C28

[Marc Miller]

Baseline set-up information for Birel C28

[Marc Miller]

Hello everyone,

Below you will find baseline set-up information for the most popular junior karting chassis in North America, the Birel C28.

Our suggestions:
- Tie-rods: mount the tie rod ends underneath the spindle arms, not above.
- Remove front bar

Front width: Start with 2 thick spacers on inside of wheel
Front wheels: Douglas 4.75" spun aluminum bearing mount wheels

Seat measurements for standard Tillett Cut Down seat:
48cm (from front bar heal area to left lip of seat)
48.5cm (from front bar heal area to right lip of seat)
22cm from axle to top of seat (from very top)

Rear Axle: 1040mm F axle
Rear hubs: standard gold 30mmx35mm Freeline hubs
Rear width: start with 46.5" (inches) using Douglas 5x5.5" spun aluminum wheels

You can widen the rear of the kart to help free it up based on track conditions.

[davidkakb]

I purchased a used Birel C28 and their setup was similar only they were using a B axle instead of the F you post here. Can you give me some more info on what the tradeoffs are for using one vs. the other? Thanks, David

[Edward louis]

we use the F earlier in the yr when grip and track temps are down. then switch to the B

[Marc Miller]

Hi Edward -

Just for everyone's reference, our national team rarely uses the B axle even when the track rubbers up. It is certainly an option, but going too soft may bind up the chassis. Just adding to this for reference.

[TCowen]

What rear percentages are ideal? We are running the Yamaha Rookie Sportsman in Daytona and on the 950mm with no weight it scales out at 55% rear and the weight is right on the money. Don't want to move the seat if we don't need to as he is comfortable as he is. Is this too much rear %?

[kart95]

I'm wonding if the chassis setup should be different for a micro vs. mini Rotax and the c28 chassis?

Also, can anyone comment on the rear height adjustment baseline starting point?

[Marc Miller]

What rear percentages are ideal? We are running the Yamaha Rookie Sportsman in Daytona and on the 950mm with no weight it scales out at 55% rear and the weight is right on the money. Don't want to move the seat if we don't need to as he is comfortable as he is. Is this too much rear %?

We don't scare the karts - so try it this way and report back to how it goes. Good luck!

[Marc Miller]

I'm wonding if the chassis setup should be different for a micro vs. mini Rotax and the c28 chassis?

Also, can anyone comment on the rear height adjustment baseline starting point?

Typically not, though with the higher HP of the Micro, you may need more grip so castor/camber may come more into play.

[bill berzabek]

I was wondering what affect a shorter or longer axle will have on handling. Instead of the base 1040mm axle what affect would a 1000mm axle have or 1060mm axle have.

Thanks in advance.

[Chris Lobaugh]

A longer axle creates more side bite or "grip". Conversely a shorter axle has less side bite and helps "free" the rear of the kart up.

[J-Dubya]

My boy has a c28 with a Gazelle, we are totally new, and have just begun to try yo wrap my head around chassis setup. I have heard read conflicting advice, so I am very pleased to find this resource.

First, can you recommend a good book or reading to learn about chassis setup particulary for the cadet racer?

My boy is on the small side 51" 52#'s. First of all we are looking to get a good seat setup. Is the baseline setup good for a smaller kid (has Noonan pedal platform setup)? With a smaller lighter kid, would it be advantageous to munt the seat incrementally higher? Ar e there other departures or directions from the baseline setup that should be considered for a smaller kid?

Is axle hardness/softness a function only of track conditions or does the driver size factor into the setup?

One guy was mentioning that I might want to munt balast high to help with weight tranfer -- is this the right thinking?

I am confused by axle width, the comment in the post above says width increases grip, but I have heard and read that a wider axle promotes oversteer. Is this a function of entry or exit?...

Thanks,
jw