Chain size question

Kent

Member
Messages
127
Reaction score
5
Location
Willits, California (Northern California)
I have a chain with no size marked on it. Looking at the chain measuring chart On BMI's site. It looks to be 428.

https://www.bmikarts.com/Measure-Go-Kart-Chain-Size

My measurements show......

Roller width.....1/4" / .250" / 6.3500mm

Roller diameter......5/16" / .3125" / 7.9375mm

Pitch.....1/2" / .500" / 12.7001mm

When I look at sprockets etc. I never see "for 428 chain". I see many for 41/40 and per the chart those are very close to 428. Is it alright to use parts that indicate "for 41/40" with this chain ???
 

itsid

Moderator
Staff member
Messages
11,548
Reaction score
77
Location
Ruhrpott [Germany]
actually that's not 428 chain,
that's likely 420 chain instead
Roller dia for 428 is 8.5mm inner width is 7.95mm (5/16")
and for 420 chain it's 7.77mm Rollers and 6.35mm (1/4") inner width

420 chain is fully compatible with #41 sprockets
(identical Pitch, Roller diameter and inner width)

420 is just way stronger than #41

And no, to answer your question..
true 428 chain should NOT be used with #40 or #41 sprockets.
despite all of them being half inch pitched.

luckily that's not what you have ;)

'sid
 

Joe-405

Enjoying New Projects
Messages
2,640
Reaction score
37
Location
Oklahoma
So #40 chain will work for the 420 sprockets???

You can use #420 chain on a 41 or 40 sprocket but not the other way.

#40 is narrow
#41 is wider
#420 is wider than any of the above

I know cause I had to on my alsport and my last mini Dragbike. I hope I said that right. Lol
 

itsid

Moderator
Staff member
Messages
11,548
Reaction score
77
Location
Ruhrpott [Germany]
So #40 chain will work for the 420 sprockets???

One would like to think.. but actually not the best idea..

#40 uses 7.95mm rollers and has 7.95mm inner width

sprocket width isn't ideal, and Rollerclearance will be diminished
so ther will be premature wear (noisier chain).
(it may fit though)

Same holds true for #41 sprockets btw..
but everyone's ignoring that too..

the #40/#41 sprockets you find are hopefully taking care of that,
putting the roller clearance at max for #41 and at min for #40 chain at least.

420 sprockets however will likely don't give a shirt about ANSI chain
and thus the #40 roller might be too big
(min roller seat on a 420 should be 7.85mm 0.1mm too small for a pressfit)


Sorry Joe, the other way around, #40 is the largest(widest),
#41 and 420 are actually identical in dimension,
420 uses bigger pins and thicker plates though and thus is stronger than #41 [and even than #40 at times]


'sid
 
Top