Under Development.
But let me add 2 cents quickly.
1. Check the Wheels
They'll put cheap wheels on a bike. Shimano R500s are cheap wheels. They look good, but they are heavy as lead. Wheels are the one place you want to pay extra and NOT cheap out (because rolling weight is more important than frame weight). So, check the wheels, find out what they weigh (all modern wheels have their weights listed online. A good set of wheels - without tubes or tires or skewers - should weight less than 1.8kg. Great ones can be 1.4 or 1.5kg. Cheap wheels can weigh 2.5kg. so, when you are aiming for a complete bike weight of 7 - 7.5kg, 1 extra kilo can make a huge difference.
The Weight Weenies website is a great place to check the weights on various components, even tires.
2. Check the Groupset
They put cheap components on that might look good, but are... cheap. Cheap means more plastic, less metal, less good feel, less precise operation (the Click!)
Shimano and SRAM and Campagnolo are the major brand names. Their prestige models (each company has 5+ models just like BMW has a 3- 5 and 7-series) are Dura Ace then Ultegra (Shimano). In Campagnolo, the top end is Record and then Chorus. Then Athena or maybe Centaur (they keep changing the names of this stuff) . In SRAM, Red (the top) > Force > Rival.
Each model level up - in a new bike - should cost you + $500 to $1000. Dura Ace over Ultegra? +$1000. Ultegra from 105? +750. etc.
But if you are considering a bike and you see it is equipped with Tiagra, Sora, or some really low end Shimano stuff (I can't even find the name. it's like a number 2300?) and in Campagnolo, Xenon. In SRAM, Apex, just know that they are cheap. They should work.... fine. For a while. But they will not have the click and feel of Dura Ace. Just saying. (once you've tried Dura Ace you will know the diference.)
That said, smart riders will accept the middle of the range gear. (Though most riders are too proud to drop below the #2 in any gruppo lineup, so Ultegra in Shimano.) In Shimano the reasonable cutoff is 105. In Campy, Centaur, in SRAM Rival
Note too that generally Campagnolo gear is much more expensive than Shimano (+25-35%) which is why you don't see it on many store issue bikes. Also, each Campagnolo model of gear ranks half a notch higher in performance and prestige than it's comparable alternative in Shimano. So, while Centaur and 105 are both #3 in their respective companies line up, Centaur is more generally valued than 105.
3. Check for mismatched groupsets.
They were called groupsets because originally all the components you put on your bike matched and in theory worked better together. All the parts even used to come in a fancy presentation box - right down to matching stem, seatpost, headset, hubs, pedals and bottom bracket. All Dura Ace or 600 (the original name for the Ultegra-level), or all Chorus for instance.
But there is no such honour any more. A rear derailleur IS admittedly where most of the action happens (except for possibly the brifters which are where you will FEEL most of the action happening.) And a rear derailleur is also the largest piece of real estate of a bike's components (compared to brifters, front derailleurs and brake calipers). SO, the RD is like the billboard of bike components. It's where you can most easily see what the model of the groupset is when you sidle up beside another rider. ("Hey, what's he riding? Did he splurge for Record or Dura Ace or did he cheap out on Sora." Generally Sora = Ignorance and amateurism.)
So, is it surprising that bike shops and manufacturer's next cheat is to slap on a higher end Rear derailleur and then cheap out on all the other components? So, you might spy an Ultegra RD (Quality!!) but check the other components? do they match up? Often you'll see an Ultegra RD but Sora or Tiagra brifters and FD. And even worse, generic brake calipers like Tektro.
So, be aware.
More later
But let me add 2 cents quickly.
1. Check the Wheels
They'll put cheap wheels on a bike. Shimano R500s are cheap wheels. They look good, but they are heavy as lead. Wheels are the one place you want to pay extra and NOT cheap out (because rolling weight is more important than frame weight). So, check the wheels, find out what they weigh (all modern wheels have their weights listed online. A good set of wheels - without tubes or tires or skewers - should weight less than 1.8kg. Great ones can be 1.4 or 1.5kg. Cheap wheels can weigh 2.5kg. so, when you are aiming for a complete bike weight of 7 - 7.5kg, 1 extra kilo can make a huge difference.
The Weight Weenies website is a great place to check the weights on various components, even tires.
2. Check the Groupset
They put cheap components on that might look good, but are... cheap. Cheap means more plastic, less metal, less good feel, less precise operation (the Click!)
Shimano and SRAM and Campagnolo are the major brand names. Their prestige models (each company has 5+ models just like BMW has a 3- 5 and 7-series) are Dura Ace then Ultegra (Shimano). In Campagnolo, the top end is Record and then Chorus. Then Athena or maybe Centaur (they keep changing the names of this stuff) . In SRAM, Red (the top) > Force > Rival.
Each model level up - in a new bike - should cost you + $500 to $1000. Dura Ace over Ultegra? +$1000. Ultegra from 105? +750. etc.
But if you are considering a bike and you see it is equipped with Tiagra, Sora, or some really low end Shimano stuff (I can't even find the name. it's like a number 2300?) and in Campagnolo, Xenon. In SRAM, Apex, just know that they are cheap. They should work.... fine. For a while. But they will not have the click and feel of Dura Ace. Just saying. (once you've tried Dura Ace you will know the diference.)
That said, smart riders will accept the middle of the range gear. (Though most riders are too proud to drop below the #2 in any gruppo lineup, so Ultegra in Shimano.) In Shimano the reasonable cutoff is 105. In Campy, Centaur, in SRAM Rival
Note too that generally Campagnolo gear is much more expensive than Shimano (+25-35%) which is why you don't see it on many store issue bikes. Also, each Campagnolo model of gear ranks half a notch higher in performance and prestige than it's comparable alternative in Shimano. So, while Centaur and 105 are both #3 in their respective companies line up, Centaur is more generally valued than 105.
3. Check for mismatched groupsets.
They were called groupsets because originally all the components you put on your bike matched and in theory worked better together. All the parts even used to come in a fancy presentation box - right down to matching stem, seatpost, headset, hubs, pedals and bottom bracket. All Dura Ace or 600 (the original name for the Ultegra-level), or all Chorus for instance.
But there is no such honour any more. A rear derailleur IS admittedly where most of the action happens (except for possibly the brifters which are where you will FEEL most of the action happening.) And a rear derailleur is also the largest piece of real estate of a bike's components (compared to brifters, front derailleurs and brake calipers). SO, the RD is like the billboard of bike components. It's where you can most easily see what the model of the groupset is when you sidle up beside another rider. ("Hey, what's he riding? Did he splurge for Record or Dura Ace or did he cheap out on Sora." Generally Sora = Ignorance and amateurism.)
So, is it surprising that bike shops and manufacturer's next cheat is to slap on a higher end Rear derailleur and then cheap out on all the other components? So, you might spy an Ultegra RD (Quality!!) but check the other components? do they match up? Often you'll see an Ultegra RD but Sora or Tiagra brifters and FD. And even worse, generic brake calipers like Tektro.
So, be aware.
More later
