mikethe

Hi,
Soon I have the following TT race - what do you think: Regular bike would be better?
Thanks,

datlas 

Especially if the course has lots of twists and turns, yes regular bike.

mikethe

This is the route:

datlas 

It's my own personal bias (I know several people who have crashed using TT bikes) but I still vote for regular.

tomato coupe

What advantage do you think you would gain from a road bike?

datlas 

Climbs better. Handles better.

TT bike is best for flatter and straighter courses.

Trakhak

Regular bike with clamp-on aero bars. Most of the aero benefit of a full-on TT bike but with road bike handling.

tomato coupe

Sure, but what advantages would there be on this course? It looks pretty straight and most of the climbing and descending are at fairly low angles.

burnthesheep

Run the Google street view and see where the turns seem to correspond with the slopes on the route map from what appears to be Strava.

If the turns are in spots that would always cause you to brake hard and lose downhill momentum, sure it might not matter much.

If they're not, TT bike all the freaking way. My "speed distribution" chart from some local TT's have me accumulate several minutes at 30+, 35+ mph during the roll. I have a big enough gear I usually can keep pedalling at a comfy cadence in the mid 30's mph downhill.

You just have to practice it. Practice by finding shorter distance similar % grade hills where you can ride it back and forth. Do it out of aero, then do it in aero. Then do it in aero applying a bit more and more power. Then find a new route with same kind of shorter downhill you can repeat that has a small curve to the road. Then practice that.

On "rollers" the magic of the TT bike is the speed you keep as you start ascending small rollers and hold cresting it and starting down the other side.

GhostRider62

TT bike for sure.

Road bike would generally only be faster if it were a hilltop finish and average gradient is over 7-8%.

Iride01 

If you have both bikes, then you ought to easily be able to determine which bike is faster for you in those conditions.

What is the average grade and max grade on those hills? Not the average for the entire course.

Is this actually done as a time trial with timed release out of the gate? If instead you are riding in bunches, then the road bike for certain.

mikethe

Did - some of the sharpest turns are in high gradient, plus the mid point U-turn...

mikethe

The avg grade on the hills ~3.5%. And yes - it's a proper UCI TT race timed out of the gate.

merlinextraligh

Average gradient of 3.5%, if you’re riding at a competitive pace, you’ll still be climbing at a speed where aero will make more difference than weight.

Unless the descents are so technical that you would lose time on the tt bike, I’d definitely go with the tt bike.


FWIW, Masters Nationals in Utah had a course with more climbing than that and we wen went with a full tt setup.

To me, your biggest issue is big enough gear for the descents so you can pedal at an efficient cadence on the fast sections.

tempocyclist

Without any other info, so just from looking at that profile and route map, I'd be using my TT bike for sure.

burnthesheep

Then just come out of aero for the tight turn on the bad slope. That in a way actually makes the choice easily TT as the rest of the elevation will be without the troublesome turns.

Our weeknight club TT is an out/back of about 6.7mi and multiple repeats of it for more advanced riders. It has some high speed s-turns each out/back. The speed profile for that route is pretty much "over 30mph" or "under 25mph" nothing much in between. With two downhill pieces briefly I hit about 40mph.

Just run the biggest front ring difference your FD can willingly shift so that you don't spin out where it's safe to keep getting it. And/or also a good broad selection of rear cogs like an 11-30t cassette versus the tight arrangement you might run for a pan flat run.

Carbonfiberboy 

Yeah, TT. I've used a road bike with clip-ons for decades, even have dual clip-ons on our tandem. It is quite amazing how fast one can get going on descents if one has the gears and the rpm. I once had a woman on a TT bike ride with our group in the mountains. She did fine, climbed fine, no trouble in corners. You need a big gearing spread to keep the rpms up on the climbs. The trickiest thing on hilly courses is figuring optimal effort for each section.

merlinextraligh

The 105% solution. Mathematically, you loose more time on the slow uphill sections than you gain on the fast downhill. So you want to putt out more of your effort on the uphill.

Determine the power you can maintain for the length of the event. You then want to go a bit over what is sustainable on the uphill, recover on the downhill.

Hence 105% uphill. 95% downhill and 100% on the flats.

Without a power meter, perceived effort on the uphill should be above what you feel you can sustain for the distance but a notch below completely blowing up.

burnthesheep

Physiologically also, one cannot put out threshold power if they go too much over threshold for the overs. Hence why it's like 105% or something. It only really works out fine if you have some really really short rollers of like 20 seconds or so you could hammer over it to keep the moment up then do a slight recovery down then settle back in.

This is where some workouts like over/unders with shorter and harder overs come into play. Not just good for the training stimulus but dealing with that kind of effort.

tomato coupe

Yep. The other thing to keep in mind is that "overs" on an uphill section generally last longer than overs on the corresponding downhill section, so the effort on the downhill can be more overer while still allowing for an adequate recovery. The math gets a little more complicated than simply comparing 105% on the uphill versus 105% on the downhill.

burnthesheep

Yes, it's also very personal. I just say you have to practice it enough to figure out what you can handle or do.

Our weeknight club TT uses the same out/back probably 6x a year and folks train on it also when traffic is lower. So you can really "figure it out" and it becomes second nature when you need to handle roller hills on another route.

The weeknight club TT run has both hill parts where you go over/under "just a hair" and ones where you "hammer" for like 15 or 20 seconds at VO2+.