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I tried the search feature, but I guess I was typing in the correct wording. I have a vintage gold tub running stock. 30* casters and I'd like to try out some 25* but can't seem to find any. I know I can use B4 blocks but which ones will give me 25* caster? Thanks in advance gents

While we are on this subject, can somebody clarify what a 25 degree block is? Does it give me 5 degree overall castor or 25 degree overall castor. What I mean is, if I put a pin through the arm mount and set it on a protractor with the arm mount pin on my 0 line, where will the king pin point?
Thanks

25 degree caster will give you 25 degrees referenced from vertical. If you put the hinge pin in the caster block the king pin will be offset from perpendicular 5 degrees. This because the arms would normally ride at 30 degrees from horizontal due to kickup angle.

The b4 has a 25 degree kick up so in order to get 25 degree on a gold tub you need a 20 degree b4 caster block. Gold tub pickup is 30 degree and 5 degrees is the difference.

I would like to point out that he means if you put the hinge pin through the arm and caster block, the king pin through the hub carrier and caster block will be 5 degrees from perpendicular to the hinge pin. I had to read it a few times.
Why do people prefer 25 over 30? Rc10 30 degree blocks seem to do pretty well on my car. What's the advantage?

Right, nose plate angle should be 30 degrees. If my hinge pin and king pins in the castor block were 90 degrees apart, it would be a 30 degree layback angle on the king pin thus a 30 degree castor block right? 25 Degrees seems like a lot, it sounds very agressive to me.

Exactly. That much caster gives you better stability.

So 5 degrees less (30 vs 25) gives more steering?

Yes, all other variables the same.

Less castor means the tire stays flatter giving you more mid/ exit steering but decreases straight line stability.

More castor gives more initial steering but less exit steering. Straight line stability is also increased.

joel45acp wrote:I tried the search feature, but I guess I was typing in the correct wording. I have a vintage gold tub running stock. 30* casters and I'd like to try out some 25* but can't seem to find any. I know I can use B4 blocks but which ones will give me 25* caster? Thanks in advance gents

Sorry to hijack your thread.

If a B4 has a 25 degree kick up then the B4 20 degree castor blocks would give you 25 degrees castor on the 30 degree RC10 kick up.

Wow! Ask for a bowl of rice and I got a seven course meal. Hahaha. You gents rock. Thanks a bunch guys.

Would this still apply if I used the 20* B4 caster blocks on a B3/T3 to get 25 * caster? Thanks again gents.

yep