R32Z seating/axle

[Graham Odell]

Sorry, this is really long but the only wany to fully explain my situation.

I just have some questions regarding the setup of my R32Z... (its a 2001 model, doesn't seem to be sold anymore).
The kart is on the pace during testing the day before a race, or in the early heats but late in the day (and not always a significant amount of rubber has gone down), the karts feels "tight", understeers and doesn't want to release from corners. It hops if there IS a lot of rubber down.
Early in the morning the rear end is loose all through the corner but not as the weekend goes on.
Usual setup is:

45-45.5" front.
55" rear.
2 seat stays each side (reduced to 1, or even none on the engine side).
Bridgestone YGKS. (Racing in Rotax Max). 12psi from cold.
Front bar in.
Rear Bar out.

Local Birel dealer came to look at the kart at the track this weekend. First thing he did was measure the seat. He said it was too far back and I was applying too much weight to the rear when cornering as I'm 6ft. But he admitted was wasn't really an option to move it forward as I wouldn't fit in the kart well (knees nearly hitting steering wheel as it is).
Instead he suggested lowering the ride height front and rear which helped a bit but I don't nkow if it was the final solution. He also suggested an option would be to use a softer axle as standard to compensate.

I'm just wondering firstly if you would have the correct seat fitting dimensions, its a Tillett seat which came with the kart.
Secondly, as a matter of opinion, would you consider the softer axle a good option.

I'm fairly experienced but am having a hard time since switching to this chassis in getting it right for all conditions... it can literally go from front of the grid right down the field as a day progresses and any (small) amount of grip is layed... I'm baffled.

Thanks a million!!

[Vernon Head]

I'm not an expert, but I've driven my R932 in Rotax quite a bit. Yes, I would go to a soft axle and short hubs if that's not enough. You could also lower the seat. Another trick is to add a tooth on the rear sprocket to compensate for the extra grip and many times loss of power due to more heat in the engine.

[Vernon Head]

Graham:

Since I last posted I've purchased a kart just like yours and raced it in TAG Parilla. Where I'm racing we use Yokohama YO-1 tires, which are a bit harder than YGKs. I put in the F axle last weekend to cure a front vibration that I'm reading as a small hop. The kart works quite well with the softer axle and I think you should try it. It's not pushing at all and I love the brakes.

[Graham Odell]

Hi Vernon,
Thanks for the info.

We bought the kart 2nd hand a year ago and it had a non-Birel axle with no markings so we had no idea what stiffness it was. This was slightly bent after I recieved a shunt from another kart and the Birel dealer here gave us the F axle to install, the standard axle on most of his karts here.

However, I picked up a softer (B, I think) axle to other day. Someone was selling a lot of birel part locally. its a brand new axle but was a going for practically nothing since the guy just wanted to shift all the old parts. I'm gonna install this this week and see how it goes at the weekend. Nothing lost really even if it doesn't cure the problems.

I'm looking into the possibility the chassis might just be past its best but if the softer axle helped any bit that'd be great until we could afford to get a new chassis later on.

Cheers!

[Garry Lobaugh]

Just a follow up to this thread: When is a chassis too old? The down and dirty answer is " When you make changes and nothing happens on the stop watch".

Long ago I was taught by a veteran coach: Never let the driver have more than five laps. A good driver will make adjustments in their driving style to compensate for the chassis change. So consider all of the above as an attempt to be helpful in your future testing and plans.

[Graham Odell]

Thanks Gary,
The chassis is a few years old now. It looks in great condition and we were told it was hardly used but they said the same about the engine and the engine tuner had a good laugh at that when he first saw it. So I'm guessing it's had a good hard life between myself and the previous owner.

Have been told by a few sources now a lack of responsiveness in changes seems to signify the chassis is loosing its "spring" and thats exactly what it is. Having driven on new chassis when I was in 4 cycle racing some time back I'm starting to realise I probably need to pony up and get a new frame if I want to be right at the front again.

I'm probably making too big a deal about this but we're on a tight budget, hadn't planned on a new chassis before the end of this season... oh well.... can only do your best, eh?

Cheers guys, you're great!

[Garry Lobaugh]

A few of our dealers have good new frames at a decent price. For example Q31 Z models and others are on closeout. Sometimes just buying a new frame turns out to be a bigger hastle than planned. for example the bearing cassetts may have changes or the floor pan might be different, but at least it is an option for you.

Another way to tell if a kart is ragged out, is by looking from the bottom up, unless of course it has been repainted. Our view is a kart that is wearing out has the appearance of an abused kart. So just because a kart may have age, but not use, does not mean the metall has been flexed out. To me the flexed out is after use and that usually shows on the bottom of the frame. That is our experience after 12 years of working with the Birel product.
Give us more feed back as your situation unfolds. If you are near one of the MRP dealers, see if they have a demo kart or will work with you in finding a good unit for your needs.