Bootie or no Bootie(s)

[Zoro]

Opinions on when to wear them for TTs.
Who has the lightest ones?

Shoes are getting slicker. They do weigh something.

I'm not sold on sub-30mph/50kph TTs needing them. Especially in the case of juniors that are typically spinning faster.

[eric]

I only do uphill TTs so I am no aero weenie. But I'd use them for flat TTs even at mid 20 mph speeds.
At the top of the pedal stroke the foot is moving forward relative to the bike. So the feet are going significantly faster than the rest of the bike and rider.

Which BTW is why your feet get cold so easily in the winter: increased heat loss via convection.

I think the numbers are in Cycling Science but can't find my copy right now.

[WMW]

There are some tests that show a detriment to booties that are not windproof.

[Dalai]

There are some tests that show a detriment to booties that are not windproof.

That is why I bought up a number of pairs of the previous model of Pearl Izumi Barrier Lite shoe covers (previous model had a rear 3/4 zip).

[WMW]

I'm guessing you like PIs? Are the velcro ones no good?

[Dalai]

The PI's have tested well for me and others in the wind tunnel... Not sure of the current closing method, but after the zippered model they went for a slip on which was more likely stretch and become loose over time unlike the zippered version.

[prendrefeu]

Since booties are prone to not being wind proof, you're wearing them for a specific limited time event, and they limit your ability to adjust your shoes while you are riding and you won't adjust your shoes anyway in a TT, why not just wrap your shoes in some clear packing tape? Guaranteed wind-friendly, waterproof, temporary. People tape their helmet vents shut, do it for your shoes, save some cash.

[Dalai]

Taping vents is definitely not UCI legal and pretty certain clear packing tape over shoes is either... Covers like the IP covers are windproof.

[WMW]

I may pick up some of the PIs anyway, since places are selling them cheap. Some people complain about the ankles getting loose, but I have large ankles and calves. Plus I'm not shy about modifying pretty much everything.

What sort of benefit did you and others see in the wind tunnel?

[WMW]

The PI's have tested well for me and others in the wind tunnel...

Do you have any sizing tips? Follow the recommendation or size up or down?

[Dalai]

I wear size 42 Specialized shoes and size Large PI covers and find these nice and snug.

[Dalai]

What sort of benefit did you and others see in the wind tunnel?

About 65G of drag or 0.75 second per kilometer.

[WMW]

I wear size 42 Specialized shoes and size Large PI covers and find these nice and snug.

Hmm... I was going to get L but they probably wouldn't fit on my size 44s.

I have large ankles and calves also. Might as well go big. I can get out the needle and thread if necessary.

.75 sec/km is a pretty huge speed improvement!

[Dalai]

I have skinny ankles and the zippered version has continued to be snug. Checked my stash last night - still have two more NOS pairs in the cupboard.

Noting the time savings, it actually now makes me feel a little better that my IP times hadn't improved recently. Since the UCI banned shoe covers indoors on the track I have had to find a extra 2.25' elsewhere over 3km to ride the same times as before...

[AGW]

I wear 42 in PI shoes and the medium Barrier Lites fit perfectly. They're tough to put on due to being a barely-stretchable slip-on (and my SPD-SL cleats are huge), but I don't think a large would be as snug.