mick355

iTrader: (14)

Hi mini gurus
After a bit of gearbox building advice as I'm rebuilding mine again
It seems every time I try to run inchups I'm certain to blow the gearbox.
This time I'm using the reinforced gear set but I think there is another problem. Perhaps a misalignment of the shafts in the chassis? I purchased the bearings of m chassis so I'm pretty sure they are correct, but they are loose in the gears?
I'm also finding that when the motor is out all seems well. As soon as I tighten the motor screws it seems to bind. To get around this I run the screws very lightly tightened. But the slightest bump shifts the motor and strips the spur. It all seems worse after replacing the chassis. Any insight would be greatly appreciated

Mick

niznai

It sounds like you need to do a little bit of detective work to ascertain if the motor screws pinch the g'box and screw things up for you. Use two screws long enough to poke out the other side and use nuts instead of the motor and do everything up as if you were bolting the motor to the car and then test again to see how free the gears are by sticking your finger through the motor hole and feeling how easily the gear inside spins (perhaps it's a good idea to not have other gears in yet, and definitely detach the driveshafts).

My guess is you're pinching the bearings in the other gears when you're doing up the motor screws. This might mean the gear shafts are too short and the chassis halves press the cups against the bearings (or who knows what plastic distortion is at play in the chassis halves). If this is the case, short of trying another set of shafts (which may or may not solve the problem) I don't see other options apart form making your own shafts a tad longer or using some small washers/shims of appropriate diameter inside the chassis gear shaft locating cups.

What's "inchups"?

filippimini

Hi Guys,

Ive just purchased this adjustable upper arm set http://www.tamiyausa.com/product/ite...oduct-id=54182

But it seems as though the arms are too long for the the front. It would push my camber in the wrong direction.

Can anyone confirm?

sosidge

That set of arms is for the rear only. There is a separate set for the front.

mick355

iTrader: (14)

Thanks niznai
Inchups are what we call the larger ride wheels and tyres
Mc34 sc32/36 etc
I might try building the car again with another chassis

filippimini

Thanks sosidge. It seems odd that they provide two sets of arms in the packet. Spares I guess.

Ive not seen the front arms anywhere.
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Edit.
I guess this is them? http://www.tamiyausa.com/product/ite...oduct-id=54529
I'd prefer adjustable arms.

Granpa

Having a misalignment of the shafts is nearly impossible if you used the proper sized bearings. The bearings should fit snugly in the chassis and easily in the gears. I'm pretty sure your problem does not lay here.

The most likely causes are the wrong pitch pinion. The Mini uses a metric pitch and is not a 48 pitch gear. Also, are you using the pinion setting tool that came with the gear set. If you didn't, that could easily cause the conditions you describe.

axle182

iTrader: (18)

Straight line? Weird. Alot of the front runner A main guys in Wcics are running 500,000 to 1M and have plenty of steering. Key is to sauce those front tires well, and of course, the rest of the chassis setup.

monkeyracing

iTrader: (10)

These are good. They provide you with just enough adjustment to make a difference, but not so much that your car will become a swine. I run the 17mm ones, for a little extra camber. It's pretty much what you'd do with an adjustable anyway.

mick355

iTrader: (14)

Thanks grandpa

The pinion is correct. The diff bearings are snug but the bearings in the gears are not as tight as I would have expected. I replaced the shafts with a new set and put another motor plate in which seems to have improved things on the bench anyway. My concern is that you can really loose a lot of speed through a tight gearbox

niznai

Something is definitely pinching your bearings then. Any flashing inside the chassis halves? Maybe around the area where the shafts locate? Any imperfection that would affect the bearings (allow the chassis to pinch)?

caltek1

iTrader: (38)

Ryan,

I tried both the 1mm longer and 1mm shorter front fixed upper arms with the inch ups and went back to the kit supplied items. I found them best for driving styl. The shorter items will give 1 degree front camber, but this does not take into account your ride height/ shock length and the longest will give you 1 degree of postive camber agin dependant on your ride height.

Regarding the gearbox issue, did you check that the spur gear is not binding on the RHS chassis half. In a previous kit there was a binding issue easily rectified with a dremel. It was in the area with the intermediate spur and spur gear itself. The other thing I would check is the shafts themselves for excessive wear. The steel shafts do wear out over time.

I would also get one of the other mini guys in Melbourne to check your car in case you have overlooked something.

Regards,

Calvin.

mick355

iTrader: (14)

Thanks Calvin
Seems like it may have been the shafts
I was running one carbon and one solid after running out of spares.
I've replaced them with new hollow steels and it seems very smooth now. You car still bind it a little if you over tighten the motor screws but I think that will always be a problem with the design.

disaac

iTrader: (10)

I had the same problem with my mo5v2 using a tekin gen2 motor 20t pinion , the gear box would bind if I tighten the screws too much, so I moved the top screw to the forward most hole and I haven't had a problem since, even in heavy crashes the gear box stays nice and free.

monkeyracing

iTrader: (10)

I've been wondering about this binding/noise when the screws are snugged down. Is this more of a problem with the v2 revision? I've been running with the motor screws really loose - so loose they've been falling out. I saw a little relief with a few gearbox screws loosened by a thread. Is this just a misalignment issue with the gearbox plastics?