Tire Changer - Harbor Freight
Freshman User
Joined: Nov 2004
Posts: 39
Likes: 1
From: Wyoming, Michigan
My understanding on tire balance: They should be balanced for the intended use because of resonance & harmonics. A freeway driven car balance for maybe 60mph, an Autobahn driven Benz maybe 100mph, and a Bonneville raced SOHC F100 maybe 180.
Cargo Master
Joined: Dec 2004
Posts: 2,232
Likes: 3
From: NE Texas
No a properly balanced tire/wheel is a properly balanced tire/wheel. Now, what you describe requires a more precise balance as the speed goes up, but just because you are going to run the tire/wheel at 120 MPH does not mean that it has to be spun at that speed to get an accurate balance.
An improperly balanced tire/wheel will show up as low as about 45 mph. Also balance is not the only thing that cause high speed tire/wheel vibration. There is a variable called Road Force Variation (RFV.) This is basically measuring stiff spots in the tire. If the tire has excessive RFV, it can be PERFECTLY balanced and still exhibit vibration that will worsen with increasing speed.
When you have a tire/wheel combination in which you cannot eliminate vibration with a standard computer spin balancer the next step should be analysis on a Hunter GSP9700. This machine not only analyzes wheel balance, but also has a pressure wheel that analyzes RFV. In some cases the RFV can be offset by the placement of weights, or repositioning of the tire on the wheel, but if RFV is excessive, this machine will tell you when the tire is bad.
In the old days, with the oncar spin balancers such as the early hunter, the tire/wheel did in fact have to be spun to the desired balance speed, but technology has come a long way. In some cases you can get a better balance with an old hunter or bear on car balancer, but in almost all of these cases it is due to the rare case where the brake rotor or drum is out of balance and must be compensated for.
The other problem with these systems is that in practice, they only achieve a static balance and are not sophisticated enough to indicate placement of weights on the inboard plane.
Have a great day,
Doc
An improperly balanced tire/wheel will show up as low as about 45 mph. Also balance is not the only thing that cause high speed tire/wheel vibration. There is a variable called Road Force Variation (RFV.) This is basically measuring stiff spots in the tire. If the tire has excessive RFV, it can be PERFECTLY balanced and still exhibit vibration that will worsen with increasing speed.
When you have a tire/wheel combination in which you cannot eliminate vibration with a standard computer spin balancer the next step should be analysis on a Hunter GSP9700. This machine not only analyzes wheel balance, but also has a pressure wheel that analyzes RFV. In some cases the RFV can be offset by the placement of weights, or repositioning of the tire on the wheel, but if RFV is excessive, this machine will tell you when the tire is bad.
In the old days, with the oncar spin balancers such as the early hunter, the tire/wheel did in fact have to be spun to the desired balance speed, but technology has come a long way. In some cases you can get a better balance with an old hunter or bear on car balancer, but in almost all of these cases it is due to the rare case where the brake rotor or drum is out of balance and must be compensated for.
The other problem with these systems is that in practice, they only achieve a static balance and are not sophisticated enough to indicate placement of weights on the inboard plane.
Have a great day,
Doc
Freshman User
Joined: Nov 2004
Posts: 39
Likes: 1
From: Wyoming, Michigan
Balance
Thanks for the explanation. Wasn't aware of RFV. Up here in the salty winter roads of the north country rusting rotors/drums could affect balance of hi-miles vehicles. On car spinn-balance used to be the norm. up-grade for bubble bal. B4 computer bal./ off car.
Originally Posted by MBDiagMan
No a properly balanced tire/wheel is a properly balanced tire/wheel. Now, what you describe requires a more precise balance as the speed goes up, but just because you are going to run the tire/wheel at 120 MPH does not mean that it has to be spun at that speed to get an accurate balance.
An improperly balanced tire/wheel will show up as low as about 45 mph. Also balance is not the only thing that cause high speed tire/wheel vibration. There is a variable called Road Force Variation (RFV.) This is basically measuring stiff spots in the tire. If the tire has excessive RFV, it can be PERFECTLY balanced and still exhibit vibration that will worsen with increasing speed.
When you have a tire/wheel combination in which you cannot eliminate vibration with a standard computer spin balancer the next step should be analysis on a Hunter GSP9700. This machine not only analyzes wheel balance, but also has a pressure wheel that analyzes RFV. In some cases the RFV can be offset by the placement of weights, or repositioning of the tire on the wheel, but if RFV is excessive, this machine will tell you when the tire is bad.
In the old days, with the oncar spin balancers such as the early hunter, the tire/wheel did in fact have to be spun to the desired balance speed, but technology has come a long way. In some cases you can get a better balance with an old hunter or bear on car balancer, but in almost all of these cases it is due to the rare case where the brake rotor or drum is out of balance and must be compensated for.
The other problem with these systems is that in practice, they only achieve a static balance and are not sophisticated enough to indicate placement of weights on the inboard plane.
Have a great day,
Doc
An improperly balanced tire/wheel will show up as low as about 45 mph. Also balance is not the only thing that cause high speed tire/wheel vibration. There is a variable called Road Force Variation (RFV.) This is basically measuring stiff spots in the tire. If the tire has excessive RFV, it can be PERFECTLY balanced and still exhibit vibration that will worsen with increasing speed.
When you have a tire/wheel combination in which you cannot eliminate vibration with a standard computer spin balancer the next step should be analysis on a Hunter GSP9700. This machine not only analyzes wheel balance, but also has a pressure wheel that analyzes RFV. In some cases the RFV can be offset by the placement of weights, or repositioning of the tire on the wheel, but if RFV is excessive, this machine will tell you when the tire is bad.
In the old days, with the oncar spin balancers such as the early hunter, the tire/wheel did in fact have to be spun to the desired balance speed, but technology has come a long way. In some cases you can get a better balance with an old hunter or bear on car balancer, but in almost all of these cases it is due to the rare case where the brake rotor or drum is out of balance and must be compensated for.
The other problem with these systems is that in practice, they only achieve a static balance and are not sophisticated enough to indicate placement of weights on the inboard plane.
Have a great day,
Doc
Junior User
Joined: Jun 2005
Posts: 55
Likes: 0
I bought one of these, mouned it in concrete with stud and redheads, but used butterfly nuts so I could put it out of the way when not using it, which is alot since I couldn't figure out how the bead breaker/pry bar can not only pull the tire off a rim, but also be moved around to pull the rest of the tire off the rim?
The guys at the tire shops make it look so easy, but then they spent more than $40 bucks on their pnuematic tire machines... Do I need another pry tool or should I just get rid of the changer?
The guys at the tire shops make it look so easy, but then they spent more than $40 bucks on their pnuematic tire machines... Do I need another pry tool or should I just get rid of the changer?
Senior User
Joined: Feb 2004
Posts: 111
Likes: 0
From: Orange County, So. Calif
They are manual tire changers, which means 'manual labor.'
My Harbor Flake machine came w/ bead breakers, 2, and one roll off/roll on bar. 1 breaker is mounted on the machine and is used for the bottom bead. Second breaker slips over the center post and breaks the top bead. And the roll on/off bar is used for just that. No big deal, yet. Read on...
Removing the tire is easy, "IF" you do it correctly, but first some basics: Your rim has two outer bead seating areas, and a depressed 'drop center' area between the bead areas. To remove a tire first break both beads. Then you push the tire bead down from the rim and insert the roll off/on bar into the slight opening that results. (Note that the bar will be slanting inward towards the center post to accomplish this.) Next you pull the top end of the bar down and against the center bar while pushing the opposite side of the tire down so it will slide into the drop center area as you pull the roll off/on bar down and around the rim. Presto, the top side of the tire is rolled off the rim. Repeat the same thing on the bottom side of the tire by pulling up on the tire and again inserting the roll off/on bar, pulling the bar down while pushing tire into the drop center, etc...
Lubrication helps on the tire bead areas, both removing and installing. WD, really soapy stuff, etc, will make your day easier...
Again, if you don't use the drop center area, you are not going to remove or install anything passenger car/light truck wise. Not talking about split rims, etc, here, OK?
hotrod/Paul
My Harbor Flake machine came w/ bead breakers, 2, and one roll off/roll on bar. 1 breaker is mounted on the machine and is used for the bottom bead. Second breaker slips over the center post and breaks the top bead. And the roll on/off bar is used for just that. No big deal, yet. Read on...
Removing the tire is easy, "IF" you do it correctly, but first some basics: Your rim has two outer bead seating areas, and a depressed 'drop center' area between the bead areas. To remove a tire first break both beads. Then you push the tire bead down from the rim and insert the roll off/on bar into the slight opening that results. (Note that the bar will be slanting inward towards the center post to accomplish this.) Next you pull the top end of the bar down and against the center bar while pushing the opposite side of the tire down so it will slide into the drop center area as you pull the roll off/on bar down and around the rim. Presto, the top side of the tire is rolled off the rim. Repeat the same thing on the bottom side of the tire by pulling up on the tire and again inserting the roll off/on bar, pulling the bar down while pushing tire into the drop center, etc...
Lubrication helps on the tire bead areas, both removing and installing. WD, really soapy stuff, etc, will make your day easier...
Again, if you don't use the drop center area, you are not going to remove or install anything passenger car/light truck wise. Not talking about split rims, etc, here, OK?
hotrod/Paul
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
Don't EVEN talk about split rims. I changed a bunch of those back in the old days. It took a lot of care to put them back together properly. I saw a lot of people just slap them back together without cleaning them up. They are still scary!
I wonder what a RFV machine would have thought of those old nylon ply tires? Remember flat spots?
thump thump thump thump... -HEHE!
Damn, I am showing my age here!
I wonder what a RFV machine would have thought of those old nylon ply tires? Remember flat spots?
thump thump thump thump... -HEHE!
Damn, I am showing my age here!
Last edited by Torque1st; Jun 21, 2005 at 01:49 AM.
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
I have one of the tire changers, but I just use it for a bead breaker right now, as I rent here, and don't have the space to mount it at all. I just nailed a 2x4 to the wall, put the back side of the base under it, and it keeps it from rising up while breaking the beads. I do not have a second bead breaker, I just have to break them both on the floor. I have the tire spoons to do the rest. i like to use Armor all or such to lube the beads with, I figure it protects the tire as well as makes it quite slick...
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