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GOM SPORT CHASSIS

Review by HaCo

A while ago I was looking for a universal rally chassis. The two things I wanted the chassis to have were a drop arm and 4WD. The main reason for this is that I have two Carrera rally cars laying around here which I never drive because I don't like the way they drive. I never drove a chassis with a drop arm before, so I was looking forward to what it can do...

I found some options when looking for a chassis, but the GOM Sport (#GOM-2501) chassis looked the most complete to me, the only thing I needed to add was an SCX type motor. I ordered the chassis at Pendle Slot Racing (thanks a lot for the quick and cheap delivery!) and some days later a box arrived here in Belgium and this is what I found in it:

The back of the package shows a Lancia 037 jumping in the 1000 Lakes Rally, it makes you dream away immediately.

Build-Up:

In the package you find the chassis, together with a motor mount, slot shoe, wires, a belt, some screws and bolts and the body supports.

As I didn't find a lot of info about the chassis on the web, maybe it's a good idea to put it here:

Wheelbase 73,5-78,5(81,5)mm
Front Width 58mm
Rear Width 60mm
Front Axle Width 54mm
Read Axle Width 51mm
Weight (with motor) 64gr

When measuring the wheels and axles I discovered some special things. First of all the pulley was in some soft plastic and second: out of the four wheels, there were 3 different types.

Ok, so I have a Peugeot 307 WRC from Carrera which I want to build onto this chassis. I also havean SCX RX-42 motor from a slot-it-ed Aston Martin DB9R which I will use too. I start setting the

wheelbase to the correct position, but I encounter a problem. On the front of the chassis there are 2 rings to hold something, and they hinder to take the maximum position. That's why I have put the 81,5mm between brackets. I had to cut those rings away to get in the right (max) position for the Peugeot 307 WRC.

Second I had to place the motor in its motor mount. The GOM chassis consist of three parts:

So, the motor goes in the motor mount and the motor mount should be fixed on the mount that is holding the rear axle. That assembly should be fixed on the top part which holds the front axle and the drop arm.

When mounting the motor mount on the mount that holds the rear axle I encountered another problem. As this is an in-line chassis, the centre of the axle of the motor should be at the same height as the centre of the rear axle. But this wasn't the case at all, it is sitting like 4mm lower than it should. The gears don't match and it is impossible to let the motor rotate. So, I had to add some spacers under the motor mount to get it higher. But then the supplied screws where to short. Because of using longer screws, the mount wouldn't fit any more under the upper part of the chassis. What I'm trying to say is that had to mess around to get it working. I must be mounting it completely wrong, or the supplied motor mount was not correct.

I think the supplied hardware (bolts and screws) weren't supplied correct either. When opening the package the upper and bottom part of the chassis was fixed with self-tapping screws. But when you take a close look at the chassis, you can see there is a place for putting nuts. So in that place I think you need to use bolts and nuts (I replaced it in my chassis with the IMO right hardware). I think that the self-tapping screws should be used to hold the motor mount, when the right one is supplied.

You can see that the screw of the motor mount are sticking out of the chassis, which isn't very nice either.

Ok, the motor is fixed now. It's time to put the body on. When trying that I encountered another problem. The supplied drop arm can be fixed at three positions. Even at the most far position from the front the drop arm is still way to long.

It's bizarre, because a user posted an image of the same chassis on the forum and there the drop arm looks a lot shorter. So I started to make one by myself, this is the result:

As you can see this drop arm is a lot shorter than the supplied one. This allowed me to mount in in the middle position.

The side body mounts are supplied with the chassis. With a marker I was able to position them on the body, using double sided tape I fixed them to the body.

With the body mounted on the chassis it should look like this:

And that is the bottom of the chassis:

There are still some things I didn't mention about the chassis:

  • The drop arm is supplied with a spring and a set screw. With the set screw you can set-up how deep the drop arm goes into your chassis.

  • There is a set screw above the bushings that hold the front axle. The bushings can move vertically and with the set screw you can limit that movement.

  • The belt is quite tense, but of course on the maximum wheelbase that is tenser than on the minimum. It is so tense that I can rotate the 'heavy' SCX motor by rotating the front wheels.

  • I almost cut the supplied wires shorter, but of course they are so long that the drop arm can fall... :-)

Track Test:

I quickly build a little home track with R1 hairpins and R1 90° corners to test this car on a track with short turns (that is rallying of course...). My home track is NINCO, which offers a lot of grip. I use zero grip tires on the rear to get some slide fun on the track with all my rally cars. But first an 'out of the box' test.

I was very surprised by how silent the car was, it was awesome: an SCX motor in a car that is actually silent... awesome! It handled pretty well through the corners, the supplied tires felt very soft and it was visible on the track. After some laps the motor felt VERY hot, so I decided to remove the belt as it was very tense... wow, suddenly a lot more power came out of the car and a bright smile appeared on my face: this beautiful 307 that was for a long while not moving because it had such a bad Carrera chassis was now going awesomely well!! In the kitchen I found another small belt that was a lot less tense and yep 4WD was back, but smooth this time.

But eh, I don't like to have so much grip, so I removed the rear tires and replaced them with zero grips of Slot-IT. The car was very fun to drive.

I also did a little test on the drop-arm. I made a small bump on the track. My SCX Ford Focus ran 2x over it well, 1x it flied off, tested at high speed. The GOM chassis never flew off at high speed. When going slow over the bump the Focus lost power, the GOM passed very nice.

Final Verdict:

Pro's:

  • I like the concept of the chassis. It's not very expensive and it allows me to make my Carrera Rally cars a lot faster.

  • You can do quite a lot of settings in the front.

  • The supplied axes, crown gear and bushings look like to be of a good quality. The rear bushings are of the same concept as Slot-It chassis.

  • With the supplied body supports the body will not fall of.

  • It's silent.

Con's:

  • The wrong motor mount supplied with the chassis.

  • Incorrect supplied hardware (maybe if the motor mount was right, the supplied hardware would be too).

  • Long drop arm.

  • Too much belt tension.

If all the parts would be right on the chassis, it would have been perfect for me. After doing all the mods I am very happy with the chassis. I contacted GOM about the things that were missing but didn't get an answer yet.

   Lo-Fi Version Time is now: 25th October 2014 - 18:07
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