Tokamak
SILVER Star
- Thread starter
- #21
3030D vs TR0305A
[I guess I don't understand why there's no expansion in the knuckle itself as the arms and bearing caps are tightened. Both the ball and the knuckle are cast and machined. The knuckle is beefier and supported by the spindle but I'd think it would still flex during initial assembly.
]
The measurements I made were with the centering tool compressing the ball. I normalized the graph to 0 at the highest compression so the chart could be related to shim thickness rather than compression.
When installing the knuckle noticed that the spindle plate would not fit directly. Measured the knuckle opening where the spindle plate bolts on and it was .010" taller than it was wide. That is the expansion of the knuckle you were wondering about and maybe why the spring pull preload with the SST tool and the knuckle are slightly different after assembly. Had already bolted up the seal on the back so couldn't get a measurement with and without the spindle plate undistorting the knuckle. May be worth unbolting the seal to find out the difference.
[I have heard of folks both increasing AND decreasing preload when running really large tires to either make turning easier or prevent bearing wear depending on the camp each was in. All parties were commonly breaking things and thus doing a fair bit of disassembly/reassembly. I was never offered any proof or survival rate stats so it was pure shovel conjecture to me.]
From what was measured don't think I would ever lower the preload. Loose bearings pounding around have to be worse than constant contact bearings under a heavier load. The shock load from pounding can break stuff fast.
Found some interesting things about the trunion bearings.
Koyo 3030D
14 rollers
Roller lenght .310
14 x .310 = 4.34" roller contact length
70% of the TR0305
.600" overall thickness (used)
Koyo TR0305A
15 Rollers
Roller length .410
15 x .410 = 6.15" roller contact length
40% more than 3030D
.623" overall thickness (new)
Contact angle is the same.
Assume the same spherical contact face so contact area becomes contact length.
Is one better than the other? Could you run the TR0350A at 40% more preload?
I'm sure both bearings are stronger than stock conditions would put them through.
[I guess I don't understand why there's no expansion in the knuckle itself as the arms and bearing caps are tightened. Both the ball and the knuckle are cast and machined. The knuckle is beefier and supported by the spindle but I'd think it would still flex during initial assembly.
]The measurements I made were with the centering tool compressing the ball. I normalized the graph to 0 at the highest compression so the chart could be related to shim thickness rather than compression.
When installing the knuckle noticed that the spindle plate would not fit directly. Measured the knuckle opening where the spindle plate bolts on and it was .010" taller than it was wide. That is the expansion of the knuckle you were wondering about and maybe why the spring pull preload with the SST tool and the knuckle are slightly different after assembly. Had already bolted up the seal on the back so couldn't get a measurement with and without the spindle plate undistorting the knuckle. May be worth unbolting the seal to find out the difference.
[I have heard of folks both increasing AND decreasing preload when running really large tires to either make turning easier or prevent bearing wear depending on the camp each was in. All parties were commonly breaking things and thus doing a fair bit of disassembly/reassembly. I was never offered any proof or survival rate stats so it was pure shovel conjecture to me.]
From what was measured don't think I would ever lower the preload. Loose bearings pounding around have to be worse than constant contact bearings under a heavier load. The shock load from pounding can break stuff fast.
Found some interesting things about the trunion bearings.
Koyo 3030D
14 rollers
Roller lenght .310
14 x .310 = 4.34" roller contact length
70% of the TR0305
.600" overall thickness (used)
Koyo TR0305A
15 Rollers
Roller length .410
15 x .410 = 6.15" roller contact length
40% more than 3030D
.623" overall thickness (new)
Contact angle is the same.
Assume the same spherical contact face so contact area becomes contact length.
Is one better than the other? Could you run the TR0350A at 40% more preload?
I'm sure both bearings are stronger than stock conditions would put them through.
