Question about bike speed and first tri.

in a sprint race i go totally by feel.

normally at a level just slower than when i feel like i am going to puke. for me i know i can run well off this and still put in a good bike time.

for a first race, i would go hard, but keep it in check, the run is going to seem a lot harder than you think. build into it over the first mile or so to let your HR come down from the swim, then just start pushing.

you wont get it perfect this time around, go hard, and see what happens on the run.
assuming you are trainining its not going to go to horribly even if you bike a bit hard, and you need to have something to base the next one/training off of.

if its dead flat/no wind, using speeds from training can help, but speed on its own is not going to be the best way to pace, i would go by feel.

remember its still a 45ish min bike at that pace. if you held 20mph for 30 miles though there is really no reason why you cant stay over 20 for this i dont think.

For sprints, you will pretty much go all out the entire time, but never so hard that you will fail the run.

Try this calculator and field test and average in the lower part of Steady state and you will have enough left for a great run.

http://nencycling.org/wiki/cts_trainright_field_test_calculator

Generally, speed isn't really a good indicator of how hard you're working because the course, pavement, wind, etc can vary so much.

I would say for you, you need to go by RPE (rate of perceived exertion) and make sure you listen very closely to what your body is telling you so you can avoid destroying yourself before the run. I would practice listening in training and trying to notice when you're pushing too hard.

If you can, I think it would be pretty helpful as well to go and ride the race course if possible. You might be able to better tell what you might be able to hold if you've ridden it once. RPE still applies.

In the future, you could use Heart Rate and possibly eventually a powertap to measure you effort more analytically.

Most of all HAVE FUN. Good luck!

thanks for the information everyone, it is very helpful!

One thing you might want to think about.  Riding 20 MPH in a group for 30 miles is a lot easier than riding 30 miles alone at 20 MPH.  Remember you are getting about a 30% reduction in effort if you are in the draft of a pack/group vice riding alone.  

Good luck on the Tri, do some test rides over your race distance and see what effort/speed you are able to maintain and apply it to your race.  Remember to save some for the run after.

Greg 

riding in a group is easier then solo....having said that...you are riding double the distance.  so you should be fine holding 20 mph.

it is possible your run speed might slow down a little. 

i would recommend going on a solo ride this weekend, do maybe 20-25 miles just by yourself and see how you do.  don't push it too hard but a pace you think you can maintain where you aren't overly exerted.  try maintaining 20 mph for 3-5 miles then see how is your body reacting.  are legs stiff?  can you breath easy?   maybe you can go faster....maybe even do a quick 1-2 mile run after just to see how you feel.

I am doing my first tri soon as well.  The friend who first talked me into this last winter suggest I do a "practice tri" before the event.  I did it Sunday and was very glad I did.

For me it was much easier than I thought it would be and I learned a lot.  Now I know how to pace myself for the swim and bike to still have enough for the run.  Aug 9 is coming soon and your training may not allow it, but if you can I would recommend it.

As a worst case you will be able to say you won your age group in your first triathlon, before you tell them that you were the only one.

Speed depends A LOT on the course (e.g. wind, hills, other bike traffic), and clearly 20mph in group is much easier than 20mph solo. Set your own speed based on effort level & don't look for someone to pace with (drafting in most sanctioned tris is a penalty). 

I mismanaged my bike effort during my 1st tri & hammered the full distance.  Suffered for it on the run with stiffness & leg cramps.  Most rec starting bike moderately in easier gear & ramping up your effort to fairly hard but not quite max.  Last mile or so spin faster/easier gear to get the legs loose.  Last few hundred yards before transition area try dropping your heels alternately to stretch the calves a little.  I tried that approach last time & ran much better time (for me) with less effort on much more difficult hilly course.

It's good you are developing a plan, and you'll learn a lot.  But remember Rule #1 for 1st tri-

HAVE FUN!!!!!!

Just as a side comment... on my group rides... WITH DRAFTING... I'll keep anywhere from a 17.2 - 18.5 mph average.

At my sprint tri on Sat I kept a 19.8 mph average. I never see that kind of average in the group.

I attribute it to stopping/going and that affecting my overall average.

Either way, I always know that in a race I will go 1-2 mph FASTER than I do a in group ride.

You need to get a faster group.

Actually I find my drafting speed within a group on my road bike to be relatively equivalent to my solo speed on aerobars and my tri bike.