Shredded Spur Gear

[John Clark]

My Spur was on its way out, and today it went to plastic heaven. Anyone have any pros (other than strength) or cons (other than weight) on using a metal spur?

 

[FastEddy]

With a metal spur you must keep the mesh exact at all times, otherwise you will eat both the clutch bell and your spur gear.

You will hear many opinions going either way. Cost is the biggest drawback. You could buy 8-10 plastic spurs for the price of 1 metal one.

I prefer the metal one for its durability on the racetrack.

 

[Mike c.]

true, metal is stronger BUT its hard on the tranny and you'll need to upgrade the tranny gears too. so if ya got the mony its worth it

 

[NCNitro]

I prefer a plastic spur, first for the reason Eddy stated that both the cluth and spur gear will wear much quicker, especially if the mesh is not perfect. Second I would rather have my weak link be the spur as opposed to the tranny gears. I have never stripped a plastic spur yet. Proper gear mesh is the key no matter which way you decide to go.

 

[x_789]

Originally posted by NCNitro
I prefer a plastic spur, first for the reason Eddy stated that both the cluth and spur gear will wear much quicker, especially if the mesh is not perfect. Second I would rather have my weak link be the spur as opposed to the tranny gears. I have never stripped a plastic spur yet. Proper gear mesh is the key no matter which way you decide to go.

Thanks for typing all that for me NC. I tottaly agree with NC. Plastic Spurs are cheap and if the mesh is set correctly they rarely wear out. Lastly its alot easier and cheaper to replace a spur than it is to deal with tranny parts. X

 

[El Pirata]

Originally posted by FastEddy
Cost is the biggest drawback. You could buy 8-10 plastic spurs for the price of 1 metal one.

Not if your good buddy Sky hooks you up with one for free.

 

[FastEddy]

Not to get on anyone’s bad side but the spur shouldn’t come into play at any point as far as being the weak link.

Money well spent is on an upgrade for the slipper clutch. The slipper is designed to take and disperse any un wanted torque to protect the spur and tyranny gears. Either get additional friction pegs (The little red Zippo flint looking do-dads) or an RRP double slipper. Proper adjustment is a must. If you aren’t sure how to properly adjust your spur gear just ask.

 

[SkyMaxx]

I am a metal spur gear afficionado. I also am one of the first in my area to run the RRP dual slipper disk set-up (at least that is what my LHS told me when I bought the first one they got in).

You can go either way on using metal or plastic spurs. The longevity of both is going to be determined by how well you maintain your vehicle. If you don't check the mesh once in a while, and it goes out...expect to eat up a spur gear. If the mesh goes out on a plastic spur, you lose a three dollar piece of plastic. If it goes out on a metal spur, the cost for repairs goes up quite a bit. You might end up replacing a spur, a clutch bell, a slipper clutch, the guts of your tranny, etc, etc.

The performance differences a plastic versus a metal spur would gain you...

The metal gear will spin up a little slower, but will maintain stable rpms and for a lot longer than plastic when you take the throttle off. This means you don't necessarily have to stay on the gas to maintain your speed. The drawback on this is that it takes longer for the load on the tranny to come off (the metal spur doesn't spin down too quickly). This poses a problem for those who enjoy switching between forward and reverse frequently (don't know many who do...so the drawback isn't as bad).

Conversely, the plastic gear spins up much more quickly and also slows down more quickly. This necessitates a steady strain from the engine, but removes the drawback for those who want to switch to reverse often.

Either way, the majority of the posts in this thread are dead on and give good reasoning. Properly set up, any type spur should last a great while. I have been running the same metal spur gear for about 6 months. I upgraded mine to the RRP Steel set-up and gave my Kimbrough Steel gear to Pirata. I know I haven't had any problems with mine, and believe he hasn't had any with his.

As for weak links, you must have one designed into your power train somewhere. The spur gear is one such area. The design of the system is that of a floating gear, and the brunt of any pain should be born by the slipper clutch mechanism. Most people screw that set-up up (as Eddy alluded to) and thus the spur bears the pain and usually loses.

I have chosen to run a full metal set-up and made my weak link my center drive shafts. I'm kind of happy I did...I've had to replace a couple in the recent past and the cost has been minimal (both time and money). I still check the mesh on the spur/clutchbell prior to each session. Good habits in the form of pre and post flight maintenance on your RC will make for happier motoring in the long term.

Hope this long winded (my norm) response is informative and helpful.

 

[FastEddy]

Everything you wanted to know and more.
Good job. I think I learnd something.

 

[John Clark]

Thanks a lot for all the great info! The second time I ever had the thing out, my brother-in-law hit a rock at about 30 mph, and broke the engine mount as well as cracking the front center drive shaft and the fuel tank. When the mount broke, the clutch bell moved away from the spur a little, and I wore it down quite a bit before I realized what had happened.

I was originally thinking steel spur = stronger = better, but not at the cost of new tranny gears. I'm more of the "grip it and rip it" type of guy (and no, there's no sexual metephor there). I'm not into doing too much pre-trip inspection, so consequently expect to pay a little more for repairs/maintenance.

So another couple of questions before I make up my mind. How do additional friction pegs protect the transmission? Does this not increase the friction, thereby transmitting more force to the tranny input with less slippage? Or with extra pegs are you supposed to loosen the nut on the spur some?

And as for adjustment, I've been leaving a tiny little bit of play, so that the spur/clutch bell will spin freely when spun by hand. Is this correct? I followed Homo-Queen's instructions on his site with the plastic bag thing, but that seemed too tight to me.

Thanks in advance for any help.

 

[SkyMaxx]

The extra friction pegs are a must for metal gears (or the dual slipper disk set by RRP). Yes, you are correct. The extra pegs are for added friction. The heavier metal gear will need more to engage the slipper clutch. If they are not in place, you will melt the existing six pretty quickly and not get the grip on the spur that you need. As for running 12 pegs on a plastic gear, I recommend loosening the slipper nut a tad as you will not require the same amount of pressure on the plates for 12 pegs as you do for 6.

As for adjusting the mesh, the plastic bag method works great. I use a double thickness of plastic bag between the spur and clutch bell. Press the engine over to compress the plastic. Place a dab of lock-tite (blue) on the screws holding the engine mounts in place and tighten them down. Then I withdraw the bag...and voila...perfect gear mesh.

 

[John Clark]

Thanks man, I'll try doubling up the plastic as you suggest. A single thickness didn't seem to give the right lash to me.

 

[FastEddy]

A quick and easy way to adjust your slipper.

Place your Maxx against a wall or your hold it in place on the surface you will be driving on. Loosen the slipper nut a bit. Give your truck some throttle. At this point the slipper should spin before your tires break traction. Tighten the slipper nut 1/16th of a turn give it some throttle again. Continue this process until your tires break traction before the slipper spins. At this point back the slipper nut off 1/16th of a turn.

Your slipper should spin about ¼ to ½ turn at the same time your tires break traction. You can use a dab of fingernail polish to make a mark on your spur to help you see how far it’s turning.

If you are taking big air loosen it another 1/32-1/16 of a turn, don’t expect to be doing any wheelies. If you want to show off on 2 wheels tighten it up but don’t forget to reset it when your done.

Using more friction pegs will give you a smoother slip with a plastic spur. If it’s in the budget the RRP double slipper is a great product.

 

[John Clark]

Thanks Eddie. Bought the plastic spur today, and some more pegs. Will give your adjustment technique a try.

 

[backspur]

It looks like you have made a good choice on your purchase. Personally, I'm a fan of plastic spur gears. They hold up fine if you keep your mesh adjusted. The way I look at it is that stripping a spur gear is inevitable, unless you drive like a one-armed blind girl. Why not make a $3 spur gear the weak link.
Instead of the Traxxas slipper pegs I use 1/8" steel differential balls in the spur gear. They last almost indefinetely and are cheaper. The AE diff balls are less than $2 for a package of 18. I think that they provide more consistent slip, as well.

 

[John Clark]

Thanks Backspur, I was thinking the same thing. I really like the idea of using diff balls instead of slipper pegs. Just a quick question though. The holes in the spur seem much smaller than 1/8". Did you drill the spur out, or are they smaller then 1/8th?