Dumb question, but what's the difference? I see cable kits designated for MTB or road use, but I don't know how the cables would be any different... different ends? different diameter cable? can someone explain?

Working with Shimano and SRAM groups on my bikes I can say that Cable Housing are the same. Usually Brake Cable housing is 5mm in diameter and Shifter Cable housing can be either 4mm or 5mm.

Shifter Cables are the same for both Road and MTB. The ends look like little barrels. Brake Cables are different. Road Bike brake cables have mushroom like ends where as MTB brake cables have barrel like ends.

But most kits these days have both heads on either side and you cut off the one you don't need. It's more cost-effective for everyone.

housing the same and strength the same, but the difference is in the barrel ends on the ends of the cables. the different types to accomidate either conventional mtb levers or road hooded types.

It may be cost effective, but sometimes its still better to get a single purpose kit. For example, when running new inner cables into a TT bike with internal cabling, I find its better to buy the single ended Dura-Ace cable kit because the unterminated end is welded. The welded end does not snag or fray while being fed through all of the housing bends.

MTB cables are designated so because the tips are shaped like a coin. Where a Road cable is shaped more like a corn-dog.
A lot of the inexpensive cable has both ends to it but some has only one.

OK so I am looking for a Shimano MTB Shifter and Brake Cables and Housing, I want the shift and Brake housing colors to match except all I keep finding are Shimano PTFE Road Brake Cable and Housing Set, same for shifting, which I assume won't work on a MTB? Assuming MTB and Road shift cable sets are the same and can be used interchangeably on MTB bikes or Road bikes. Please correct me if I'm wrong I just want to get the right parts, I am already almost done working on my own bike this is for my father's bike. Also I do want any off brand recommendations, I will only use Shimano products.

I like the barrel vs pear for the brake cable end.. difference..

some levers use the barrel shaped end and let it freely rotate to keep it a straight pull as the lever is pulled around its pivot.

gear cables, yes, are thinner , but Campagnolo requires a smaller end button,
put a Shimano type gear cable in and it will jam in the shifter..

cables in economy sets with a button on both ends lack the quality ans smoothness of die drawn slicked cable that have 1 fitting

and more importantly IMO the cable that was hot cut at the factory is not going to be fighting you
as much as one that frays easily where you cut off the opposite end.





....

so then i shouldn't tell you about JAGWIRE cable kits in a rainbow of color choices, and super nice feel with a great reputation as to their quality...

https://www.ebay.com/itm/JAGWIRE-MOU...wAAOSwDk5UGh6J

JAGWIRE also makes shift cable kits in all their possible colors... but you don't want them because..... ?

+1