axle choice by chassis...32mm vs 30mm

[Mark Enderlein]

Does a base line set up on a green track change the type of axle you would use on a 32mm chassis vs a 30mm chassis? Basically, Would you start with a harder axle on a 32 vs. a softer one in 30, or visa versa? How about with alot of rubber?
IS Axle tuning done on a radius? (harder with no grip, softer with some grip, harder with to much rubber (to decrease to much jacking)?).
Thanks....it was a debate this weekend. Chris

[David Yourd]

Sorry to rehash this thread, but I am interested in what Mark brings up. Am I right to assume that in extreme sticky track conditions you actually stiffen the chassis and axle to get the chassis to jack slower? Conversely, in very slick conditions - softer chassis and axle to let the chassis "work?"

Do you think any of this transfers to New Castle? We are thinking of doing Robopong again this year. We struggled with chassis set up last year. Thanks Chris for your post about the Dousman set up.

Dave

[Chris Lobaugh]

There are so many variables to consider...I think that the axle choice will be fairly similar between a 30mm chassis and a 32mm chassis with the exception of say an R30CY and an RX32 SV for example as the karts are so completely different with the way the bearings mount in the rear of the kart, the different front torsion bars, lack of a side rail, different spindles, etc. Normally (keeping in mind that there are no absolutes) when there is no rubber on the track (especially in a parking lot) a softer axle (B) will help the kart "work" better. When there is no grip on the track it doesn't matter how stiff you make the rear of the kart as a stiff axle will only make the rear slide more. A softer axle not only will flex easier, but, it will be less likely to push the front...if a kart pushes on entry it will slide on exit (90% of the time). As the track starts to take rubber you can run a more standard axle (F) and test with the middle bearing (in or out really depends on the configuration of the track and the weight of the driver/category). From there is starts to get a bit tricky and again there are so many variables to consider (chassis, seat, driver size/style, tires, weight, engine package, etc.) and of course the weather. In the spring and fall when there are lots of karts running on a given track the condition is more "tacky" then super sticky...you don't see lot's of rubber on the track and you can more than likely go softer with the axle to free it up again. However, when it is hot out, and there are lots of karts running on a given track you will see the rubber go down in sheets on the track. At this point you need to go harder with the axle (M) to keep the kart free. A soft axle will release the iside rear tire momentarily and then set it back down and you can hear the engine bog down (and 90% of the time the front of the kart pushes on exit). If you are at a national event and you want to inure that the kart stays free in the rubber you can also move the seat forward 7mm. I hope this helps...