Carbon fiber vs. fiberglass/plastic shoe sole

[VeloVT]

Carbon soles are stiffer. This is different than being more supportive. If you seriously need more support than you currently have, carbon soles are not going to be an improvement -- you would probably be better served by insoles. Stiffness aids power transfer. I have a pair of carbon sole Sidis (though not the most expensive model) and a pair of standard sole Sidis (nylon probably?). The carbon soles are a bit stiffer. It IS *slightly* noticeable to me. If I were 190 lbs and putting out 500 watts on a regular basis, it might be a bigger deal, but I would say for the purposes of most primarily recreational riders (and maybe I am making an assumption about you here that I shouldn't, so say so if I am) once you are looking at a dedicated road shoe, the sole material is not hugely important, it's more gravy. It's not a revelatory difference for me.

But, that said, fit is pretty important, and all of my Sidis are much better fitting than my old, low-end Shimano road shoes. (Haven't tried the higher-end Shimanos though...).

If you have $$$ burning a hole in your pocket, by all means buy the most expensive, lightest, stiffest shoes you can justify. But I am of the opinion that the bling road shoe thing is more about style and having expensive gear than it is about power -- not to say that more expensive shoes don't have some nice features (I really like the BOA closure that Specialized puts on its top of the line shoes, for instance), but the performance difference gets smaller and smaller the higher you go up the line.

[NYer in MTL]

Thanks- that's what I needed to know. I think I'm gonna go with a less expensive shoe for now. If I find that I want something more I can always upgrade, but for now I think a lower end shoe should be sufficient.
Getting insoles is also a great idea. I will look into that.

[Grog]

I've had Specialized shoes with Carbon Fiber soles. I now have Sidis (with nylon soles, I hear) and I don't see a noticeable difference. I haven't taken them on 20+km climbs though, but even at the end of long rides (over 100 km with hard hills) they're doing well.

[Aggie_Ama]

I have Sidis non-carbon soles but I use Aline Insoles in my shoes. These insoles are stiff and really helped me with foot pain. They work to correct alignment issues which I had due to really high arches.

[Bike Goddess]

I use Superfeet insoles. They have a website which will help you determine which one to use. I also use Superfeet in my hiking shoes.

Got them at REI about 4 yrs ago and it solved most of my foot issues.

[aicabsolut]

You might want to check with a podiatrist about what kind of sole you need. I know this is different than arthritis, but a friend of mine has been having some nerve problems in one of her feet. They removed the nerve, but she's still having a lot of pain months later. Her doctor said she needs to give up her carbon soles, because they are too stiff and aggravating her problems. She's also getting custom orthotics.

So, for efficient power transfer, stability, and comfort the lightest, stiffest shoe is best. For specific medical problems, though, it could depend. A stiff sole may support your painful joints better, but you may just need the right insert.

[NYer in MTL]

Thanks for all the info! I think I'm going to go with the Pearl Izumi Vagabonds, they were the most comfortable that I tried (and conveniently the least expensive). I went to the podiatrist a few weeks ago, and he didnt say specifically whether carbon was preferable over nylon or not, but rather that I just need cycling specific shoes that have (relatively) firm soles. I am also getting custom orthotics from him, but he said they wont fit in cycling shoes. I will look into the other insole options for sure, and I'll see how my feet feel once I start riding with the right shoes.