Gear Diff VS Ball DIff
11-07-2007, 05:03 AM
#1
Gear Diff VS Ball DIff
Guys which is better gear diff. or ball diff.?
11-07-2007, 05:53 AM
#2
Tech Regular
Control --> ball diff.
Ease of assembly and maintenance --> gear diff.
Ease of assembly and maintenance --> gear diff.
11-07-2007, 06:49 AM
#3
Hi
You need to search for the answers...
Go down to Borders, Kinokuniya, Times or MPH and refer to page 80 of the latest copy (December issue) of Radio Control Car Action...
You need to search for the answers...
Go down to Borders, Kinokuniya, Times or MPH and refer to page 80 of the latest copy (December issue) of Radio Control Car Action...
11-07-2007, 06:56 AM
#4
Tech Regular
Which shelf is it on? I went to borders a week ago but did not see RCCA on the magazine shelves.
11-07-2007, 07:37 AM
#5
11-07-2007, 09:34 AM
#6
hi,
The following assumes 1/10 electric car diffs. 1/8 diffs are more difficult to explain (Torsen etc...)
You should first try to understand why a car requires a differential in the first place. If you really understand, the rest of this post will be nothing more than a confirmation shot.
A gear diff is more durable and is maintenance free until the gears wear out, by then the car itself should have worn out. You can run them dry(no grease) or with grease of different viscosity. Tamiya Anti Wear is a very thick type of grease as compared to Tamiya Ceramic grease. The type of grease used affects the amount of tightness. Thicker oil/grease = Tighter diff action.
Gear diff have less consistant performance due to grease heating up during long runs causing the grease to loose viscosity, or by grease leaking out of the diff housing after prolonged use. Greased diffs require top up to maintain performance.
A ball diff requires more maintenance, replacement of diff balls and diff rings. The main advantage of a ball diff is ease of adjustability of tightness. A car's differentials affect its driving characteristics a great deal. A driver who is able to setup his differential well will have the advantage of a better handling car. Some say ball diffs may be allowed to slip by not tightening the assembly too much, allowing the slippage to control torque going to the rear wheels. Contrary to popular belief a slipping diff will quickly overheat and damage the diff. If your car can't handle without allowing the rear diff to slip, you need to look elsewhere, diffs must not slip. Tightness is easily adjusted by tightening or loosening the screw.
Tighter(Looser) FRONT diff:
- More(Less) stability when braking into corners
- Less(More) corner entry/exit response
- Less(More) mid corner steering
Tighter(Looser) REAR diff:
- Increases(Decreases) on-throttle steering
- Better(Less) acceleration when grip is high
- More(Less) on-throttle oversteer
- More(Less) turn-in understeer
The following assumes 1/10 electric car diffs. 1/8 diffs are more difficult to explain (Torsen etc...)
You should first try to understand why a car requires a differential in the first place. If you really understand, the rest of this post will be nothing more than a confirmation shot.
A gear diff is more durable and is maintenance free until the gears wear out, by then the car itself should have worn out. You can run them dry(no grease) or with grease of different viscosity. Tamiya Anti Wear is a very thick type of grease as compared to Tamiya Ceramic grease. The type of grease used affects the amount of tightness. Thicker oil/grease = Tighter diff action.
Gear diff have less consistant performance due to grease heating up during long runs causing the grease to loose viscosity, or by grease leaking out of the diff housing after prolonged use. Greased diffs require top up to maintain performance.
A ball diff requires more maintenance, replacement of diff balls and diff rings. The main advantage of a ball diff is ease of adjustability of tightness. A car's differentials affect its driving characteristics a great deal. A driver who is able to setup his differential well will have the advantage of a better handling car. Some say ball diffs may be allowed to slip by not tightening the assembly too much, allowing the slippage to control torque going to the rear wheels. Contrary to popular belief a slipping diff will quickly overheat and damage the diff. If your car can't handle without allowing the rear diff to slip, you need to look elsewhere, diffs must not slip. Tightness is easily adjusted by tightening or loosening the screw.
Tighter(Looser) FRONT diff:
- More(Less) stability when braking into corners
- Less(More) corner entry/exit response
- Less(More) mid corner steering
Tighter(Looser) REAR diff:
- Increases(Decreases) on-throttle steering
- Better(Less) acceleration when grip is high
- More(Less) on-throttle oversteer
- More(Less) turn-in understeer
11-07-2007, 03:16 PM
#7
Tech Apprentice
Ray..
Always Learn something new in this forum...
thumbs up for ur great and easy to understand explaination bro..
Ive read a thousand times on Tamiya Radio Control Guide Book on diff, but still catch no ball...
So if i want to upgrade to ball diff..
do i need to change both front and rear diff or its ok to upgrade on one of them.? front?
TIA
Always Learn something new in this forum...
thumbs up for ur great and easy to understand explaination bro..
Ive read a thousand times on Tamiya Radio Control Guide Book on diff, but still catch no ball...
So if i want to upgrade to ball diff..
do i need to change both front and rear diff or its ok to upgrade on one of them.? front?
TIA
11-08-2007, 12:07 AM
#8
You can change only 1 diff, no need to change both at the same time, usually the rear diff to ball diff first.
Glad it helped.
Glad it helped.
11-08-2007, 03:17 AM
#9
Is ball diff. disposable? when one part spoil do you need to replace all.
Any shops selling parts by parts like
1. ball bearing
2. steel ball
3. ring gear
4. etc
Which part is prone to get spoil?
Any shops selling parts by parts like
1. ball bearing
2. steel ball
3. ring gear
4. etc
Which part is prone to get spoil?
11-08-2007, 10:05 AM
#10
Disposable?
It really depends on your budget, if you are rich, your whole car is disposable, if you are on a tight budget, you will run your tires until the inserts fall out. Me, always on a controlled budget, I will only buy stuff which I am very sure will improve my laptimes, the biggest problem with my car is still the driver, not the equipment. Seriously.
Usually the balls are easy to damage if you tighten the diff too much in the beginning. Otherwise they will just become dirty/flat spotted after prolong usage and will make your ball diff feel like there is sand inside(Gritty is the common term). Diff rings will need replacement after maybe 3 changes of balls. Every 3 set of balls to 1 set of rings. Depends on how often you run and rebuilt. If you change the balls and the diff still feels gritty, then you can be sure you need new diff rings.
The shop that you bought the car from will usually stock parts for the car/diff etc. Bearings, gears, balls, diff rings. May come in a set.
You can get REALLY cheap steel balls from ball bearing shops, SKF Bearings, for example. Google for SKF Bearings Singapore. You will never have to worry about diff balls again.
It really depends on your budget, if you are rich, your whole car is disposable, if you are on a tight budget, you will run your tires until the inserts fall out. Me, always on a controlled budget, I will only buy stuff which I am very sure will improve my laptimes, the biggest problem with my car is still the driver, not the equipment. Seriously.
Usually the balls are easy to damage if you tighten the diff too much in the beginning. Otherwise they will just become dirty/flat spotted after prolong usage and will make your ball diff feel like there is sand inside(Gritty is the common term). Diff rings will need replacement after maybe 3 changes of balls. Every 3 set of balls to 1 set of rings. Depends on how often you run and rebuilt. If you change the balls and the diff still feels gritty, then you can be sure you need new diff rings.
The shop that you bought the car from will usually stock parts for the car/diff etc. Bearings, gears, balls, diff rings. May come in a set.
You can get REALLY cheap steel balls from ball bearing shops, SKF Bearings, for example. Google for SKF Bearings Singapore. You will never have to worry about diff balls again.
11-26-2007, 06:42 AM
#11
Anyone had the experience of buying a new ball diff or just replaced an entire set of ball and diff rings just to find that the diff is STILL not smooth? The diff still feels like it has tight spots when you rotate them? Especially true when you try to make the diff assembly tight for tuning purpose.
Try assembling/tightening the diff screw slowly, while AT THE SAME TIME, rotate the diff outdrives. The idea is, not to allow one contact point of the ball/diff ring to remain as you tighten. When done correctly, the result is a diff with no flat spots. Flat spot on the balls or dents diff rings causes the diff to feel rough when tightened.
Try assembling/tightening the diff screw slowly, while AT THE SAME TIME, rotate the diff outdrives. The idea is, not to allow one contact point of the ball/diff ring to remain as you tighten. When done correctly, the result is a diff with no flat spots. Flat spot on the balls or dents diff rings causes the diff to feel rough when tightened.
11-26-2007, 07:26 AM
#12
Ray, is that like using the diff balls to 'wear' a groove onto the diff plates?
11-26-2007, 08:38 AM
#13
Nov, erm... no. How should i put it?
Lets illustrate the other extreme of diff building, I will call it the "wrong way":
- I put everything in place, then I begin to screw the diff together, all at once, I tighten the diff ALL THE WAY, with speed and force, to the desired tightness, without once spining the diff to make it work.
- So what happens? If the balls are harder, the balls will make a VERY TINY dent in the diff rings. If you have 8 balls, there will be 8 tiny dents on the diff ring on each diff ring where the balls touch the diff ring. If the rings are harder than the ball, the balls will be dented by the rings. Each ball will have 2 tiny flat dents on the position where it touches the ring. These dents will make the diff feel rough.
So spining the diff while you tighten will REDUCE the chance of these dents forming, because the ball-to-diff ring contact points keep changing.
This phenomenon is very real for steel/alum diff outdrives, plastic ones are more forgiving cause they flex abit if you over tighten.
Wearing a groove on the diff plates/rings happens after the diff has been working/spining for long periods of time. Its a normal "wear pattern", when this groove becomes too deep, the diff loses tightness and requires retightening. Thats the break-in process. Of course, when tightening doesn't help anymore, its time to replace parts. I always try to break-in the diff with 2 volts on a sliver can while holding 1 wheel. Then after that, recheck the tightness. But nowadays...lazy la. Esp my M03, wa piang... so many screws. F103GT easier a bit. TCs easiest, open one side camber link can liao. But take it easy, heat builds up between ball and ring. Take breaks even when breaking in.
Lets illustrate the other extreme of diff building, I will call it the "wrong way":
- I put everything in place, then I begin to screw the diff together, all at once, I tighten the diff ALL THE WAY, with speed and force, to the desired tightness, without once spining the diff to make it work.
- So what happens? If the balls are harder, the balls will make a VERY TINY dent in the diff rings. If you have 8 balls, there will be 8 tiny dents on the diff ring on each diff ring where the balls touch the diff ring. If the rings are harder than the ball, the balls will be dented by the rings. Each ball will have 2 tiny flat dents on the position where it touches the ring. These dents will make the diff feel rough.
So spining the diff while you tighten will REDUCE the chance of these dents forming, because the ball-to-diff ring contact points keep changing.
This phenomenon is very real for steel/alum diff outdrives, plastic ones are more forgiving cause they flex abit if you over tighten.
Wearing a groove on the diff plates/rings happens after the diff has been working/spining for long periods of time. Its a normal "wear pattern", when this groove becomes too deep, the diff loses tightness and requires retightening. Thats the break-in process. Of course, when tightening doesn't help anymore, its time to replace parts. I always try to break-in the diff with 2 volts on a sliver can while holding 1 wheel. Then after that, recheck the tightness. But nowadays...lazy la. Esp my M03, wa piang... so many screws. F103GT easier a bit. TCs easiest, open one side camber link can liao. But take it easy, heat builds up between ball and ring. Take breaks even when breaking in.
Last edited by Ray Lan; 11-26-2007 at 09:07 AM.
11-26-2007, 08:50 AM
#14
In engineering, things always look good/okay from far, but if you zoom in to see everything in detail, alot can go wrong.
Thats the difference between a well designed and poorly designed mechanical part. To get accurate and minimum tolerance in parts requires alot of painstaking precision which is expensive. Thats why quality always cost more.
My solution? Cheap. Buy lots of 0.1 - 0.3mm shims in many sizes, takes up the slack/freeplay. Works wonders in making the part perform better, longer.
Cheap/lightweight/strong, you can only chose 2.
Thats the difference between a well designed and poorly designed mechanical part. To get accurate and minimum tolerance in parts requires alot of painstaking precision which is expensive. Thats why quality always cost more.
My solution? Cheap. Buy lots of 0.1 - 0.3mm shims in many sizes, takes up the slack/freeplay. Works wonders in making the part perform better, longer.
Cheap/lightweight/strong, you can only chose 2.
02-18-2011, 11:37 PM
#15
Hy there!
Found this thread and wanted to restart it again.
Now with so many drivers switched to the new available spec R gear diffs for the top level TC, can anybody share the esperience about the major differences in handling (laptimes) with the gear and the ball diff?
Also a compare in wich class wich diff suits better?
Any input would be helpful
Greetings Rainer
Found this thread and wanted to restart it again.
Now with so many drivers switched to the new available spec R gear diffs for the top level TC, can anybody share the esperience about the major differences in handling (laptimes) with the gear and the ball diff?
Also a compare in wich class wich diff suits better?
Any input would be helpful
Greetings Rainer
