Tightening the chain?

[ceo012384]

Originally Posted by Gas Man

Please... do explain. The only difference I see would be some difference in weight. Otherwise the weight of the bike is still pressing down on the swingarm.

I'm thinking outloud here.

The weight is resting at different points depending if it is applied at the spools (by the stand) or at the axle (when resting on the ground), which would change sag since the lever arm acting on the shock has effectively changed. Also, the tire itself is a spring and damper so that effects things as well, it is like adding another spring in series, so it takes some deflection too. To add some angle to it via the kickstand can change things as well, i.e. some stiction is plausible. All of those things would tend to make the suspension not compress as much, which would give you a tighter chain slack reading than with the bike on a rear stand.

The differences would be slight.... but when you're trying to measure chain slack with a couple millimeter precision I think they would be significant enough to consider.

Not sure if I've explained myself well, but it makes sense to me. Also my shop manual very specifically says to have the tire off the ground to do it, which sort of encouraged my thinking about this.

[Gas Man]

And as I said earlier that they are suppose to be adjusted with the rider on the bike. So yes that I agree. But somebody didn't want to hear my point on that so I didn't think anybody would want to hear anything about weight distribution.

[ceo012384]

Originally Posted by Gas Man

And as I said earlier that they are suppose to be adjusted with the rider on the bike. So yes that I agree. But somebody didn't want to hear my point on that so I didn't think anybody would want to hear anything about weight distribution.

If you knew what the chain slack specification was supposed to be with the rider on the bike, I would agree with you that using the rider might allow the chain to be set to be at a better tension throughout the range of the suspension's travel.

But the specifications for chain slack are given, at least in my shop manual, for the case without the rider on there. So if you set the slack to that same specification with the rider on the bike it would be wayyyyy off.

[No Worries]

Put the bike on it's center stand and check the free play. Oh wait, the manufacturers got rid of center stands because they weigh a few pounds. Or their lawyers made them get rid of center stands because some rider pulled a groin muscle lifting the bike up. The most useful things I ever had on a bike, the kick starter and center stand, are now ancient history.

[Gas Man]

Totally agreed NW!!!

ceo... then some bikes are different. Personally I would think you should set it with the rider. If not that is like setting the suspension without the rider.

Further, if you ever have your bike "dialed" in at a track day... they will always tell you that your OE chain specs are too tight. That if you fully unload the suspension the chain will get too tight and inhibit the suspensions travel. Happened to me...

[ceo012384]

Originally Posted by Gas Man

they will always tell you that your OE chain specs are too tight. That if you fully unload the suspension the chain will get too tight and inhibit the suspensions travel. Happened to me...

Agreed for sure. My spec is between 35-45mm... I leave it at the slack side, I try to keep it at 45mm or a little bit more maybe. You use so much more of the travel when riding hard or at the track... don't want to fuck up that output shaft!

[Gas Man]

I would think you would over pull the chain and cause tight spots first... but who knows.

[ceo012384]

Originally Posted by Gas Man

I would think you would over pull the chain and cause tight spots first... but who knows.

I have heard someone riding a bike with a too-tight chain. When their rear shock compressed passed a certain point (e.g. hit a large bump or something), you could hear the motor laboring due to all the radial loading on the output shaft. VERY VERY bad for the bike. Ouchie.