Can you use bar soap as a shampoo substitute for soft dreadlocks?

Extremely soft dreads are easy without a bar soap, using baking soda and herbs for wash and vinegar and herbs as a rinse. (See links).

Bar soaps which are good for dreads include any all-natural soaps without residue; however, products containing SLS (sodium lauryl sulfate) or SLES (sodium laureth sulfate) are not recommended.

Baking soda works better then any soap, though.

if you mean bar soap like dove the answer is yes and no..you can use any soap, but it is not best to
the reason being most soaps leave residue, soap scum, this builds up in dreads and is hard to remove
young dreads this will slow even prevent dreading, but mature dreads are able to not be harmed except for the buildup of scum.
incidentally, this is the reason dread wax never made sense. dread wax is residue that never comes out of dreads and is water proof.
residues and dreads are not a good combination

if its a specific type of bar soap, post the ingredients in the products forum (adding new links to products, and the wax issue)

the rule of thumb is..use as natural as can be, with the least residues
the baking soda cleans twice as good as any soap though