2009 KT Sprocket Teeth Alignment On Hubs

[Mike Conley]

(***This something I discovered while assembling a 2009 King Tiger so it probably don't pertain to any KTs other than the '09sI)

I was just out in the garage and started assembling the sprockets on the hubs. I aligned the dimples as prescribed.

I put the sprockets on, both dished sides out, and after I got a couple of bolts in each side I noticed when the assembly was setting on it's side (on the sprockets four teeth) the assembly rocked a good bit, with it setting on two teeth (one each side) or the other two teeth.

I took them off the hub and looked at the sprocket holes, aligning them. When the two sprockets are both dished toward the outsides the teeth are off (see pic with flat sides together).

When I reverse the back (hull) sprocket to face in to the hub (see pic with dish side in) and align holes, the teeth line up perfectly. Installed this way on the hub, with holes aligned, there is NO rocking when the assembly is sitting on it's four teeth on the table.

With the hub IN the rear dish of the sprocket the teeth still go in the track holes, each a little more to the middle.

SO, my question is: should I put both dish sides out (per manual) and have the teeth a little misaligned with each side OR install the inside sprocket with the dish groove against the hub and the sprocket and then the teeth totally align?

I think I'm going to go with the rear (inside) hub with the dish against the hub. That way the sprocket teeth align, even if I loose just a minor fraction of the teeth being closer together... (***CHANGED MY MIND! I'm drilling all new holes! Read Below!!!)

[Phil Young]

Hi Mike
Could one of the sprockets be machined on the wrong side? I haven’t checked mine yet.

[Mike Conley]

Hi Phil!

I've check every combination possible. Switched every sprocket with each other, sprocket sets, hubs/sprockets, different hub holes (which will need to be drilled out because every sprocket has holes off a tiny bit on one side).

I even tried a different BEEER (one of my wife's Corona's! (with lime!))! But the teeth are offset unless one of the sides has the dish in. I measured the milled lip in to the sprocket and if it's reversed IN, it would set the sprockets closer by 2.34mm. I did that and put the hub with sprockets in a length of track and there's still good play in the teeth side to side.

After I get the motors installed I always start the hub spinning then LIGHTLY hold a disk grinder just to the very tip of the teeth to put a SO SLIGHT bevel on the tops of the teeth so they have a better chance of guiding in to the track holes. I've did that with the T1 & Panther and they're HAPPY!

I'm going to reverse the inner sprockets and put their step on the inside so the teeth will be fully inline side to side. But if that don't work well after I've ran it I'll just pull the hubs off and flip the inside sprockets... AIN'T NOTH'IN BUT A THANG!!!

[Mike Conley]

HEY! I done figured this out!!! I was just going to the fridge to get another ICE COLD BEVERAGE and I had one of them EPIFERMIES!!

Tomorrow I'm going to put a sprocket on each hub, aligning the sprocket holes HALF WAY between the hub holes! Mark each hole lightly, then drill the hub holes and bolt the sprockets on.

THEN I'm going to place the inside sprockets (with the step OUT) between the holes on each hub, put the assembly on it's side with all four teeth resting on a FLAT surface (and I'll even align the dimples just to be sure!), mark those holes on the hub and drill them. That way no 'old' holes will be wobbled out, they'll be all NEW holes with no play. AND the teeth will be equal across.

Then all the 'new' hub sprocket holes will be between the 'original' hub sprocket holes! The teeth will be perfectly inline across and everything will be right with the world!!!

That's what I'm going to do! SEE, a good COLD beeer fridge stimerlates tha brane and makes ya THANK!!!

Mike (the ONE in Kentucky!)

[Tom Wittstock]

Mike, go to youtube type in 1/6th rc King Tiger Tank and watch the video that East Coast Armory put togerther it is Video #2. Its all there for you he talks about the sprocket

[Mike Conley]

Thanks Tom!

I just watched the whole youtube video of John (who I'm a good customer of) at ECA show how to enlarge the hub & sprocket holes so bolts go in easier. And that's good!

BUT I don't think drilling out the existing holes where they are in the hub & sprockets will give adequate leeway to turn the sprockets enough to align up teeth, one side with the other. There's a pretty good shift that has to be done to align the teeth with each side and I think larger holes ain't enough.

I'm still planning to offset the sprocket holes on the hub, redrill new hub holes to the M3 size of bolts I'm using, and make sure the teeth are HAPPY with the other side teeth perfectly.

Thanks for the video! Mike

[Phil Young]

Hi Mike
Glad you got things sorted out. Beer usually solves a lot of problems!
You might need a bigger fridge!
All the best, Phil.

[Armortek]

Probably worth clarifying that this is a 2009 King Tiger kit.
Glad you have found solution Mike.
Kian

[Mike Conley]

YES!! Sorry I neglagated (FORGOT!) to mention this is a 2009 King Tiger I'm working on!

So before you start drilling holes everywhere on the hubs check to see if all four teeth set on a flat surface without rocking.

Thanks for reminding me Kian!!

Mike