My shoes are generally sized 8.5 or, in rare cases, 9. Based on my home measurements, my feet are wide.

A pair of Pearl Izumi cycling shoes sized at 43 which, according to their website, is a US sizing equivalent between 9 and 9.5. Since these are my first ever cycling shoes, I don't know how tight they ought to be.

When I tried a nice looking, but more expensive pair of Giro shoes sized at 43.5, they felt absolutely fantastic. The shoe was firm on my feet but did not wiggle. I could feel that I was wearing the shoes but I did not feel much pressure from the sides.

With the Pearl Izumi shoes, however, I could very much feel the sides and I can't tell if it's too tight or not. It certainly doesn't hurt but I can definitely feel the sides putting on pressure on my feet. I don't feel any tingling and it's not painful but it was not nearly as comfy as the Giro shoes. The odd thing is that on Amazon, people are saying that the shoe accommodated their wider feet and yet for me, even though size 43 is sizing up compared to the chart, it doesn't feel all that amazing.

I would of got those Giro shoes right then and there but they were much more expensive than the Pearl Izumi shoes which were only $40 for closeout.

Should I keep those Pearl Izumi shoes? Will they fit better over time? Are Giro shoes wider than Pearl Izumi ones?

We all have our own specific anatomy. When it comes to things like shoes, what someone else says about them really does not matter a whole lot. You will also not be able to get a definitive answer to that question. You are in the best position to judge fit and comfort of those shoes for your feet.

My personal experience with cycling shoes is that I want them to have quite a bit of space. I am not looking for anything that feels tight or snug. Instead, I like it when shoes give my feet quite some space, and you can tighten them down with clamps/velcro to have them tight enough that there is no "wiggle" when in use. I think that it is generally a good idea to go for the shoes that feel right when you try them on.

I like my shoes tight.

I got lucky, i wear a 46 and when i ordered the Diadora they said they had a pretty wide toe box and i am super happy with the fit...If they were too tight i would get rid of them and look for something else..comfort is paramount.

I like my shoes loose so I can wear extra socks in the cool weather, and so that my feet can swell in the hot weather.

Given that cycling shoes of that caliber are made with a rigid plastic sole and plastic or synthetic leather-type materials, you shouldn't expect the shoes to stretch or change much over time. That only gets more true the more expensive the shoes get. That being said, cycling shoes are bale to be tighter than, say, running shoes, because they don't need to cushion your foot or flex. So, as long as you can wear your shoes comfortably while putting some pressure on your feet, you should be okay.

Personally, after climbing for four years, it's hard to find shoes too tight for me. I like the very snug feeling around my foot; it gives a sense of precision. If they seem like they may be uncomfortable, don't wear the shoe. If they seem snug, they're probably fine.

+1 for shoes with a little room/width in the forefoot. In my experience, it helps prevent hot spots or numbness. It allows for the slight swelling of feet that occurs in hot weather. It allows for better air circulation around the foot. It doesn't restrict blood flow which helps preventing getting cold feet in cooler weather.

I just recently bought two pairs PI X-Alp series mountain bike shoes for me and my son. I normally wear a 46 but needed a 47 and probably could have worn a 48. My son normally wears a US 9.5 but needed a 45 in the PI shoes. I checked the online reviews and most said to buy a size or two larger than normal.

What model are you referring to? Check online reviews.

Many find their feet swell while riding. I'd error on the loose side if you can't find a perfect fit.

Here's your answer. Don't scrimp on the contact points. You'll reap dividends in comfort, long after you've paid for the shoes.

Yes, although good fitting shoes don't have to be expensive. I love my LG Ergo Air shoes that the local shop had on closeout for $100.

I like my shoes snug but like room in the toebox. If you stand and try to walk they should feel very snug remember they are for riding not walking. In my sizing I have a pair of LG's that are size 46 that are perfect and a pair of Giro Privateer (offroad) size 46.5 and just picked up a pair of Giro Trans (road) size 47.

1. unlikely that fit will change very much. yes, shoes tend to start to bend in the right place, but they don't change much. someone will argue that. whatever.
2. original post says "no pain" "doesn't hurt" "no tingling" ... so not quite sure what needs fixing here, but if it ain't broke, yada yada.
3. "not nearly as comfy." want more comfy? buy the "more comfy," but I think you'll know more after a few hundred miles in the current shoe. my prior shoes were quite adequate until I started doing > 50 milers. now wearing significantly larger ones and happy again. go figure.