I'm about to purchase a road bike for my daughter. I'm looking to purchase the best bike for the money in the low end, as she'll grow out of the bike over the next 4-5 years. As I look at the bikes, I'm torn with Sora, Tiagra, and 105 differences. I'm hoping to ride with her as much as possible and would like to give her every reasonable benefit to keep up with me so I don't have to slow down as much. I'd also like to make sure I purchase at a level that will reduce maintenance and difficulties.

So two main questions.

How much difference is there between Sora, Tiagra, and 105? I was hoping to go 105, but the cost may be too high. Is there a line I shouldn't go below?

Also, I have Ultegra & 105 parts that I may hand down over time that I'd like to swap hers out for the better parts, such as wheels with an ultegra cassette with a better set of wheels. Are they compatible? Or does the derailer match the cassette? How about shifters? etc..?

Thanks

The components won't affect her speed.

I would get her Sora, because she will grow out of the bike soon (like you said).

Plus, she won't know the difference.

+1 to "it's the engine, not the bike."

Regarding compatibility, figure that 8-speed goes with 8-speed, 9- with 9-, etc. Some hubs will work with anything up to 10-speed cassettes, but some won't -- check on that before you start buying anything else.

I'm thinking of changing a flat-bar bike to drop bars, and I was debating whether to treat it to some Dura-Ace & Ultegra stuff I've got. The thing is, it's 9-speed now, so not only would I have to use the shifters and both derailleurs, but I'd also have to get a cassette and chain (and maybe swap cranks, too) and a 10-speed compatible rear hub (or a whole wheel). I figure that I'll just get some Tiagra 9-sp shifters instead and be done with it; they're pretty good stuff these days anyway.

If you really want to have a good time riding together, I'd suggest to start thinking about a tandem.

I disagree - the sora thumb levers may be difficult for small hands to hit while in the drops.

To the OP: if you're not concerned about 9 vs. 10 speed, I would buy Tiagra for her.

They're all pretty much OK.

Sora - if you can reach the thumb levers and don't have a problem with them, or the whatever-speed, it's OK.
Tiagra - pretty good group but, unless it's changed in the past year, is 9 speed only.
105 - Good group, 10 speed, so compatible with higher level stuff.

In general the only things that aren't compatible between the three are the shifters and cassette, they need to be changed at the same time due to the different # of gears.

I have a Sora/2200 bike (Shimano 2200 is LESS than Sora) and it's flawless. Get her a 2200 or 2300 or Sora spec - even if she becomes a serious racer, it will not hold her back. Today's intro road bikes are awesome - can't go wrong.

How old/what height is your daughter, anyway? Chances are she might outgrow it before 4 years.

If she's going to grow out of the bike, I wouldn't get her anything too nice. Sora is a perfectly fine groupset if well tuned. I'm sure the newer Sora, which is nine speeds, is even nicer.

Group compatibility depends on the shifters. If you have a ten speed shifter, you'll need a ten speed cassette and chain. All the derailleurs should work fine... if you wanted to use a Sora derailleur with DA shifters you could, or DA derailleur with Sora shifters. If you have a triple shifter you can use it for both doubles and triples, however you can only use a double shifter for a double crankset.

I'd go Tiagra and if you want to upgrade later you just need to swap the right shifter and the cassette. The rear Tiagra derailleur will work in 10 speed.

Allez steel double. start her off with down tube shifters

Isn't Campy shifters have thumb shifters?
Anyhoo, if she's just starting, you can get either Sora or Tiagra bicycles. They are solid and reliable without busting the bank. Being a newbie, she will problly fall a few times. So it be a shame to scrap up those Ultegra bits.
In the end of the day, it's the human fitness that counts + tune state of the bike that really matters. Unless if it's SRAM. Instant WIN.

Either get a Tiagra/Sora mix (Tiagra shifters, everything else Sora), or 105...

Personally I hate only having 7 speeds, so I plan on getting 105 on my next bike.

I'd say Tiagra, so she can get used to the "normal" brifters instead of the Sora ones. I don't think entry-level Tiagra bikes are that much more than Sora anyway, are they?

"Normal" brifters? Geez.... better not let a Campy folk read this.

Depends. A bike with a Tiagra RD & FD with Sora/2300 brifters will be cheaper. For road bikes, the expensive stuff is on the shifters. However most folks concentrate on the RD/FD. And the mfg knows it as they often market their products accordingly.
FYI, Shimano has RT500 shifters too which has the "normal" brifters.

Sora's thumb buttons are harder to reach and won't dump half the cassette in one shove like Campy's thumb levers do (and I like Campy's in every way except for how they keep me from putting my thumbs wherever I want). I wouldn't call them equal at all.

I would get Tiagra. Even if she will grow out of it, if you really wanted to save money, you could just buy a bigger frame and move the parts, then wait till she's done growing to get her a Bike with Ultegra or even the Sram gruppos. If she really is into and wants to race, then a mid to high end carbon bike is not an option.

The thing about Tiagra that's great for an entry level cyclist is the Integrated Optical Gear Display. Sora has this too, but that's Sora.

You could, get a bike with Shimano Tiagra shifters, running Sora Front and Rear derailleurs.

I don't understand why no one (except the last poster) pointed out that the parts don't have to stay with the frame. Thus, you might spring for 105 right now, understanding that you may have to move the parts over later on.

OTOH you can get her Sora and tell her she needs to learn to do her own adjustments and maintenance. In my experience that's been the big difference between groupsets - not so much how well they shift (they will all shift well) but how much maladjustment they can tolerate before performance begins to diminish.

Thanks guys, great info as usual.

She's 12, and about 5'3, tall for her age. We'll buy a size or two up, and adjust the saddle and stem so she has some room to grow.