Video of chain during chassis dyno run

[RussMcB]

This is kinda interesting. Earlier this year I took my race car to a chassis dyno to see if the engine was okay (it felt down on power at the previous race). During a run someone noticed a lot of movement in the chain. We video'd it on the next run.

http://www.vimeo.com/1131103

Even though the video seems to show the chain is way too loose, it wasn't really loose when felt by hand. I adjust my chains tighter now.

PS. This is my first video host post. I'm not sure if it's easily viewable by everyone. We'll see ...

[formulasuper]

Russ, the video views fine on my vintage computer but it isn't nearly as scary as it was standing 5 feet from it on the dyno!

[Tom Sprecher]

And Arthur had the camera and his face up in there.

[old dog]

Russ, Can you explain your chain tightening procedure?

ie; do you find the tight spot in the chain and then tighten the chain until you have 1/2" of up and down play?

[RussMcB]

Russ, Can you explain your chain tightening procedure?

ie; do you find the tight spot in the chain and then tighten the chain until you have 1/2" of up and down play?

Before, I'd tighten it so I had about 3/8 - 1/2" movement. Now (after seeing the video) I tighten it until just before I think I may be putting too much load on the chain and bearings.

My system does not have a idler sprocket for tensioning. I simply change the distance between sprockets (via shims). I think an idler sprocket would help control unwanted gyrations. I may add an idler sprocket someday. I've thought about it often but haven't gotten a good mental picture of a mount I could fabricate. There isn't much room in that area, and no nice perpendicular square tubing to build off of.

[old dog]

[quote=RussMcB;176598]Before, I'd tighten it so I had about 3/8 - 1/2" movement. Now (after seeing the video) I tighten it until just before I think I may be putting too much load on the chain and bearings.

I guess if you think about it. You don't "tension" the chain anymore than the engine does while under full load. On a bike, you need some "slack" to allow the swing arm to work through it's arc and tension and slacken the chain. I'm just wondering if we need ANY "slack" in our aplications?

BTW: cool video but kind of scary!

[996kyle]

Very cool video !

If the chain is too tight it makes shifting gears more difficult, at least on our Stohr with a 2007 GSXR!. We have found that a little play makes shifting easier/smoother.

Cheers
Kyle

[Nicholas Belling]

But be careful on the hard snap downshifts.. the chain can do some pretty extreme snaps from its slop.. which can make the chain run clooser upon its movement to structural bars or components around or close to the chain vs static rollout movement checking.

[Brands]

I always run my chain on the slack side - keeps it cooler, less power loss. I've seen some footage of a moto GP bike chain and it moves more than yours Russ so I wouldn't be too worried. Knock on wood I've never broken a chain in three intensive years racing bike engined cars. I always throughly clean them after each race and put them in a zip lock bag full of chain lube. I have two chains that I rotate every two races or so. Maybe a bit extreme but as I said I've not had one let go - it makes a BIG mess when it does.

[Messenger Racing]

During the development of the MX-1, we have used the gopro hero camera shooting video of each of our chain tensioner designs. We mounted the camera on the rear upper a-arm and got excellent video of about 1hour of race simulations (10-20minutes per run). What you see in you video is nothing compared to what it would do under up and down shifts. The big movement is under shifts. That being said, I would not keep tightening it, bad idea. If you are concerned about it hitting things, move them! At our last test we ran something like 900 mb of chain video. I encourage all new designs to do the same.

Jay Messenger
MX-1 FB/DSR
Muleshoe, Texas USA

[ReynardF1000]

That looks great as is. At the most you may want to only slightly tighten it. The chassis WILL flex some even with the strongest mounting designs.

[2BWise]

I'd be wary over tightening the chain as it could do some serious damage if it were to snap. When tensioning a chain I will 1)find the tight spot 2)tension it until I get about .5" movement up and down 3)check it after a session. It shouldn't need a retension for awhile. The biggest issue is with the amount of grip produced with two rear tires and the shock loads that are sent thru the chain when shifting and on the dyno the resonances at certain wheel speeds. The resonances on the dyno can be pretty rough and have caused problems in the past. After having issues we moved to a 520 DID with riveted master link and have had no problems since. If you're worried about it put an idler gear in to help minimize the oscillations when it resonances.

[carnut169]

520 is smaller than 530, correct? Are you sure the 520 is up to the task? Pretty much everyone I know of runs the 530....

[carnut169]

Hey Jay... how about posting your video?

[Messenger Racing]

I will have to edit something up and put it on youtube. Quality will be marginal but I will work on it. The old website has been neglected as building as become very intense.

JM