Wheel-Tire Balancing
#1
02-19-2014, 11:04 AM
Wheel-Tire Balancing
Here is my procedure for balancing my tires to get as close to optimal balance as possible. Thought I would post for the benefit of others just because I see so many folks doing it wrong (or "good nuff") but I want to get closer to optimal. Even if you don't balance your own tires knowing how it is done and how to know when it is being done incorrectly is valuable.
What you need:
1. Wheel Weights: These are good. 1/8 oz is about 3.5 grams. Note: Smaller weights are zinc/bismuth -- these are steel. Okay but I would like to find a zinc or best yet -- bismuth source of weights). Smaller weight amounts also let you split the weight from side to side if you are statically balancing.
2. Static Balancer: Many on the market. I would be interested in knowing which manufacture makes the best one (low friction bearings mean a more accurate balance). Using low friction ceramic bearings on the balancer might be a great upgrade to get to a more precision static balance. Maglev (magnetic levitation) bearings truly have NO FRICTION would be ideal! If you know of such a balancer please tell me about it.
3. Motorcycle Jack: I just use a 3 ton automobile jack to pick front or rear up (under center frame of bike with a 2x4 under the kick stand). But there are some motorcycle specific lifts and jacks out there that would be handy. Saw one for $35 that was a 3" high platform double scissor that would be ideal for use with an air rachet wrench on it to raise and lower!
4. Tools: Torque Wrench; Loctite RED Threadlocker (or Blue); acetone (as degreaser for nut/bolt threads); ratchet wrench, 24mm (6 point preferred) for axle nut; 10mm (12 point required) for caliper mounting bolts; 3mm Allen-Hex socket for pinch bolts.
Torque Info (VRod -- All years): Keep in mind that Loctite RED is not truly permanent -- nuts/bolts still removable but with greater effort. Also best to set your torque wrench to middle of each range (below) to account for calibration inaccuracies.
24mm Axle nut (1): 68-75 Nm (50-55 ft-lbs), Loctite RED (Permanent)
10mm Caliper mount bolts (2) 38-52Nm (28-38 ft-lbs), Loctite BLUE (Semi-permanent)
5mm Front Fork Pinch Bolts (2): 16 Nm (11 ft-lbs), Loctite RED (Permanent)
STATIC BALANCING PROCEDURE
a. REMOVE WHEEL AND OLD TIRE: Remove the wheel from the motorcycle and remove the old tire. Note: There are ways to do this without purchasing any special equipment. You should do a YouTube search for "Zip Tie Tire Change" to find out how and "DIY bead breaker." You will find good instructions there on how to do this. When YOU control the process end-to-end you can spend more time and tweak things to get to an optimal balance that many professionals don't take the time to do.
b. CLEAN UP THE WHEEL: Remove the old weights from the wheel and any adhesive residue that may be left. Wash the wheel with the rotors attached (taking care not to get the wheel bearings wet -- if not sealed type bearings then remove them). Let the wheel dry COMPLETELY (water remaining will throw off the balance.)
c. CLEAN UP THE TIRE: Tires often come with various stickers on them and these should be removed completely including the adhesive residue. Do this as these things will wear off later and have a small impact on your overall balance. Note any balance compensation dots (or marks on the sidewalls). Pirelli uses red dots to indicate the lightest point of the tire, Dunlop uses a yellow dot. If there are no balance compensation marks on the tire then skip to g. to install the tire on the wheel.
d. PLACE WHEEL (NO TIRE) ON STATIC BALANCER: Ensure the balancer is on steady footing and it is level and install the wheel on it giving it a spin to ensure that it rotates freely in both directions. Let it settle to a stop. NOTE: The more friction free the bearings are the more accurate your balancing results. The more friction free the bearings are the longer the wheel will spin (if you want to test). Note: Ensure that any tire pressure sensor (TPS) system you have and valve stem (with cap), and rotors are installed as well.
e. FIND WHEEL HEAVY POINT: Assuming the wheel has stopped and the heaviest point is at the bottom you should test that by grabbing the bottom and turning the heavy point of the wheel 90 degrees in one direction holding it there (to remove any momentum) and then letting it fall to settle again. The faster it falls the more out of balance the wheel is and so the more weight it will need to bring it into a balanced condition. Once it settles mark the bottom of the wheel with a small chalk mark (heaviest point). Now do the same thing again but this time turn the heavy point 90 degrees in the other direction and let it fall. The caulk mark should be again at the bottom. If it is then good. if not then keep doing this till you can find the heaviest point (at bottom). Note: If you get a slightly different mark location (maybe in inch apart or so) but consistent depending on the direction you are turning the wheel you have some resistance in the bearings that are affecting your balance setup and the balance point is likely the center point between these two points.
f. BALANCE COMPENSATION ALIGNMENT: If you have balance compensation dots (or marks) on the sidewall of the tire this is the lightest point of the tire. You should install it onto the wheel (rim) so that that mark aligns with the heaviest point of the wheel (that you marked above) and the sidewall arrow indicating direction of tire rotation is correct when you finally install it onto the motorcycle. This will bring the wheel-tire closer to balance so that final balance will use fewer weights. Skip to h.
g. NO BALANCE COMPENSATION -- INSTALL TIRE: If you do not have any balance compensation then install the tire ensuring the arrow on the side-wall indicating direction of tire rotation will be correct when the wheel is installed on the motorcycle. Note: It is a myth that the heaviest point of the wheel is adjacent to the valve stem -- you must determine the heaviest point to take full advantage of balance compensation.
h. BALANCE THE WHEEL-TIRE: Place the wheel (with tire installed) onto the balancer and give it a spin in both directions to ensure it spins freely and let it settle. It shoud settle with the top of the tire being the lightest point. Mark that point on the tire sidewall with a small chalk mark. Test this by turning the wheel 90 degrees in one direction, holding it and then letting it settle again. The chalk mark should be at the top. Try turning it 90 degees in the opposite direction and repeat this until you are confident you have found the lighest point of the wheel-tire. Using a small piece of tape locate a weight to the top on the inside of the rim (do not permanently fasten the weight yet).
Retest your balance. If you still have a light point the chalk mark should rise to the top. The faster it rises the more out of balance the wheel-tire is. The slower it moves the closer to balance it is. Add a second weight on top on the other side of the wheel (directly across from the other weight on the opposite side) and retest. If it still needs more weight then add more weight alternating beween sides and moving the line of weights so that their full lenght centers at the top (lightest point) of the wheel-tire.
The objective is to use as few weights as possible to attain perfect balance while splitting the weight evenly top opposite side of the wheel. The reason you want to split the weights as you are assuming there is no dual-plane counter imblance already in the wheel and you don't want to create one.
A dual-plane counter imblance cannot be observed using a static balancer (you must use a dynamic balancer, aka computer spin-balancer to correct for that). Search YouTube for "dual plane counter imbalance" to see an explanation of at this concept. That said, balancing the wheels dynamically provides the best possible balance and saftey. Though many motorcycle shops don't do this I would like you to know that a dual-plane counter-imbalance will cause your front wheel to wobble and though it may not be noticable it will be felt in your handlebars as vibration and if you ever have a wheel-bearing go out or other problem the imbalance will make the front wheel prone to "death wobble" (look that up on YouTube for an example as well).
i. SET THE WEIGHTS PERMANENTLY: Remove the backing from the adhesive on the weights (one-by-one) and place them in the same location as before but as close to the center plane of the wheel as possible. Note: Use acetone, alcohol or other degreaser to remove any oils/grease at the adhesion point to ensure good adhesion. Also note when dynamically balancing wheels the weights are place as far out from the center plane as possible (closest to where the rim meets the tire as possible).
j. RETEST: Retest the balance of the wheel to ensure that it has no heavy point (or light point for that matter). If you give the wheel a spin and mark the top and do this several times the marks should appear to be random (not all line up around one half of the wheel). If the marks are all on one half of the wheel after numberous spins then your wheel is still out of balance and you must remove the weights and go back and re-do.
k. INSTALL: Install the wheel on the motorcycle. Repack bearings in bearing grease. Consider fresh wheel bearings or even the new technology ceramic bearings which lower rolling resistance of the wheel, improve longevity,improve performance and fuel economy. Tighten the axle nut until all the side-to-side play is is gone then spin the wheel to ensure it spins smoothly. Torque it half way to full torque, spin again, torque it all the way. Note on Torque Wrench Care: Take the tension off your torque wrench after use by setting it to 0 Nm (Foot Pounds) before you put it away so it will hold its correct calibration.
Done.
PS Please offer your own observations/tweaks as you see fit.
What you need:
1. Wheel Weights: These are good. 1/8 oz is about 3.5 grams. Note: Smaller weights are zinc/bismuth -- these are steel. Okay but I would like to find a zinc or best yet -- bismuth source of weights). Smaller weight amounts also let you split the weight from side to side if you are statically balancing.
2. Static Balancer: Many on the market. I would be interested in knowing which manufacture makes the best one (low friction bearings mean a more accurate balance). Using low friction ceramic bearings on the balancer might be a great upgrade to get to a more precision static balance. Maglev (magnetic levitation) bearings truly have NO FRICTION would be ideal! If you know of such a balancer please tell me about it.
3. Motorcycle Jack: I just use a 3 ton automobile jack to pick front or rear up (under center frame of bike with a 2x4 under the kick stand). But there are some motorcycle specific lifts and jacks out there that would be handy. Saw one for $35 that was a 3" high platform double scissor that would be ideal for use with an air rachet wrench on it to raise and lower!
4. Tools: Torque Wrench; Loctite RED Threadlocker (or Blue); acetone (as degreaser for nut/bolt threads); ratchet wrench, 24mm (6 point preferred) for axle nut; 10mm (12 point required) for caliper mounting bolts; 3mm Allen-Hex socket for pinch bolts.
Torque Info (VRod -- All years): Keep in mind that Loctite RED is not truly permanent -- nuts/bolts still removable but with greater effort. Also best to set your torque wrench to middle of each range (below) to account for calibration inaccuracies.
24mm Axle nut (1): 68-75 Nm (50-55 ft-lbs), Loctite RED (Permanent)
10mm Caliper mount bolts (2) 38-52Nm (28-38 ft-lbs), Loctite BLUE (Semi-permanent)
5mm Front Fork Pinch Bolts (2): 16 Nm (11 ft-lbs), Loctite RED (Permanent)
STATIC BALANCING PROCEDURE
a. REMOVE WHEEL AND OLD TIRE: Remove the wheel from the motorcycle and remove the old tire. Note: There are ways to do this without purchasing any special equipment. You should do a YouTube search for "Zip Tie Tire Change" to find out how and "DIY bead breaker." You will find good instructions there on how to do this. When YOU control the process end-to-end you can spend more time and tweak things to get to an optimal balance that many professionals don't take the time to do.
b. CLEAN UP THE WHEEL: Remove the old weights from the wheel and any adhesive residue that may be left. Wash the wheel with the rotors attached (taking care not to get the wheel bearings wet -- if not sealed type bearings then remove them). Let the wheel dry COMPLETELY (water remaining will throw off the balance.)
c. CLEAN UP THE TIRE: Tires often come with various stickers on them and these should be removed completely including the adhesive residue. Do this as these things will wear off later and have a small impact on your overall balance. Note any balance compensation dots (or marks on the sidewalls). Pirelli uses red dots to indicate the lightest point of the tire, Dunlop uses a yellow dot. If there are no balance compensation marks on the tire then skip to g. to install the tire on the wheel.
d. PLACE WHEEL (NO TIRE) ON STATIC BALANCER: Ensure the balancer is on steady footing and it is level and install the wheel on it giving it a spin to ensure that it rotates freely in both directions. Let it settle to a stop. NOTE: The more friction free the bearings are the more accurate your balancing results. The more friction free the bearings are the longer the wheel will spin (if you want to test). Note: Ensure that any tire pressure sensor (TPS) system you have and valve stem (with cap), and rotors are installed as well.
e. FIND WHEEL HEAVY POINT: Assuming the wheel has stopped and the heaviest point is at the bottom you should test that by grabbing the bottom and turning the heavy point of the wheel 90 degrees in one direction holding it there (to remove any momentum) and then letting it fall to settle again. The faster it falls the more out of balance the wheel is and so the more weight it will need to bring it into a balanced condition. Once it settles mark the bottom of the wheel with a small chalk mark (heaviest point). Now do the same thing again but this time turn the heavy point 90 degrees in the other direction and let it fall. The caulk mark should be again at the bottom. If it is then good. if not then keep doing this till you can find the heaviest point (at bottom). Note: If you get a slightly different mark location (maybe in inch apart or so) but consistent depending on the direction you are turning the wheel you have some resistance in the bearings that are affecting your balance setup and the balance point is likely the center point between these two points.
f. BALANCE COMPENSATION ALIGNMENT: If you have balance compensation dots (or marks) on the sidewall of the tire this is the lightest point of the tire. You should install it onto the wheel (rim) so that that mark aligns with the heaviest point of the wheel (that you marked above) and the sidewall arrow indicating direction of tire rotation is correct when you finally install it onto the motorcycle. This will bring the wheel-tire closer to balance so that final balance will use fewer weights. Skip to h.
g. NO BALANCE COMPENSATION -- INSTALL TIRE: If you do not have any balance compensation then install the tire ensuring the arrow on the side-wall indicating direction of tire rotation will be correct when the wheel is installed on the motorcycle. Note: It is a myth that the heaviest point of the wheel is adjacent to the valve stem -- you must determine the heaviest point to take full advantage of balance compensation.
h. BALANCE THE WHEEL-TIRE: Place the wheel (with tire installed) onto the balancer and give it a spin in both directions to ensure it spins freely and let it settle. It shoud settle with the top of the tire being the lightest point. Mark that point on the tire sidewall with a small chalk mark. Test this by turning the wheel 90 degrees in one direction, holding it and then letting it settle again. The chalk mark should be at the top. Try turning it 90 degees in the opposite direction and repeat this until you are confident you have found the lighest point of the wheel-tire. Using a small piece of tape locate a weight to the top on the inside of the rim (do not permanently fasten the weight yet).
Retest your balance. If you still have a light point the chalk mark should rise to the top. The faster it rises the more out of balance the wheel-tire is. The slower it moves the closer to balance it is. Add a second weight on top on the other side of the wheel (directly across from the other weight on the opposite side) and retest. If it still needs more weight then add more weight alternating beween sides and moving the line of weights so that their full lenght centers at the top (lightest point) of the wheel-tire.
The objective is to use as few weights as possible to attain perfect balance while splitting the weight evenly top opposite side of the wheel. The reason you want to split the weights as you are assuming there is no dual-plane counter imblance already in the wheel and you don't want to create one.
A dual-plane counter imblance cannot be observed using a static balancer (you must use a dynamic balancer, aka computer spin-balancer to correct for that). Search YouTube for "dual plane counter imbalance" to see an explanation of at this concept. That said, balancing the wheels dynamically provides the best possible balance and saftey. Though many motorcycle shops don't do this I would like you to know that a dual-plane counter-imbalance will cause your front wheel to wobble and though it may not be noticable it will be felt in your handlebars as vibration and if you ever have a wheel-bearing go out or other problem the imbalance will make the front wheel prone to "death wobble" (look that up on YouTube for an example as well).
i. SET THE WEIGHTS PERMANENTLY: Remove the backing from the adhesive on the weights (one-by-one) and place them in the same location as before but as close to the center plane of the wheel as possible. Note: Use acetone, alcohol or other degreaser to remove any oils/grease at the adhesion point to ensure good adhesion. Also note when dynamically balancing wheels the weights are place as far out from the center plane as possible (closest to where the rim meets the tire as possible).
j. RETEST: Retest the balance of the wheel to ensure that it has no heavy point (or light point for that matter). If you give the wheel a spin and mark the top and do this several times the marks should appear to be random (not all line up around one half of the wheel). If the marks are all on one half of the wheel after numberous spins then your wheel is still out of balance and you must remove the weights and go back and re-do.
k. INSTALL: Install the wheel on the motorcycle. Repack bearings in bearing grease. Consider fresh wheel bearings or even the new technology ceramic bearings which lower rolling resistance of the wheel, improve longevity,improve performance and fuel economy. Tighten the axle nut until all the side-to-side play is is gone then spin the wheel to ensure it spins smoothly. Torque it half way to full torque, spin again, torque it all the way. Note on Torque Wrench Care: Take the tension off your torque wrench after use by setting it to 0 Nm (Foot Pounds) before you put it away so it will hold its correct calibration.
Done.
PS Please offer your own observations/tweaks as you see fit.
Last edited by JayDRod; 02-23-2014 at 02:37 PM. Reason: Added torque specs and all bolt/nut sizes.
#2
02-21-2014, 04:44 PM
Here are a few short YouTube video links demonstrating how you can do your own tires without a lot of special tools:
1. TUTORIAL ON STATIC VS DYNAMIC BALANCE: Note wobble in the example when imbalance is dynamic. Not a big deal on a skinny motorcycle tire but having a dynamic imbalance cannot be corrected by static balancing and causes some wobble. Forget that it is "industrial balancing" -- same principles apply.
2. OPEN TIRE TO PATCH IT: Demonstration of Zip-Tie method of MC tire removal (for patch). Easier to bead-break the tire if there is 5 psi still in it though (he let all the air out of it):
3. STATIC BALANCING DEMO: Here is one way to do the final balancing. I like the fact he is splitting the weights on both sides. He skipped the Balance Compensation alignment which may have allowed him to use fewer weights though. Also, don't use duct tape, etc. to hold the weights on "extra good" -- this changes the balance somewhat. Decrease area where weights will be added so the adhesive works well. Also, another mistake he made was putting the weights towards the outer edge of the rim. As close to the centerline as possible is best when you are static balancing (or you could inadvertently cause a dynamic imbalance). In fact the why his wheel is designed he may have been able to put the weights on the center-line (if the imbalance was in an open area of this wheel).
1. TUTORIAL ON STATIC VS DYNAMIC BALANCE: Note wobble in the example when imbalance is dynamic. Not a big deal on a skinny motorcycle tire but having a dynamic imbalance cannot be corrected by static balancing and causes some wobble. Forget that it is "industrial balancing" -- same principles apply.
2. OPEN TIRE TO PATCH IT: Demonstration of Zip-Tie method of MC tire removal (for patch). Easier to bead-break the tire if there is 5 psi still in it though (he let all the air out of it):
3. STATIC BALANCING DEMO: Here is one way to do the final balancing. I like the fact he is splitting the weights on both sides. He skipped the Balance Compensation alignment which may have allowed him to use fewer weights though. Also, don't use duct tape, etc. to hold the weights on "extra good" -- this changes the balance somewhat. Decrease area where weights will be added so the adhesive works well. Also, another mistake he made was putting the weights towards the outer edge of the rim. As close to the centerline as possible is best when you are static balancing (or you could inadvertently cause a dynamic imbalance). In fact the why his wheel is designed he may have been able to put the weights on the center-line (if the imbalance was in an open area of this wheel).
Last edited by JayDRod; 02-21-2014 at 04:46 PM. Reason: Added bolding
#3
02-23-2014, 01:18 PM
Results -- Getting Front Wheel Balance (Motorsports - Fredericksburg, VA)
I decided to take the front wheel in to this shop because I wasn't happy with the HD dealer balance and the location specializes in power cruisers (Vmax) and racing cycles and is staffed by true track racers. Also the guy in service seemed to know what he was talking about re: giving me a dynamic "spin" balance on the front wheel. I pointed out the balance compensation dots (two of them.. I think double light at this point -- Pirelli Night Dragon). He told me they would find the true heavy point on the wheel and locate the balance compensation dots there correctly (not at valve stem -- it is a myth that this is always the heaviest point). As it would turn out... the guy was just agreeing to everything I said and ignoring me completely!
AFTER WORK -- SAME OLD WEIGHTS -- SAME LOCATION! When I got the wheel back (20 min) it had the new tire on it and rotation was correct however the same old two 7.5g weights (together on one side) were still there. I balked at that... there is no way that they could find the heavy point on the wheel (on a manual static balancer) without first removing those weights! The guy told me he saw the weight "zero out" himself and assured me it was an accurate balance nonetheless. I also noted the balance compensation dots set over the valve stem location (it is possible this is the heavy spot).
RETEST OF BALANCE SHOWED WHEEL WAS NOT BALANCED. They were very nice and very professional. They let me go back into the shop with the wheel so I could see their operation and they would spin up the wheel to show me the balance. The mechanic put the wheel on the spin balancer (a very old SnapOn balancer designed only for motorcycle wheels) and spun it up to 50 MPH. The wheel was 7.0 grams off balance. The guy swore it zeroed out and I said, "I believe you." (I was thinking he carefully balanced this time now the customer was looking over his shoulder). The same weight adjustment but about 45 degrees of change in location. He took the old weights off and put two new zinc (this is good -- smaller than steel) at the new location on the same side of the wheel and out towards the edge (incorrectly -- close to the tire). He spun it up and it balanced to 0.0g.
THEIR OLD PROTOCOL & ARGUING THE NEGATIVE. He told me their protocol calls for aligning the balance compensation dots with the valve stem (not what I was told). This is probably pretty good for light weight racing wheels that would likely be very close to perfect balance or out of balance by a very small amount but the V-Rod wheel is much heavier and likely the heavy spot is not at the valve stem -- their protocol is ok... less than optimal. But he claims to be a 180 MPH+ racer and balances his tires this way! Maybe so but I tell him that if there is a mechanical breakdown (front bearings, etc.) his wheel will not automatically seek balance if it is free to wobble and has a dual-plane dynamic imbalance. So it isn't something that may bother him if something catastrophic doesn't happen. Plus... how do you know that the high-freq handlebar vibration that seems to wear your arms out over time isn't due to wobble? All good arguments I think.
OUTDATED EQUIPMENT AND METHODS BACKSTAGE IN A MODERN FACILITY. Their SnapOn spin balancer was not a Dynamic one... it offered only static (single center plane balance) but by spinning the wheel and using the integral computer to identify the balance point and amount of weight. I was pretty surprised to see that the service manager and the mechanic himself seemed to be a bit out dated in their thinking. But I appreciated their service.
IMPROVING BALANCE AND INSTALLING WHEEL. Anyway... I thanked them and took the wheel home then marked the center of the weighted location on the wheel with a small mark, then took the weights off splitting them side to side and placing them close in on the wheel. This would remove any slight counter-imbalance that might be admitted from having all the weight on one side (and far outward on the wheel). I put the wheel on (using only a 3 ton car jack to boost the front of frame to get the front wheel a few centimeters off the ground). Really you only have to remove one caliper to get the wheel off and on. I used white lithium on he axle as a counter-seize. I cleaned the threads of all fasteners in acetone to degrease and used Loctite Threadlocker RED (permanent) on the axle nut and pinch bolts and caliper bolts and torqued them to spec. NOTE: When I was removing the wheel the rear pinch bolt was so loose I could remove it with my fingers!! No damage but WTF! I think a tremendous risk I was operating under and unaware!!!
Lessons Learned:
1. YOU REMOVE OLD WEIGHTS YOURSELF. Take the old weights off yourself or the mechanic may throw the new tire on and give it a spin -- good nuff!! (It isn't his wheel -- the customer will never know the difference). Taking the old weights off will put the wheel-tire into an out of balance condition forcing them to correct for it -- better yet -- as if you can watch and get them to go to zero imbalance (with retest).
2. LOOK AT THEIR EQUIPMENT. Try to get a look at their balancer... if it is old and beat up or if it won't do dynamic balancing don't go there! (At least for your front wheel.) They should be able to balance to at least 1/2 gram (preferably) and the spin balancer should have two weight indicators (for both sides of the wheel) and be run in Dynamic mode (even dynamic balancers can be run in static mode).
3. FIND YOUR WHEEL'S HEAVY POINT AND MARK IT. Get a manual balancer for your home garage and mark your wheel permanently showing its heavy point.
4. INDUSTRIAL BALANCE YOUR WHEEL--HAND PICK TIRES WITH NO BALANCE COMPENSATION DOTS. Or better yet get a industrial balancing company to balance your wheel with rotors installed by grinding some metal (weight) off the inside of the wheel then you always start with a balanced wheel and then buy tires that have no balance compensation dots on them (they also have no light/heavy spot -- close to balance). Then you should be able to balance with very little or even no added weights.
AFTER WORK -- SAME OLD WEIGHTS -- SAME LOCATION! When I got the wheel back (20 min) it had the new tire on it and rotation was correct however the same old two 7.5g weights (together on one side) were still there. I balked at that... there is no way that they could find the heavy point on the wheel (on a manual static balancer) without first removing those weights! The guy told me he saw the weight "zero out" himself and assured me it was an accurate balance nonetheless. I also noted the balance compensation dots set over the valve stem location (it is possible this is the heavy spot).
RETEST OF BALANCE SHOWED WHEEL WAS NOT BALANCED. They were very nice and very professional. They let me go back into the shop with the wheel so I could see their operation and they would spin up the wheel to show me the balance. The mechanic put the wheel on the spin balancer (a very old SnapOn balancer designed only for motorcycle wheels) and spun it up to 50 MPH. The wheel was 7.0 grams off balance. The guy swore it zeroed out and I said, "I believe you." (I was thinking he carefully balanced this time now the customer was looking over his shoulder). The same weight adjustment but about 45 degrees of change in location. He took the old weights off and put two new zinc (this is good -- smaller than steel) at the new location on the same side of the wheel and out towards the edge (incorrectly -- close to the tire). He spun it up and it balanced to 0.0g.
THEIR OLD PROTOCOL & ARGUING THE NEGATIVE. He told me their protocol calls for aligning the balance compensation dots with the valve stem (not what I was told). This is probably pretty good for light weight racing wheels that would likely be very close to perfect balance or out of balance by a very small amount but the V-Rod wheel is much heavier and likely the heavy spot is not at the valve stem -- their protocol is ok... less than optimal. But he claims to be a 180 MPH+ racer and balances his tires this way! Maybe so but I tell him that if there is a mechanical breakdown (front bearings, etc.) his wheel will not automatically seek balance if it is free to wobble and has a dual-plane dynamic imbalance. So it isn't something that may bother him if something catastrophic doesn't happen. Plus... how do you know that the high-freq handlebar vibration that seems to wear your arms out over time isn't due to wobble? All good arguments I think.
OUTDATED EQUIPMENT AND METHODS BACKSTAGE IN A MODERN FACILITY. Their SnapOn spin balancer was not a Dynamic one... it offered only static (single center plane balance) but by spinning the wheel and using the integral computer to identify the balance point and amount of weight. I was pretty surprised to see that the service manager and the mechanic himself seemed to be a bit out dated in their thinking. But I appreciated their service.
IMPROVING BALANCE AND INSTALLING WHEEL. Anyway... I thanked them and took the wheel home then marked the center of the weighted location on the wheel with a small mark, then took the weights off splitting them side to side and placing them close in on the wheel. This would remove any slight counter-imbalance that might be admitted from having all the weight on one side (and far outward on the wheel). I put the wheel on (using only a 3 ton car jack to boost the front of frame to get the front wheel a few centimeters off the ground). Really you only have to remove one caliper to get the wheel off and on. I used white lithium on he axle as a counter-seize. I cleaned the threads of all fasteners in acetone to degrease and used Loctite Threadlocker RED (permanent) on the axle nut and pinch bolts and caliper bolts and torqued them to spec. NOTE: When I was removing the wheel the rear pinch bolt was so loose I could remove it with my fingers!! No damage but WTF! I think a tremendous risk I was operating under and unaware!!!
Lessons Learned:
1. YOU REMOVE OLD WEIGHTS YOURSELF. Take the old weights off yourself or the mechanic may throw the new tire on and give it a spin -- good nuff!! (It isn't his wheel -- the customer will never know the difference). Taking the old weights off will put the wheel-tire into an out of balance condition forcing them to correct for it -- better yet -- as if you can watch and get them to go to zero imbalance (with retest).
2. LOOK AT THEIR EQUIPMENT. Try to get a look at their balancer... if it is old and beat up or if it won't do dynamic balancing don't go there! (At least for your front wheel.) They should be able to balance to at least 1/2 gram (preferably) and the spin balancer should have two weight indicators (for both sides of the wheel) and be run in Dynamic mode (even dynamic balancers can be run in static mode).
3. FIND YOUR WHEEL'S HEAVY POINT AND MARK IT. Get a manual balancer for your home garage and mark your wheel permanently showing its heavy point.
4. INDUSTRIAL BALANCE YOUR WHEEL--HAND PICK TIRES WITH NO BALANCE COMPENSATION DOTS. Or better yet get a industrial balancing company to balance your wheel with rotors installed by grinding some metal (weight) off the inside of the wheel then you always start with a balanced wheel and then buy tires that have no balance compensation dots on them (they also have no light/heavy spot -- close to balance). Then you should be able to balance with very little or even no added weights.
Last edited by JayDRod; 02-23-2014 at 01:50 PM. Reason: Lessons learned info re: removing old weights yourself.
#4
03-06-2014, 06:29 PM
Bad Balance When You Aren't Providing Oversight
The Pirelli Night Dragon's balance compensation dots (Dunlop using a single yellow dot) to indicate the lightest point of the tire. This should be aligned with the heaviest part of the wheel (it is a myth that this is always the location of the valve stem).
Take a look... see adhesive spot on left? This is the position of the two 7.5 gram weights on the wheel I took in to have the tire changed out on. After I got home and began mounting it I realized the same exact weights were on the tire in the same position! I thought, "Hell... they didn't balance!" So I took the wheel back. They spun it up on the computer balancer and the balance was way off... same weight but 15 to 20 degrees off. You can see the new weight position on the right.
The difference... 1st time I wasn't there (and they don't give a **** -- not their bike) 2nd time I was looking over their shoulder.
Until I can find someone with a good high-speed dynamic balancer (automotive shop with motorcycle hub adapters?) The above is what I did to improve the static balance I got. Splitting the 15 grams that were on one side of the wheel to the opposite sides of the wheel and setting them in a far as possible toward the center plane of the wheel will prevent this from causing any additional dual-plane dynamic imbalance. I tested the bike out at 85 mph and the front end was exceptionally smooth -- better than I have experienced ever (I thought my bike was icy smooth already -- nope!) I am wonder what a true dynamic balance would do... after all we are riding on two gyroscopes and using gyroscopic procession to "steer" so it makes good sense to have the "gyroscopes" tuned!
Last edited by JayDRod; 03-06-2014 at 07:47 PM. Reason: Added balance compensation indicator info and photo
Thread
Thread Starter
Forum
Replies
Last Post
