Wheel Alignments

[posplayr]

I just wanted to start this new thread in case my other thread continues on with this topic. I would rather it be here as it will be easier to find and reference.

Here is how it started.

http://www.thegsresources.com/_forum/showpost.php?p=1073152&postcount=129


From Tone:

Re- wheel alignment

As some of you know i worked on a straightening jig in an accident repair shop for a while & can tell you the accepable misalignment can be up to 4mm on some models as stock we "straightened" quite a few brand new frames for racers to bring them within 1mm of alignment or less & this is what i always aim for on my own bikes

Although this is the ideal, on a bike made up from a number of different parts that were never supposed to fit together the ideal is sometimes not acheivable due to the many variables involved

As posplar says a small misalignment can be tuned out by ajusting the wheel slightly more on one side than the other, the chain will allow you to do this by around 1mm without adverse effects on chain or sprocket life, although it is always better to avoid this if possible

When checking the wheel alignment do not use the ajusters at all ! leave them completely slack & push the wheel all the way forward within the slots & nip it up, the reason for this is that the marks on the ajusters are notoriously poor & the wheel will not be straight if you use them & the front edge of the ajuster slots is usually a fairly accurate place to start your measurements from while with the rear it is not always the case

summary .... 4mm of misalignment is just about acceptable but personally i wouldnt be happy with that
1mm or less is the ideal but not always acheivable
2mm to 2.5mm is the most misalignment you should be aiming for in my opinion & if that is not acheivable you did something wrong somewhere along the line

Hope it helps tone

Edit 7/27/2012
Some pictures of doing a rear wheel to front wheel alighnment doing the string method.


Wheel alighnment using the sting method. I had a thin 600 lbs test kite line so it worked well.

I used this setup to keep the lines tight, the 30 lbs black box was propped up on a wooden block to keep the lines tight .

Quick check on chain alignment. Put 6 ft level against the tire and measured how much lateral offset there was the length of the chain. Looks like less than a link plate width. By measuring left and right forward and backward (4 equal measurements on the disks) confirms the wheels are aligned. Set the rear chain tension, then adjust the right hand side to make all 4 equal.

One last simple thing is to check the chain alignment with the wheel. I used a level below the chain and checked the alignment over the length of the chain. The level rests on the tire but for a chain it is close enough.

 

[tone]

Hi pos
Good idea to start this thread mate & sorry for cluttering up your build thread with my previous ramblings

I'll post a couple of things here in the hope that it may help people with wheel alignment issues.
Ive previously written my way of doing the job at home without specialist equipment so wont repeat that here unless someone REALLY needs it

For alignment checks i use either a long (8') plasterers straight edge or a lazer line but you can use any known good straight edge, using a long length of straight steel box with blocks or pegs welded to it that touch the rear wheel rim rather than the tyre is also good

Getting the bike set up straight & level before you start & not moving it during the process is vital to getting an acurate measurement & a plumb line hanging from the headstock will help with this & also help with centralising the front wheel

hope it helps tone

 

[justin caise]

Ive previously written my way of doing the job at home without specialist equipment so wont repeat that here unless someone REALLY needs it

I'd like that info - can you just post a link in the above post?

Thaks, JC

 

[jwhelan65]

Jim,
First off great start to what will be a very informative thread. I have a couple of questions. Is it easier to dial this in with the engine out of the frame? And if so I, do yo think a laser and a straight edge of some sort would be most accurate? Based on my notes, approximate measurements and past conversations with Rob I am close to a 1mm variance. The only reason I am asking is I will soon have it stripped down to the frame for powder coating and will have to reassemble the entire thing.

 

[salty_monk]

I'm going to pick up a laser level to do mine as I also need to measure sprocket alignment

Dan

 

[tone]

I would like to point out that while they are related wheel alignment & chain alignment are two different things & really should be treated as such as it saves confusion, by all means have a quick look to make sure you will get the chain through but then ignore it untill the wheel alignment is sorted

Repeat after me ..... wheel alignment then chain alignment ..... wheel alignment then chain alignment ad infinitum

Joe you can sort your wheel alignment with the engine either in or out mate, obviously you will need your swingarm wheels & forks etc in & tightened up though, In answer to your question about straight edges or lazers, i find a good straight edge & steel rule more accurate as it can be difficult to get lazer fixed solidly so it wont move & awkward to measure to a light beam floating in mid air, i use my lazerline for quick checks & not a lot else

tone

 

[tone]

I'd like that info - can you just post a link in the above post?

Thaks, JC

I found it in the middle of someone else's build thread but it was written to relate to that bike really so to avoid confusion i'll write it out again here, just wait a while as it may take some time

 

[jwhelan65]

I would like to point out that while they are related wheel alignment & chain alignment are two different things & really should be treated as such as it saves confusion, by all means have a quick look to make sure you will get the chain through but then ignore it untill the wheel alignment is sorted

Repeat after me ..... wheel alignment then chain alignment ..... wheel alignment then chain alignment ad infinitum

Joe you can sort your wheel alignment with the engine either in or out mate, obviously you will need your swingarm wheels & forks etc in & tightened up though, In answer to your question about straight edges or lazers, i find a good straight edge & steel rule more accurate as it can be difficult to get lazer fixed solidly so it wont move & awkward to measure to a light beam floating in mid air, i use my lazerline for quick checks & not a lot else

tone

Thanks tone,

I am sure I will be referencing this thread frequently. I think I am relatively close but I will definitly dial you when get to that point on my build. It all coming apart soon.

thanks man!

 

[Guest]

Hi pos
Good idea to start this thread mate & sorry for cluttering up your build thread with my previous ramblings

I'll post a couple of things here in the hope that it may help people with wheel alignment issues.
Ive previously written my way of doing the job at home without specialist equipment so wont repeat that here unless someone REALLY needs it

For alignment checks i use either a long (8') plasterers straight edge or a lazer line but you can use any known good straight edge, using a long length of straight steel box with blocks or pegs welded to it that touch the rear wheel rim rather than the tyre is also good

Getting the bike set up straight & level before you start & not moving it during the process is vital to getting an acurate measurement & a plumb line hanging from the headstock will help with this & also help with centralising the front wheel

hope it helps tone

I used a string wrapped around the back tire and projected forward to just touch the front of the rear wheel, and out past the front tire. It projects a parallel line to see if the rear tire is running straight.

 

[tone]

I used a string wrapped around the back tire and projected forward to just touch the front of the rear wheel, and out past the front tire. It projects a parallel line to see if the rear tire is running straight.

Hello mate
This method works reasonably well but it can be difficult to keep tension on the string while taking measurements & you will always be measuring off the rear tyre rather than the rim, tyres are not always perfectly fitted or made so you can be out by over 1mm easily

Having said that its not too much of a problem if everything else is spot on & ive used this method in the past but my feeling is that the 1mm mentioned above in conjunction with other variables could push me over my self imposed limit for misalignment so prefer to use a straight edge

cheers tone

 

[ryonker]

Thanks for this thread.

Tone, when you do your explanation, can you include some photos as well?

Thanks!

Rick

 

[tone]

Well here goes this may sound complicated but its not really that difficult once you have the idea firmly in your head

First off i must say this is not meant to be a difinitive guide to wheel alignment its just what ive learnt over the years & how i do things at home, Reasonble accuracy can be achieved this way eg within my self imposed limits of up to 2.5 mm of misalignment & very often you can get to the almost perfect 1mm, any less than that with 100% certainty & you will need to do it properly on a jig

The first job is to get your tools together, you will need an 8' long straight edge, small level, wooden blocks or bricks, a steel rule, tape rule, & axle stands or another way of supporting the bike.
NOTE when i say straight edge i do mean STRAIGHT ! bent twisted or warped wood/tube or your granny's knicker elastic will NOT do

#1 Next set the bike up on flat level ground supported on the axle stands making sure that you have enough room for the straight edge to lie along the rear wheel & project past the front rim without getting caught up on anything such as the stands themselves the bikes centre stand or exhaust etc
Make sure the bike is sitting level across the frame from left to right, you may need to shim the stands to achieve this, use the level & take the time it makes things easier later on, KEEP checking at every stage

#2 Once happy with that we need to get the front forks facing in the right general direction, measuring from a fixed point on the frame to the yokes either side is a good start, A plumb line hanging from the headstock can also be a good guide but dont worry about getting it spot on too much that will come later If you can chock the wheel in this position it will help later on check level !

#3 Push the rear wheel fully forward in the ajuster slots & nip it up

#4 Now lay your straight edge along the rear wheel touching the tyre & supported on the blocks & projecting past the front so that it is a few inches up the wheel & you can measure in to the rim of the both wheels around 10 or 12" apart
Meaure in to the rear wheel rim in 2 places (front & rear) using the steel rule, both measurements should be the same but because of the tyre it may not be, ajust untill it is & then be VERY CAREFUL not to move the straight edge again & make a note of the measurements just in case

#5 Now measure in to the front wheel in a similar manner, almost certainly you will have 2 different measurements this is because the wheel is not straight so you need to ajust untill it is, eg both measurments the same

RE-CHECK THE REAR MEASURMENT & THE FRAME LEVELS AT THIS POINT & AJUST AS NEEDED take your time here & keep checking as in #1,4&5 untill all is well

#6 Thats the difficult bit done now measure the distance in to the front wheel in 2 places (front & rear) & note it down

#7 do not move the bike in any way
Just move your straight edge & blocks & repeat the measuring process on the other side

#If all has gone well you will now have 2 measurments written down
EG : left side distance in to the front wheel 30mm
right side distance in to the front wheel 40mm

In this example there is a differance of 10mm which means the wheel has to move to the right by half the differance (5mm) for it to be central & lined up with the front & its time to think about spacing it correctly :dancing:

If i get a sunny day I'll drag one of my bikes out & set it up for demo pics but its not looking good for this weekend

Hope it helps guys & questions are welcome
cheers tone