I am currently riding a coaster-brake single speed to and from work. The rear hub is crap and I would rather have a flip-flop hub on the rear. Is it as easy as removing all the mechanisms on there and putting the wheel in, or is conversion needed? The bike is from Indiana University's Little 500 (https://iusf.indiana.edu/little500/ri...500-bikes.html), and there are no quick release levers...just washers and hex nuts. I know I'll have to put a brake caliper/lever on, but the coaster brake mechanism allows leads to slack in the chain every two months or so.

you'll need a flip-flop hub. if it's a nutted axle hub, the axle can be the same length and diameter as the one you have. if the axle on the new hub is a hollow axle designed for use with a quick release, the axle needs to be the same diameter, but will need to be shorter, depending on the inside width of your dropouts.

then the current hub will need to be removed from the rear wheel and the new hub installed, which may require a new set of spokes depending on the flange height of your new hub flanges.

i am skeptical as to whether your problems involving chain slack will be resolved with this modification though, spontaneous chain slack is usually caused by loose axle nuts and/or long term chain wear. but without looking at it, it's hard to tell for sure.

I'd recommend a single speed ,instead.
You can get a cheap freewheel hub in a machine built wheel, with another solid nutted axle.
a Shop can re-tension the spokes and re center the axle to turn it into a single speed wheel,
screw a freewheel on and fit 2 brakes on it and you are good to go.

Or just get a fix/fix or fix/free flip-flop wheel and skip the hoopla of having to fart around with re-centering and re-dishing. By the time you pay a shop to do that, you're probably around the cost of an inexpensive hipster wheel anyhow.

(I cut costs by building my own, but my fix/fix wheelsets were $98 in material costs.)

a coaster brake hub has 110mm spacing, whereas a track/ single-speed specific hub has 120mm spacing. if you use a road hub modified for SS use, that's a 130mm spaced hub. you might be able to fit a 120mm track hub in that frame, but anything wider is going to not work very well.

If this helps at all, a picture:



Hope this helps with an answer...if not, time for LBS visit.

Just saying single Freewheel hub wont need frame spreading,
you can get a 110 width out of the thing.

just a mechanic, who turned a dumpster derailleur bike into a single speed
for just the cost of the freewheel.
5 speed starts out at 120, asymmetric, easy to lose 10 mm while making it symmetrical.

I think this might do the trick...120mm spacing on the rear:

https://handspunwheels.com/products/view_product/1814/

Thoughts or comments on this brand of wheel/hub/rim?