#25 chain dilemma

[zippinaround]

so i ordered 25h chain a while back for a build i've been at for a while now , just today was lining up the drive sprocket (6 tooth) with the driven sprocket (90 tooth) first thing was the chain isnt long enough but thats not the dilemma , i joined the original chain that was fitted to the mini moto to the 25h chain thing is the 25h won't go around the driven sprocket but the original chain will?

I had checked before i ordered the 25h chain but went back and rechecked and indeed they are the same pitch 1/4" so why wont the 25h go around the 90 tooth?

is it different sideplate thickness?

 

[Frankenstein]

The sprocket could be too thick, are either one of them used? How far around does it go?

If the chain doesn't bed 100% to the sprocket the chain will get too short and will lump on the teeth, only way around that is wider chain or thinner sprocket,

 

[zippinaround]

The sprocket could be too thick, are either one of them used? How far around does it go?

If the chain doesn't bed 100% to the sprocket the chain will get too short and will lump on the teeth, only way around that is wider chain or thinner sprocket,

no both span new , it goes around 1/4 way around then starts lumping , so you reckon if i shave a bit off the sprocket should do the trick? if the pitch , roller width, roller diameter and pin diameter are all the same the only difference could be sideplate thickness right? just measured the sideplates with a verniers seems the 25h is around .2mm thicker so i need to machine .2mm off the sprocket.actually gonna measure the roller width, roller diameter and pin diameter first just make sure they are the same before i do!

 

[Frankenstein]

Yep, shave it off slowly with a grinder or belt sander or whatever you will think works best. Mills are fun too, just keep the metal cool so you don't burn the temper out.

 

[FurryOnTheInside]

Side plate thickness gives you your outside width which shouldn't matter. Roller width is your internal width..
But if it fits right down onto the teeth, but only 1/4 of the way around the sprocket, then the width is probably right but maybe the driven sprocket and original chain are worn together?
Is the pitch really the same, when you measure over several links? Chain wear on a bicycle is usually measured over ten full links otherwise the differences are hard to spot.

 

[Frankenstein]

Side plate thickness gives you your outside width which shouldn't matter. Roller width is your internal width..
But if it fits right down onto the teeth, but only 1/4 of the way around the sprocket, then the width is probably right but maybe the driven sprocket and original chain are worn together?
Is the pitch really the same, when you measure over several links? Chain wear on a bicycle is usually measured over ten full links otherwise the differences are hard to spot.

He says both are new..

 

[zippinaround]

The width of the rollers are the same but the thickness of the sideplates make the internal width different , gonna try find the original sprocket tomorrow and check the width of that , but after measuring both chains the only difference I can see is the sideplates making the internal width about .4mm difference. Was also searching around looking for standard #25 chain but it seems everyone only sells the 25h only 25 I could find was a 10 ft roll from the US for 30€ .

 

[Frankenstein]

. 4 smaller or larger?

 

[zippinaround]

. 4 smaller or larger?

Smaller

 

[Frankenstein]

There's the answer then.