Upgrade or convert?

[brit_in_oz]

Hi

New to the forum, I have just got back into cycling since the doctor said my blood pressure was too high. Anyway I have a mountain bike slight hybrid (Giant Sedona DX) which is great for bike paths and the bush but i want to start to ride to work again about 25km away.
8 years ago i did a corporate triathlon and bought a second hand 'Repco Elite RX tri series' bike. Its nice and light and I enjoyed risding it, but its been in storage a few years and needs a good service including new tyres, tubes, rear cassette, chain, gear wire etc. It also has down tube gears not STI type and i think these would be a improvement for ease of riding.
My question is, with the components I list below do you think its worth servicing and repalcing what I need (which I guess would be 300 buck plus?) or invest in a new bike? Is it worth upgrading to STi shifters or a waste of money on an older bike?

Repco Elite RX tri series
Frame CoMo 4130 alloy
Shimano RX100 gears
7 cog rear cassette, 42/52 teeth front cogs
Retro fitted Profile drop bars
Alesa rims

 

[garage sale GT]

Sometimes it is enough to replace a chain. You may not need a new cassette because the clunking and skipping stop with a new chain.

7 speed freewheels had a different spacing between the cogs than 7 or 8 speed cassettes. Some say a shifter meant for one system works with a geartrain of the other system but ymmv. Sheldonbrown.com has more info. I think the cassette sti's have all gone to 9 speed but I believe the 7 speed freewheel ones are still being manufactured because they're what the low, low end bikes get.

You can't upgrade to 9 or 10 speed without a new hub. If your bike is aluminum then you probably shouldn't spread the frame apart for the wider hub.

You may have to scrounge ebay to find your parts.

There's also the Modolo Morphos system which is designed to be retrofitted to bikes not equipped with sti.

I'd personally stick with downtube shifters. They're fine for commuting.

 

[ToffoIsMe]

Sometimes it is enough to replace a chain. You may not need a new cassette because the clunking and skipping stop with a new chain.

Depending on how long the chain and cassette have been mated together, and how many miles are on them, it is VERY possible that the cassette is worn to match the chain. If this is the case, then replacing the chain without replacing the cassette may actually make the shifting worse. It is always a good idea to replace the chain and cassette/freewheel together, especially if they are in questionable condition. The exception to this would be people who keep an eye on their drivetrain and replace chains before they stretch enough to wear out the rear cogs with it.

If you are already looking at $300ish to get your bike working, then it may be worth it to invest in a low end road bike. Something in the $600-$800 range will have an aluminum frame/fork (possibly carbon fork depending on the manufacturer), STI chifters, and brand new components all around. This will result in a lighter weight, smoother riding bicycle. You also don't want to forget the warranties that are included on a new bike, and any kind of service plan that your LBS includes with a bike purchase. Many decent shops will include some sort of basic tune up package for free for at least a year, and sometimes as long as the lifetime of the bike.