Urethane Bushing Vs. Spring Pull Bar

[djexidus]

Just wanting some input from others... Both must have advantages and disadvantages, I have only ever used progressive spring pull bar, which is pretty tunable for different track conditions with preload. What are the benefits of the biscuit bars? Are they better or worse for high horsepower conditions or different track conditions? What is a good biscuit rate/color to start with on a clamped BPRC modified? I know with the spring we would shoot for around 3 inches of travel, what do you look for in a biscuit bar for travel? May try one, so just looking for some input.

[racin6mod]

I switched to the urethane last year,you can tune by mixing rates I have a blue and a red buscuit stacked to get a progressive rate. A spring will loose rate and a urethane will crack after time. I felt like the urethane had more forward bite but thats just my oppinion.

[Dirtrace54]

Schoony is right on this on what he said. The red/blue biscuit combo is used by a couple guys on Shaw cars.

Heres a good link for biscuit tuning. Shaw and Speedway (Afco) both use these parts.
http://www.rightfootperformance.net/tech/pdf/Polyurethane%20Spring%20Bushings.pdf

[kraftkar7x]

Shaw has a progressive doing that is rated to be just like the urethane biscuit bars...