In the last two installments, I showed you how I dismount and mount tires on my homemade equipment. While that’s all fine and dandy, it’s of no use without balancing that newly installed tire, unless: a) you’re not planning on exceeding 80kph or b) you are trying to avoid the dentist by rattling all your teeth free from your head.
That wheel and tire above? That’s today’s subject matter. It’s an old winter tire freshly mounted on a steel rim, to be used as a full-size spare when TSD rallying. I have blown up tires on TSD rallies (“double caution: rough texas gate”) and you can’t keep rallying on a donut spare, hence the need for a full-sizer.
While dismounting the old tire is a good time to remove any of the old wheel weights from the wheel. I like to keep the old weights and reuse them. I don’t know if you already knew this about me but I’m really damn cheap.
As you can see above, they tend to come in three varieties: stick-on weights (as seen on the right), hammer-on weights for steel wheels (top), and hammer-on weights for aluminum wheels (bottom). Stick-on weights can be used on either aluminum or steel wheels (unless they’re too rusty to stick to) and are my preferred weight for nice wheels as they don’t leave scratches like the hammer-on variety. The difference in the two hammer-on types are how they clamp to the wheel edge - aluminum wheels tend to be much thicker than steelies. They don’t stay put if you’re using the wrong type.
When balancing wheels at home, you simply let gravity be your guide. The heaviest part of the wheel wants to be at the bottom. To let that heavy spot rotate around, the wheel needs to rotate with minimal friction holding it back, and needs to be rotated around its exact centre.
These cones and rod from No-Mar are used to find a centre axis for the wheel to rotate around. They are threaded onto the rod, which clamps the wheel in place and if used correctly will push the wheel onto the cone into the exact centre.
Though it depends on the wheel, I find I get the best centring with one large cone (narrow side in) on the inside of the wheel, and the small cone (narrow side out) on the outside of the wheel. Like so:
I have since found an other cheaper, and possibly better cone set that I would have bought had I known about it at the time!
The rod rides on skateboard bearings held up by homemade supports on jackstands.
The dust shields have been removed from the bearings to reduce friction and help them spin. The jackstands make this setup both height and width adjustable, and it doesn’t take much space when not in use. Ideally the stands should be no farther apart than necessary, to reduce any flexing in the rod.
I like to give the wheel a spin while watching from the top. This will show if the wheel is mounted off-centre by a variation in the tread height as it rotates around. It can also show any side-to-side bends in your wheel, but there’s not much that can be done about that at home.
If I am satisfied that the wheel is centred properly, it is stopped by hand. It should start turning again all by itself. It will eventually settle, with the heavy part at the bottom. I like to mark this heavy spot with a soapstone pencil or chalk.
I like to double- and triple-check the heavy spot by moving it to either side and ensuring it returns to the same spot. With some wheels, it might vary by an inch or two, in which case I simply take an average position of the heavy spot.
With the heavy spot found at the bottom, the light spot is found directly across the wheel at the top. Adding weight to the light spot until it is exactly as heavy as the heavy spot balances the wheel. I like to start by adding a heavy weight - just tapping the hammer-on weight enough to hold it in place, not to fully mount it.
Hmm… with the weight in place the wheel moved, but the weight is close to the top. Needs more weight.
Now it’s at the bottom part of the wheel. Too much weight. It’s not all the way to the very bottom, which would indicate way too much weight, but just slightly low.
The weights I have temporarily installed on the wheel are the top two. They are a 35g (1.25 oz) weight and a 14g (0.5 oz) weight, and are too heavy at 49g. Looking through my used weights, I found the bottom two weights at 21g apiece, totaling 42g. Let’s give that a shot.
It’s always best to split hammer-on weights between the inside and outside of the wheel, if possible (instead of putting both on one edge of the wheel). Especially with wider wheels, you can run into an issue of dynamic imbalance where the wheel can be off-balance across the width of the tire tread, even though it may be in total static balance as balanced with a setup like this. Spreading the weight on both sides of the wheel minimizes this effect. Expensive computer balancers, as used at a professional tire shop, are required to calculate dynamic balance. A good static balancing can be nearly as good, and can be done at home.
If you were to use stick-on weights, you can reduce dynamic imbalance by placing them in the centre of the wheel, thusly:
(Though they are just sitting in the wheel for this picture, I like to reuse the stick-on weights with the use of foamy two-sided tape.)
The two 21g weights are installed on opposite sides of the wheel, but at the same spot along the circumference.
…and with the weights at the 3 o'clock or 9 o'clock position, where they can exert the maximum gravitational effect, the wheel doesn’t move. Balance is achieved! Or at least, a close approximation. Satisfied, I hammer them the rest of the way on the wheel for a permanent fix.
On daily driven wheels I will be very exacting about balance. If the wheel moves at all from the 3 o'clock position or the 9 o'clock position, even just a little bit, I will try moving or changing the weights slightly to get an exact balance with no tire movement. It takes some fidgeting, but it’s worth the exactitude if you’ll be doing much highway travel on the wheels. Even a minor vibration gets annoying on long trips.
Balancing wheels takes time, but as with any task the amount of time required gets shorter with experience. I have now balanced around 20 tires or so, and I can now get one done in about 5 minutes. My first tire probably took 30 minutes or more.
There is only so much help to be found by reading about it - experience is key. That, and watch some damn Youtube videos - they’re worth so much more than what you’ve just read here! This is something you need to see in action to understand, I think.
YouTube: How to balance a motorcycle wheel
YouTube: No-Mar static motorcycle wheel balancer
YouTube: Black Widow tire balancer
YouTube: Scudman balancer
Costs:
$105 - No-Mar balancing rod & cones (incl. shipping)
$7 - skateboard bearings (ebay)
$1 - nuts & bolts
==$113
Incidentals:
Steel from my pile o’ scraps
Part 1: Dismounting
Part 2: Mounting
Part 3: Balancing
That wheel and tire above? That’s today’s subject matter. It’s an old winter tire freshly mounted on a steel rim, to be used as a full-size spare when TSD rallying. I have blown up tires on TSD rallies (“double caution: rough texas gate”) and you can’t keep rallying on a donut spare, hence the need for a full-sizer.
While dismounting the old tire is a good time to remove any of the old wheel weights from the wheel. I like to keep the old weights and reuse them. I don’t know if you already knew this about me but I’m really damn cheap.
As you can see above, they tend to come in three varieties: stick-on weights (as seen on the right), hammer-on weights for steel wheels (top), and hammer-on weights for aluminum wheels (bottom). Stick-on weights can be used on either aluminum or steel wheels (unless they’re too rusty to stick to) and are my preferred weight for nice wheels as they don’t leave scratches like the hammer-on variety. The difference in the two hammer-on types are how they clamp to the wheel edge - aluminum wheels tend to be much thicker than steelies. They don’t stay put if you’re using the wrong type.
When balancing wheels at home, you simply let gravity be your guide. The heaviest part of the wheel wants to be at the bottom. To let that heavy spot rotate around, the wheel needs to rotate with minimal friction holding it back, and needs to be rotated around its exact centre.
These cones and rod from No-Mar are used to find a centre axis for the wheel to rotate around. They are threaded onto the rod, which clamps the wheel in place and if used correctly will push the wheel onto the cone into the exact centre.
Though it depends on the wheel, I find I get the best centring with one large cone (narrow side in) on the inside of the wheel, and the small cone (narrow side out) on the outside of the wheel. Like so:
I have since found an other cheaper, and possibly better cone set that I would have bought had I known about it at the time!
The rod rides on skateboard bearings held up by homemade supports on jackstands.
The dust shields have been removed from the bearings to reduce friction and help them spin. The jackstands make this setup both height and width adjustable, and it doesn’t take much space when not in use. Ideally the stands should be no farther apart than necessary, to reduce any flexing in the rod.
I like to give the wheel a spin while watching from the top. This will show if the wheel is mounted off-centre by a variation in the tread height as it rotates around. It can also show any side-to-side bends in your wheel, but there’s not much that can be done about that at home.
If I am satisfied that the wheel is centred properly, it is stopped by hand. It should start turning again all by itself. It will eventually settle, with the heavy part at the bottom. I like to mark this heavy spot with a soapstone pencil or chalk.
I like to double- and triple-check the heavy spot by moving it to either side and ensuring it returns to the same spot. With some wheels, it might vary by an inch or two, in which case I simply take an average position of the heavy spot.
With the heavy spot found at the bottom, the light spot is found directly across the wheel at the top. Adding weight to the light spot until it is exactly as heavy as the heavy spot balances the wheel. I like to start by adding a heavy weight - just tapping the hammer-on weight enough to hold it in place, not to fully mount it.
Hmm… with the weight in place the wheel moved, but the weight is close to the top. Needs more weight.
Now it’s at the bottom part of the wheel. Too much weight. It’s not all the way to the very bottom, which would indicate way too much weight, but just slightly low.
The weights I have temporarily installed on the wheel are the top two. They are a 35g (1.25 oz) weight and a 14g (0.5 oz) weight, and are too heavy at 49g. Looking through my used weights, I found the bottom two weights at 21g apiece, totaling 42g. Let’s give that a shot.
It’s always best to split hammer-on weights between the inside and outside of the wheel, if possible (instead of putting both on one edge of the wheel). Especially with wider wheels, you can run into an issue of dynamic imbalance where the wheel can be off-balance across the width of the tire tread, even though it may be in total static balance as balanced with a setup like this. Spreading the weight on both sides of the wheel minimizes this effect. Expensive computer balancers, as used at a professional tire shop, are required to calculate dynamic balance. A good static balancing can be nearly as good, and can be done at home.
If you were to use stick-on weights, you can reduce dynamic imbalance by placing them in the centre of the wheel, thusly:
(Though they are just sitting in the wheel for this picture, I like to reuse the stick-on weights with the use of foamy two-sided tape.)
The two 21g weights are installed on opposite sides of the wheel, but at the same spot along the circumference.
…and with the weights at the 3 o'clock or 9 o'clock position, where they can exert the maximum gravitational effect, the wheel doesn’t move. Balance is achieved! Or at least, a close approximation. Satisfied, I hammer them the rest of the way on the wheel for a permanent fix.
On daily driven wheels I will be very exacting about balance. If the wheel moves at all from the 3 o'clock position or the 9 o'clock position, even just a little bit, I will try moving or changing the weights slightly to get an exact balance with no tire movement. It takes some fidgeting, but it’s worth the exactitude if you’ll be doing much highway travel on the wheels. Even a minor vibration gets annoying on long trips.
Balancing wheels takes time, but as with any task the amount of time required gets shorter with experience. I have now balanced around 20 tires or so, and I can now get one done in about 5 minutes. My first tire probably took 30 minutes or more.
There is only so much help to be found by reading about it - experience is key. That, and watch some damn Youtube videos - they’re worth so much more than what you’ve just read here! This is something you need to see in action to understand, I think.
YouTube: How to balance a motorcycle wheel
YouTube: No-Mar static motorcycle wheel balancer
YouTube: Black Widow tire balancer
YouTube: Scudman balancer
Costs:
$105 - No-Mar balancing rod & cones (incl. shipping)
$7 - skateboard bearings (ebay)
$1 - nuts & bolts
==$113
Incidentals:
Steel from my pile o’ scraps
Part 1: Dismounting
Part 2: Mounting
Part 3: Balancing
No comments:
Post a Comment