Balancing Issue: Cooper's on T/T-D's
11-27-2016, 11:51 AM
#1
Pro
Thread Starter
Balancing Issue: Cooper's on T/T-D's
I also posted in "Wheels & Tires", but no replies yet...
'76 Vette - Installed new Cooper Cobra tires on AR Torq Thrust D's and the balance measurements were horrendous! One needed 7.5 oz on inner, and 8.5 on outer (That's ONE POUND!). The other was "slightly better" at 4.25 inner, and 9 oz outer.
The rims are American Racing Torq Thrust D's 15" x 8" w/ 4" backspace, Tires are Cooper Cobra 255/60/15. Since backspace is so great (as compared to today's style rims on new cars), when adding weight for front(face) side, it's actually going in the center (4" backspace on an 8" rim), but the machine (Hunter 9600) was set up w/ the correct measurements/parameters, so takes this all into account when displaying where and how much weight to add. Used stick-on style weights.
I've had these rims for 10+ years w/ BFG's and FS Firehawks, but never had balancing numbers like this!
Are tires defective? Is there a better way to balance these? I'd hate to use "tap-on" style weights on the outer/face-side (if that's better...?)
Ideas/suggestions...???
'76 Vette - Installed new Cooper Cobra tires on AR Torq Thrust D's and the balance measurements were horrendous! One needed 7.5 oz on inner, and 8.5 on outer (That's ONE POUND!). The other was "slightly better" at 4.25 inner, and 9 oz outer.
The rims are American Racing Torq Thrust D's 15" x 8" w/ 4" backspace, Tires are Cooper Cobra 255/60/15. Since backspace is so great (as compared to today's style rims on new cars), when adding weight for front(face) side, it's actually going in the center (4" backspace on an 8" rim), but the machine (Hunter 9600) was set up w/ the correct measurements/parameters, so takes this all into account when displaying where and how much weight to add. Used stick-on style weights.
I've had these rims for 10+ years w/ BFG's and FS Firehawks, but never had balancing numbers like this!
Are tires defective? Is there a better way to balance these? I'd hate to use "tap-on" style weights on the outer/face-side (if that's better...?)
Ideas/suggestions...???
11-27-2016, 12:35 PM
#2
Melting Slicks
Find a shop that has a "road force" balancing machine. It simulates the weight of the car on the wheels, and shows the heavy spots. What they do then is break down the tires and put the heavy side of the tire on the light side of the wheel. This minimizes the amount of weights needed.
But its possible the installer did not do the job properly in the first place. Its critical how the wheel is centered on the machine.
BUT the tires may actually be defective!!!
But its possible the installer did not do the job properly in the first place. Its critical how the wheel is centered on the machine.
BUT the tires may actually be defective!!!
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DR'76 (11-27-2016)
11-27-2016, 03:40 PM
#3
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St. Jude Donor '05
BTDT if the tires are that far out they are no good youll have issues take them back. Should need very little weight
11-27-2016, 04:41 PM
#4
did the tire installer try to reposition the tires on the wheel?
11-27-2016, 10:05 PM
#5
Pro
Thread Starter
Well, actually, *I'm* the installer... in case I wasn't thinking about something obvious, I wasn't going to admit it! I'm a technician by trade, and have installed many tires, but we do have a designated "tire / front-end" guy who does the majority of tire installs/balancing/alignments, etc... But since this was for my personal vehicle, I did these myself...
"mikem350" and "MelWff": I did check the "road force" measurements, and they were surprisingly good. 5 lb. and 7 lb. Our machine gives us a warning when they exceed 25 lb, which can then *usually* be corrected, unless the rim is bent and/or the tire is truly defective. Since my numbers were so low, I didn't bother to try correcting w/ this method, but will give it a shot...
"cuisinartvette": Agreed, these numbers are ridiculous!
I'll run it by our "tire guy", but do think something is fishy w/ these tires!!!
Thanks for input!
"mikem350" and "MelWff": I did check the "road force" measurements, and they were surprisingly good. 5 lb. and 7 lb. Our machine gives us a warning when they exceed 25 lb, which can then *usually* be corrected, unless the rim is bent and/or the tire is truly defective. Since my numbers were so low, I didn't bother to try correcting w/ this method, but will give it a shot...
"cuisinartvette": Agreed, these numbers are ridiculous!
I'll run it by our "tire guy", but do think something is fishy w/ these tires!!!
Thanks for input!
11-29-2016, 10:40 PM
#6
Pro
Thread Starter
Well, it looks like the tires aren't so bad after all! Here's what I did today:
I set the balancer up to measure for tap-on weights. The results were a much more respectable 2.25 oz per side (not "wonderful", but not terribly bad). I then removed the tire to see how much imbalance was from tire and how much was from the wheel. The bare rim had an imbalance of 1.25 oz outer and 0.75 oz inner, so that left 1.0 oz and 1.5 oz imbalance of the tire. Again, far-from perfect, but for what I paid for them, I guess I'm OK w/ it!
I now need to find "shiny" tap-on weights for the outer/face side of my polished aluminum rims. I work for a German manufacturer who's customers would never accept tap-on weights on their "precious" vehicle, so was only able to find a handful of them laying about the shop, but they were an awful "battleship grey", and I'd just hate to see these on the outside surface of the TT's!
So, I still can't explain how I had better luck w/ previous tires and was able to use stick-ons, but a majority of the imbalance was actually from my rims... Hmmmm??? And the date codes were "0915" and "0516" (a year apart, but not too old - I've installed much older tires on cars worth way much more than my house!)
Thanks again for the suggestions/advice/information
I set the balancer up to measure for tap-on weights. The results were a much more respectable 2.25 oz per side (not "wonderful", but not terribly bad). I then removed the tire to see how much imbalance was from tire and how much was from the wheel. The bare rim had an imbalance of 1.25 oz outer and 0.75 oz inner, so that left 1.0 oz and 1.5 oz imbalance of the tire. Again, far-from perfect, but for what I paid for them, I guess I'm OK w/ it!
I now need to find "shiny" tap-on weights for the outer/face side of my polished aluminum rims. I work for a German manufacturer who's customers would never accept tap-on weights on their "precious" vehicle, so was only able to find a handful of them laying about the shop, but they were an awful "battleship grey", and I'd just hate to see these on the outside surface of the TT's!
So, I still can't explain how I had better luck w/ previous tires and was able to use stick-ons, but a majority of the imbalance was actually from my rims... Hmmmm??? And the date codes were "0915" and "0516" (a year apart, but not too old - I've installed much older tires on cars worth way much more than my house!)
Thanks again for the suggestions/advice/information
11-30-2016, 07:06 AM
#7
Drifting
Well, it looks like the tires aren't so bad after all! Here's what I did today:
I set the balancer up to measure for tap-on weights. The results were a much more respectable 2.25 oz per side (not "wonderful", but not terribly bad). I then removed the tire to see how much imbalance was from tire and how much was from the wheel. The bare rim had an imbalance of 1.25 oz outer and 0.75 oz inner, so that left 1.0 oz and 1.5 oz imbalance of the tire. Again, far-from perfect, but for what I paid for them, I guess I'm OK w/ it!
I now need to find "shiny" tap-on weights for the outer/face side of my polished aluminum rims. I work for a German manufacturer who's customers would never accept tap-on weights on their "precious" vehicle, so was only able to find a handful of them laying about the shop, but they were an awful "battleship grey", and I'd just hate to see these on the outside surface of the TT's!
So, I still can't explain how I had better luck w/ previous tires and was able to use stick-ons, but a majority of the imbalance was actually from my rims... Hmmmm??? And the date codes were "0915" and "0516" (a year apart, but not too old - I've installed much older tires on cars worth way much more than my house!)
Thanks again for the suggestions/advice/information
I set the balancer up to measure for tap-on weights. The results were a much more respectable 2.25 oz per side (not "wonderful", but not terribly bad). I then removed the tire to see how much imbalance was from tire and how much was from the wheel. The bare rim had an imbalance of 1.25 oz outer and 0.75 oz inner, so that left 1.0 oz and 1.5 oz imbalance of the tire. Again, far-from perfect, but for what I paid for them, I guess I'm OK w/ it!
I now need to find "shiny" tap-on weights for the outer/face side of my polished aluminum rims. I work for a German manufacturer who's customers would never accept tap-on weights on their "precious" vehicle, so was only able to find a handful of them laying about the shop, but they were an awful "battleship grey", and I'd just hate to see these on the outside surface of the TT's!
So, I still can't explain how I had better luck w/ previous tires and was able to use stick-ons, but a majority of the imbalance was actually from my rims... Hmmmm??? And the date codes were "0915" and "0516" (a year apart, but not too old - I've installed much older tires on cars worth way much more than my house!)
Thanks again for the suggestions/advice/information
Like suggested earlier, try spinning the tire on the rim this can give you a huge advantage when it comes to balancing.
On my tires I did the static balance- no wheel weights on the outside. I'm running the stick on weights in the wheel. I then use nicely cut pieces of foil tape to cover and hold them in place. You cannot even see it unless you really look
11-30-2016, 08:02 AM
#8
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St. Jude Donor '09-'10-'11
Glad you got the issue sorted out. It could just be that you have been lucky in tire placement all those times in the past.
12-01-2016, 05:36 AM
#9
Pro
Thread Starter
Just a little update: I tried the static balance, but the balancer just wasn't cooperating! It kept indicating to put weights on top of each other, so not sure what was going on there...? I may need a lesson on using this method???
I did spin the tires per the balancer's recommendation and got the tire w/ 7 lb road force down to 3 lb (the 5 lb tire stayed at 5 lb, but an improvement overall)
I did spin the tires per the balancer's recommendation and got the tire w/ 7 lb road force down to 3 lb (the 5 lb tire stayed at 5 lb, but an improvement overall)
12-01-2016, 09:59 AM
#10
Team Owner
I suspect there is some issue with THAT wheel installing properly on the balancer. There may be some interference at the mounting face or some binding in the stud holes. The wheel/tire was likely 'cocked' when your first checked it.
But, that could mean that THAT wheel is going to have trouble installing correctly on your vehicle, as well. Check it all out to be sure there is not some [physical] problem with wheel installation.
But, that could mean that THAT wheel is going to have trouble installing correctly on your vehicle, as well. Check it all out to be sure there is not some [physical] problem with wheel installation.
12-01-2016, 11:43 AM
#11
be careful if you use weights that clip onto the rim of the wheel, if they let go at speed they will crack your fender.
12-01-2016, 10:12 PM
#12
Pro
Thread Starter
7T1vette: Will double-check before installing on car... still need to mount and balance the fronts. 
MelWff: Good point! Another reason to avoid the tap-ons!
MelWff: Good point! Another reason to avoid the tap-ons!