My 99 Electra glide has a 21" front wheel installed by previous owner. The mechanical Speedo drive quit working and now I need a new one. Does anyone know if the ratio changes, I believe it's 2240:60 with a stock 16" wheel. I would like my speedometer and mileage to be correct. Any info would be appreciated. Been searching all over online and can't figure it out.

 

It's overall tie size that will decide if it needs changed or not.
I.E. if the stock tire is 23" tall with a 16" rim, & your new tire is 23" with a 21" rim your tire is still 23".
I'm just pulling those numbers out of my *** for demonstrative purposes though.
You will need to figure out stock tire size vs current tire size.

 

If your transmission has the cut out for the speed sensor.....you run a digital speedometer with more options.

The Road Kings already has the cut out. All 2000+ Electra Glides has the cut out.

I have only seen THREE ‘99 Electra Glides come from the factory with the cut out with a block off plate installed. You might have one of these rare ones.