Birel - Briggs 206 Hopping in Turns on MG Red

My Birel came with a 40mm 1000mm axle.
I am using some Douglas spun Aluminum wheels with more offset and that makes my rear track just 1300mm (1400mm is the limit per the rulebook).
Kart started hopping which made me get long 110mm hubs. The hopping is so bad that I am just a passenger in fast corners.
Arrow (the only owners manual I found) suggests 1370-1380mm with the MG Red tires.

What class are you running? Unless it’s 206 or similar, 1300mm rear track is way narrow for anything with some HP.

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Yes its 206 with MG red. I am trying 1360mm next. The hopping needs to stop otherwise my ribs suffer too much and driving is also not so much fun. I will try it this weekend and report back.

Do you have any video? Hop can be caused by many factors, although track width is certainly a good place to start.

What model Birel is this?

Sorry, no video yet but I will make one if it does not go away.
Its a MY21 Birel AM29, axle is 40x3x1000-B, 75mm hub- all the way in.
Maybe a little background. I was running the original Birel MAG wheels and there was some hopping. Switching to the Aluminum douglas wheels made hopping worse, I noticed that the wheel offset is 7mm less (less rear track). So there seems to be a trend.
All speculation is difficult, I will report back after this weekend.

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@Ben_Stahl @StahlRacing can hopefully give you some pointers but that sounds really wide on the rear track for a 40mm 206 setup.

Seat position (Vertical and longitudinal) might be worth noting as well.
If it had hasnt been mentioned already, inspect the frame and seat brackets very closely for cracks.

I’m on my third AM29 chassis now.

Are you running the front bar and seat struts? I’ve found that a spacer and a half in the front is best with the metal bar and two full spacers with the plastic. Very comparable setup but I use the plastic bar on tracks that have more low speed technical corners. If you’re not running the bar and struts I’d start there.

If you are, my rear track is 5-5.25” rim to frame rail.

I’m on Lecont Reds