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First thing to do is identify the tranny ,if automatic and make sure its shifting thru ALL the gears.
IF it is ,, or if you have a stick shift ,, change the rear end gears is only method to increase top speed or lower engine noise,,, if you have the power to spare..
FAST FRED
I have a ? what do i need
to do to my trannie to get
more speed and less scream
out of my engine? please help
any advise is good
Thanx
You haven't given us enough information to really give you a definitive answer, i.e. auto or manual, 4- or 5-speed, single or dual range rear end, size of bus, size and type of engine.
In most transmissions, automatic or manual, the highest gear is direct. In order to get the RPM's down at road speed you will need to get a lower numerically, higher speed rear end.
If your bus has 10-hole Budd wheels this can be accomplished relatively easily and economically by going to a larger wheel which will turn fewer times every mile.
If you have spoke wheels you will have to change your rear end ratio.
One caveat, if your bus is gas powered, make sure your bus has enough HP to pull higher speeds.
Most gas buses are doing about the best they can to turn 60MPH on the flat and really dog down on the hills.
One way to check to see if your bus will be able to turn the higher speeds is to check your manifold vacuum at your top speed.
If your are pulling less than 10" of vacuum you probably won't be able to go much faster regardless of the final gearing.
It takes a lot of HP to push or pull a bus through the air as well as down the road.
Good luck and happy trails.
Mark O.
I have a ? what do i need
to do to my trannie to get
more speed and less scream
out of my engine? please help
any advise is good
Thanx
I have a ? what do i need
to do to my trannie to get
more speed and less scream
out of my engine? please help
any advise is good
Thanx
++++++++++
Hello Hippie Joe
I don't want to argue with the previous writer or doubt his word, but in my experience unless you have REALLY small tires and wheels, just going to a bigger wheel probably won't help. The rest of his advice is sound.
However, on my bus I went from 11:00X20 tires/wheels to 12:00x22.5 tires/wheels and experienced NO difference. Virtually no noticeable change in top end, engine RPM, etc. Before I had stood them up side by side and there wasn't half an inch of height difference anyway.
My opinion and the opionion of my friends is that you need to change hour rear end. And the other fella is right, you haven't given us enough info. What motor/tranny and current rear end are you running now? And waht size tires? THAT will lead to a more helpful discussion
See ya, and feel free to email me if hou can't get help from anyone else. Ilove buses!
I have a ? what do i need
to do to my trannie to get
more speed and less scream
out of my engine? please help
any advise is good
Thanx
++++++++++
Hello Hippie Joe
I don't want to argue with the previous writer or doubt his word, but in my experience unless you have REALLY small tires and wheels, just going to a bigger wheel probably won't help. The rest of his advice is sound.
However, on my bus I went from 11:00X20 tires/wheels to 12:00x22.5 tires/wheels and experienced NO difference. Virtually no noticeable change in top end, engine RPM, etc. Before I had stood them up side by side and there wasn't half an inch of height difference anyway.
My opinion and the opionion of my friends is that you need to change hour rear end. And the other fella is right, you haven't given us enough info. What motor/tranny and current rear end are you running now? And waht size tires? THAT will lead to a more helpful discussion
See ya, and feel free to email me if hou can't get help from anyone else. Ilove buses!
Of course, these are generalizations/averages. Different manufacturers will make things differently so to make sure of your calculations you will need to measure your own tires.
As you can see on the chart, going from a 11.00X20 to a 12X22.5 is not a calculable difference.
I would agree the gentleman didn't experience a change by going to tubeless tires. If the gentleman had gone to a 12X24.5 he would have seen the same difference had he gone from a 9.00X20 to a 11X22.5 or a 10.00X20.
Changing the number of rotations a tire makes in a mile by 15 or 20 RPM's can make a significant difference.
I have a ? what do i need
to do to my trannie to get
more speed and less scream
out of my engine? please help
any advise is good
Thanx
++++++++++
Hello Hippie Joe
I don't want to argue with the previous writer or doubt his word, but in my experience unless you have REALLY small tires and wheels, just going to a bigger wheel probably won't help. The rest of his advice is sound.
However, on my bus I went from 11:00X20 tires/wheels to 12:00x22.5 tires/wheels and experienced NO difference. Virtually no noticeable change in top end, engine RPM, etc. Before I had stood them up side by side and there wasn't half an inch of height difference anyway.
My opinion and the opionion of my friends is that you need to change hour rear end. And the other fella is right, you haven't given us enough info. What motor/tranny and current rear end are you running now? And waht size tires? THAT will lead to a more helpful discussion
See ya, and feel free to email me if hou can't get help from anyone else. Ilove buses!
Of course, these are generalizations/averages. Different manufacturers will make things differently so to make sure of your calculations you will need to measure your own tires.
As you can see on the chart, going from a 11.00X20 to a 12X22.5 is not a calculable difference.
I would agree the gentleman didn't experience a change by going to tubeless tires. If the gentleman had gone to a 12X24.5 he would have seen the same difference had he gone from a 9.00X20 to a 11X22.5 or a 10.00X20.
Changing the number of rotations a tire makes in a mile by 15 or 20 RPM's can make a significant difference.
Good luck and happy trails.
Mark O.
Mark would you please tell me the exact formula you used to figure out the tire revolutions per mile. Thanks,Mike
Of course, these are generalizations/averages. Different manufacturers will make things differently so to make sure of your calculations you will need to measure your own tires.
As you can see on the chart, going from a 11.00X20 to a 12X22.5 is not a calculable difference.
I would agree the gentleman didn't experience a change by going to tubeless tires. If the gentleman had gone to a 12X24.5 he would have seen the same difference had he gone from a 9.00X20 to a 11X22.5 or a 10.00X20.
Changing the number of rotations a tire makes in a mile by 15 or 20 RPM's can make a significant difference.
Good luck and happy trails.
Mark O.
So, moving a bit off topic, does moving from a tube type tire to a tubeless improve the ride?
Of course, these are generalizations/averages. Different manufacturers will make things differently so to make sure of your calculations you will need to measure your own tires.
As you can see on the chart, going from a 11.00X20 to a 12X22.5 is not a calculable difference.
I would agree the gentleman didn't experience a change by going to tubeless tires. If the gentleman had gone to a 12X24.5 he would have seen the same difference had he gone from a 9.00X20 to a 11X22.5 or a 10.00X20.
Changing the number of rotations a tire makes in a mile by 15 or 20 RPM's can make a significant difference.
Good luck and happy trails.
Mark O.
So, moving a bit off topic, does moving from a tube type tire to a tubeless improve the ride?
John the Busboy
I have always found the tubeless ride better. They also seem to go more miles than the tube type. And around here at least, the tubeless are considerably cheaper than the tube type plus the cost of the tube.
As for the formula for figuring out RPM's, I think it is circumfrence divided into 5280.
I cheated by using the chart the state of WA uses in the "SPECIFICATIONS FOR SCHOOL BUSES".
It is so much easier using someone else's work. <G>
As for the formula for figuring out RPM's, I think it is circumfrence divided into 5280.
I cheated by using the chart the state of WA uses in the "SPECIFICATIONS FOR SCHOOL BUSES".
It is so much easier using someone else's work. <G>
Mark O.
To use the formula above for revolutions (by the tire) per mile, the tire diameter needs to be expressed in feet, or alternatively, the 5280 (ft/mile) value could be converted to inches.
The following is a formula I use for relating rpm (motor revs per minute, not tire revs per mile) to mph, final drive gearing, transmission gearing and tire diameter.
rpm = (mph X rearend ratio X trans. ratio) / (tire dia. X .002975)
Notes 1. trans. ratio in high gear is generally 1:1 (trans. ratio =1 )unless the transmission is an overdrive 2. The actual rpm in an automatic transmission vehicle will usually be higher than the formula will calculate due to torque converter slippage. The formula is still usefull for approximating rpm differences due to changes in tire diameter and gearing.
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