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Best method to set alignment and chain tension? #395115
09/19/11 4:36 pm
09/19/11 4:36 pm
Joined: Feb 2006
Posts: 1,097
Toronto, Ontario, Canada
Matthew in TO Offline OP
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I had a flat rear tire. Once repaired I put the rear wheel back on. I pulled the wheel backward until I though the chain tension was good - at the very far side of the rear sprocket I could pull the chain a little less than 1/8". This was with the bike on the centre stand, with no weight on the rear wheel. I set each of the chain tensioners so that the amount of threads past the tensioners was equal, my thinking being this would set accurate chain alignment.

I was surprised that the chain tensioners stop you from pushing the wheel in too far, but do nothing to stop you from pulling the wheel out too far, at least until the torque stay stops you. Perhaps I've done something wrong, but I've had the wheel off before.

What's the best way for one person to check and set chain alignment and tension? My Work Shop manual says there should be weight on the wheel, so I could ask someone to sit on the bike as I set the tension. I feel that my wheel alignment is off as the bike feels very light in left turns, like it wants to tip over, and feels like it's very slightly leaning to one side in a straight line.

Last edited by Matthew in TO; 09/19/11 4:37 pm.

1970 Triumph T100S (1969 T100S motor)
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Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395125
09/19/11 5:37 pm
09/19/11 5:37 pm
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Maui Hawaii
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I have a gadget that clamps to the sprocket. It has a pointer that you use to sight down and align to the chain run. It takes a little practice to use but it works.
Old timers don't need it. They just sight with one eye and move the wheel to and fro until they see the sprocket align with the chain.
As always, use the tightest spot on the chain to measure your adjustment, then when it needs adjustment later move each adjuster the same amount. There should be an unladed measurement for chain tension, if not, then you can use tie downs across the shocks to pre-load the rear suspension.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395137
09/19/11 6:33 pm
09/19/11 6:33 pm
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I use a wire hanger and a zip tie. Bend the wire hanger into a straight line and put a 90 degree bend in one end. Put the zip tie on the other end and tighten it down. Put the 90 degree bend at the center of the swinarm pivot and slide the zip tie to mark the center of the axle. Use it to check that each side is equally distant. Once your squared up then turn the axle adjusters 1/4 turn at a time to set the chain tension.



Scott

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395144
09/19/11 7:15 pm
09/19/11 7:15 pm
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Originally Posted By: Matthew in TO
I had a flat rear tire. Once repaired I put the rear wheel back on. I pulled the wheel backward until I though the chain tension was good - at the very far side of the rear sprocket I could pull the chain a little less than 1/8".


Sounds like you were checking your chain or sprocket for wear. The tension is checked about halfway between the sprockets.

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395151
09/19/11 7:51 pm
09/19/11 7:51 pm
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Posts: 1,097
Toronto, Ontario, Canada
Matthew in TO Offline OP
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Am I correct in saying that the chain adjusters prevent the rear wheel from pulling forward towards the engine, but do not prevent the wheel from pulling backwards? I find this a tricky method to work with, since I can set the threads of the two adjusters the same, but the risk is that the wheel isn't entirely against the forward stop in the swingarm. Thus I'd think I had it all aligned but one wheel bolt may be slightly forward or backward - impacting alignment.

Other than this, and a flat tire, my bike's been running great this season, put on about 1,500 miles. Tach's blown, but that rebuild will wait until the winter.

Last edited by Matthew in TO; 09/19/11 7:52 pm.

1970 Triumph T100S (1969 T100S motor)
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395165
09/19/11 9:00 pm
09/19/11 9:00 pm
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The axle nut holds the wheel in place. Once it is torqued the adjusters don't factor into it any more. You are correct that the adjusters hold the wheel forward but not backward which is why you shouldn't be counting on the same number of threads to get the wheel aligned (too many variables). The correct way to align the wheel is to make sure each side is equal between the swingarm pivot and the axle regardless of what the threads tell you. Tighten the axle nut forward to ensure you aren't pulling the wheel backward and ruining your alignment. Once the axle nut is tightened you could back off the adjusters and the wheel won't move. They are purely for setting wheel alignment while the axle nut is loose.
Scott

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395184
09/19/11 11:03 pm
09/19/11 11:03 pm
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rstar45 Offline
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Originally Posted By: Matthew in TO
Am I correct in saying that the chain adjusters prevent the rear wheel from pulling forward towards the engine, but do not prevent the wheel from pulling backwards?

Yes

Originally Posted By: Matthew in TO
I find this a tricky method to work with, since I can set the threads of the two adjusters the same, but the risk is that the wheel isn't entirely against the forward stop in the swingarm.


I'll sometimes smack the tire with a no bounce hammer to seat the adjusters against the swingarm, but if the axle is loose you should be able to just push it forward.

Originally Posted By: Matthew in TO
Thus I'd think I had it all aligned but one wheel bolt may be slightly forward or backward - impacting alignment.


Now a true alignment is another story, but try to see that the chain is straight with the sprockets.

Re: Best method to set alignment and chain tension? [Re: rstar45] #395194
09/19/11 11:57 pm
09/19/11 11:57 pm
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Farmington,Connecticut,USA
JBMorris Offline
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Matt,

I use the new rotor on my '78 to help set the alignment.

Use the adjusters as required then put a weight on the brake pedal to hold alignment.

Back off the adjusters then cinch up the spindle.

Front off the adjusters ready for next time.

For reference, i have a set of German Architectural Trammel points aluminium gizmo similar to mentioned above.


1978 Bonneville T140V PX
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395231
09/20/11 6:27 am
09/20/11 6:27 am
Joined: Jun 2007
Posts: 5,854
Maui Hawaii
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Whilst sitting astride the rear tire on a shop scooter, pull down on the chain to pull the rear wheel sharply forward. Now. with your left foot, give the tire a solid boot, insuring the ride side of the axle is slammed home.
Kind of bike calesthenics type of thing. You get the drift.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395274
09/20/11 3:03 pm
09/20/11 3:03 pm
Joined: Jul 2009
Posts: 3,549
Vic. Australia
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Pete R - R.I.P. Offline
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Originally Posted By: Matthew in TO
I feel that my wheel alignment is off as the bike feels very light in left turns, like it wants to tip over, and feels like it's very slightly leaning to one side in a straight line.

It's not unusual for a unit Triumph to feel heavy on the primary side,because they are.Apart from the front brake-plate, everything heavy is on the primary side;especially on the engine.Centre of gravity for an engine/gearbox is typically 4mm from the crankcase parting line.
The fix for this is to keep the front wheel dead centre in the forks,and offset the rear wheel 1/16" toward the primary side (2-15/16" between the rim centre and sprocket centre).
Then,you'll have a bike that behaves itself;but it won't happen if one or both wheels are 1/32" out of position.

Put the bike on the centre-stand and find the tightest position of the chain;they always have a spot that's a little bit tighter and if you spin the wheel a couple of times you'll find it.Loosen the axle and adjust adjust it on the primary side until there's a little over 1" up and down freeplay on the lower run of the chain.
Go to the front of the bike and line up the front wheel so it points toward the centre of the rear wheel.Eyesight is pretty good;you don't necessarily need a string line or straight edge.
Go to the rear wheel and adjust the timing-side of the axle until the rear wheel points toward the centre of the front wheel.

Check the chain tension again,and adjust both adjusters the same amount to get it right(about 3/4"-1" freplay).Turn the rear wheel 1/2 turn and check that it still points to the centre of the front wheel;adjust if necessary (split the difference). Tighten the axle.

Turn the rear wheel back to the tight spot in the chain.Compress the rear springs to 1/2-travel and see if there is still some freeplay in the chain,not dead tight.
That will get you close enough.

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395288
09/20/11 4:31 pm
09/20/11 4:31 pm
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Emsworth, sunny south of Engla...
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dave jones Offline
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I would say that if the frame is vaguely straight and all the correct engine/ wheel spacers are in place then you can just set the wheels in line with an old strip light tube as a straight edge. If you set the wheels then the chain alignment should be ok. If it isn't you need to check the spacers or get the frame/ swinging arm checked. They are never exactly straight after 40 odd years. The trouble with the coat hanger method is that it isn't necessarily right to have the adjusters equal.

On a 650 they say to use 3/4" freeplay on the chain with an average rider on the bike. I think Stuart said that a good way is to get the swingingarm horizontal and measure 3/8" at the tightest point. You could put the bike on the stand, remove the shocks, block the tyre up and measure. Once you have done this you can put the shocks back on and note the tension with the rear wheel off the ground which is the easiest way to check it. I don't bother doing this, of course! I get my brother to sit on the machine because he is more "average" than me!

If anyone is interested I put an Iwis (Jwis?) chain on my bike and use a hot wax/ graphite bath to lubricate it and it has lasted way, way longer than any Renold chain I have used. It is just a standard width non 'o' ring chain.

Dave

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395309
09/20/11 6:50 pm
09/20/11 6:50 pm
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NY
OriginalScott Offline
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Quote:
The trouble with the coat hanger method is that it isn't necessarily right to have the adjusters equal.


You measure from the center of the swingarm to the center of the axle, not the adjusters. Each side should be the same. If you get each side equal and your chain is not running true then you have a tweaked frame, swingarm, or the wrong engine spacers. BTW if you align the rear wheel with the front wheel and your chain is not running true, then something else is wrong. To get the wheel squared in the swingarm you use the distance between the swingarm pivot and the axle.

Everyone is so eager to post the "correct" method when there are several ways to get the rear wheel squared up. I understand that a coat hanger is too ghetto for some to use as a precision instrument of measurement. By all means use a welding rod or a tape measure if it makes you feel better.




Scott

Re: Best method to set alignment and chain tension? [Re: OriginalScott] #395316
09/20/11 7:42 pm
09/20/11 7:42 pm
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Farmington,Connecticut,USA
JBMorris Offline
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Originally Posted By: OriginalScott
You measure from the center of the swingarm to the center of the axle, not the adjusters. Each side should be the same.


I understood what you meant and found your method ingenius.

I use an aluminum beam compass setup simply because i have one:


This method is only exact if the swingarm bolts are an equal distance from the supporting brackets.


1978 Bonneville T140V PX
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395317
09/20/11 7:45 pm
09/20/11 7:45 pm
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Emsworth, sunny south of Engla...
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I didn't quite understand the concept at first but it is a good idea I can see now. All I meant was that if you have a 90 degree bend in the front frame you can still get the coat hanger measurement correct.

I just get my info out of the manual, being a Luddite.

dave

Last edited by dave jones; 09/20/11 7:58 pm.
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395333
09/20/11 9:00 pm
09/20/11 9:00 pm
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Kent, UK
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"Once repaired I put the rear wheel back on. I pulled the wheel backward until I though the chain tension was good - at the very far side of the rear sprocket I could pull the chain a little less than 1/8". This was with the bike on the centre stand, with no weight on the rear wheel."

As noted above, that's a rough guide to chain stretch, but is not the adjustment for chain tension. I hope you didn't ride it with that setting!

Nick


"1967 TR6R"
Re: Best method to set alignment and chain tension? [Re: Nick_Smith] #395443
09/21/11 1:16 pm
09/21/11 1:16 pm
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Posts: 1,097
Toronto, Ontario, Canada
Matthew in TO Offline OP
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Originally Posted By: Nick_Smith
As noted above, that's a rough guide to chain stretch, but is not the adjustment for chain tension. I hope you didn't ride it with that setting!Nick
Only briefly, a few times to the local greasy spoon. That's why I'm here - I know I've done it wrong as the bike's not riding true.

I'll do the above to confirm chain/wheel alignment. Next question - do I have to have load on the bike when checking for chain movement? I now understand that I should check for chain up and down movement in the middle span between fore and aft sprockets. If I have the bike without load on the centre stand is the chain adjustment not possible?


1970 Triumph T100S (1969 T100S motor)
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395512
09/21/11 7:27 pm
09/21/11 7:27 pm
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The tightest point in your chain tension occurs when the swing arm is in alignment or level with the swing arm pivot and the gearbox sprocket. If you put your bike on the centerstand, the chain tension is usually a little slack. Many handbooks have an adjustment that is carried out on the centerstand, but if you really want to know if your chain is correctly adjusted, you should preload the suspension until the swing arm is level. Then find the tightest point and adjust to allow a little slack, perhaps 3/8" or so. You don't need 5/8" or 3/4" as many handbooks say. When you get your chain right, everything feels better. Less driveline slop, and smoother shifts could result.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Best method to set alignment and chain tension? [Re: HawaiianTiger] #395514
09/21/11 8:00 pm
09/21/11 8:00 pm
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Farmington,Connecticut,USA
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Hi Bill (HT)

Originally Posted By: HawaiianTiger
you should preload the suspension until the swing arm is level. Then find the tightest point and adjust to allow a little slack, perhaps 3/8


I am curious as to just how you do this.

Years ago, while showing my bike to a friend, he noticed my chain was too tight.

Since then iv'e replaced the chain and both sprockets as well as the clutch center section.

I spent a few buck$ on this so i'm interested!

Aloha

Last edited by Brien Morrissey; 09/21/11 8:01 pm.

1978 Bonneville T140V PX
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395586
09/22/11 6:51 am
09/22/11 6:51 am
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Maui Hawaii
HawaiianTiger Offline

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I use a tie-down across the shocks until the swing arm is in line with the pivot and gearbox sprocket. It helps if you have a center stand and use it. If on the side stand, your bike will probably fall over.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Best method to set alignment and chain tension? [Re: HawaiianTiger] #395744
09/23/11 7:26 am
09/23/11 7:26 am
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Toronto, Ontario, Canada
Matthew in TO Offline OP
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Originally Posted By: HawaiianTiger
The tightest point in your chain tension occurs when the swing arm is in alignment or level with the swing arm pivot and the gearbox sprocket. If you put your bike on the centerstand, the chain tension is usually a little slack. Many handbooks have an adjustment that is carried out on the centerstand, but if you really want to know if your chain is correctly adjusted, you should preload the suspension until the swing arm is level. Then find the tightest point and adjust to allow a little slack, perhaps 3/8" or so. You don't need 5/8" or 3/4" as many handbooks say. When you get your chain right, everything feels better. Less driveline slop, and smoother shifts could result.
Bill
Am I squeezing the top and bottom runs of the drive chain together, or just pressing down the top run, or pulling up the bottom run? My Workshop manual just says check for 1" travel, while my Hayes manual just says it's simple to do. I need instructions, thanks.


1970 Triumph T100S (1969 T100S motor)
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395746
09/23/11 7:53 am
09/23/11 7:53 am
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Pete R - R.I.P. Offline
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Just move the bottom run of the chain up and down.If it moves 1",you've done what the workshop manual says.Spin the wheel around a few times,to make sure it doesn't get any tighter in a different spot.
When you compress the suspension,there should still be some freeplay.

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395756
09/23/11 9:02 am
09/23/11 9:02 am
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Emsworth, sunny south of Engla...
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Pete means 1" total up and down moement of the bottom run. Pull it down with normal hand pressure and then push it up as far as it will go.

Dave

Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395804
09/23/11 3:16 pm
09/23/11 3:16 pm
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Toronto, Ontario, Canada
Matthew in TO Offline OP
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Just to confirm, 1" total up and down, means 1/2" up and 1/2" down?


1970 Triumph T100S (1969 T100S motor)
Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395819
09/23/11 5:41 pm
09/23/11 5:41 pm
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Shingle Springs, California
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You need to load the wheel to the center of the arc of the swingarm, which is level when the bike is on the center stand. As Bill says, 3/8" slack at that point. The chain will be correctly adjusted. If adjusted this way, the no load slack will be fine.


Bob


73 Triumph T140 Main Ride
70 Bonnie
67 BSA West Coast Hornet

56 Chevy

Who are the brain police?



Re: Best method to set alignment and chain tension? [Re: Matthew in TO] #395828
09/23/11 6:05 pm
09/23/11 6:05 pm
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Hi Matthew,

Originally Posted By: Matthew in TO
What's the best way for one person to check and set chain alignment and tension?
I feel that my wheel alignment is off

Afaict, you need three separate answers.

Then, it depends on how accurate you want the finished job. As accurate as possible means you should remove the tyres and the primary drive, then you can put a straight edge on the wheel rims - allowing for a wider rear rim - and the two final drive sprockets; that'll tell you whether the wheels can be in line when the sprockets are in line or whether something's bent or not spaced correctly. Also, you might want to consider putting the bike on a level you can take a reference from, so you can tell if the wheels are vertical too. grin

That said, it's possible to get nearly as accurate without stripping the bike down quite so far. wink

Imho, setting the rear wheel alignment with reference to the swinging arm is a waste of time - tells you nothing. Particularly John Healy and Pete R have posted about lack of parallels in engines - camshafts not parallel with crankshaft, gearbox shafts not parallel with crankshaft, crankcase mouth not parallel with crankshaft, etc., etc. So what makes anyone think the cycle parts were built any more accurately? Moreover, even if they were, there can be few, if any, one-owner machines that've also never been dropped, possibly bending frame, forks, swinging arm, wheel rims, etc.

If the rear tyre and rim are the same width as the front tyre and rim, Dave's suggestion of using an old strip-light bulb against the tyre walls is pretty accurate; however, bear in mind that we're talking reference points that're some six feet apart, so any irregularities in the edge of the rear tyre - tread gaps, writing on the wall - will be magnified around the front tyre. This is even more inaccurate if the rear tyre and/or rim are wider than the front, so you have to put the straight-edge on both sides of the rear wheel and measure the gap each side of the front wheel.

Fwiw, some years ago, thanks to the fortuitous coincidence of materials and time, I devised something of a gadget. Two lengths of square-section ally tube about eight feet long (aluminium for lightness, square section for stiffness, length to reach past both wheels); in the rear wheel area in one surface of each tube, two slots for little ally blocks wide enough to sit on the rim and space the tube off the tyre; two threaded holes through each tube, one side left-hand, the other right-hand (I used metric threads for ease of availability; two correspondingly-threaded rods, l-h on one end, r-h on the other, knurled in the middle.

The gadget is assembled with a tube each side of the wheels and threaded rods through the rear wheel spokes. As the rods are turned, the tubes are drawn together, then you fiddle a bit 'til the blocks are on each side of the rear rim. The reason for the knurling is you can turn the rods between thumb and forefinger but not apply so much force that you bend the tubes or rip out a thread. Anyroadup, with gadget assembled on rear wheel, you can measure any front wheel gap wherever, and the effect of turning the rear-wheel adjusters is immediately obvious at the front.

Once I have wheel alignment correct, I now use a builder's laser level on the rear sprocket to check chain alignment. By all means, now check if the rear wheel is central in the swinging arm. If something's not straight, then you can immediately work out what the problem is, and whether you're going to fix it or compromise. grin

Turning to your chain tension question, absolutely the wrong way is to take any manual "slack on the centrestand" figure as gospel; I've yet to own a Britbike where it was correct.

As others have said, the chain is tightest when the centres of the two final-drive sprockets and the swinging arm pivot are in a line. Renold's advice (many years ago, when they still sold chains for motorcycles wink ) was that the slack in this position should still be about the same as the pitch of the chain - i.e. 5/8" for a 5/8" x 3/8" (530) or 5/8" x 1/4" (520) chain. When you've tensioned your bike's chain correctly in this position, then put it on the centrestand with the suspension extended and measure and note the "slack on the centrestand" figure for future reference.

Reason for doing it this way is the gearbox sprocket centre is never in the same position relative to the cycle parts (even on a Japanese bike) so one manual figure can never be correct for all bikes of that model. Moreover, Britbike gearbox sprocket centres are further from the cycle parts than on other makes of bike, which exacerbates any difference.

Measuring chain slack - I lie on the garage floor with a steel ruler against the swinging arm about mid-way between gearbox and rear wheel sprockets. I push the chain up hard enough to take the slack out of the top run, measuring the distance it moves up the steel rule. I turn the rear wheel adjusters equally as necessary 'til this measurement meets my requirement.

Finally, I hate to rain on anyone's parade but, if you have tight spots in your chain, your chain lube ain't working and you're getting corrosion between the pins and rollers. frown I've posted on here several times about the continuous chain lubrication available with the likes of Scottoilers; fwiw, the oldest Scottoiler-lubricated chain I have is a 19-year-old one (bought in 1992) with about 13,000 miles on it. And no tight spots. wink

Hth.

Regards,

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