Track Tac

question about chains

W

W5R

New member
I have noticed something from running at several tracks locally and am wondering what others think about it. When it comes to chains and how tight you run it, why are so many people trying to run their chain so loose, that it becomes a constant problem keeping the chain from coming off when on the track? Do people think having the chain that loose is a benefit as far as rolling resistance is concerned? I have played around with chain slack a bit and what I noticed is that with the chain excessively loose, I was giving up a little speed on the starts when the clutch hits, but with the chain tighter like I normally keep it, I always get a jump on the start, enough to where when starting outside pole I could almost always be the leader by the time we got to the entry of turn 1-2. Not sure about where everyone else races or how everyone else feels about this, but to me its really annoying when you have that one or 2 racers on the track who cause a caution every 3 laps because their chain keeps coming off, which holds up the race having to wait for them to put it back on every time. One of the tracks where we race used to not have any rules where if you cause a certain amount of cautions you are black flagged, but recently they changed the rule to where if you cause 2 cautions you are off the track. It would be nice to see every track around here do that since it does seem to make the loose chain guys tighten up their chain and not throw a caution every few laps of a 20 lap race. What's everyone else's opinion on this topic? Is there people who think its a benefit running the chain that loose?

I dont use a chain guide anymore, I just use the PMI gear guards on the sprocket hub and make sure my chain is lined up like it should be and I rarely ever have chain issues unless its just a very rough track that bends the gear guards and causes problems.
 
I would give a repy to this, having 40 years of M/C experience, but that would only bring on at least 100 posts on how I have no idea what I am doing, saying, etc.
The best I will say is, if you have a problem with it coming off, it's too loose.
If it causes binding friction, it's too tight.

Good luck sifting through 500 replies that won't answer your question, or one may be right...
 
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I'd rather have a chain too tight and stay in the race than too loose and always going to the back of the pack when the chain comes off. They are going to the rear when the chain causes them to stop, aren't they ?
Ditto that if the chain is coming off, it's tooo loose.
 
Oh man. My pet peeve. Chain tension you say? In reality that is about the least of the problems in getting a chain to stay on, live a long life and transmit the torque well. Chains are a PAIN to get right. The tension, or better stated "Slack" is just one of 3 big items that are got wrong and got wrong often.

1. Alignment- Keep the laser guided gadget in the tool box. They are cool but this can be eyeballed in almost every case to dead nuts. If you run a fully enclosed chain and rear sprocket. Not so much. Get behind and above the rear sprocket and slowly roll the axle backwards. Watch the teeth come up through the chain pitch. Center them, allow for the left-right imperfection of the gear, split the difference and call it good. You're there.

2. Concentric rear sprocket- It needs to be a near perfect circle. 2 piece gears and an axle hub that is just not right can make you speak in tongues by the time its corrected. Whoever built the thing must have been working off of prints for a triangle? With some time and effort, there are ways to make it right.

3. Overall length of the chain and the free space between driver and sprocket- There is a ratio of sweet success there. 9 tooth driver and an 88 rear gear to dominate the Fish Bowl 500? Better plan on sliding the engine to get enough links to deal with the big draft angle.

With the above worked through and cleaned up, I have yet to see a # 35 chain that did not perform incredibly well with 5/8-3/4" of slack, measured vertically at mid free span. Without those items worked out, or in the case of a complete noodle of a chassis, 1.5" is still not enough.
 
Bumpy, anytime someone throws a chain and brings out a caution, they go to the back for it....thats the reason I just don't see why people would take that chance, and thats why im asking if there is supposed to be some kind of perceived benefit to running the chain so loose like that. Its a huge pet peeve of mine also, just about as annoying as one of those people that will run you into the infield everytime you try to pass lol
 
I've worked with several chain guide gizmos over the years, but I can't say they really helped me (and some seemed to always get in the way).
I've raced 2-cycle and 4-cycle karts - with drivers as low as 8 teeth and driven gears as high as 76 teeth - and rarely had trouble if I just made sure everything was aligned and spinning freely (as astglenn suggests). I do like to set up my rear gear carrier so it can move side-to-side on the axle a little, but otherwise alignment with about 3/4" of slack (in the middle) works good for me. It is possible to rob some power if the chain is too tight, but it has to be very tight before it becomes significant.

We have track rules that send you to the back if your chain comes off, and bringing out three cautions (for any reason) puts you on the trailer. So I'm willing to tolerate a slight possible friction loss due to chain bind rather than have the chain come off.


People whose chains keep coming off annoy me too. More than once I have gone to their pit to help fix it. Usually the problem is that their motor mount is loose or crooked.
 
ChainDraggone and be done with chains coming off!! Never ran a gear guard and never ever had a chain come off! Never move motor mount again on kart! Change rear gears in about 1 minute to a minute and a half! These things work!!
 
W5R I just don't see why people would take that chance
Yeah. I don't understand that idea either. You've got to finish to win and if you keep going to the rear, winning is not in your future.
I spend a lot of time aligning my motor to sprocket hub initially. I do it by sight much like ASTGLENN does. I make my measure/guestimate
of chain slack at the side cover bolt which on my set up is near the chain. That way I am using a fixed reference point on my checks and
we shoot for ~ 1" up and down slack at that point.
I also agree that hubs and sprockets are made by 3 fingered blind monkeys, cause they ain't round.
 
2. Concentric rear sprocket- It needs to be a near perfect circle. 2 piece gears and an axle hub that is just not right can make you speak in tongues by the time its corrected. Whoever built the thing must have been working off of prints for a triangle? With some time and effort, there are ways to make it right.


LOL so true
 
I stood and watched them make sprockets at Horstman. There is no way they cannot be round. What does happen, the center hole on the sprocket is just a little bigger than the center shoulder on the sprocket holder. It takes a little effort but you can get them lined up.
 
Who's to say the chains are coming off because they are too loose?

A magnitude of problems can exist for chains to blow off....stretched chain, bad gear, bent hub, too loose, too tight, bad motor mount. Ive seen it all

My rule of thumb has always been to run a QUALITY motor mount (I prefer the PRC Flip), a QUALITY chain that I change OFTEN (like an Xtreme 120L) and continuously check my gears for wear and imperfections

I have also gotten away from the "chain guide" hype. To me, there are way too many variables that can cause a failure with a chain guide vs chain guards to make them worth running.
 
SKH MOTORSPORTS WROTE IT THE MOST EFFECTIVE WAY TO STOP UN WANTED CHAIN PROBLEMS IS LEARN How the DragGone works to increase its interaction whit the engine and chain. I can not stand to be at a race local or national event and wait for racers to PUT THEIR CHAIN BACK ON 3 DIFFERENT TIMES AND GO BACK TO THE SPOT THEY WERE IN.

It slows down the show and upsets thoes who have prepared to go race... And do not quote lose their chains while racing!
DragGONE
 
While JP is right, there are a number of things that can cause a chain to come off, the most common cause we have seen is setting it up waaay too loose, followed by a loose motor mount. If it comes off because of either of those more than once, the reason is simple - you can't fix stupid.
 
The Chaindraggone is a great piece to have...Most seem to think it adds too much resistance to the chain but most only see that when it is on the stand. When you sit the kart down on the ground you can see the chain slack up which makes what you felt go away. The same will hold true with a regular mount if it is 1-2 inches of slack on the stand it will be looser than that when you sit it on the ground and/or seated in the kart due to the chassis flex. The Chaindraggone does not decrease hp or put too much drag on an engine. In fact it does the opposite due to the fact that it eliminates chainwrap on the clutch driver. I have never had to change a chain unless I stretched it. I have never had a chain come off due to a normal racing condition..The only time my chain ever came off with a Chaindraggone with no gear guards was when I flipped the kart! Their are several advantages to having a draggone! You can keep you numbers in the kart more consistant due to not having to move the engine forward or backwards after a gear change, no gear guards are needed with it, VERY fast gear changes as easily done in under a minute! Tons of adjustment side to side. Get with Scot he can explain better than I can about the benefits of using one!
 
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