Dumb Question
 

So I'm a novice when it comes to knowing road bikes and upgrading components, that being said I replaced the rear wheel on my 2016 Giant Defy 5 with a DT Swiss P1800 last week. I have ridden my bike 3 times since then I have noticed I am struggling in the higher gears where as before I had no issue. I guess what I'm asking is this normal? I was hoping by replacing the tire, it needed to be replaced, I would gain faster riding times but it seems to have slowed me down and feel like I'm riding through mud in the last two high gears. Can someone explain to me where I went wrong or if I'm just a buffoon and what I'm experiencing is normal. Thanks

Does the cassette match? Different gearing might make it feel "heavier" but theoretically you'd at least be moving faster with the higher perceived effort.

There are no dumb questions, only dumb people who ask questions.

Now that I've fulfilled that temptation, is it the same cassette?

Yes, if you kept the same cassette your gearing should be unchanged. You mentioned changing both the wheel and the tire. Did you replace the tire with another of the same size? If not you may need to adjust the air pressure. And some tires just ride better than others.;)

Yes the same cassette and same tire/tube

Was something installed wrong? Maybe the tire pressure is off? You said you replaced the tire but is it with the exact same one or the same model?

Any change to the chainline angle? With all my bikes, old school freewheels through Dura Ace cassettes, there's a sweet spot of the two or three middle cogs. Anything outside that begins to feel slightly more draggy. Not enough to matter in any significant, consistently measurable way in my ride data. But outside that narrow sweet spot range pedaling feels slightly draggy, getting worse as I approach cross-chaining. It might make a whopping 1 or 2 watt difference, which won't matter much with my mediocre engine.

I suspect the sound is part of it. When I can hear a slight chain noise my mind tells me it feels slower.

Occasionally I've swapped freewheels, cassettes or individual cogs to get the gearing I prefer in that sweet spot, just so it feels right -- even though I can't prove it matters.

You installed the wheel incorrectly and a brake is rubbing?

I'm nowhere near that confident to do the work. I had the bike shop I bought the bike from do the work.

Same tube and tire. Unless they put in a new tube for free and didn't tell me.

that being said what psi do you guys keep your tires at? I'm 5'10" 185lbs.

I’m about the same size, and I run about 95psi in a true 25mm tire (Vittoria Rubino Pros), and about 85psi on a pseudo 25mm (Continental GP4K SII, 25mm advertised, measured at 28mm). Lower than that may technically be faster, but it feels weird to me, as I used to run 110psi on 23s and 25s before I started experimenting. What model and size of tire do you have?

Definitely just spin the rear wheel by hand while you’re standing next to the bike - check to see if the brakes are rubbing, or in extreme cases, if there’s chainstay rub, which would mean the wheel just wasn’t seated in the dropout properly.

Also, check how much clearance your tire has between both the seatstays and chainstays. A wider rim could cause even the same tire to balloon out a bit more, which would reduce clearance. On harder efforts, your frame could flex 2mm (or more) side to side when you’re cranking, causing the wheel to rub.

Lastly, does the wheel itself spin freely on the axle? Take it off the bike, put it between your two hands, and spin the wheel with your fingers. Does it take a while to spin down? Does it feel like it’s grinding or bumping? These could be markers for a poorly adjusted or worn hub. Unlikely if the shop bought the wheel new, but they may have been too busy to do a cursory check like that. Alternatively, if you bought the wheel used, something like that could be a more legitimate concern.

Are you sure the tooth count on the front and rear are the same as your other bike?

I see people struggling to pedal their bikes all the time when I ride. They have lower gear ratios available but for some reason they think it's better to use the high ratio gears.

Pedal the gear combo that you can easily pedal. However you are right to question if there might be something else making it difficult. But I can't see that from here.

This really is the most likely hypothesis. All the other answers would be subtle differences at most.

Dragging brake can be quite hard.

So, even if the shop installed it, it’s quite posssible the brake caliper got pushed out of alignment.

Another possibilities is the wheel is not seated fully in the dropout.

Something mechanical is not working correctly . Or the lack of any real speed advantage from the new wheel is making you feel like it’s slower because it doesn’t meet your expectation it would be easier.

One simple test: Pick the back wheel up off the ground, and spin it. Does it spin freely?