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Discussions Question and Answer Forums Electric Scooter, Bike, and Go Kart Repair Forum

BFO5T (05T) - T8F 8mm Chain - #25 chain ??

BFO5T? 8mm? #25 chain? Are these all terms for a #25 chain or is that wrong?

Only #25 chain is #25 chain, however, there is #25 (standard -duty) and #25H (heavy-duty) #25 chain. Virtually all electric scooters, bikes, and go-karts that have a 0.25" pitch chain use 25H chain.


T8F chain is what we also refer to as 8mm chain and it is the type of chain that is used on electric scooters, bikes, and go-karts that have an 8mm pitch chain.


BF05T (05T) chain is gas engine timing chain and it is usually has 05T stamped on its outer plates. BF05T chain is sometimes mistakenly sold as 8mm pitch chain for electric scooters, bikes, and go-karts. BF05T chain has an 8mm pitch, however, its roller diameter, width between inner plates, pin length, and pin diameter is different than T8F chain. BF05T chain's slightly larger roller diameter may wear out T8F sprockets faster than T8F chain will, and its smaller pin diameter will cause BF05T chain to wear out faster than T8F chain.


Here is a dimension specifications chart for both T8F and BF05T chain which shows the size differences between these two chains.



BF05T vs T8F Chain, 05T vs T8F Chain, T8F vs #25 Chain, T8F vs 25H Chain

Ok that's great thanks for your reply. I'm finding it difficult to find a 44 tooth rear wheel sprocket for a #25 chain with a 4 bolt pattern. Can you advise where I could find one? Is using an 8mm chain sprocket out if the question to be used with a #25 chain? The reason I ask is because the only 44 tooth wheel sprocket I can find with the 4 bolt pattern is for an 8mm T8F chain.

44 tooth wheel sprockets for #25 chain that fit the Razor E300 scooter are not available. However, we have a solution to be able to install a 44 tooth sprocket for 8mm T8F chain onto the Razor E300. 


Please read our reply on this forum topic for more information: https://electricscooterparts.freshdesk.com/support/discussions/topics/1000088388

I was ideally hoping to put a 15 tooth motor sprocket on it also. I have already bought the motor sprocket which is for #25 chain, so I was wondering if I was to have a 44 tooth wheel sprocket made that I can use with the #25 chain, then what are the actual specs I would need to ask for. Ie centre hole size and 4 bolt pattern measurements etc? I genuinely have no idea what I would specifically need to ask for.
I assume that it would be out of the question to use the motor sprocket I have along with the 8mm sprocket you suggested due to the difference in chains required, ie mix 8mm wheel sprocket with #25 motor sprocket?
Also, is #25 chain 6mm?

#25 chain is an imperial size and not a metric size, so 6mm chain is not the same as #25 chain. 


#25 chain will not work with 8mm sprockets and 8mm chain will not work with #25 sprockets.


Here are the dimensions that need to be specified when ordered a custom-made chain sprocket which will be bolted onto a 4-hole freewheel.


Custom-Freewheel-Sprocket-Machining-Specifications.png
Custom-Freew...
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Thanks for that. It's a big help. What measurements do #25 chain equate to?

Here are the measurements for #25 and #25H chain.


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