Front & Rear Gear Differential

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.

keithlaw 發表於 2011-6-1 13:55

                               
登錄/註冊後可看大圖

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.

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?

keithlaw 發表於 2011-6-1 22:05

                               
登錄/註冊後可看大圖

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.  

"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?

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.

keithlaw 發表於 2011-6-1 19:40

                               
登錄/註冊後可看大圖

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.

回復 hk_sdu 的帖子

C Hing,

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

Thanks All !!

^^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...

yokomo 發表於 2011-6-2 08:51

                               
登錄/註冊後可看大圖

回復 hk_sdu 的帖子

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

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

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)

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 !!

yokomo 發表於 2011-6-2 13:28

                               
登錄/註冊後可看大圖

回復 lung1 的帖子

Gear diff (cons):

front gear diff~~~~

lung1 發表於 2011-6-2 13:24

                               
登錄/註冊後可看大圖

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

Swing Shaft will be the same as rear one?

Player 發表於 2011-6-2 13:46

                               
登錄/註冊後可看大圖

Swing Shaft will be the same as rear one?

almost same depend what gear diff you are using.

What a good answer from Lung1

singlau714 發表於 2011-6-2 12:54

                               
登錄/註冊後可看大圖

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

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

singlau714 發表於 2011-6-2 21:43

                               
登錄/註冊後可看大圖

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.