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Old 04-20-2002, 03:44 PM   #466
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When a diff feels "gritty", then its time to replace it right?

Well what should I do when the diff is gritty right out of the box? And just what counts as being "gritty"?

I don't have much experience with ball diffs, and I don't know what the optimal tightness is, but, the only time it is buttery smooth (like a zero resistance bevel diff) is when it is too loose (can turn pulley with outdrives held still).

The tighter I make it, the more resistance when turning the outdrives (in opposing directions), the more gritty it feels.

No matter what tightness, it feels like there's a piece of sand paper in there with the balls. So what's the deal here? This was the way it felt brand new, and this is still how it feels after 4 packs and a re-put-together of the diff.

What is strange though is, if I try to push the diff together, that is pushing with the outdrives in towards the centre, the harder I push, the smoother it is. Yet tightening it makes it grittier.
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Old 04-20-2002, 06:05 PM   #467
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Your diff isn't the problem the thrust bearing needs rebuilt, it;s the 2 washers with 6 or 8 little balls that goes in the outdrive that is making the diff feel "gritty" almost always use lots and lots of grease in there.
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Old 04-20-2002, 09:49 PM   #468
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...yes... that makes sense.
Thanks Impactplayr, i'll look into that asap.
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Old 04-20-2002, 10:04 PM   #469
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hey, thanks for that! i always thought that the gritty feel meant a flattened diff ball or a deeply grooved diff ring, until i assembled a brand new diff that feels gritty.

what's with the unassembled thrust bearings though? is there a difference between getting a one-piece thrust bearing, with the balls already held in place between the two plates? Tamiya offered this as an option to the 03/manta ray diff.... just wondering....
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Old 04-21-2002, 08:05 AM   #470
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The unassembled thrust bearing is kind of a double cost cutting measure, as you can figure it makes the kit cheaper to produce, but when you have to rebuild it it is also cheaper because if the washers are worn you can just flip them over instead of replacing a $7-$15 unit (yes I have seen some thrust units sell for as much as $15), thus cutting the cost by almost half for you. However the "freeball" units can cause their own set of problems. If care isn't taken when assembling the balls can collect on one side and lock up the assembly, That is why I always replace these units with a captured ball unit from Losi or Associated which uses the stock washers, but has a little ring that incases the balls and allows for proper lubrication, where the completely enclosed unit is much harder to lubricate.
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Old 04-22-2002, 10:12 AM   #471
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Steering knuckle question:

What is the effect of reversing the steering knuckles: ie swapping C1 and C2? Does this change castor? If so, How much? Has anyone measured this?

The TA04 tuning guides doesn't say much.
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Old 04-22-2002, 01:48 PM   #472
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Hi guys:

For my birthday, my girlfriend has gave me a TA04-S (cos I wanna raced the TCS, here at Spain). I've spent three hours reading the 16 pages long thread. And I got some ideas.

Talking with some friends who own the R I have done a listing of pieces that I need to upgrade.

First of all, change the gear diffs for ball diffs. Anyone knows if the ball diffs are available with the lightweight outdrives?
Put the center one-way (it comes with two plastic pulleys).
Change the shocks ? (it comes with the black plastic shocs) and buy a set of springs.

I noticed that some had problems with the front belt (too much tension). Mine it's the same (all the belt vertical travel is about 3mm). My question is: I have this problem. If affirmative, should I ask for a replacement chassis?

For the rest of options, maybe the motor plate and the upper plate of chasis (stock is plastic). Any other options can apply as 'relatively needed'?
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Old 04-22-2002, 02:09 PM   #473
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Corse-R

The Lightweight Diff Halves are not avalable in a diff set. They are only available by themselves.

The Center One way is nice. The Alum shocks work well also. Since your getting the springs you should get the sway bars also.

The chassis problem was with the R graphite reinforced tub.

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Old 04-22-2002, 05:17 PM   #474
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If I were you, i'd leave the gear diffs in. Those Tamiya gear diffs are sealed so well they will never need a rebuild! I compared them with ball diffs and didn't feel a major performance difference. I doubt the speed increase with the lightweight outdrives will be significant.

Also, the Tamiya plastic shocks are one of the smoothest plastic shocks available. To save money, i'd leave them in as well. Besides, I prefer working with preload spacers than collars.

A better option is the updated carbon chassis. The stock plastic chassis is HEAVY and makes the front belt tight. The *updated* carbon chassis fixes these problems. A carbon upper deck will make the car look cleaner as well.

The one-ways will help in proper conditions.
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Old 04-22-2002, 06:25 PM   #475
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Quote:
Originally posted by linger
Steering knuckle question:

What is the effect of reversing the steering knuckles: ie swapping C1 and C2? Does this change castor? If so, How much? Has anyone measured this?

The TA04 tuning guides doesn't say much.
It doesn't change castor. If C2 is on the right, the front tires will lay lower to the ground. (the steering knuckles are asymetrical)

This effect actually causes the front roll centre to be lower compared to say if C1 were on the right. This change is very minor compared to changing a camber link on the shock tower, but in good grip conditions, it can be felt.
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Old 04-22-2002, 06:32 PM   #476
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Corse R: The TA04 has 2 types of centre one ways available, the plastic ones and the metal ones. I'd suggest you get the metal ones. You will need

53474 Alu Top Pulley


and the centre one way itself... uh drat i don't ahve the part number... basically the plastic ones may wear out, i don't have 'em but i myself wear the plastic pulleys all the time (I run full time 4wd usually)

Hope i helped abit..
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Old 04-22-2002, 10:38 PM   #477
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Found it.

53489 TA04 Alu. Center One-Way Pulley



Use this and the other pulley. I doubt the wear rate of the plastic one, which is 53450
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Old 04-22-2002, 10:55 PM   #478
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the plastic centre pulleys work great also...

but i think the problem of wearing it out is not so problematic,...wat makes mi worry when running my 04r is getting sand or even small rocks in between the gears n pulleys,then the sand/small rocks will eat into the plastic spur thus u will have clipped gears which will bring down ur car's performance...
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Old 04-25-2002, 03:48 AM   #479
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Hey dudes,
Do any of you guys run progressive springs on your TA04s? Apart from the TGX springs I believe tamiya doesn't have any for 1/10 TCs. Any other brands can fit? Thanks!

~Alvin
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Old 04-25-2002, 06:20 AM   #480
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The smaller plastic pulleys are problematic for all cars. I dont mean they wear out over night, but if you drive alot they will last a few months. They mainly just wear themselves out, they probably turn 2-3 times the revolutions as the ball diff pulleys. The ball diff pulleys see the same rocks, and dust the driver pulleys see, but because they are larger they do not wear out as quickly. I use the aluminum center pulleys, and believe it or not you can use 2 aluminums to replace the 2 plastic ones, That is if you dont want to use the one way pulley in combination with 1 aluminum pulley for full time 4wd.
All you do is slide 2 aluminum pulleys in place like the plastic ones did (side by side, set screws on opposite ends from each other) tighten the set screw like the aluminum holder did to hold the plastic pulleys in place on the shaft flat spot, Now you will need to tighten down the other aluminum pulley, But theres no flat spot? well tighten it down to make a mark on the shaft, then take the shaft out and make a flat spot with a file, or rotory tool. Put her back together, Now you have 2 aluminum pulleys, with out the one way for full time 4wd. This may not be allowed at a TCS even, but Tamiya should make a shaft with 2 flat spots to do this conversion. Mine sure have lasted a long time!
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