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Old 07-05-2007, 07:41 AM   #15361
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In stock you'll find that you maybe able to get away with having the diff a TOUCH loose. And it should give you a bit more handling through the corners.

Anything higher than stock though you want to make sure your diff is pretty tight.
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Old 07-15-2007, 08:10 AM   #15362
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hi guys.....


I've finally decided enough x box 360 and forza for awhile,and started RC racing again.....haven't even used the PRO 4 since the unofficial HPI challenge last year in NJ(where I finished 4th in the a,against ALL types of cars......)


anyway,I've found,in the last 3 weeks,that the PRO 4 is still more than capable of running with the newest 07 xrays....(and this is against racers that have been running all winter,no less....)..


last year,during the challenge,I noticed some noise in the rear diff..I took the diff apart,and ddin't notice anything.....so i ran the car,barking diff and all....

now that I've run the car a few times this year,I've found that the gear teeth were rounding off,a slight curving,and the gears are slipping(clicking),under throttle....

I'm running a 4.5 with Li Po....any hints,or truicks to make the gears last?.......the diffs aren't loosening(I'm using the HD nut...)...just wearing..........thanks....


BTW,the brushless,combined with a shaft drive,is a BEAST out of the hole........it EATS the belt cars......BTW,guys are blowing diffs and belts on the 07 xrays,using the same set up.......so I would like to stay PRO 4 if I can.........
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Old 07-15-2007, 08:36 PM   #15363
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I ran the same set-up on my Pro 4...Novak 4.5/li-po. The torque of brushless motors causes the pinion/diff gear to skip under heavy acceleration. Eventually, you will strip that plastic pinion, which is a pain to get to because of all of the screws to access the rear diff. Solution? NONE. Metal gears would be the obvious fit, but electric cars are prized on being light and no one makes this gear in metal, so, it aint happening. Best bet, load up on these plastic gears, make sure you shim properly to avoid the diff from sliding inside the housing and if possible, control the compulsion to throttle hard (yea right). The Pro 4 is a beast, but running brushless (particularly the low winds) puts too much of a strain on the drivetrain.
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Old 07-15-2007, 09:08 PM   #15364
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Quote:
Originally Posted by bxpitbull View Post
I ran the same set-up on my Pro 4...Novak 4.5/li-po. The torque of brushless motors causes the pinion/diff gear to skip under heavy acceleration. Eventually, you will strip that plastic pinion, which is a pain to get to because of all of the screws to access the rear diff. Solution? NONE. Metal gears would be the obvious fit, but electric cars are prized on being light and no one makes this gear in metal, so, it aint happening. Best bet, load up on these plastic gears, make sure you shim properly to avoid the diff from sliding inside the housing and if possible, control the compulsion to throttle hard (yea right). The Pro 4 is a beast, but running brushless (particularly the low winds) puts too much of a strain on the drivetrain.
thanks pitbull.....

guys running the 07 xray are melting diffs ...and from what I can see,so are the tc5 guys..........I guess Brushless affects us all.....

I'm gonna call my friend at HPI tommorow,see if he has any advice....

how do you think the pro 4 compares to the current generation of cars?...I love mine,to be honest......
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Old 07-15-2007, 09:37 PM   #15365
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Its the best Latemodel Dirt Oval car I have ever driven.Fast like a nascar,nascar,nascar.
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Old 07-16-2007, 02:20 AM   #15366
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There are genuine 19T bevel gears available for the pro 4

And Square i believe make an aluminium 39T bevel gear but ive never seen one.
http://www.rc-square.com/parts22.htm
SHP-19

I would try contacting rc-champ to see if they have the bevel gear and to confirm if it is aluminium
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Old 07-16-2007, 07:29 AM   #15367
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Default I love the car

Personally, I love the car. The only problem I've encountered since going brushless is melting diffs (had metal ones custom made) and the chewing of pinions inside the diffs. Aside of that, the car drove like a dream. I have a Cyclone now that I must say is a rocket, but is a wee bit more finicky. Once its dialed, it's dialed. The Pro4 in my opinion, is not as prone to losing its settings after a crash, but oh well.
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Old 07-24-2007, 10:57 AM   #15368
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Default Pro 4 Rear Differential issues

Ive built my diff acording to the manual, but im still facing issues with it. after every 1 or 2 run's im having to rebuild the rear diff because it sounds/feels like its spinning itself loose. is any one else facing this?
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Old 07-24-2007, 12:44 PM   #15369
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Quote:
Originally Posted by mangoman View Post
There are genuine 19T bevel gears available for the pro 4

And Square i believe make an aluminium 39T bevel gear but ive never seen one.
http://www.rc-square.com/parts22.htm
SHP-19

I would try contacting rc-champ to see if they have the bevel gear and to confirm if it is aluminium
yes..the square bevel gear is aluminum.. don't recommend.. you'll end up breaking some other part of the drivetrain. plus it will run louder than normal.


Quote:
Originally Posted by unashamed View Post
Ive built my diff acording to the manual, but im still facing issues with it. after every 1 or 2 run's im having to rebuild the rear diff because it sounds/feels like its spinning itself loose. is any one else facing this?
This was a common problems. diff screw loosening. are you using the new T-nut? that will help keep it tight along with a drop of blue locktite...
the alternative is using the TC3 Diff screw and nut.
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Old 07-24-2007, 01:22 PM   #15370
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Quote:
Originally Posted by unashamed View Post
Ive built my diff acording to the manual, but im still facing issues with it. after every 1 or 2 run's im having to rebuild the rear diff because it sounds/feels like its spinning itself loose. is any one else facing this?
Did you readjust after your initial battery pack? if so then..............
I noticed when I had mine, after a few rebuilds, the locking in the diff nut wears quickly, replace the nut and its good. Nuts were cheap so I usually put a new one when the diff got rebuilt. Now if its a new nut already, I couldnt possibly imagine what would be wrong w/ it
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Old 07-24-2007, 01:30 PM   #15371
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Quote:
Originally Posted by rc-zombies View Post
yes..the square bevel gear is aluminum.. don't recommend.. you'll end up breaking some other part of the drivetrain. plus it will run louder than normal.




This was a common problems. diff screw loosening. are you using the new T-nut? that will help keep it tight along with a drop of blue locktite...
the alternative is using the TC3 Diff screw and nut.

I was having the same issues.......I found out 2 things,and last week the diff,with a 4.5 performed great,and did not loosen at all......

after rebuilding the diff 6 times,and always

having it loosen,I replaced the spring......

you would not believe the amount of tension a new spring has and I really think it made the difference in not coming loose......BTW,I am also using the cyclone HD nut,but the ONLY thing I changed last week was the spring.....

even the nut didn't stop it from getting loose...

second,I MADE SURE the gears had very little side to side slop....I ended up using 2 .2 silver shims,and a .1 copper between the rh ball bearing and outdrive(HPI only calls for 1 silver).......

I still have the tiniest bit of gear play,but thats all....

I also built a new diff with all new parts and used the associated bolt in this one(since the cyclones are NOT available......)....

that is in the car as we speak,I will run it tonite and post hear later....




BTW,I haven't even run an RC car in 8 months......after 3 weeks,I'm only a tick behind the top 2 guys who raced all winter(mini z''s)
and have been running 07 x rays since may.........

I'm faster than everyone else,regardless of what they....

only sayiing this to let you know,the PRO 4 is still a VERY capable car...and the shaft drive and 4.5 on a road course is a killer combo...


if anyone wants to race,we run tues nites in Nanuet NY.........you need a PT,5 bucks,and have to like a casual(but conpetitive) attitude......we use road rail,and EVEYONE helps set up and take down........


come run,have fun....................................BTW,we all run Bl 4.5s.......all mod,no stock racing.......
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Old 07-24-2007, 01:39 PM   #15372
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Quote:
Originally Posted by fastharry View Post
I was having the same issues.......I found out 2 things,and last week the diff,with a 4.5 performed great,and did not loosen at all......

after rebuilding the diff 6 times,and always

having it loosen,I replaced the spring......

you would not believe the amount of tension a new spring has and I really think it made the difference in not coming loose......BTW,I am also using the cyclone HD nut,but the ONLY thing I changed last week was the spring.....

even the nut didn't stop it from getting loose...

second,I MADE SURE the gears had very little side to side slop....I ended up using 2 .2 silver shims,and a .1 copper between the rh ball bearing and outdrive(HPI only calls for 1 silver).......

I still have the tiniest bit of gear play,but thats all....

I also built a new diff with all new parts and used the associated bolt in this one(since the cyclones are NOT available......)....

that is in the car as we speak,I will run it tonite and post hear later....

i never had a diff problem when i ran the pro 4 with the 4.5 motor
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Old 07-24-2007, 02:03 PM   #15373
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Since getting the custom made aluminum, no more diff loosening. The ring gear that feeds the bevel still gets chomped, but thats from heavy acclerating and braking
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Old 07-24-2007, 02:06 PM   #15374
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Hey Harry, how far is that from Bruckner in the Bronx? I have been looking for a track to catch wreck. Li-pos allowed?
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Old 07-24-2007, 02:53 PM   #15375
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Quote:
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Hey Harry, how far is that from Bruckner in the Bronx? I have been looking for a track to catch wreck. Li-pos allowed?
its right down the road from Bruckner in nanuet.....

lipos allowed,and needed....
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