install new model

Open "gta3.img" in IMG Tools.
Backup "freeway.dff" , "freeway.txd" and "bikeh.ifp"by extracting it.
Replace "freeway.dff" , "freeway.txd" and "bikeh.ifp" with these files in this zip.
Recompile the archive.

you can find "handling.cfg" in "\GTA San Andreas\data" directory,
Open "handling.cfg" with notepad , find and replace
This is not standard handling setting.
This is special handling setting and additional parameters.
These are applied when using the "IS_BIKE" flag.