How to Build a Lasting Axle - Ramzi Ray Rahimih
Build tips provided by WPL RC member Ramzi Ray Rahimih
Hello fellow WPL members..
Heres some tips on how make your axle gears last longer and what not to do to prevent such mishap. For nearly 2 years, ive been running an RC workshop that build and fixes many types of RC's (actually my RC history has gone way back since 2005).. But i am more specialized in building and fixing WPL, MN and JJRC rig or rigs that used the same parts as mentioned above..
I see some you guys have troubles in working with the axles at most. I have to say that wpl axles is more challenging compared with 10th scale crawlers that doesn't need much work in adjusting the gear mesh. There are several factors that contributes to axle gears failures in wpl such as choice of wheels, weight of wheels, weight of the rig, drive shaft angles, gear mesh spacing, type of gears, type of thread lock used, type of grease and frequency of maintenance..
Wheels and weights
- size of wheels and its weight does effects the performance of your rig and the durability of the axles. Since this WPL gearbox doesn't have a slipper clutch to compensate such torque from the motor, all of those load and stresses goes directly into your axle. I realize standard WPL wheels size will makes the axle lasts longer with weigts not exceeding 75 grams per wheel. Larger and heavier wheels can cause a lot of stress towards the axles (so far MN wheels with proper weight can work with wpl axes no problem)..
Weight of your rig
- most customers that sent their rigs here for repairs have weights exceeding 1.7kg (3.7lbs). We do play hard with our rigs here so i have to come up with certain solutions and methods to extend the lifespan of the WPL axles. Normal trail or ultra slow crawling would not have much issue with weight here. I would suggest keeping your rigs weight 1.5kg or below to lessen the loads on the axles. My C14 Tonka axles and gears lasts up to a year and i pushed that rig pretty hard. It weighs in around 1.2kg (2.6lbs) with battery, winch and wheel weights (wpl kit tires and rims)
Drive shaft angles
- the angle of your drive is also crucial to lessen the wears on the cvd or universal joint as well to extend the lifespan of the axle pinion gear bearings and the gear itself.. Make sure not to make the angle too extreme for better load distribution from the gearbox to the axle
Gear mesh and spacing
- this is something that most people have trouble with.. The gears must not be too close (or you'll lessen the lifespan of the bearing around the pinion gear) or too far (you'll worn out the gears even faster than usual due to less surface area). Either you put some washer behind the pinion gears to get it closer to the ring gear or crown gear or adjust the ring gear or crown gear closer to the pinion.. In some case, you have to remove one of the bearing near the ring gear so that it can be adjusted freely (even with just one bearing near the ring gear wont effect much of the axle performance).
Type of gears
- theres 5 types of gears available in the market for the WPL axles of which not many know.
1. Monkey metal (alloy gears that came with the rtr's usually in dull silver)
2. Brass gears (gold color)
3. Tempered steel or hardened steel gears (matte black color)
4. Stainless steel gears (bright silver color and doesn't stick to magnets)
5. Anodized black steel gears (basically just a stainless steel gears Anodized in black and usually can be identified by its glossy black finish or satine black finish and it doesn't stick to magnets)
- the alloy gears works just alright in rtr configuration but with proper maintenance, it will last very long.
- brass gears is harder than alloy gears but heavier than all of the gears mentioned above but is less durable then gears number 3, 4 and 5.. It still can last very long with proper maintenance or an application where theres not much loads is applied to it. In fact my C24-1 designated as C24-1 Marlin Crawler still used the brass gears for ultra slow crawling. I used heavy grease and maintained it accordingly since brass produced more metal dust after the alloy gears
- tempered steel gears is quite hard and wears pretty less and will outlived the brass gears. My C14 Tonka still used the same tempered steel gears on the rear axle even after a year.
- stainless steel gears is the hardest compared with the gears mentioned above.. It hardly wears that much even with less maintenance. But this gear is the trickiest to work with and to make it run smooth in the axles but once you got it right, it will outlived your pinion bearings. For over a year, my front tempered steel gears worn out faster than the rear, so i changed the front gears with stainless one since the loads of the front axle is greater especially if your steering angle is very sharp.
- Anodized steel is basically the same as stainless steel gears but was Anodized in black. Same durability as the stainless steel gears.
- one of the mistakes usually made by people who is new to the hobby is not applying thread lock to their grub screws in the axle (wheel hex, steering joints, drive shaft and gears) doesn't matter how tight you turn your screws, it will eventually getting loose due to the constant vibration and stresses. Blue loctite works just fine for lighter rigs and easier yo remove incase you need to change the gears or doing some maintenance. For a stronger solution, i would suggest the red loctite as it will last very long or will not move around at all.. But it requires some heat to remove the screws.. Be sure to wait 24hours after applying the loctite before playing with your rig. And pleas3 find a proper hexdriver for the grub screws and never use the ellen key provided if you're planning on screwing it tight as it will damage the hex and cause more troubles.
Types of grease
- choosing a proper grease is no different than any other RC or any other 10th scale crawler. Heavier grease is usually preferred for this type of application. The red automobile grease or ones sold in hobby shop works just fine. But i preferred the CVD grease as it will become lighter in heavier use.
- never ever neglect the maintenence of your rigs even if its just a "toy".. Proper maintenence will ensure better pleasure in playing with your rig for the coming days.. I usually maintains my rig once every 2-3 weeks depending on how hard your play with it..
Hope these tips will helps you guys in building better rigs and to prevent any break down while trailing with your WPL. Sorry for the long post but there was no any other way.. Cheers.