Reddit reviews SHIMANO SM-CS50 Housing Stops Concave Mount

If you have taped over downtube shifter bosses and added a clamp on stop, you might use these instead for a cleaner system: http://www.amazon.com/Shimano-SM-CS50-Housing-Stops-Concave/dp/B000C534P6

Yes there is, but all in all, it's likely to take anywhere from $120-200.

The key part is downtube cable stops (like this) that stops the shift housing. You'll also need to find brifters that work with your bike. I believe on a 7 speed, you can use 8 speed shifters as well, so either one. And you can pick something up on ebay for probably around $100. Then you'll need to get new shift housing and cables ($10-30) and install everything. If you're not comfortable doing it yourself (and then tuning your shifting) then you may want to go talk with your LBS and get a quote; you may be able to pick up the brifters used and have them install everything.

You definitely need something there in order to get the shifters going. You can either use the drop down shifters, which I have found for decent prices on ebay, but also some at exorbitant prices. Like I have bought some 105 7-speed and dura ace 6-speed each for less than $10 but some people slap 'classic' or 'rare' on it and charge $50-100. You can also get some of these without buying the shift lever bosses, but it has to be the right diameter for the down tube, and I'm thinking the r300 tube is too narrow for that bike. But, measure so that you know for sure.

Also, what type of rear derailleur is on there? This will determine the type of shifters you get. The ones linked are 8-speed shifters, but I use with a 7-speed rear derailleur by locking out the last cog. It looks like you have an RSX on there that is 7-speed, but if you can find the model number, you can confirm this for sure.

Also, you can get these that screw on to the shift lever bosses so that you can run brifters like these. I did this on an old bike that had shift bosses for drop-downs, and it worked out nicely and was relatively simple, and the linked brifters came with cables. Or, you could always change the bar to a flat one and get something more economical from the mountain line, and the flat bar may be an easier ride if your dad is older.

Hope it helps!

Their standard bar end works, though you may need a base plate if you want it to sit flush: https://www.amazon.com/SHIMANO-SM-CS50-Housing-Stops-Concave/dp/B000C534P6