Sprint Course bike choice
BY: JJakes on 2011-03-13 6:19 PM

I'm doing a sprint "adventure" race (paddle/bike/run) in a month and biked the likely course today. It was cold and windy (it's just off a Bay). Supposedly it's going to be 3 loops of roughly 4.5 miles. It's fairly flat, in that there are no big or long climbs. However, there are also 23 turns, nearly all of them 90 degrees with one 150 degree turn. There are 4-5 short climbs or bumps and a number of false flats. I stayed in my aero bars most of the ride but definitely got out for some of the turns and bumps. It could have been the wind, or the fact that I'm sick (felt not great this morning, but now have a fever/nausea) but I was much slower than I expected to be (like 2-3mph).

Or it could just be that the course is more tricky than I was expecting.

I'm now wondering if it makes sense to ride my road bike instead of my tri bike. The gearing is slightly different (11-23 v. 12-25) and the road bike is definitely lighter. But I had the thought that if I'm taking all these corners and getting up out of the saddle for the short climbs, maybe it makes more sense to take the road bike.

The roads were not closed to traffic today, and there are probably 6-7 stop signs to slow down for, so I'm wondering if it'd be faster to have a lighter bike to accelerate and corner. I think traffic will not be closed on race day, but there will likely be plenty of volunteers so perhaps you don't have to stop or slow down as much.

Also, I rode alone today and it occurred to me that during 3 laps, they'll be a lot of folks on the road at the same time.

On flatter courses in the past, I'm probably roughly 2 mph faster on my tri bike, riding solo, than on my road bike.

What say you - road or tri bike for race day?

Thanks!

RE: Sprint Course bike choice
BY: rhff on 2011-03-13 6:33 PM

I would go with the road bike just to be closer to the brakes...I doubt it will be a non-drafting event. My personal rule is that if it's at all technical or non-draft, safety takes precedence over 1-2mph of speed and the road bike would be my choice. Sounds like a really cool race, we have one here in Ontario for emergency services personnel-paddle, mountain bike, run/orienteering (8 hour team race).

RE: Sprint Course bike choice
BY: jgerbodegrant on 2011-03-13 7:48 PM

Disagree with the above poster. The statement above pretty much answers your question.
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RE: Sprint Course bike choice
BY: sevrdhed on 2011-03-14 7:46 AM

Yeah, you said you're able to stay in your aero bars for the majority of the ride - that'll make it worth it to bring the TT bike.

 

The only real reason you'd  have to swap to the road bike would be if you were getting out of your aero bars on every one of those corners and bleeding off speed... doesn't sound like that's the case.

RE: Sprint Course bike choice
BY: SCamp07 on 2011-03-14 8:31 AM

I'm in the road bike group. 23 turns through a 4.5 mile loop is a lot of up and down time. Add in the fact that there will be other racers out there and I would want the handling that comes with the roadie.

Is it possible to go out and ride the course on your road bike before race day?

RE: Sprint Course bike choice
BY: Leegoocrap on 2011-03-14 10:15 AM

If you are ever in question, ride your tri bike. Even if you are sitting up a good portion of it, you are still going to be faster than you are on your road bike.

 

Change the gearing if you need to, not the bike.

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RE: Sprint Course bike choice
BY: d00d on 2011-03-14 1:52 PM

Road bike all the way...

Road bikes are better for technical courses.

Good luck! Sounds like a fun race!

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RE: Sprint Course bike choice
BY: Leegoocrap on 2011-03-14 2:41 PM

 

I'd love to see some examples of why this is true.

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RE: Sprint Course bike choice
BY: JJakes on 2011-03-14 3:21 PM

Thanks for all the good input so far.

I'm planning on heading back this week with both bikes to check the time difference. So that's one part of it.

The other part is that on race day, they'll be 100-200 other people out on the course. So if this was a time trial where riders are evenly spaced by start times, and maybe you pass one person the whole time (or none at all), I'd go with the tri/TT bike. But I'm guessing on laps 2 and 3, I'll have to pass multiple times. It's likely I won't be able to take every corner as fast as I'd like or take the line I'd like. I'm guessing the route will be pretty clogged.

I'm leaning towards the tri bike. I'll let you know how the time trial test goes later this week.

RE: Sprint Course bike choice
BY: SCamp07 on 2011-03-14 3:27 PM

 

Not to be a (mod edit) starter, but I would like to see some examples of why this is true.

Isn't the advantage of a tri bike that you are in a more aerodynamic position? If you sit up on a tri bike and a road bike why would you still be faster on a tri bike? If your most efficient position on a tri setup is in aero wouldn't you be in an inefficient position is you are sitting up. On the opposite side, wouldn't the roadie position be more optimal sitting up than the tri?

 

RE: Sprint Course bike choice
BY: smilford on 2011-03-14 3:28 PM

TT Bike, no question. Yes your road bike can handle better, but it shouldn't be a huge difference. Not enough to counter 1mph difference in speed.

If you ride your road bike, you just gave up time.

RE: Sprint Course bike choice
BY: RedCorvette on 2011-03-14 3:36 PM



Sounds like a vote for the tri bike to me.

Mark
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RE: Sprint Course bike choice
BY: Leegoocrap on 2011-03-14 3:41 PM

The advantage of a tri bike is indeed in it's positioning. Would you plan to ride 100% of the ride on the bullhorns of the tri bike? In that case, indeed you may be faster on the road bike. However, even on VERY technical courses, we know this just isn't true... you are going to ride at least some portion of it in aero. (the two very unlikely times I could see this is if it were very technical...unlike most "technical" sprint triathlons... and raining/snowing/etc. Also, if fear was an issue and you were simply afraid to get down in the aerobars... which is a valid reason to ride the road bike.) It's just as unlikely to say that you would ride 100% of the time in the drops of your drop bars. Some portion of the time you'll be on the hoods, which is generally an inferior aero position.

The time you are in aero however, you just have such an advantage (considering your position is at least passable) over being in the drops that it WILL make you faster. Aerodynamics are always at work... it's BS when you read "if you aren't in aero 99% of the ride you are slower than on your road bike."  - No. You aren't. Unless you are Greg LeMond'ish in your road bike positioning or sit up extremely tall in the front of your tri bike. There is a reason pro's and tour de france riders ride a tt bike in almost every tt (i think there was one exception when they were climbing the alps) since 89'. It's faster.

 

Again, there are good reasons to ride a road bike over a tri bike. Generally speaking, speed is not one of them.

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RE: Sprint Course bike choice
BY: tri808 on 2011-03-14 3:59 PM

TT bike...no question.

IMO, the course doesn't sound that technical.  If you're talking about the entire race meaning bombing down 5% grades at 40+ mph...then we can talk about sacrificing speed for safety.

Ok...lets do some math.  Assuming 23 turns, over 13.5 miles, that's 1 turn every 0.59 miles.  At 20 mph, that assumes one turn every 106 seconds.  Even a poor handler of the bike should only need to get out of aero for 6 seconds on a turn...if at all.  So...even if you use a TT bike, and get out of aero for every single turn...the ratio of aero to non aero would be 100 seconds aero and 6 seconds non aero.  That's over 94% of the time.

 

RE: Sprint Course bike choice
BY: gsmacleod on 2011-03-14 4:10 PM

I would ride the tribike without question; however if you are more comfortable on the road bike then I would suggest either more time on the tribike until you are comfortable or take the road bike.

There is an oly race I've done the last couple of years that is 8 laps of a 5km loop; each loop has 6 90* turns and a 180* and the course is typically crowded after the first couple of laps. However, worst case, over an ~8.5 minute lap I would spend 2 minutes out of aero (and probably much less) setting up for and navigating turns. So, worst case, 6.5 minutes per lap (~50 minutes of total ride time) spent in aero going faster than if I was on my road bike.

Shane
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RE: Sprint Course bike choice
BY: JJakes on 2011-03-14 4:42 PM

Just to clarify - it's 23 turns per lap or 69 turns over the 13.5 mile course. That's closer to one turn every 0.2 miles.

RE: Sprint Course bike choice
BY: gsmacleod on 2011-03-14 5:04 PM

Do you need to get out of aero for every turn? If so, can you still ride aero for the .2 miles between turns?

Shane
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RE: Sprint Course bike choice
BY: d00d on 2011-03-14 5:44 PM

If there are quite a bit of turns (not bends) on the course, you're probably going to be getting out of the aerobars, for cornering and braking...

The OP did post there were quite a bit of turns on the course...

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Strength does not come from physical capacity.
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RE: Sprint Course bike choice
BY: tri808 on 2011-03-14 6:19 PM

Ok...so triple the time you're out of aero.  So you're still aero 82% of the time, and out of aero 18% of the time.  Again...this assumes you need to get out of aero on every single turn...and for 6 seconds...which is generous at best given it's a race...not a training ride.

ETA:  I am hesitant to believe that this course is actually that technical.  Can anyone actually show me a map of what a 4.5 mile loop with twenty-two 90 degree turns and one 150 degree turn looks like?  It must be like a maze or something...in which case the entire course has to be closed off to traffic, which means you can hold much more speed and take a more aggressive line during the race than during a training ride of the same route when cars are present.

Edited by tri808 2011-03-14 6:29 PM