19 replies to this topic

[Pablo]

Anybody know why the C11 center section in 30 thou is a much shorter WB (rear axle to flag) than the 25 thou version ?

I just noticed this today, getting ready for the GTP race at the Cozine Classic 8/9 Jan.

Can't decide which one to use

[Pappy]

Didn't know that, Pablo. I think the X25 is shorter than the C11 and is faster. I think I would go with the shorter 30 thousands center section.

[Koford fan]

Yea X25 is shorter than C11(x24), X25 is about 119.??mm  / X24 is 125mm (From center of axle to center of pan)

[Pablo]

OK thanks, that may help in my final decision, but my original question remains.

Why would a different steel thickness in the same chassis change the WB ?

The 30 thou C11 is about 4.7" and the 25 thou is about 4.97", a significant difference.

Also, the designs of the front ends are also completely different, which puzzles me even more 

Maybe it's all a moot point, and I need to go to another version entirely.

I admit I haven't kept up with the progression of 11/21/24/25 etc.

 

I want a 30 thou center section, 25 thou (steel) independent pans, and it must house the PS 4002 FK motor.

[Ralph Thorne]

Because the 25 thou is not as strong so it needed a beefier front end and coined guide tongue.

[Pablo]

Thanks Ralph, that explains the design difference perfectly.

But, why the WB difference ?

[kvanpelt]

Hi Paul 

 

These are C11 center sections in .025 and .030, as I tried to show on the lined paper, exactly the same length.

 

The X25 looks like the .030 C11 but is shorter. Sorry I don't have one for comparison. It does not have the nubs where the bite bar lays across. Maybe that is the chassis you have!?

Attached Images

• 

[Pablo]

Now I know I'm wrong somewhere, because my photo doesn't look anything like yours.

Like I said before, I have not kept up with the JK chassis changes.

 

Here is the C11 .025 in foreground, and the .030 (something) in the background

 

[kvanpelt]

Notice where the bite bar lays across the center section. The X25 is smooth and the C11 has nubs.

[Pablo]

OK thanks guys, now I'm sure I was comparing apples to oranges.

I'm back on track, thanks to y'all.

[kvanpelt]

I don't know if Ralph or Danny use the guide stiffener, but I don't think they are necessary on the .030 thick chassis.

[Ralph Thorne]

I don't use a stiffener on the X25 myself. I do on the C11 though as the guide is not coined.

[Danny Zona]

No guide stiffener, IMO. I don't even use them on the thin .025 but I tend to stay out of wrecks, most of the time. Lol

[Pablo]

One (of many) things I learned from DZ on these chassis, a stiffener/doubler merely makes the bend happen in a different place.

Sans doubler, the bend is easier to locate

[Pappy]

 I tend to stay out of wrecks, most of the time. Lol

I just don't go fast enough to bend anything. 

[Pablo]

We love you just as you are, Butch

[Rob Voska]

JK came out with the 1 pc pan for a C11 but ISRA would not pass it due to wheelbase so he had to make a new center section & called it the X25.   Also at that time Mossetti was legal until the wheelbase was found to be to long. 

At the time it was Turboflex chassis, Mossetti & some Parma stuff but everyone ran Turbo's.

 

Most guys run a few small pcs of body armor under the rear bite bar to raise the pans on an X25.

[Pablo]

Thanks Rob

[CoastalAngler1]

I like the way DZ calls the short center, a 9mm...

[Danny Zona]

I like the way DZ calls the short center, a 9mm...

.9mm Lol