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Old 07-20-2014, 06:04 AM   #21646
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What diff are we talking about? The ball diff needs to be built as per the manual with all the right washers in the right positions and you need to use Tamiya AW grease in it (forget the ball diff grease, that doesn't last).

What wheels are you using? Suzuki Swift? They are a brittle plastic. Get some of the older wheels if you can or aftermarket, they have a softer plastic that doesn't break that easily, or Mini wheels (not ideal, again, but better).

You don't need harder gears, the kit ones are perfect. Your diff was slipping big time (if it's a balldiff you didn't build it right, if it's a gear diff, you didn't build it right).

The gear diff shouldn't slip anyway. The only possibility is if you didn't do up the diff screws properly. Use Tamiya AW grease in it and shim if you want, but not that necessary.

There is also the possibility you stripped the outdrive inner splines. Ccheck and address cause (what driveshats do you use? dogbones? Cv joints?- you may need to use the little foam discs to keep the outdrives fully in and engaged with the diff gears.
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Old 07-20-2014, 02:54 PM   #21647
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Does anyone know what the part number for the Tamiya Mini's Slick tires is?
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Old 07-20-2014, 03:55 PM   #21648
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Quote:
Originally Posted by niznai View Post
What diff are we talking about? The ball diff needs to be built as per the manual with all the right washers in the right positions and you need to use Tamiya AW grease in it (forget the ball diff grease, that doesn't last).

What wheels are you using? Suzuki Swift? They are a brittle plastic. Get some of the older wheels if you can or aftermarket, they have a softer plastic that doesn't break that easily, or Mini wheels (not ideal, again, but better).

You don't need harder gears, the kit ones are perfect. Your diff was slipping big time (if it's a balldiff you didn't build it right, if it's a gear diff, you didn't build it right).

The gear diff shouldn't slip anyway. The only possibility is if you didn't do up the diff screws properly. Use Tamiya AW grease in it and shim if you want, but not that necessary.

There is also the possibility you stripped the outdrive inner splines. Ccheck and address cause (what driveshats do you use? dogbones? Cv joints?- you may need to use the little foam discs to keep the outdrives fully in and engaged with the diff gears.
Currently all the gears and diff are stock from the kit, besides the fact they have bearings instead of bushes.

I did notice there is a slight crack in the end of the gearbox joint (BA25) where it meets the drive shaft (BA29). you can see it in this picture, but the drive shaft doesn't come close to the chipped of bit.

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Old 07-20-2014, 05:32 PM   #21649
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Not to be insulting, but is your pinion on tight? Seen them come loose many, many times. It's likely that or a stripped spur.
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Old 07-20-2014, 10:34 PM   #21650
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Hi Guys,

I was at the track today and ran into a few walls which resulted in a few issues.
The first being, I keep breaking the rims right around the hex drive. Is this common for a beginner? Today it actually cracked and before I noticed I had rounded the hex drive.

The second thing I had an issue with was the gears. It just wasn't getting power down and it felt like the gears had stripped. So tonight I pulled it apart and the gears seam fine. Is there anything else I should be looking at? How do I check the diff is working?
I've ordered the harder gears to put in while its apart. I can't find a gear oil diff anywhere, so I am going to try the ear plug method. Did someone say you could use tyre inserts as well?
I hate to say this, but from what's been posted, it sounds mostly due to improper or careless assembly. When all else fails, read the instructions.

If a tire and wheel are fully seated on the hex drive, before you place and tighten the wheel nut, the conditions you describe are almost impossible.

I'd suggest you disassemble the front part of your chassis and start over.
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Old 07-21-2014, 02:07 AM   #21651
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Minis are not a beast, but they do require careful assembly. Over enthusiastic screwing can break a lot of parts, pinch bearings, and so on (generally termed screw-ups for obvious reasons).

I recommend strip down and assembly with manual in front and checking at each step that things don't bind and move freely. That includes wheels/wheel nuts. It's easy to overtighten and pinch the bearings which results in the car being undriveable.

Granpa might be onto something there as well with the wheel not being fully seated on the hexes (easy to overlook).
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Old 07-21-2014, 02:30 AM   #21652
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Quote:
Originally Posted by filippimini View Post
Hi Guys,

I was at the track today and ran into a few walls which resulted in a few issues.
The first being, I keep breaking the rims right around the hex drive. Is this common for a beginner? Today it actually cracked and before I noticed I had rounded the hex drive.

The second thing I had an issue with was the gears. It just wasn't getting power down and it felt like the gears had stripped. So tonight I pulled it apart and the gears seam fine. Is there anything else I should be looking at? How do I check the diff is working?
I've ordered the harder gears to put in while its apart. I can't find a gear oil diff anywhere, so I am going to try the ear plug method. Did someone say you could use tyre inserts as well?
I read your post again and have to go with Granpa on this one... sound almost impossible.
The wheels are simple enough, if you hit something to hard or at the wrong angle they break, bad luck. If your gears are the problem you'll hear it or see it.
The thing you describe with the gears is baffling. Only things I can think of are driveshafts and motor. I've found using the kit setup (o-rings in diff cup) can cause binding when cornering. You can check that by spinning the drive-line with the chassis in your hand and then compressing the suspension. All should spin freely during compression, if not try some foam in the diff cups. I look for about 1cm of compression from full droop.
About the motor I can only say check your temps regularly, if they get too high your motor could be toast and feel like loss of power. Let us know how you get on, it could all be down to the broken wheel...
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Old 07-21-2014, 03:12 AM   #21653
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To have cracked the outdrive already would require some pretty big hits. It looks like you have also popped the shock bottom over the ball as well which takes a pretty big hit too considering it is protected by the bumper.

You acknowledged in your post that you were hitting the track markers a lot - most people deny that they hit anything when they break their car - so I suspect you spent more time in the markers than on the track...

It looks like you may still be running the plastic wheel hexes, I would replace them with the aluminium clamping ones (#53569 is the direct replacement) as they can't be crushed by overtightening and are a better fit in the wheel hexes too.

My advice, rebuild the car carefully and thoroughly, replace the parts you have damaged and broken, and drive more carefully. If you are about to hit something, release the throttle. Powering on through impacts breaks stuff, if the wheels stop suddenly and the motor is still going full pelt, something is going to break.
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Old 07-21-2014, 05:46 AM   #21654
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Hi all,

Thanks for taking your time to respond. I'll try and answer some questions.
- Yes the pinion is tight.
- Yes I had a bit hit in the front end, but the suspension mount actually popped over like that when I was removing the top mount.
- The wheel hex rounded because the wheel had cracked away around the hex drive. I believe this is what was the cause of the lack of power as only one wheel was driving.
First problem solved.

I have stripped the front end, cleaned the bearings and gear and rebuilt it as per the manual, but I still get the same loud noise from the gears. After a few test, I feel confident that the noise is coming from the pinion and first gear. It doesn't look like the gear is damaged as they appear to mesh well. I will replace the gears and bearings and see how it goes.

Ryan
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Old 07-21-2014, 05:55 AM   #21655
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And now back to our usual programming
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Old 07-21-2014, 06:08 AM   #21656
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What i have found is that some gears has a lot of slope in the bearing place. the bearing should get inside thoughly, when they are loose you can damage gears and you will have more noise in the gear box.

Now in my mini I have a mixed gears set, one tamiya white, one tamiya black and the diff is the 3 racing gear diff. For one of my club mate the best combo was ride "fast gears" idle with tamiya white spur and stock gear diff.

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Old 07-21-2014, 06:26 AM   #21657
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Hi Jimjay.

What do you mean by 'slope in the bearing place'? Are you referring to slop in how the bearings sit in the gear? as in they are loose? The bearings in the middle gear (the long one) are a really loose. In fact they fall out. I tried the plastic kit bushes and they are also loose. Hopefully this is the problem and the new gear set fixes it.

Ryan
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Old 07-21-2014, 06:37 AM   #21658
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Yes, that is the idea. The bearing has to be thight fited to the gear, if they are loose you will have problems.

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Old 07-21-2014, 08:29 AM   #21659
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These gears are noisy by their nature. I wouldn't sweat it.
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Old 07-21-2014, 08:52 AM   #21660
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Quote:
Originally Posted by filippimini View Post
Hi all,

Thanks for taking your time to respond. I'll try and answer some questions.
- Yes the pinion is tight.
- Yes I had a bit hit in the front end, but the suspension mount actually popped over like that when I was removing the top mount.
- The wheel hex rounded because the wheel had cracked away around the hex drive. I believe this is what was the cause of the lack of power as only one wheel was driving.
First problem solved.

I have stripped the front end, cleaned the bearings and gear and rebuilt it as per the manual, but I still get the same loud noise from the gears. After a few test, I feel confident that the noise is coming from the pinion and first gear. It doesn't look like the gear is damaged as they appear to mesh well. I will replace the gears and bearings and see how it goes.

Ryan
This will be hard for some to do, but take your car and have one of the local Mini "experts" take a look. It could be something really simple. Trying to diagnose the problem here is difficult and can lead to more problems. These are simple little cars, but it's easy to screw up. I've done my share.

From your post and the way you describe how the hexes broke, it was due to an error in assembling the wheel to the axle. The wheel and the hex had to be misaligned to cause the damage you describe. You should place the wheel on the axle, line up the hex and seat the wheel, then put the wheel nut on. For a wheel to be loose on the axle as described can only happen if the drive pin is missing in the hex or the wheel is damaged as you say and the wheel nut is loose.

Also, in a Mini, a little gear noise is normal. They are not quiet like a TC and are noisy especially with a B/L motor.
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