy 420 chain will only create huge additional drive resistance (parasitic resistance), which will ruthlessly eat up your high speed and abruptly lower your speed by 2 to 4 mph (miles per hour).
Many novices who have just entered the pit are especially easy to step on a mine. They always feel that the thicker the parts, the better. They have to force a heavy chain for a small displacement machine-this is definitely the fastest “shortcut” to destroy the fastest speed “. What really determines the speed ceiling of your car is actually the pitch of the chain, the dead weight per unit length, and the physical diameter of the toothed disc. This is where we need to knock.
RPM Chain Selection Pyramid Rule
Playing modification depends on hard data to speak, not on one’s head. How exactly does chain size affect the ultimate tail speed? Directly apply the following “RPM Chain Selection Pyramid Rule” to see through the essence.

R-Ratio Resolution: 35 The pitch of the chain is 3/8 inch. This means that with the same physical diameter of the toothed disc, you can cram more teeth. This not only allows you to make extremely delicate fine adjustments to the gear ratio, but more importantly, you can control the size of the gear plate within a reasonable range, and completely avoid the chassis ground clearance caused by the large gear plate is too low, and the bottom is scratched on the track. The embarrassment of sparks.

P-parasitic drag (Parasitic Drag): The heavier the chain, the more crankshaft kinetic energy is consumed to turn. The 420 chain eats up the horsepower that should have been transmitted to the rear wheels, causing the explosive power of the high-speed section to dry up.
M-ultimate tensile strength (Max Tensile Limit): the chain is broken, the speed is zero. The bearing limit of the 35 chain is about 15 horsepower. Beyond this critical point, the torque of the large machine will directly tear the rollers apart.

35 chain: speed password brought by low quality
35 The chain drains the last tail speed by very low parasitic resistance. It weighs only about 0.24 pounds per foot and runs with minimal inertia. On the kart and mini-motorcycle tracks, the lightweight rotating mass is directly equivalent to a higher tail speed.

Spacing dimension and tooth ratio calibration
Small spacing is the core of achieving radical extreme gear ratio. The 3/8 inch pitch of the 35 chain means that a 60-tooth backtoothed disc is only about 7.16 inches in diameter.

If you use a 1/2 inch pitch 420 chain to make the same 60 teeth, the diameter of the toothed disc will directly skyrocket to 9.5 inches. This pan-size toothed disc is bound to scrape against the tarmac when it is bent. The 35 chain allows you to use the large toothed disc for precise gear ratio calibration without scruple, while maintaining critical ground clearance.

Pit-Avoidance Guide: The Critical Point of Chain Break
The high torque machine will definitely kill 35 chains. The track technicians all know very well that once the modified Predator 212 or large displacement 420cc machine is pushed to more than 15 horsepower, the torque burst at the moment of starting will directly exceed the tensile limit of the 3/16 inch wide roller. Using a 35 chain on a straight-line acceleration car will inevitably result in a broken chain and usually dry-shatter your clutch cover incidentally.

420 chain: born for the survival of large torque
The only purpose of the 420 chain is to keep the high horsepower on the ground and prevent the transmission from collapsing. It uses 1/2 inch spacing and thicker 5/16 inch rollers, which are born to resist the torque impact of large displacement refitting machines or extreme reduction ratios.

Coping with large cylinder horsepower
Breakthrough 15 horsepower engine hard requirements 420 the tensile strength of the chain. When you replace the machine with forged connecting rods, heavy valve springs and oversized carburetors, the power output will become extremely violent. The 420 chain can absorb this impact load. You sacrifice a few miles of extreme speed efficiency in exchange for the entire drive system not to disintegrate and fly out halfway.

Pit Avoidance Guide: Parasitic Drag Penalty
“Over-chaining” is the most vulnerable low-level mistake made by speed-seeking players. 420 chain weighs about 0.41 pounds per foot-almost twice the weight of a 35 chain.

Hanging the 420 chain on an original 6.5 horsepower engine is tantamount to forcing a pony to pull heavy steel belts. This thing is like stepping on the brakes all the time on your crankshaft. Since the engine simply doesn’t have enough horsepower to overcome the rotational inertia of the heavy chain, your tail speed will be abruptly eaten.

Track Measured Collision: Predator 212 Engine 35 vs 420 Data
Horsepower machine cable diagrams and track lap times will tear apart all paper theories. We did a back-to-back test of radar speed measurement on the 1/4 mile straight with the same second-stage (Stage 2)Predator 212cc engine (accurate output of 12 horsepower).

The gear ratio is locked at 3.0:1, and the tire pressure is exactly the same. The only variable is the overall replacement of the clutch, back gear and chain from #35 to #420.

Data doesn’t lie. The 420 chain set dropped 2.3 mph directly and could not climb the 7,100 RPM peak speed zone of this machine at all. The rotating mass of the 420 chain directly locks the potential of the engine. If you fight purely at extreme speed and your machine is under 15 horsepower, this is the end of the argument: 35 chain crushing wins.

FAQ
Can I install the 420 chain on the clutch of the 35?
Absolutely not. The spacing of the 420 chain is 1/2 inch and the roller width is 5/16 inch; the tooth spacing of the 35 clutch is designed for 3/8 inch. The two tooth positions cannot be completely engaged, and the clutch gear will be broken in the moment of forced hard sleeve starting.

35 chain and 420 chain which is heavier?
420 chains are much heavier. A standard 420 chain weighs about 0.41 pounds per foot, while a 35 chain weighs only about 0.24 pounds per foot.

Will heavier chains reduce vehicle speed?
Yes. The heavy chain increases the rotating mass. The engine must spend more horsepower to physically drive this heavy chain, which will directly eat up the speed of the tail section of the small displacement machine, causing the extreme speed to drop.

35 chain can withstand how many horsepower?
A high-quality #35 race chain can safely withstand between 13 and 15 horsepower. Forcibly matching an engine that exceeds this torque limit will directly break the chain when accelerating at full throttle.

Why do many original mini motorcycles use 420 chains?
Many original mini motorcycles (such as Coleman CT200U) come standard with 420 chains because they are positioned for rough cross-country use, carrying the weight of adults and climbing steep slopes, and require extremely strong low torsion bearing capacity, not for running at high speed on flat ground.

In order to increase the speed, can I change the 420 chain of the kart to 35?
Yes. You must replace the clutch (or torque converter gear) and the rear axle large tooth plate at the same time, making sure that all transmission parts are 3/8 inch #35 specifications. Due to the reduced parasitic resistance, your tail speed will increase after the change.

What does “420” in the 420 chain mean?
The first digit “4” indicates that the spacing is 4/8 inch (I. e. 1/2 inch). The latter “20” represents the width of the roller, which is about 2.0 1/8 inch (I. e. 1/4 inch, but in fact its inner width is to fit the 5/16 inch tooth plate thickness).