Sora and Tiagra

Sora/Tiagra is fine for a rec. cyclist. I did my first couple of years of tris, plus a handful of du's and other events on a bike with a sora/tiagra mix.

With 105, you'll get lighter, more durable components and probably more cogs on the cassette. I think Sora is only 8-speed while 105 is 10.

Sora also has a less ergonomic shift lever than Tiagra or 105. With Tiagra/105, there's a "paddle" behind the brake lever that controls the shifting, while with Sora, you have to push the whole brake lever to shift, which can make shifting awkward.

Did my first 4 or 5 tri's, 2 MS 150 fundraisers and a century on a Giant FCR2 with Tiagra and flat bars.
It works fine.

Sora and Tiagra are perfectly functional groups and while 105 is usually recommended for racing, I think much of this comes from bike racing where you often have neutral support; since every Shimano wheel is going to have a ten speed cassette, if you have a rear wheel issue in a bike race and you are running a 9 (or 8) speed setup then you are basically finished. 

Further, Sora and Tiagra, as the lower end groups, tend to be specced on the lower end frames with lower end wheels so most athletes who are looking at racing are going to spend more money on the entire package and as a result get at least 105 level components on their racing bike.

My current commuter, which was my first real road bike and was purchased used, has Tiagra and I have over 10,000km on it (not sure how much over) and other than replacing the chain, a cassette and cables, I have had few issues with it.  Besides lots of training and now commuting, I have raced this bike in four triathlons (three of them were draft legal events) and several crits.

I have recently built up a new road bike with full Dura Ace and while the shifting is crisper and the components are lighter (and shinier) I never felt that it was the components on my bike that were holding me back.

Shane

Quality.

If you want good, reliable components which aren't going to break on you, get 105.

2 cents.

I dont mean to highjack the thread, but i currently run all Sora components(9spd)and would like to upgrade. Would it be possible to change to everything to 105 with the Sora shifters?

Current Tiagra seems to be about the same quality as the last year they made 9 speed 105.  However, the first year they made 10 speed 105 there were many people who talked about how much 105 improved from the 9 speed group.

I sold my old seven speed Nishiki (with 105 downtube shifters) this winter to a buddy as a winter/rain bike.  Very solid bike and I didn't really want to sell it but one of my road bikes had to go.  While I really liked the bike (and had no issues with the downtube shifters) you will most likely love the change to STI.

Shane

You could (with 9 speed 105 components) but I wouldn't unless something needs to be replaced.  What would you be hoping to gain by switching to 105?

Shane

since every Shimano wheel is going to have a ten speed cassette, if you have a rear wheel issue in a bike race and you are running a 9 (or 8) speed setup then you are basically finished. 

Huh?  Sorry to hijack but that statement just seems out there.  Are you talking bike racing or Triathlons?  For Tri's if you have serious wheel issues you are done for either way.  Its not like many people carry a spare cassette with them (9 or 10 speed)?  Sag wagon (for longer races) may have parts but they are just as likely to have 9-speed parts.   As it is I run a 9-speed ultegra cassette and many others run 9-speed also. 

To the OP, yes Sora or Tiagra is fine for the Rec rider. 

Looking to gain an extra gear. I live in South Florida where its flat as all. So i dont need any big gears in the back. I just want to upgrade to 105. But i guess i have to change everything. Anyway i can get away with upgrading the crank to a 10speed 105?

Good question, what do you expect to gain?
 
Adding to this, everyone should realize you can replace pieces and don't have to do the whole thing (assuming you aren't going 9 speed to 10 speed).  I am not an expert on this so if a real expert chimes in listen to that person. 

At one point I had a Sora Front Deraileur with an Ultegra rear Deraileur, Dura Ace cranks and an ultegra cassette.  All 9 Speed.   

I picked up an Ultegra front deraileur for next to nothing and replaced the Sora piece.  Mainly for vanity reasons.  If your looking to get better gearing you can look at getting a cassette with different gearing.  I just picked up a cassette that is geared more for flat courses then hills.  If that is not enough you can replace your cranks with different lengths or a compact crank.

If your not sure about this stuff your first stop should be your LBS to discuss the options with them.

The OP asked about where the recommendation to run 105 or higher comes from so I posted:



As you say, this usually doesn't matter with triathlon so it really doesn't matter that much if you are only racing tri.

Shane

Do you mean to go from 8 to 9 speed (or 9 to 10)?  Or do you just want to change the gearing that you have available on your bike?

If that latter, then you can change either chainrings or cassette to gain the additional gearing.  You should be able to change to 10 speed 105 crankset while keeping everything else the same but unless you are changing the actual chainring sizes, you are going to notice very little (if any) difference.

Shane