Downloaded the Sidi Shoe Sizer and printed it out. Standing on it tells me:
Left Foot: 46.5 ish
Right Foot: 46

Broke out a ruler (only has mm and cm, so inches are calculated) and carefully measured my foot:

Right foot
26.9 cm long 10.59"
10.3 cm wide 4.055"

Left foot
27.3 cm long 10.748"
9.8 cm wide 3.858"

Measurements start from 0 cm

Then, using an international shoe size calculator lookup table it tells me the closest sizes are:

Right foot: 43
Left foot: 44

Can anyone tell me what's going on? Are the Sidi sizes non-standard? Is my .pdf printout incorrectly sized?

I've ordered a set of size 43 Genius 5's from the UK. Thinking them to be too small, I had them removed from my order. Now I'm confused and not sure.

And foot wizards out there that can assist? Cheers!

Ok mystery is beginning to unravel.

A4 =! US Letter

Sidi Shoe Sizer says 'make one continous strip that measures 20". Two US Letter sheets would stack to a length of 22". One sheet is cut to line up with the other. Sidi does not specify if the measurement is from the edge of the sheets or from the black lines at the boundry of the sizer printout (not the physical paper boundry).

My measured physical paper lenght of the two joined sheets is:

53 centimeters = 20.8661417 in

So a problem is either with the difference in paper sizes, 'zoom/shrink' to fit of the laser printer, or a combo.

Search for the answer continues (on my lunch break!!!)...

Whatever size calculator you use, Sidi's run small. If you have any shoes with Euro sizing that you can compare, go one Euro size larger, especially if you are up in the 46 area. At least go 0.5 Euro size larger.

You have 2 different sized feet. I do too, even more pronounced. I either would have had to buy 2 pairs of shoes and get ride of the odd size in each, or just get a custom set of shoes. I opted for the latter.

Mine run large. 48 in a regular shoe, 47 in a Sidi.

Cheers guys.

More info:

My current shoes are EXUSTAR Carbon Road Shoes (E-SR212) size 44 Euro.

They feel very comfortable and hold my heel and mid part of my shoe down well, but my toes can wiggle around and they just have a netting over the top of the toe area. The left big toe touches the top of the shoe, the right one does not.

I sort of have monster big toes. They're longer then the other toes on each foot by about 1 cm, so they are the first thing to make contact with the front of the shoe.

My Sidi's fit me to a tee (45), but that's with a thin sock. And I have what is called a slightly low volume foot. So they run a bit small, which is what I have heard from others.

What you should do is visit a store that sells them. In Canada, that's MEC. In the States, higher end bike shops or perhaps REI?

My socks are Assos skinwebs which are quite thin. (Thank you xmas!!!)

I'm in Sydney, Australia.

Most of the serious bike shops sell them. The Genius 5's are all around AUD$350 or so. That's AUD$100-150 more then I can get them online overseas. I support the shops I like already in other ways so this is a question of being able to have Sidis or not. Not where to get them, as my budget is limited at the moment. That said, I don't feel right trying on the shoes at the shop with no intention of buying them their. Similarly, I know that the shops have no intention of pricematching to this degree.

Buying shoes by mail order seems like a recipe for disaster unless they're a model (or at least make) that you've worn before and know your size in.

Go with $20 or $30 of accessories in hand (stuff you likely need anyway). Ask to try on some Sidis, explain you probably aren't buying them, but want to get sized up to see if they're for you.

Any reasonable bike shop employee will see the $10 or $15 in markup in your hand, and realize that it's worth their while to do you a favour and let you try some shoes on.

I don't know about Sidi's shoe sizer but I wear a 46 Dominator, which should be a 11.25" or a size 12. The shoes fit nicely and feel great. When I began shopping for shoes I tried on 44's, which should have fit but didn't. So, the chart may or may not be a useful tool but be sure to try on shoes before buying a pair. Just because they're your size doesn't mean they'll fit you.

Those printable charts are crap...always!
What size athletic shoe do you wear?

Is it that hard to go try some on?

I have not found Sidi Shoes to run small. I wear a US size 8.5 and wear a 42.5 Sidi, which is just what most conversion charts show. A US size 9 would be a 43.

Nothing beats trying them on. I found a store that carried them, but all they had was a 42 or 43. One was too small and the other too large, so I ordered 42.5 and they fit.

When I bought Rocket 7 shoes, I had them send me a 42D and a 42.5D. The 42.5 was too big.

Now I've got D2 shoes in a 42.5 wide.

I always thought I was a size 12 but I wear a size 46 in Sidi.
47 seemed a scosche too big.

OP-

always measure your feet at the end of the day, when they are at their largest.

+1

US size 12=46 Sidi for me, in the Mega.

Completely correct. You can buy anything else mail order, but shoes must be bought in a store. And do not go to a store and find the right fit, and then go order the same shoes online. That makes you a real d--bag.

I think that trying on shoes in a shop, only to subsequently buy a pair online is not behaviour of the highest order. How about printing off an internet page to show what you'd have to pay if you bought them online, then going to the shop and trying them on? If they are good, then discuss the best price they can do them for, showing them the internet price. Explain that you want their business to survive, and let them try to meet you in the middle. They will still make a fair profit, and you'll still have a LBS to visit and try on your next pair of shoes at some time in the future. It's a win-win situation if it pans out correctly. Surely the fact that you can walk out of the shop with your new shoes, rather than wait for ages is worth something? Eventually the shop owner will get onto his wholesaler/importer and demand lower prices if you do haggle.

Canceled my 43 size order at TotalCycling.

Ordered all black Genius 5 2009 size 44 from Probikekit for 99 GBP. Grabbed two sets of grey Look Keo Grip cleats for 11.5 GBP. Sure beats the 45 AUD I had to pay for my last set of Keo Grips at my LBS when I snapped the top clip in part of a previous set. Took advantage of a 7.6 GBP discount from a coupon code on this forum.

The shoes look fantastic. They fit very well. They don't appear to have any heal cup retention adjustment so I'm hoping when I get out on the road I won't have any heal lift issues.

Cheers guys.

So the OP's experience would seem to confirm, when in doubt with Sidi, go one size larger than the size converters might suggest, because they run small.

So for the "buy online" doubters, there's two successful internet Sidi purchases based on feedback from this forum; the OP and me.

+1 on that...I wear a US 14.5 which is usually a 49 or 50 Euro...I wear 51 Sidi's

FWIW I'm european so I know what my size for shoes should be (50). The sidi measurement was WAY off (and yes, I did print it out correctly). I ended up getting some Shimano's on sale instead, as these are my first clipless shoes.

I think you need to go 2 models up to get the heal system. I love my Sidi's, but get megas to have just a little extra room.

I've worn a 46 in Time (Carnac), Shimano, and Sidi for the past 20 years. Length seems pretty standard to me. WIDTH might well be your problem.

Yes, I took the punt without trying them on and am happy. If I had gone with the 43, the big toe on my longer foot would have been painfully pressed against the front of the shoe. I could probably do with one 44 and one 43 or 43.5 but I'm not quite prepared to shell out for that.

Had my first weekend of riding in the Sidi shoes.
~70 km on Saturday
~50 km on Sunday

I'm convinced, they feel great.

One difference I noticed, compared to my all velcro carbon sole Exustar Taiwanese shoes was that towards the end of the Saturday ride my feet felt like they were under quite a lot of pressure in the shoe (in the width). I just clicked them out a bit to give me some more room. I think my feet just naturally expand a bit from the prolonged exertion and my old shoes weren't snug enough to make the difference too noticeable.