What is the least expensive group of componenets that would reliably switch gears (front and rear) under load?

Thank you in advance.

I'm not sure what you mean. All components will shift under load to a point, though it may not be good for them. You should ease up pedal pressure when shifting regardless of the components you're using.

I am new to biking but I was under impression (possibly erroneous) that good quality components allow quick and reliable switching while going uphill without having to lose momentum.

If this isn't the case, what is it that differentiates more expensive components?

With modern ramps and pins on chainrings and current cassette cog designs virtually all levels of Shimano derailleur components will shift under high loads. The same is true for SRAM and Campagnolo components. This will increase wear however and the chance of broken or dropped chains. Pro riders shift under high load all the time but are not buying their own bikes or components. Occasionally they have a problem too as one of the Schleck brothers did in the Tour De France when he dropped a chain during a mountain stage.

More expensive components are better finished, have better bearing and bushing materials and are lighter as they have more aluminum in their construction. At the high end it is forged rather than cast aluminum or stamped steel. These days components may also use titanium or carbon fiber for some parts too as with Campagnolo titanium cog cassettes. These sacrifice long life for reduced weight.

I shift my rear derailleur under load all the time. Sure it's louder and it takes more effort for the chain to get over to where the derailleur is telling it to go, but it works. Now the front, I go out of my way to not shift under load. I try to shift to the appropriate chainring shortly before I actually need it. Otherwise, I will likely get some stupid chainsuck going on (middle non-stock ring seems to be ghetto in some way). I already have a chaincatcher so I won't drop the chain. I have a triple, which is admittedly more finicky than a double or compact double.

Higher end components will let you shift faster and at higher loads. However, it's not exactly like you're going to lose a tremendous amount of momentum in the quarter second it takes to ease up and shift. If you're riding in a competitive group and want to respond to an attack up a hill, then Sora is going to force you to remain seated and soft-pedal until you shift down a gear or two before you stand up to respond. With Ultegra I can shift while I'm coming out of the saddle. It will still kick and let me know it's unhappy but it will shift unlike Sora. I've gotten stupid a few times doing this and almost sent myself over the handlebars because I didn't until the gear was engaged before really pushing it. It still shifts, but that much jerking is not good for you or the bike. I've ridden SRAM Red and it is noticeably better than Ultegra. Very quick shifts and it seems to shift under moderate load much better although I didn't go crazy on it since it wasn't my bike to abuse. The holy grail is of course Dura-Ace Di2. Never ridden it, but I've watched people shift it while sprinting on a trainer.

That's an amazing engineering feat; no other groupset comes close. There's a bigger difference between Di2 and mechanical Dura-Ace than there is between Sora (lowest end) and mechanical Dura-Ace. In the real world, however, my Ultegra is more than sufficient. You really don't need to be able to shift while hammering.

It may take a bit of mental effort and practice but it is easy enough to just take the load off the pedals whenever you change gears. Front derailler and you may be lucky enough to get away with it but the chance of a "Clean" change is not very good. But as I say- Practice just taking the load off the pedals when changing. Millions of us do with no problems and it is only for 1/2 turn of the crank at the most and you do not even notice any slow up in speed.

Exactly. Its very easy to lose the chain shifting the front. I shift the rear all the time while out of the saddle, both up and downshifts, but I would NEVER shift the front while out of the saddle.

You only need to ease up on the pedal pressure for a moment. With good timing, you shouldn't lose any momentum. bk

I was going to mention Di2, too. One of the recent posts about it said that they've actually programmed the front derailleur to shift at a certain point in the crank's rotation, pulling the chain exactly onto the pins that guide it onto the teeth.

That's the only groupset I've heard about so far that lets the front shift under heavy load. I remember how much people were talking about it when it debuted on the bike trade show circuit (probably Interbike). They all tried their hardest to make it misshift and it never failed.

I still softpedal on shifts, though; DA/Ultegra on one bike, flatbar Tiagra on another, Sram MTB group on a third.

Regarding compatibility, I recommend 105. That is good enough as well.

I can shift my AW3 speed going up hill with just a moment's pause.
and reading the terrain and planning how you will use your gear ratios

is the difference between a cyclist, and someone who just owns a bike.

the engineers design for the latter, thats why all the shifting aides were added.

^This is the ultimate bike snob snotty comment.

I heard the same thing from older riders in the late 80s/early nineties. Luckily, people get to decide for themselves, and neither you nor old grumpy men with wool tights can arbitrarily impose a restriction on what skill - apart from riding a bike - people need before considering themselves a cyclist.

I also heard similar things from computer jerks complaining how Windows allows almost anyone to use a computer... back when Unix was the OS of choice you had to know how to navigate around cyberspace with a black screen and text-only commands, and that was better. Oh the horror of allowing people who aren't obsessed with the technology to share our hobbies!

In my early days of cycling- 20 years ago- I was a person who had a cycle. Luckily I rode with cyclists. They taught me a lot- One of which was how to change gear under pressure when going up hills. They got fed up with hearing me graunch the gears as I changed. Took about 2 or 3 rides with plenty of steep hills and I knew how to change gears without messing up the cassette or the chain.

Yeah, but unlike with the bike analogy, we Unix people had it right

Seriously now, getting the most out of your drive train takes a bit of practice. I installed a new setup that while better, I still need to get used to it before I can shift off the saddle as smoothly as I did before. It used to be quite funny; I would race my buddy up the hill and I would shift as smoothly as if I was sitting on flat terrain. He tried to shift on the hill once...

Ive ridden my loaded tour bike through a dozen or more countries up mountains and such.

on old fashioned friction shifters, I like the ones in the end of the handlebar ,
6 or 7 speed freewheels and a triple crank without ramps and shift pins.

Seems newer freewheels will shift too willingly when you wish they don't
due to tooth profile changes..



I worked in Bikeshops for years on the index stuff ,
the New gets replaced every year by the Newer.

But not necessarily better, just the industry has decided to run a gee whiz race with each other . I don't have to sell it any more.
(would love to see the fully automated machines in the factorys that put this stuff out by the millions)

I wish I had copied down an Old Italian's saying that like technologically driven indexing,
(or engineers get their mortgage paid and a new Boat, laying on more complexity) ,

on what was a fine, simple purely functional machine,..

is like sex with rubber boots on .. or some kind of analogy like that .


I'm back to Internal gear hubs these days, the derailleur sport bike goes out occasionally.
wears Laundry, often, in the house..