For Fellow OCDers...Chain and Wheel Alignment

[Wearyeyed]

Today I cleaned and lubed my chain, and I remembered a little detail I had noticed last month...

I used a modified "string method" of aligning the thrust-line (rear wheel to front wheel), basically taking one of those construction laser levels that can shoot either a horizontal of vertical line, and is self-leveling internally.

Using a bucket to set the device about 3' from the rear of the bike, and situating it such that the beam *just* kisses the rear and leading edges of the rear tire projecting towards the front, I get a nice laser line on the floor and the wall in front of the bike.

Taking a measurement (I used a vernier caliper, to *really* split atoms along side my laser) from the edge of the front tire at approximately the point corresponding to the center of the contact patch to the laser-line (it shows-up nicely when cast upon the caliper), I adjusted the rear wheel until both sides were equal.

In thousandths...

ANYWAY, prior to the alignment, and after, I noticed the chain rides on the sprocket such that the sprocket is biased toward the inboard part of the chain.

I've checked this on the stand, after long rides, after short rides, cold, hot, standing on my head, etc., and it clearly does NOT want to ride on the center of the rollers.

There IS a tiny gap remaining; it's not jammed-up against the inboard links, but it is clearly off-center.

So, here's the question...is this a "problem" and if so, what can be done about it?

Adjusting the rear wheel to coax the chain to the center is not a perfect solution; over the width of the sprocket I am simply splitting the distance, leaving the sprocket not parallel to the front sprocket, and the thrust-line will be inevitably off.

So, the way I see it, it's shims or shut-the-heck-up and just ride it...

What say you?

 

[FB400]

I admire your detail oriented-ness and it seems it would be a shame to let such an articulate post go unresponded to for this long.

After changing my front sprocket I don't think I got the alignment thing right. Albeit I am not scrutinizing it to the level of agonizing detail you describe I sometimes notice a muted, very mild thumping kind of rythym from the rear tire. It is only noticeable when the bike is moderately leaned over. Perhaps the dynabeads are not doing their job but it only started after the sprocket change.

I like your method of using a lazer level and to be honest I have had one in my garage in orginal packaging, never used. The winter is coming so this just be the perfect project to get me started in modding season.

Thanks for the OCD contribution, it is appreciated.

 

[Nick329]

Today I cleaned and lubed my chain, and I remembered a little detail I had noticed last month...

I used a modified "string method" of aligning the thrust-line (rear wheel to front wheel), basically taking one of those construction laser levels that can shoot either a horizontal of vertical line, and is self-leveling internally.

Using a bucket to set the device about 3' from the rear of the bike, and situating it such that the beam *just* kisses the rear and leading edges of the rear tire projecting towards the front, I get a nice laser line on the floor and the wall in front of the bike.

Taking a measurement (I used a vernier caliper, to *really* split atoms along side my laser) from the edge of the front tire at approximately the point corresponding to the center of the contact patch to the laser-line (it shows-up nicely when cast upon the caliper), I adjusted the rear wheel until both sides were equal.

In thousandths...

ANYWAY, prior to the alignment, and after, I noticed the chain rides on the sprocket such that the sprocket is biased toward the inboard part of the chain.

I've checked this on the stand, after long rides, after short rides, cold, hot, standing on my head, etc., and it clearly does NOT want to ride on the center of the rollers.

There IS a tiny gap remaining; it's not jammed-up against the inboard links, but it is clearly off-center.

So, here's the question...is this a "problem" and if so, what can be done about it?

Adjusting the rear wheel to coax the chain to the center is not a perfect solution; over the width of the sprocket I am simply splitting the distance, leaving the sprocket not parallel to the front sprocket, and the thrust-line will be inevitably off.

So, the way I see it, it's shims or shut-the-heck-up and just ride it...

What say you?

Mine is the same. When asking about it, I was told that it should ride on the sprocket that way. When I mentioned that the chain used to ride on the center (before tire change) I was told that the wheel was out of alignment.
I was told this by two people with extensive experience in motorcycles.

Just my .02

Nick

 

[Wearyeyed]

<bump>

Just realigned the rear for a set of RP3's.

*Identical* results by laser and string methods; when the wheel is thrust-aligned, the sprocket rides closest to the inboard links.

To get the sprocket closer to center on the chain, the thrust-line is off.

So, seeing as though my previous question earned only a mediocre response (and a very nice compliment from FB40, thanks), I have a new one:

Which is more important, thrust-line or chain centered on sprocket?

For now I continue to split the difference...

 

[FinalImpact]

Thrust line is likely your best target.
FYI: you could have a proper TL but have an offset which would lead to the strange contact pattern.
You can't move the front sprocket in to the engine any closure but you could shim it out. and you could shim the rear left or right or simply ignore it if based solely upon the grease patch on the chain roller. . .

One question. Is it vibration free while dialed in?

 

[Wearyeyed]

One question. Is it vibration free while dialed in?

Great question!

When the wheel is perfectly aligned, and thus the chain riding closest to the inside-edge of the sprocket, there IS a subtle, but noticeable high-frequency "flutter" I can percieve above 45 mph.

Which is *not* present when I tweak the rear wheel such that the chain rides more centered on the sprocket.

Also, I noticed the rear sprocket assembly has some funky rubber isolators in the hub, and that the sprocket doesn't necessarily *always* spin "true."

***Sorry for the edits: thinking in my head, not in front of the bike.***

I would need to shim the front sprocket "in" (which is not possible) or move the rear sprocket "out."

Any ideas how that might be accomplished?

 

[FinalImpact]

I would need to shim the front sprocket "in" (which is not possible) or move the rear sprocket "out."

Any ideas how that might be accomplished?

What is the objective evidence that says its not OK in use? You have the Chain Camera live feed? lol j/k

To move the front sprocket inward you could Shim the engine over by adding spacers to ALL of the left side frame mounting points. HAHA! Was this bike wrecked?

 

[Wearyeyed]

What is the objective evidence that says its not OK in use? You have the Chain Camera live feed? lol j/k

To move the front sprocket inward you could Shim the engine over by adding spacers to ALL of the left side frame mounting points. HAHA! Was this bike wrecked?

Nice...very funny, wise-guy.

To my knowledge, it has never been wrecked.

As far as "objective" evidence, all I have is the clear evidence the rollers are seeing more contact to the inside.

Intuitively (combined with the aforementioned "flutter" sensation) I presume the chain would be most happy carrying the load more on-center...

I cannot imagine of *all* the FZ6's produced, mine is the only one that has a chain riding off-center when the wheel is aligned.

Then again, maybe it isn't a problem.

Recently, someone posted on a thread with a picture of the inside edge of the rear sprocket worn away.

Assuming I keep the wheel aligned, I would expect to see a similar pattern in time on my own sprocket.

How about shimming the sprocket out?

Seriously, now.

 

[Wearyeyed]

Chain-cam DOES sound cool, though....