View Full Version : SRX2RM

11-08-2017, 06:14 AM
So... I got a really good deal on a Serpent Spyder SRX2-RM as my first competition grade kit, also came with 4 sets of spare front and rear wheels, but no tyres.
A bit rebuild of work on it, but not that much.

But I'm a bit confused on how the previous owner set it up, and don't see why it would be built that way.
The left side of the car, all links, dampers etc. have the orange spacers between the pivot balls and the chassis.
The right side of the car has none.

The ball diff feels really loose, when I rotate one side the other side spins the other way, without any form of resistance.
But the gearbox feels the other way around, really tight, it won't even spin free for even a second after I rotate the spur, checked everything, but cannot find anything that binds or something as it feels really smooth when I rotate any of the gears.

And lastly, the kit contains a lot of spacers for the different servo brands, but I'm using a Turnigy Trackstar TS-915 (https://hobbyking.com/en_us/trackstartm-ts-915-digital-1-10-touring-car-buggy-steering-servo-10-1kg-0-08sec-45g.html), as this is not noted in the manual, how can I determine what spacers I would need between the servo and the servo mounts?

11-08-2017, 06:47 AM

Maybe it was set up for an oval track?

I'm not 100% sure but most of the gear boxes has height spacers...if the RM is the same it would be worth checking to make sure the right spacers are installed.

Also of the car has been set up wrong or for an oval then the shock oil and piston would be worth looking at too.

What type if tracks do you race on?


11-08-2017, 06:51 AM
As for the servo spacing, you may need to play around with them. Trial and error.

I run Absima electrics and needed to play around with it a little.

11-08-2017, 08:19 AM
It was no oval track, he wanted to run it on mainly astro tracks but switched to 1:8 before actually running this car, only a few test laps were done with it.
That's why the setup really makes no sense at all for me...

Already seen that the diff height can be changed, it really feels smooth, no tight spot or anything when I turn it by hand.
But almost immediately stops when I push the spur.
I will probably pull the entire car apart and rebuild it with the base setup from the manual this weekend, that's the best thing to do right now I think.
When the base setup is OK I can work from there.

I intend to run in it 90% on 2 of the astro tracks in the neighborhood, and maybe sometimes on a dirt track which is a bit further away.
Already have schumacher tyres on the way for the astro tracks.

11-08-2017, 08:32 AM
It's probably best to strip it down and having the fun of rebuilding it ��

Have fun. Darts are good for set to and sometimes Ballistic Buggy whites on wet astro.

11-08-2017, 12:09 PM
If it's nearly new, you're in luck diff-wise: A diff that is too loose can ruin the balls, plates and main gear in no time. I recommend you rebuild it; Do you have previous experience with ball diffs?

I once built an SRX2 and found some parts needed special attention:

- The plastic shock cartridge (in which the o-rings are) can be a little tight around the shock shaft. Ensure that the shock shaft moves through it freely.
- Ensure the shock piston moves freely through the shock body - a bit of sanding (or scraping with a scalpel) might be needed, but you do need to retain the smallest possible gap between piston and shock body.
- Take care inserting the diff screw into the outdrive (because of the o-ring) - greasing it helps.
- The diff's T-nut is a plastic piece moulded around a metal nut (if I remember correctly) - it can strip if it is tightened too far (brutely). As such, check its condition during the rebuild. If it is stripped, I recommend buying the Exotek's T-nut for the Kyosho RB6; it also fits the SRX2 diff.
- Take the shocks off and check all suspension arms fall down under their own weight (virtually friction free). If not, you might need to sand or scrape a little material off the wishbones.

A free suspension and well built diff are corner stones of a good service life and good pace with any car, so its worthwhile checking it out :)

PS #1: If it turns out you are missing spacers, I recommend going to your local hardware store. They should have 6x3x0.5mm steel washers that carry out exactly the same function for only a fraction of the money :thumbsup:

PS #2: I just saw your note on the tight gearbox. If it's just somewhat tight but still moves when you turn it, it might need to be run in. Before you do, do check the condition of the bearings and see to it that no parts are obviously catching or binding.

14-08-2017, 07:59 AM
Origineelreclamebord, thanks for the tips!

I started cleaning out the shocks this weekend, all but one are very smooth.
That one also was leaking oil badly, so will probably need a new shock shaft and/or o-rings, will completely rebuild it first and see if it is still leaking then.
I have no experience with ball diffs at al, all bashers I had so far had a gear diff.

The chassis itself is really clean, and in great shape, only a few scratches, but nothing bad.
so the only parts needing attention are the gearbox and shocks, the a-arms and steering are both clean and moving free and smooth.

The gearbox is tight when I want to let it spin freely, but runs and feels really smooth when I run it by hand, so needed to be run in sounds pretty logical to me then.

14-08-2017, 01:04 PM
Glad to help out, and good to hear that the issues appear to be minor :)

If you're going to replace the o-rings of the shocks, I can recommend going for the X-rings: way smoother and they seem to keep the oil in better, too.

As for the ball diff: There are plenty of guides on Youtube that could help you. The short story is:
- It's worthwhile to sand the main diff plates with fine, wet sandpaper (600 or higher)
- A layer of grease on both diff plates is enough - the thrust bearing can use a good dab of grease so the balls stick around the diff screw.
- Compress the diff spring a few times before the diff assembly.
- Make sure the slipper slips (a whizzing noise) and not the diff (a screeching noise). When holding both wheels, the slipper should be tight enough to just lift the front end off the ground (do keep your face wel away from the car: it can very suddenly lift up if the slipper grips or is too tight).
- Run the diff in outside the car with a cordless drill (and a driveshaft) or re-check the diff setting/tightness after a few minutes of running.