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標題: Front & Rear Gear Differential [打印本頁]

作者: yokomo 時間: 2011-5-31 23:28
標題: Front & Rear Gear Differential
Do you know what is the advantage of using Front & Rear Gear Differential in 1/10 Touring?

Thanks All !!

作者: hk_sdu 時間: 2011-6-1 01:48
本帖最後由 hk_sdu 於 2011-6-1 01:48 編輯

EP touring becoming very powerful today, replace rear ball diff with rear gear diff to take the advantage of less maintenance and consistant diff effect.
Most of the player is looking for more steering by replacing front spool to front diff, with very thick diff gease, like 500k.

作者: yokomo 時間: 2011-6-1 09:03
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C Hing, thx for your comment .....

Actually, I want to try front Gear Differential with 500K.

Thanks All !!

作者: fatchickterian 時間: 2011-6-1 10:59
What will be your rear diff oil then?? 100K??
Just want to know what pepole are using! I'm new to gear diff too!!

作者: yokomo 時間: 2011-6-1 11:24
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The number shown on the that bottle is 1000.

作者: fatchickterian 時間: 2011-6-1 11:28

yokomo 發表於 2011-6-1 11:24

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The number shown on the that bottle is 1000.

C-hing, which brand is it??

so u're using 500000 front, and 1000 rear, is it right??

作者: Player 時間: 2011-6-1 11:30

yokomo 發表於 2011-6-1 11:24

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The number shown on the that bottle is 1000.

Front Spool not good?
..steering should be more sensitive ...

作者: yokomo 時間: 2011-6-1 11:58
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I am now using the one shown in the pic for Rear. For the front, I will try to use Kyosho 500K.

Thanks All !!

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作者: fatchickterian 時間: 2011-6-1 12:01

yokomo 發表於 2011-6-1 11:58

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I am now using the one shown in the pic for Rear. For the front, I will ...

Woooh, Thanks for sharing!!

作者: keithlaw 時間: 2011-6-1 13:55
本帖最後由 keithlaw 於 2011-6-1 13:56 編輯

hk_sdu 發表於 2011-6-1 01:48

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EP touring becoming very powerful today, replace rear ball diff with rear gear diff to take the adva ...

其實用 gear diff 應該係想有真車 LSD 既效果. 用gear diff oil 等佢唔好咁易出入灣 Inner Wheel Spin 失去動力. 有 gear diff oil, 當inner wheel 離地時, outer wheel 唔會冇晒力, 仲有力出灣.

以上只是本人對真車既智識放係 RC到. 有錯唔好插. 大家討論下

作者: keithlaw 時間: 2011-6-1 13:58
The denser then diff oil is, the more harder for the car to lose the torque to one unloaded wheel.

作者: keithlaw 時間: 2011-6-1 14:00
本帖最後由 keithlaw 於 2011-6-1 14:01 編輯

Spool tends to understeer a little bit, let driver has more time to control the car, but eats tire a lot.
But spool has more direct feeling.
That's what i feel

作者: fr888 時間: 2011-6-1 14:19
gear diff唔同LSD, 其實有D 1:8 車車真係有LSD

作者: yokomo 時間: 2011-6-1 14:24
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C Hing,

Can I know what is difference between gear diff & LSD?
Thanks All !!

作者: fr888 時間: 2011-6-1 14:31
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LSD is similar to normal diff, except it will "limit the slip" for the wheel with less traction so that will help the car to go for high speed corners typically

有錯物插

作者: jf813 時間: 2011-6-1 15:21
本帖最後由 jf813 於 2011-6-1 15:23 編輯

LSD for 1/8 and 1/5 have friction plates inside. The rest is like a normal diff. Under low or no load the diff will turn smoothly. But when you apply throttle or brake the diff inside housing push apart and putting pressure onto the plates. Causing the diff have "locking" effect. Same as real car LSD. Kyosho have similar design for v-one and 1/8 buggy too. But instead for friction plate it use a square block to lock the diff gear.

作者: keithlaw 時間: 2011-6-1 15:28
yes. Sure Gear Diff is not LSD. But it can help limit the slip a little

作者: hk_sdu 時間: 2011-6-1 18:04
本帖最後由 hk_sdu 於 2011-6-1 18:06 編輯

The gear diff of EP RC, in real car, they called it "OPEN DIFF". Nothing to do with LSD.

LSD is another story like jf813 c-hing said, it lock and close the diff with several different methods. At different situation. So there is 1 way, 1.5 way and 2 way LSD. Do NOT ask me what is this, you should know how to get this knowledge from Internet with tons of LSD information.

作者: hk_sdu 時間: 2011-6-1 18:09
Basic overview of LSD:

http://en.wikipedia.org/wiki/Limited_slip_differential

作者: keithlaw 時間: 2011-6-1 19:40
本帖最後由 keithlaw 於 2011-6-1 19:40 編輯

Well. It is an open diff for sure. But why people use different density diff oil? What is their main effect on the EP? People use like 500K oil in the diff.... which is really hard to turn the diff.

作者: Tinng 時間: 2011-6-1 21:22
Seem nowadays people use different oil thickness to control the front tire gripping ability during cornering. For sure, the front spool can eliminate the oversteer during corner entry even applying a heavy brake.

作者: Tinng 時間: 2011-6-1 21:28

keithlaw 發表於 2011-6-1 13:55

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其實用 gear diff 應該係想有真車 LSD 既效果. 用gear diff oil 等佢唔好咁易出入灣 Inner Wheel Spin 失 ...

The real car is using rigid chassis and inner wheels would lift up during high speed corner....our R/C touring is flexible chassis while it wont lift up inner wheel easily....so I believe LSD is for R/C buggy more than in touring R/C.

作者: keithlaw 時間: 2011-6-1 22:05
The inner wheel still lift up a lot indeed.

"Seem nowadays people use different oil thickness to control the front tire gripping ability during cornering."
How the oil control the traction?

作者: Tinng 時間: 2011-6-1 23:24

keithlaw 發表於 2011-6-1 22:05

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The inner wheel still lift up a lot indeed.

"Seem nowadays people use different oil thickness to ...

4WD touring RC car weight distribution is quite even aor balance, the suspension tuning between front and rear is pretty close + flexible chassis prohibit the weight transfer to rear or front wheel only.....so normally 1 wheel lift up is not likely to happen in 4WD onroad R/C or the suspension tunning is not perfect.

Oil thickness provide friction and delay for the differential gear to function during corner. Front tires are skidding before the gear function and so lower the traction of front tires.

作者: keithlaw 時間: 2011-6-2 00:46
"Front tires are skidding before the gear function"
Yeah, that's what i am trying to say-- both wheel will still get the same speed during cornering. The more denser the oil gets, the more both wheel can get the same amount of torque during corner and it is kinda like a 1-way LSD working on it, isn't it?

作者: hk_sdu 時間: 2011-6-2 02:00
I only have experience on FF03 comparing the gear diff with 500k oil and front spool. Gear diff provide a lot better in term of turnin, mid corner and everything. It is in between spool and ball diff.

作者: hk_sdu 時間: 2011-6-2 02:02
本帖最後由 hk_sdu 於 2011-6-2 02:05 編輯

keithlaw 發表於 2011-6-1 19:40

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Well. It is an open diff for sure. But why people use different density diff oil? What is their main ...

Thin or heavy diff oil is similar to the effect of different force apply on ball diff lock nut.

Take rear gear diff as example, it usually range from 1000 -3000 oil. Some people like to use 1000 or even 700 with a very responsive tail. Some people like 3000 which can provide a little more stable handling overall.

experience it and u will know.

作者: yokomo 時間: 2011-6-2 08:51
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C Hing,

Can I know how much 500K was added? Full or half?

Thanks All !!

作者: milkboy 時間: 2011-6-2 11:36
本帖最後由 milkboy 於 2011-6-2 11:39 編輯

^^b
good topic with clear explanation.
But not in Chinese.
^^b
I give you all 5 stars......

^^~ How about the limited slip diff, traction control.......etc...

作者: hk_sdu 時間: 2011-6-2 12:26

yokomo 發表於 2011-6-2 08:51

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C Hing,

According NT1 manual, the oil should cover the cross pin inside the diff unit. Around 70-80%

Yes, milkboy, it is very rare to have pure technical discuss in this forum without argue and finger pointing at the end

作者: singlau714 時間: 2011-6-2 12:54
What will happen if I put some thin diff oil (say 2000) at the front diff?
Any c hing tried this before?

作者: lung1 時間: 2011-6-2 13:24
本帖最後由 lung1 於 2011-6-2 15:18 編輯

i try a front and rear gear diff a few of months,
For my opinions:

Front gear diff (pros):
- provide more steering on mid-coner and coner exit
- more smooth feeling on low speed coner especially U-turn
- low maintence compare with front spool cup (very durable when using "馬x膠")
- reduce front tire over heating (tire life is longer

)

Front gear diff (cons):
- less direct feeling when acceleration and braking compare with spool
- oversteer on coner exit when using thin oil
- more cost (need buy a gear diff and change shorter dogbone)

作者: yokomo 時間: 2011-6-2 13:28
回復 lung1 的帖子

Gear diff (cons):
- less direct feeling when acceleration and braking
- oversteer on coner exit when using thin oil
- more cost (need buy a gear diff and change shorter dogbone)

Do u mean thin oil in the rear gear diff? Can I know what viscosity of oil used for front & rear gear diff? 1000 for rear & 500K for front?
Thanks All !!

作者: lung1 時間: 2011-6-2 13:30
本帖最後由 lung1 於 2011-6-2 13:31 編輯

yokomo 發表於 2011-6-2 13:28

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Gear diff (cons):

front gear diff~~~~

作者: Player 時間: 2011-6-2 13:46

lung1 發表於 2011-6-2 13:24

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i try a front and rear gear diff a few of months,
For my opinions:

Swing Shaft will be the same as rear one?

作者: lung1 時間: 2011-6-2 13:49
本帖最後由 lung1 於 2011-6-2 13:50 編輯

Player 發表於 2011-6-2 13:46

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Swing Shaft will be the same as rear one?

almost same depend what gear diff you are using.

作者: hk_sdu 時間: 2011-6-2 14:49
本帖最後由 hk_sdu 於 2011-6-2 14:49 編輯

What a good answer from Lung1

作者: fr888 時間: 2011-6-2 17:55

singlau714 發表於 2011-6-2 12:54

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What will happen if I put some thin diff oil (say 2000) at the front diff?
Any c hing tried this be ...

Will super oversteer, even offroad 1:8 buggies typically use 5k-7k oil for front

作者: singlau714 時間: 2011-6-2 21:43
By the way, why do u guys think if I use Ball Diff at front? Will it work?

作者: defcone 時間: 2011-6-2 22:06

singlau714 發表於 2011-6-2 21:43

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By the way, why do u guys think if I use Ball Diff at front? Will it work?

It will slip and make the car very hard to drive.

作者: singlau714 時間: 2011-6-2 22:16
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what if i lock it tight?

作者: Tinng 時間: 2011-6-2 22:21

singlau714 發表於 2011-6-2 22:16

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what if i lock it tight?

U cannot lock it tight...you will either break the screw or diff get loose again in first 3 mins run!

作者: fr888 時間: 2011-6-3 20:33
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