Chains Beating a dead horse with a loose chain

Discussion in 'Transmission / Drivetrain' started by Learner4life, May 7, 2016.

  1. Learner4life

    Learner4life New Member

    Hello all you noobs! I think im the only non-noob in here, I still cant figure out how everyone leveled up to noob already! Im still stuck at prenoob,, Ok so..

    Regarding 415 chains and how they have a "break in" period of "stretching" which I did not know until now, I still am not 100% sure exactly what I am supposed to do now.

    Loose chain confusion back story:
    Have rear hub adaptor and stock tension-er with a 66cc full stock post-hole digger (1 cylinder)
    This nab , didnt know that u needed to be rolling the wheel little by little while testing the tension! I just would check the tension where ever the chain was at that moment each day......... This led to unknowingly adding huge amounts of tension some days(chain spot would droop more than 2 inches, So I would add as much tension as I could the and other days leaving a ton of slack etc.

    upon doing this for the first time (bike maybe has 400 miles, engine over 2k, I panic'd at first when I saw how ever few inches of rolling the wheel and pushing on the chain... It was either too tight or very very loose.

    At first I thought I need a new chain and start over. Then I learned even with the new chain, depending on my set up, there is a "break in " period here the chain gets looser all around util its settled in.

    My options are 1)keep the current chain and correctly set up the tension-er each day and hope chain hangs in there for while
    2) Buy new 415, plan on the "stretching" break in period, oil each etc
    3) Same thing but with 41 series chain.

    Thank you for any clarification. I don't want to JUST know what to do.... I want to "understand" it

  2. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Bicycle chains don't stretch (except the original Shadow Conspiracy half link chain where the z shaped plates would straighten), they wear. There should be no initial wear, it is a gradual process. The kit chains are said to be awful. I can't disagree, haven't built mine up yet, Wont use the kit chain anyway.

    I have some experience with bmx bikes and chains as well as MTB/road. I can recommend that you get a bmx freestyle chain with one side profiled (wiggly, to fit closely on small sprockets) and the other side flat (for grinding, but also should work well with the toothless tensioner roller). The widest type of bmx "extreme" chain (3/16") is very heavy duty, but it is very heavy, like the kit chain. Fully bushed chains don't self-flush, so oiling on the bike is not going to lubricate the inside. Bushless bicycle chains can be oiled on the bike. Goggle "Sheldon Brown chain maintenance" for where I got that info (or misinformation if you disagree!)

    From what I have read and digested on this forum, a 3/16" "extreme bmx" type chain will fit onto the widest of Happy Time kit 10t drive sprockets. The normal 1/8" freestyle chains will possibly require some light filing of the sprocket side to get the chain fully seated into the teeth (and not pry out the side plates) and will probably be more sensitive to misalignment because it doesn't have a spare 1/16" of wiggle room. It is smaller (in outside dimensions) so if it breaks it can pack up in the sprocket cover.
    I have never broken any chain even when landing a bmx (doing a "chainring rock") directly on the chain, very hard, repeatedly.

    The HT kit sprocket is eccentric so it has a high and low oscillation every revolution. The rear sprocket is likely to move if using the kit rag joint. I think it is like the tides. Two oscillations, not synchronised, creating a super high (tight) and a super low (loose) every 220 rear wheel revolutions with a 44:10 as well as all the oscillations in between.
    I think that the SBP right side tensioner is the best method to copy for a homemade tensioner _if frame clearance allows_, because it is reversible (for bump starting) so it won't fold over or be excessively strained.
    **Just my thoughts on chains... Not claiming any practical experience with MBs.**
  3. Learner4life

    Learner4life New Member

    THanks for all the feedback. Chain update: After remounting my engine "seated" just right and jbwelding it, I put as much tension on the chain as it would take. I think I was afraid before to tighten it up as much as it really needed. Not to contradict anyone here, from researching this specific 415 chain that comes stock with the china kits, (and this was GOOD news for me big time) I guess the chain has a break in period and litterally will stretch a section at a time, I was about half way through this period when I first check the entire chain for slack etc so half of it was stretched longer and the other half was still the original length, meaning 4 to 6 inch sections of the chain? forgive my lack of terminology here. I decided not to get a new chain, because I figured I would just have to do this process over again. After tightening the chain a lot and closely watching it the next few days, the rest of the chain seemed to stretch also and even out. Lmao, this has to sound terrible, if comparing to bmx or the 41 series chains I guess. Explanation I found made sense, metals are elastic just like rubber, just much less elastic.–strain_curve

    Long story short, with engine mounted solid to frame and tightening chain to the point where you cannot move it up and down pretty much, unless rolling it forward and find a looser section, it rides fantastic, thankfully. Lets see how long this goofy chain lasts now.