I'm here to tell you that it's about .000000001 faster than I can ride my trail bike on a flat trail.

I have found they tend to fall behind at 10 MPH. At 9 they can still catch you. They can bite right through bibs or shorts and a jersey.

They can't do over 28 mph. I have a hill that I do repeats on. When one gets after me, I will lose him on the downhill run. The bad thing is that most of the time the fly will wait for me to come back up the hill and then it is on me again. The other day I had a yellow jacket flying all around my hand as I climbed at a blazing speed of 5 mph.

Don't know the species of fly, but I did "The Ridge" in Santa Barbara last summer, and couldn't climb fast enough to lose the flies. Seemed to need somewhere in that 7-8 mph range, and I was going so slow I turned off the auto-pause on my Garmin, which is normally set at 5mph. Going slow in the heat, with flies, truly sucks.

According to my field guide there's about 100 different species of deer fly in North America (plus the horse flies) - were you thinking of one in particular? ;-) I suppose most of them average about the same speed - 9 or 10 mph seems about right.

In central Ontario they don't usually bother me on the road bike but when I ride cottage roads through wooded areas on my mountain bike they provide a lot of incentive for me to maintain my speed up the hills. I wear heavy cotton MTB shorts and T - shirts rather than spandex and microfibre. I dread getting a flat tire! I'll do a little "speed vs bite" survey next time I'm up there.


My wife does exercise walks on the cottage roads and last year I suggested she wear one of those sticky fly patches on the back of her cap. She came back saying it didn't do any good but when she took her cap off there were about 20 flies stuck on the patch. I guess you just need a much bigger patch!

Thank you, Lord, that I live in the desert.

We were on Whiteface mountain in upstate NY and got into black flies (what they called them) and they bit hard, leaving a welt. Nasty little devils.

As do I but I also live close to a lake and lots of Horse property. It seems as if the Horse fly, even bigger than the Deer fly, is a relitive. It also seems that the Female fly of both species needs blood to produce its young or lay eggs. When I attempt to climb out of our valley I pass through a zone where the little beasties live. It seems as if they can fly faster than 10 mph but maybe they don't like to put out the effort to chase you much faster than 10. They never get me coming downhill but most often do goi uphill. I have been told they respond to darker clothing and they are attracted to Carbon Dioxide. When climbing I am breathing like a freight train and of course expelling co-2. Doubble whammy as they say. I can't remember even seeing any Deer flys very far from Lake Hughes but I do remember seeing some Horse Property out by Quartz Hill.

In the Adirondacks we have two seasons, winter and black fly.
I have done the WF race and have been lucky, they feasted on all the riders ahead of me so they were full by the time I came by, the advantages of being old and slow.

The ones in my area have teeth. (ouch)

I was riding with some guys in northern Nj near a lake and one guy says "watch out for horseflies". About 10 sec. later, one hit me right between the eyes. What a jolt! I figure the combined speed was about 40 mph.

That area is the most beautiful place to ride I have ever been, and I have been all over this country. I was there for the USA Tri. as a adopted daughter was in it and I worked at a sag station on the in and out phase. I did 2100 mile on my bike that summer. The best summer ridding ever.

We have what is locally called a sweat bee, probably a deer fly species, that will stay with you riding or running and they call all their little sweat bee buddies to come and dine on you with them. They also bite right through bibs, jerseys and running shorts like it isn't even there. When I used to finish running the road at UWF (very wooded and several streams) I'd be covered in red dots form all the bites. Left the road or trail numerous times and ran into the library of field house.

Bill

The sweat bees in alabama are really little bees. They seem to be eating or drinking sweat off my body. The problem with these little bees is that if you accidentally touch one it will sting. The stings are not very painful because they are so small but they are irritating. Also if you shake your hand and make them fly away they immediately come back.

This has always been my uneducated estimate. I ride past an old junk car lot off of one of my trails and must go around a gate at less than 10. I have always tried to get back above 10 as quickly as possible because the deer flys seem to wait at the gate.

Horse flies, I have read, can fly at up to 30 mph. I don't think they're a relative of deer flies. When I was a kid and went camping with the family, the camp's swim area had a raft. We'd all sunbathe on it, but we had to post one lookout for horseflies. After nailing them, we'd toss them into the water as an offering to the smallmouth bass living under the raft. I think the bass liked us, because we never ran out of bass food.

What I call sweat bees are actually yellowjackets, which are a type of wasp. They get very aggressive in the fall and will fly right into a pop can for the sugar. Woe be unto him who tries to drink out of that can!

To all those who think deer flies can't fly faster then 10mph. I'm telling you that you are wrong!wrong!wrong! I'm not usually one to brag about how fast I can ride, however, with those little buggers biting me in the arse I can guarantee you that I was motivated enough to break the sound barrier. That they were motivated enough to do that plus .000000001mph says something about my arse which under different cicumstances I might take as a compliment. I mean, for a couple of days my butt looked like it had measles! (kinda felt like it as well). To those who say "pictures or it didn't happen" were I a less kindly man I'd post one (censors be dammed!) and make you suffer. As it is you'll just need to have a vivid imagination.

All this aside, when I decided to go for a ride to day despite the 98* temps, it was the thought of the deerflies that made me opt for a road rather than a trail ride. I was also in the mood to use smilies as you've no doubt noticed.

Not suprised by that Deer Fly While leaving a beach side rest stop during the Bay to Bay Century, several yrs ago in Maryland, my group of 6 guys had a strong paceline going in a sweet tailwind at about 27 mph. To our astonishment, 2 or 3 large flies easily kept pace with us, mockingly, drafting and taking strong pulls at the front, for about 2 miles.

Seems like I 've heard this type of question before. Those mp fans know the rest:

Bridgekeeper: STOP!
He who would cross the Bridge of Death
Must answer me
These questions three
Ere the other side he see.

Arthur: Ask me your questions, Bridgekeeper. I am not afraid.

Bridgekeeper: What...is your name?

Arthur: King Arthur of the Britons!

Bridgekeeper: What...is your quest?

Arthur: I seek the Holy Grail!

Bridgekeeper: What...is the airspeed velocity of an unladen swallow?

Arthur: (brief pause) What do you mean, an African or a European swallow?

.

Come back here, I'll bite your kneecaps off.....its only a flesh wound.....and the ever popular, I fart in your general direction, silly Englishman..........


Leaving Monte Python behind,
Our sweat bees look like small yellow jackets but it is a bite through a proboscis not a sting from the tail. On the Gulf in August the dog flys will run you off. Riding along the Santa Rosa Island Roadway is an iffy proposition when they are out. I believe the fly at about mach 2.

Bill

"First shalt thou take out the Holy Pin. Then shalt thou count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in my sight, shall snuff it."

And now for something not completely different.


Once I encountered a horsefly going about 60 mph, but that was because it got in my car. I got bit--which hurt like the dickens. We scrambled to get the d**n thing out the open windows.

That's not surprising. They were 'surfing' on your bow wave.

Fastest flying insects.

Over the holiday I was doing 13-15 on a limestone trail and found an attack squad drafting off my front panniers.

Marc

Wrong-O. According to Wikipedia (https://en.wikipedia.org/wiki/Deer_fly ), deer flies are a genus in the horse fly family.

I have a question for you cyclists whose routes regularly bring them into contact with biting flies: Have any of you ever tried insect repellent?