A key advantage everyone has today is the absurdly high quality of bicycles. The performance per dollar is astounding. I doubt that any particular universal hint exists except fit. Fit is crucial, and I only know road bike fit.

So. Road bikes. I'm going to just address performance road biking, because that's all I know.

The most pragmatic and useful (generally) road bike fit discussions appear on Dave Moulton's bike blog. http://davesbikeblog.blogspot.com/ For the older rider, http://davesbikeblog.blogspot.com/20...mfort-and.html should prove interesting. The bent over position presents a clear problem for new road riders. The position gets one's *ss into things, gives better handling, etc. And is ultimately more comfortable. Competitive cyclist also has a nice fit page: http://www.competitivecyclist.com/za...LCULATOR_INTRO

A few problems for the older cyclist. First, bike shops tend to sell what they have and sell performance road bikes for a younger group of riders. But some tend to automatically fit more mature folks on comfort bikes. So there's confusion. Unless you're very lucky, you have to do the fit. I'll make an assumption that someone looking at a performance road bike either has or is willing to develop pretty good flexibility, can fit about like a performance rider who is 25, and is looking for nice performance, not flashing criterium cornering etc. So. Figure the top tube length, stem length, and handlebar drop. Don't worry too much about the other details, but that stuff is needed for fitting. A little drop to the handlebar really helps comfort and handling.

Fit

Most shops fit too big. This is particularly a problem with compact frames.

Compact frames are the ones with the sloping top tube, look small, fit all bodies with few sizes. They're great! But very easy to get fitted wrong.

Geometry. Two main types these days. Racing type with a 73 to 73.5 degree head tube and the "GT" type (my term) with slightly slacker head tube, down to 71.5 degrees. Depending on size. Both seem to work nicely for performance riding so long as the centerline of the most forward handlebar bend is within 1 cm of the axis of the front wheel. This is a trap. Many of the slacker angle bikes have stems way too short, giving lots of understeer and providing less control. I don't know why this is. Let's a rider fit on a frame too big. Anyone driving a performance bike hard isn't going to like the bars back from the front wheel that far. This is really important. Dave's fitting chart gives a good view of this. http://www.prodigalchild.net/Bicycle6.htm#FrameChart

An example will show the trap. Let's look at a 5'10" rider. Fits 54.5 cm CTC frame w/ 55.25 cm TT and 115 / 120 stem. I'll pull up the Specialized line. 54 & 56 available. 54.8 or 56.5 cm TT available. Stock stems are 100 mm for both. 100 mm might be too short for this bike! But is it? That's a C-C - so you need to figure the horizonal run. Probably more like 105 given the angle of modern stems. But still, a bit too short. Very likely to understeer with the stock stem. This one is easy. An older rider is likely to run short on the reach, and possible have a slightly farther back saddle. No more 120 rpm up the hills spinning, a bit more laid back. So the 54 cm with a 115 equivalant stem (I'd try a 110) would be where I'd start. I'd also be starting with about and 8 cm drop to the bars: http://davesbikeblog.blogspot.com/20...ebar-drop.html. That's a great starting fit for a 5'10" rider. But go into a shop and you'll get the 56, possibly with an 80 mm stem done high rise. Handling is out the window, tension builds in, and the bike gathers dust!!!

Now, the fit on the equivalent slack angle bike, the Roubaix: Surprise, same seat tube angle, slacker head tube angle. This one will fit even better if you can handle a 115 stem, giving effectively 120 reach. The head tube is taller, making getting the drop right easier.

Handling difference: The Tarmac will feel racy, can dive into turns, feels very quick and nimble. Roubaix feels smoother, carves turns, can still be leaned through turns very very hard. But more forgiving. With the long stem! Get the Roubaix with a short stem and it will understeer, feel unsteady, and generally be more difficult to drive.

Take a good hard look at bikes in the pro peloton. Plenty of the support riders are on basic stage race bikes like the Roubaix. Great for long distance smooth riding, can handle the tough parts. Not necessary to have a super snappy handling bike for the average rider. If you're leading out a pack in a criterium, yes, but if you're just running fast along country roads and whipping through normal road turns at reasonable (say, below 40) speeds, then the Roubaix type design is plenty. Only if sized correctly.

Anyway, there's the sizing trap. "You're 5'10" - you need a 56." Well, maybe for a long bodied young fellow to stetch out on and spin like a demon!

Frame Material

I never thought I'd be writing this. Plastic. I've been riding a long time. I've had aluminum, composite, steel, and borrowed Ti. Plastic is the ticket. Folks refer to it as "carbon," but it's plastic. Comfortable, stiff, fast. Just be careful with it, and keep in mind this is for performance road. I'm setting up my commuting bike right now, this morning, and it is aluminum/carbon. I am much less likely to kill the frame doing stupid at 7:30 am. And if I do, it's a cheap frame relatively speaking.

Carbon offers the designer the chance to most effectively contour the behavior of the frame as a whole and build in the right flex. I cannot push myself hard enough to break the carbon frame bikes I've ridden free. They stick. They're also very comfortable in general. Great material.

My second choice would be top-end steel or Ti.

Third choice is aluminum. There's something about even the best aluminum frames that rubs a certain high percentage of longer-distance riders wrong. Usually in the *ss. I've got an excellent AL / carbon frame right here. Fast, comfortable, great handling. But it is still a bit clunky compared to the nice carbon frames, and it's still harsh after 60 miles.

Recommendation

For a performance road bike for a reasonably fit or will be fit person, I'm driven to recommend a carbon compact. The compact runs great out of the saddle, especially up hill. If you're sitting down, no difference. But out of the saddle, any time the bike is flipping back and forth, the compact just feels great and goes like a rocket. Geometry? Doesn't matter too much, but I like the old Colnago approach, slightly slack head tube, long stem. In major brands, the Roubaix, Giant OCR, Madone is a bit racy, but would do (The 520 is tempting - a 21" would be a great commuter for me!); Fuji CCR.

Also, for those with stiffness problems, the woman's bikes with shorter TT are great!

Have fun. I'm riding a tiny bike for me, with a long stem, and a long seat post. Feels great!