Using hardened steel R.R. spur on 5mm 32 pitch pinions
 

Hi, i was just wondering how well the 5mm bore 32 pitch pinions hold up when driving a R.R. hardened steel spur gear (maxx spur). I have no tranny, im running the diffs straight off the spur. It's a 7.5 lb truggy with 1/8 tires, and about 8.5 lbs with medium mass maxx tires...

Just wondering if a plastic spur will hold well with more torque being transfered through it. I'll have a big plate that will grab the spur at the outer most holes, so thats where the power is transfered.

Get a mod 1, that's my advice. Ofna has got a center slipper for their dominator.

32p is asking for trouble.

I used a 51t plastic spur on my 2250 powered savage;

Im running 7XL with Quark on 5s2p A123 pack. You are sure that a 16 tooth pinion/72 spur for maxx tires; or 22 tooth/72 spur for 1/8 tires wont handle it?

I notice how there isn't much for pinion sizes for mod 1. Would there be a setup that Mike would have in stock?

A 7XL won't leave the 32p gears in tact very long.

5S on the 7XL is pushing it hot. especially with a rather direct drive. you need that tall gearing. A lower KV motor would be a better choice.

a low KV lower gearing ratio will run cooler.

Serum, 5s A123 on the 7XL isn't what I would call hot. At the nominal voltage, that's 34,000 RPM. At 3v/cell, it's closer to 31,000 RPM, which is still rather low.

14 cells makes my 7XL hot with a normal transmission. the 7XL is quite hot metal! trust me!

On 3S lipo it does well, and doesn't get too hot.

I guess I'll have to see it get hot in my Revo to believe it. Not that it doesn't run hot for you, I will just have to see it :).

Yeah, considering your location, i guess it will be about 15 degree C hotter than mine.. :p

Well the real nominal voltage for the A123 cells is more like 3.15 volts/cell. They rate at 3.3volts.

Well, will a plastic spur hold up then, would you know? It's handling how much more than if ran through a tranny, not even twice as much. On my old setup with the two DeWalt 820 size motors the spur ran perfectly fine, besides rocks getting in there, and then...

Is anyone else running a spur in direct drive?

Well, like i said;

my 2250 survived a 51t plastic spur on my heavy weight savage. And that motor has got tons and tons of torque..

as long as you don't stick to the 32p gears..

those the walt motors are not very large torquemonsters.

I read an article of an enthusiastic racer, who had better results with the stock motors than with the dewalts.

Are you kidding, one 820 DeWalt motor will murder dual Titans stock setup. You have 50% more power, and better thermals as well. It's also lighter setup, this is the motor traxxas should have used in the first place instead of the titans, if it were available that is.

Well, i'll tell you what, im going to try the 66 plastic traxxas spur running 5mm 32 pinions, and i'll let you know how it runs. Im not very hard runningmy vehicles.

Reasons i think it should work fine:

-Quark is very smooth, so reduced shock loads there
-I'm running a relatively light setup (7.5 lbs)
-there is no slack in the drive train in my setup
-i ran the DeWalts with great results

Let us know how that works out.

I'm running the Robinson plastic 66 and 72 tooth spurs and have no problems. The 66 is in the G2R with a mambamax and a 9XL, the 72 is on my G2 Gmaxx with a 4400 hv brushless currently.

Common consensus from many here states that you shouldn't run hardened pinions with hardened spurs. And don't even think about running regular steel pinions with the hardened spurs. There was a fairly lengthy discussion posted here. All the advice says to use plastic spur with the regular steel pinion.

I want to try using both hardened gears in my buggy and see what happens, but I'm half expecting there to be issues from what everyone is saying.

I really never understood the advantages of Mod1 over 32p. Mod1 teeth are bigger, but there are fewer of them meshed at any one time. Conversely, 32p teeth are smaller, but there are more of them meshed at any one time. There is a user here (can't remember who) who uses 32p spur/pinion on his BL Revo conversion with success.

Just to make sure everyone knows what im doing, im not running it through a tranny. I will have the spur connected directly up to the diffs from CVD's of course... i don't know if you knew that?

Im a little stuck for gearing though, im thinking 14 or 16 tooth pinion with a 66 T Spur directly to the diffs with 7XL on 5s2p A123 pack.

Well, way back when i had my stock emaxx, i bought the R.R. Racing spur and ran it, WOW, filings everywhere, it was noisy too. And seemed to be slower.

Exactly, i don't see an advantage running Mod1, 32 pitch in my opinion is big enough, and would be more efficient and quieter.

BrianG, what gear ratio do you think i need, 14 or 16 tooth, thats running RD Logics Spikes tires, i have some 20, and 22 tooth for 1/8 tire running also.