TYRE TRUING
Much is written about this very important 'tuning' aspect, but listen . . .
Don't even THINK about wasting time on truing tyres unless
Just get a new one.
THEN check if the wheels are round and mounted true on the good axle.
Only when you have a perfectly straight axle and properly mounted, ROUND wheels is there the slightest point in even trying to true your tyres.
Of course you might very well have some trouble in locating axles that actually fit your bushings/bearings, but that's another story and that's just one of the reasons for the existence of This other thread!
As a background to this, at yesterdays' club racing, I had a choice of two brand new (box standard) cars for a particular touring car class. Neither had been run before and I had not had much time for preparation. So I gave them both a quick twirl on the faithful Kelvin Test Bench.
One very simple thing has come up in testing brand new cars on the bench and it's this. Some brand new cars are not well lubed on arrival and some not at all! Very low speed test bench running has yielded some interesting data. If I run the car at the lowest speed at which the motor will rotate without stalling and note the amperage it pulls, simple basic lubing of motor bushes, gears and axle bushes will, on average, immediately reduce that amperage by around 20%. This is a substantial saving and well worth the knowing. So that was the first procedure and the data was confirmed - around 20% less amperage on both of them after lubing, even though the gears were already greased on arrival!
The other great thing about the bench's rolling road is that at low speed, it is SO easy to see if the car is bouncing on the roller AND also to clearly view the profile of the tyre on that roller. One of these touring cars was fine, needing only a small amount of tyre truing. But the other was an abomination! While one tyre was OK, the other showed clear daylight almost pemanently between itself and the roller. It was so bad that I decided against tyre truing and whipped the tyre off. Then it became crystal clear that the wheel itself was wobbling like a drunken demented handcart. Even the centre of the wheel could be seen to be tracing an eccentric orbit. So trying to skim the wheel was a waste of time and effort, as I reckoned the axle must be bent. So I gave up on it and raced the other car. I think I finished in the middle of the pack, quite happy, lots of fun.
But practice is what I really need - tons of it!
But perhaps the most interesting thing of all was that, after the race, I gave the car with the slightly bent axle a damned good thrashing round the track. You know what? On our imperfectly smooth track, it was hard to tell the difference in handling between this and the one with the straight axles, round wheels and trued tyres! Let me tell you how this could be. It's because the traction magnets are so powerful in these particular cars that it can almost competely disguise the wheel wobble! No other possible explanation.
Pah!!!!
More ramblings when I next feel like it!
Much is written about this very important 'tuning' aspect, but listen . . .
Don't even THINK about wasting time on truing tyres unless
- The wheels have been trued first and
- Don't even think about truing wheels until you are sure those damned axles are straight!
Just get a new one.
THEN check if the wheels are round and mounted true on the good axle.
Only when you have a perfectly straight axle and properly mounted, ROUND wheels is there the slightest point in even trying to true your tyres.
Of course you might very well have some trouble in locating axles that actually fit your bushings/bearings, but that's another story and that's just one of the reasons for the existence of This other thread!
As a background to this, at yesterdays' club racing, I had a choice of two brand new (box standard) cars for a particular touring car class. Neither had been run before and I had not had much time for preparation. So I gave them both a quick twirl on the faithful Kelvin Test Bench.
One very simple thing has come up in testing brand new cars on the bench and it's this. Some brand new cars are not well lubed on arrival and some not at all! Very low speed test bench running has yielded some interesting data. If I run the car at the lowest speed at which the motor will rotate without stalling and note the amperage it pulls, simple basic lubing of motor bushes, gears and axle bushes will, on average, immediately reduce that amperage by around 20%. This is a substantial saving and well worth the knowing. So that was the first procedure and the data was confirmed - around 20% less amperage on both of them after lubing, even though the gears were already greased on arrival!
The other great thing about the bench's rolling road is that at low speed, it is SO easy to see if the car is bouncing on the roller AND also to clearly view the profile of the tyre on that roller. One of these touring cars was fine, needing only a small amount of tyre truing. But the other was an abomination! While one tyre was OK, the other showed clear daylight almost pemanently between itself and the roller. It was so bad that I decided against tyre truing and whipped the tyre off. Then it became crystal clear that the wheel itself was wobbling like a drunken demented handcart. Even the centre of the wheel could be seen to be tracing an eccentric orbit. So trying to skim the wheel was a waste of time and effort, as I reckoned the axle must be bent. So I gave up on it and raced the other car. I think I finished in the middle of the pack, quite happy, lots of fun.
But practice is what I really need - tons of it!
But perhaps the most interesting thing of all was that, after the race, I gave the car with the slightly bent axle a damned good thrashing round the track. You know what? On our imperfectly smooth track, it was hard to tell the difference in handling between this and the one with the straight axles, round wheels and trued tyres! Let me tell you how this could be. It's because the traction magnets are so powerful in these particular cars that it can almost competely disguise the wheel wobble! No other possible explanation.
Pah!!!!

More ramblings when I next feel like it!
