I can not say anything on the 78 degrees since I bought a Principia this season which has a 76 degrees angle compared to my old roadie with the standard 73 degrees. The main difference I noticed coming of the bike now is the fact that I can start much sooner with my longer stride then before. In the past I had to take it easy otherwise I would completely crampup, now I get much faster into my running rythm without cramps.

Hope this helps a bit

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thanks
tri2b

funny you should ask this right now. during the off season i made the switch from a 73 degree road bike (adapted for tri racing) to a 78 degree tri bike. i've recently completed the first 2 races of my season and notice a big difference in my comfort level (and times) on the run. as the other post mentioned, i also feel much more "open" at the beginning of the run and can settle into my "groove" much earlier than i could before. granted, this could be just due to training better in the off season, but i think it also has something to do with being a better position on the new bike. no scientific data to back this up i'm afraid, just something i noticed.

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____________________________________________________________
"I'm happy when life's good,
and when it's bad I cry.
I've got values but I don't know how or why."
- The Who

   

73 or 78 degrees? are we talking actual seat angle or effective seat angle and how do you measure effective seat angle anyway? To take the frame's actual seat angle and make a claim based on fit and performance is ludicrous. The frame angle is only one component of many that determines the fit and how the fit is going to relate to comfort, efficiency, power output, balance, control and your ability to take in oxygen and deliver nutrients to your muscles.

Let's look just at the seat angle. That alone doesn't even determine where you are going to finally sit on the saddle relative to the bottom bracket. You have to mention what type of seatpost you are using; set back, no set back of forward. What type of saddle you use and where on the adjustment rails it is positioned on the seat post. I can take a 75 degree frame and put a straight up seatpost (Thomson) and move the saddle forward on the rails and be in a more "aggressive" position than a 78 degree frame with a set back seat post with the seat back on the rails.

The reason people typically find slacker seat angles not as "efficient" is because they don't do anything with the front end of the bike in terms of reach or height relative to the saddle contact points. If the front end of the bike was addressed to accommodate the slacker angles the athlete wouldn't have the discomfort issues associated with poor fit.

The more fittings I do, the more convinced I am that the balance component of how your body's mass is positioned between the saddle and the bars is a critical element in allowing the athlete to relax "in" the bike rather than falling forward in to the bars and getting a sensation of sitting on "top" of the bike. The relaxed position comes at a lower metabolic cost and allows the athlete to voluntarily and comfortably move around the seat to recruit different muscle groups at will. Opposed to always moving back on the saddle because the athlete finds himself being pulled forawrd and riding on the nose of the saddle, and subsequently going numb.

Bike fit is more than seat angles...it is a dynamic process and evaluation of what an individual athlete wants to and is capable of maintaining based on a myriad of factors. The bike industry wants to dummy down the process of fit rather than educate dealers and consumers. By expressing a rider's position in terms of "aggressiveness" by just taking one component, seat angle, is an insult to the consumer. That is like judging a car's performance potential by categorizing cars by wheel size. It doesn't tell you the whole story. Are 18 inch wheels faster than 16 wheels? Not enough information...

Personally, I've found that I run the fastest when I leave my bike in the transition area. Others results may differ.

Yeah, but I sometimes still forget to change shoes:)

Good Point. Though I imagine if you have Look shoes and pedals, the cleats will break off after a short while.

Me, I have Speedplay's and let me tell you, those are a b**** to run in. I think I would rather do a marathon in stilettos.

"no scientific data to back this up i'm afraid, just something i noticed."

i take that to mean that you have not applied any empiricism to your own seat angle experimentation. but there are scientific studies that mirror your own observations.

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Dan Empfield
aka Slowman

for those of you who don't know, paul levine is based in the NYC area. of all the people who've come through the FIST workshops, he's probably the one i'd recommend over just about every other for tri bike fitting, which is nice, because NYC and the northeast in general is sort of barren of good tri bike experts (boston excepted).

paul and i don't always agree as to the reasons behind why one sort of fit parameter is better than another, and we go about achieving our fits in different ways, but the end results appear to be very similar (which is all i really care about).

paul appears to post rather sparingly on our forum, i hope he posts more often in the future. and for those of you in NY/NJ who're looking for a good fitter, he's worth traveling to (but you don't necessarily need to, because for a price he'll throw his accoutrements in the van and travel to you).

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Dan Empfield
aka Slowman

In my experience it was not even a contest....I run much better off of a 78 degree bike. I switched from a 78 degree tri bike last year to a road bike in the slammed position. Not much difference in the bike splits between the two, but I could not run at all. I used the slammed set up for 8 races or so and could never run well off the bike. On longer races my legs seem to regain life after 3-4 miles but it was too late to have a decent run.

This year I am back on a 78-79 degree tri bike and my running off the bike has improved.

Just an observation that the big boys racing in the ITU circuit, which typically ride road race bikes, don't seem to have much trouble running sub 32:00 10ks off the bike. I realize that they may not be working as hard due to the races being draft legal but they still are running damn fast.

whoa, sorry! my seat angle is at about 78 - 78.5 degrees (actual, NOT the seat tube). granted, i probably feel better running off of it than i did off my old road bike partially because it does fit better and my weight is much more evenly distributed than it use to be. as i said before, all i know is how i feel after the bike, and i feel a lot better running now than i did last season with the road bike. and yes dan, i was referring to not having done any scientific research myself to back this up, but i am sure others have done it ad nauseum :)

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____________________________________________________________
"I'm happy when life's good,
and when it's bad I cry.
I've got values but I don't know how or why."
- The Who