b4 vs. gt2 castor block

[scr8p]

alright, to my eyes... just looking at pics on the internet, the b4 and gt2 castor block look the same. other than the fact that the gt2 block has an extra camber hole and the distance between the hinge pin and king pin is spread out more. is my assumption correct?

if yes, how much more will a gt2 block push the knuckle out compared to the b4 block?

also, does the gt2 have the same 25 degree kickup as a b4?

[scr8p]

eh...... the more i look at them, maybe the gt2 block isn't pushed out.

[Mark Westerfield]

GT parts (or any current AE stuff) are made from softer plastic.

[Orange]

The GT2 Castor Block comes on the B4.2 stock. And yes its 25 degree ... I would have used that on my oin car but all the hobby shops around here were out of them. It won't push it out any further than the old castor blocks. As soon as I get one, its going on my OIN car.

[Orange]

I don't know how much this helps, but here are a couple of pics... Eyeball and angle of camera makes them appear different. It was hard to take pic and hold the ruler at the same time, LOL... So ruler is just reference.

Old style B4 Castor blocks:


B4.2/GT2 Castor Blocks:


It appears wider because of the added plastic around the king pin and the added camber link hole.

[scr8p]

when i was first looking at them, it seems that the gt2 block would add a little track width. i think the added camber hole helped to make it look that way....... until you really look at it.

thanks for the pics.

[Orange]

When I saw this thread I was comparing them and thinking the same thing... I took some Calipers to them after I took these pics... They are the same for sure.

[RC104ever]

Just curious - what would be the benefit of using these vs. the original castor blocks?

[scr8p]

30 degree is the only readily available original block. most guys feel 25's are the way to go, so you have to use modern stuff to accomplish that.

that is probably the main reason.

[Orange]

I would be willing to bet the old ones will be phased out since all the current AE cars now use the 3 camber link castor blocks.

[Mark Westerfield]

Just curious - what would be the benefit of using these vs. the original castor blocks?

They have the third hole for more adjustment, and the plastic is softer so it is less likely to break.

The downside is the flex of the softer plastic does not keep geometry as accurately, and hinge pins are more likely to bind during flex (maybe why the new parts these days have extra 'tolerance').

2 hole blocks
20 degree #9592
25 degree #9580
30 degree #9593

3 hole blocks
25 degree #7919
30 degree #7922

They are all available. I think they keep them around because the team guys like running the stiffer parts (excluding chassis).

[scr8p]

the gt2 has a 25 degree kickup like the b4 right?

[Mark Westerfield]

Front nose plate kickup is 30 degrees (all the AE off-road cars have 30 degree front nose plates), the GT2 kit setup is 25 degree castor blocks.

[scr8p]

i'm talking about the chassis kickup. running them on an old rc10 (which is 30 degree) you have to + or - 5 depending on which b4 block you run since it has a 25 degree kick up. just wanted to make sure the gt2 block is the same in that respect.... and i'm guessing it is.

[Orange]

Yes 25 degree castors will give you zero (30) on rc10. If you use them backwards still zero (30). I have mine reversed to center the trailing axle on the arm better.