4WD SRB Racer

[1300GT]

It's all good Jeff, SRB top shaft gears and idler gears both have 20T. I've got a top shaft gear in place of the idler gear in the rear gearbox. That's what the rear sprocket is bolted to.

[GoMachV]

Haha right on. I have been away from Tamiya a very long time

[1300GT]

Race modded gearbox anyone?

While waiting for the front gearbox materials to arrive I chopped up the rear box a little.

I read about this mod years ago and wanted to try it. Epoxied two .016" thick cover plates over the exposed internal gears and slotted the original motor plate. Now it's got a much greater range of ratios.

I'll be adding a four point rear cage to protect the motor in case of rear enders. If the motor plate does get broken I can mill the side of the box and add a removable motor plate.

[j-sou]

Wow! That looks great!!

[1300GT]

Thanks J-sou. Next time I've got the gearbox apart I'll weigh the two halves against a stock pair.

Some pics of the front suspension to be used. I made G10 shock tower extensions and modified the shock towers, front arms and the steering hubs. The hubs are off the rear of a Progress. The shocks are Progress rears.

The reason for the long ball ends on the shocks is so that the springcups will clear the dogbones.

[1300GT]

Front gearbox made. This is coming along nicely.

I've got some engineering plastic to cover the gears. It'll be sandwiched between the two G10 plates and replace the alloy spacers.

More to come.

[RC104ever]

Now you really have my attention - love the front hubs and shock tower extensions! Would you make me a set?

Looking great, can't wait to see the finished product

[cooltoys]

Now you really have my attention - love the front hubs and shock tower extensions! Would you make me a set?

Looking great, can't wait to see the finished product

You'll have to double that.... Awesome work on the tranny..

[1300GT]

Thanks fellas. I want to see how it ends too!

I've had the Progress hubs for some time now. Optima hubs would work as well. I went with the Progress ones as they are more period correct for this build.

I had to cut down the area where the ball studs screw in to lower the overall height of the hub. Left stock they splay the front arms too far apart and the castor change through suspension travel is increased quite a bit.

[1300GT]

Front transmission installed. I lowered the gearbox into the chassis by cutting a hole where it sits and by attaching the gearbox mounts 5mm from the bottom of the box. Overall this lowers the outdrives and lessens the angle of the dogbones between the transmission and drive cups.

Overall view.

Got to make a chain guide now to keep the chain off the rear gearbox.

Lots more to come.

[RC10th]

Wow, that's some nice work Chris.

I may have a Yokomo Dogfighter chain tensioner that your welcome to have for this project if you want it. I'll have a look tonight.

[1300GT]

Thanks RJ, much appreciated. I'll be down that way in a couple of weeks. I'll PM you closer to the day.



I modded the front shock towers today to clear the outdrives. The picture shows how snug everything is up front. I was also playing around with front shock angles and the dogbones should just clear the shocks. It's gonna be close though.

Suspension back on.

The gearbox sits slightly lower than the top suspension tube which will make fitting a buggy body fairly straightforward.

[mk-Zero]

Awesome work!

[Mr. ED]

I love your project. Keep those updates coming please!

[1300GT]

Thanks fellas, I'll see what I can do about updates.


Finished the four point cage today. The G10 plate on it will serve as the shock tower.