Selecting between an Aero Road bike vs a Time Trial bike?

Discuss light weight issues concerning road bikes & parts.
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THUNDERHORSE
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by THUNDERHORSE

Ive been thinking of a new bike and wanted to know, how does an "aero road bike" (S5, F8, Foil, AR, Aerfast, etc...) perform?

Would the ride be "faster" in a calculable way, than my "normal" road bike given the same wheels?

Or would it be better to just invest in a dedicated time machine (i.e Slice, TTE, Shiv, etc...)?

If I prioritize speed over lightweight what direction would you head in?

Is there anyway to have both?
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Marin
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by Marin

The main advantage of a TT bike is the rider position. Almost all of the air resistance comes from the rider, and having the arms in front of the body and the head low makes a world of difference.

Frame aerodynamics have less impact than front wheel and handlebar shape.

Light weight doesn't make much of a difference even when climbing, but it's sure nice to ride a light bike!

by Weenie


cyclenutnz
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by cyclenutnz

A top end aero road bike will have the same aeroness as a good TT bike. But as Marin mentioned - if you can't get into your best possible TT position then it doesn't matter how 'fast' the frame is.

and there are some really good bikes in the mid price range (P2 if UCI legal, Felt IA if not, Speed Concept 7.5 if you want full integration) that allow you freedom to dial in your position with no (or barely any) compromise on equipment aero.

I'm a fan of having two good bikes set up correctly for purpose rather than a single super bike that has been bodged to do both.
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aerodynamiq
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by aerodynamiq

I'm a lot faster on my Cervélo S5 than I was on my S-Works Tarmac. Did a TT recently on the road bike. On the same course with the same conditions I clocked almost 2km/h extra speed. From 39.8 to 41.7km/h. Says lower power too, but I think the efforts are comparable.
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cobrakai
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by cobrakai

As others have said if you need something UCI legal for the TT then the difference between frame aerodynamics will be minimal but the position will not be, and while frame aerodynamics contribute rider position is the dominant drag factor so you will really want something that can get you in that forward position. If you still want a road bike I know at least the Felt AR has a reversible seat post that changes the seat tube angle from around 73 degrees to around 78 degrees. Other manufacturers might have similar capability. There is also this system: http://www.amazon.com/Redshift-Switch-A ... B00KGHZX3G which can be added to a lot of bikes. If you are doing just the rare time trial it might be worth going the convertible road bike solution, otherwise probably just get a dedicated bike.

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THUNDERHORSE
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by THUNDERHORSE

cobrakai wrote: Felt AR has a reversible seat post that changes the seat tube angle


Did not know that...


[quote=Marin]Almost all of the air resistance comes from the rider, and having the arms in front of the body and the head low makes a world of difference[/quote]


Right so an Aero road bike might be/feel "faster" than my road bike given the same wheels but a dedicated TT bike is really the tool to go up a notch and really rip at 48kph+ versus trying to scratch at that speed with a bike compromising to attempt to satisfy both.

@aerodynamiq that's cool and that's sort of what I'd expect from going from a standard to Aero. but that's why I'd like more feedback because if raw speed is my goal (and it is) I'm wondering if I should just enjoy my RB and skip straight to a TT and not entertain the gray area that is the Aero road bike (until it's time for another build.) :twisted:
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pdlpsher1
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by pdlpsher1

There are options to build an aero and light bike with an aero frame. A dedicated TT bike with aero bars would not make you faster in the hills as the weight penalty and handling deficiencies will overcome the aero advantage. Also if you do a lot of pack riding the TT bike will mostly likely be cumbersome to maneuver within the pack. I picked an aero frame and I'm looking back. I only have one road bike and this bikes can do it all. It climbs and descends like a dream. The terrain I ride on is mostly rolling with occasional big climbs thrown in. Lastly a dedicated TT bike may not give you the best comfort on rough roads. Good luck and please report on what you end up getting.


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bencolem
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by bencolem

As above, an aero road bike will be faster than a traditional road bike on the flat, but not as fast as a dedicated TT bike (all other things such as wheels being equal). I've got 4 bikes currently and my Argon 18 Nitrogen is noticeably fast than my other bikes - but my mate is in another league when on his Shiv.

It all depends what kind of riding you want to do. A TT will be faster on a flat straight course but slower up climbs and round tight courses etc compared to both a road bike an aero road bike.

McGilli
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by McGilli

Plus - if you get an aero road bike - and put on some attachable aero extensions - you're even closer to a full TT bike.
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fabriciom
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by fabriciom

Unless you are actually competing on time trials a TT bike is just for posing.

There I said it. :twisted:

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Lelandjt
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by Lelandjt

THUNDERHORSE wrote:Is there anyway to have both?

Yes, you can definitely build a pretty light, very aero bike and I think that's the way to go fastest on varying terrain with mostly smooth pavement. I'm like you where all I care about is speed. There aren't a lot of racing opportunities in Hawaii but every time I got out I can try to set a fast average speed or beat a previous Strava KOM and that's what makes road riding fun for me. My last bike was somewhat aero and 16.5lbs. For my new build I considered a TT bike but weight, handling on twisty downhills, and Maui's propensity for blustery wind made me stick with the aero road catagory. Working under a budget I built a 61cm Fuji Transonic SL with all aero parts to 14.6lb. Being both more aero and lighter than my last bike it feels very fast and the stopwatch agrees.

With a larger budget and shorter legs you could find a 1/2lb lighter aero frameset, get some lighter parts, and more aero wheels than I have. At sub 14lbs you will give up almost nothing to guys on "climbing" bikes and on the flats you'll know you have an advantage over anyone who isn't in the TT position.

I've been waiting for someone on here to do a no holds barred light/aero build so be that guy! I'm pretty proud of my results but it lacks shock value due to my frame size and budget.

pdlpsher1
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by pdlpsher1

Lelandjt wrote:Working under a budget I built a 61cm Fuji Transonic SL with all aero parts to 14.6lb.


This is an old thread so I hope no one minds if I hijack it. I also have a Fuji SL and I'm interested in your build details. Did you go with the EE brakes? My stock direct-mounted Dura Ace brakes are wonderful but heavy at 298 g. I don't think I want to give them up. My Praxis PF30 converter BB is also heavy at 156 g. but the bearings are so smooth. I did upgrade the headset to the FSA Super Light HS and saved 19 g. Lastly I once had the Extralite Aliens 4 QR at 39 g. but the front QR can't keep the front wheel centered. Now I'm using the stock Campy QRs which are heavy at 120 g. I wonder if my QR issue is specific to the Fuji SL. I'm curious on what QR you are using. If you could post your full build list that will be awesome. Thanks.

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Lelandjt
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by Lelandjt

I used Dura-ace brakes cuz I already had them, the look great, seem kinda aero, and work well. Yeah, it sucks they're heavy. I have Planet-X brakes on my previous bike and my tandem cuz they're a great $/g option.

I used the last year Sram Red 10spd BB30 crankset cuz it's pretty light, identical to the current 11spd one, and pretty cheap. I've been meaning to swap out the heavy chainrings. If I could do it again I'd get a S-Works crank and save a few more grams. You can drop a lot of weight by getting a light BB30 crank instead of your adapter and steel spindle setup.

Yeah, I got the SL headset and use a SlamThatStem bearing cover. I use the top cap system to preload the bearing, then remove it and glue a single layer of 3k carbon over the steerer.

I've got some generic Ti QRs that came with my Farsports wheels. Not the lightest but pretty light and they work. The wheels use edhubs, 20/24 CX-ray spokes w/internal alloy nipples, and 23mm wide rims that are 38mm deep in front and 50mm deep in back. I use 25mm valves that hide in the rim and the hole is covered by a small piece of electical tape. The tape gets peeled aside and a Zipp valve extender is screwed on to inflate the 23mm GP4000s.

Handlebar is Easton EC90 Aero with Lizardskins medium thickness tape done to the corners.
Stem is Profile Hammer so I can clip on their Lightning Stryke aerobar.
Saddle is ebay carbon.
Shifters, derailleurs, cassette (11-25), pedals are DA9000.
Chain is KMC X11sl.

If some money falls in my lap I'll get one of those guys to make a 1 piece saddle/seatpost for me and swap a bunch of bolts to Ti and aluminum. I coulda splurged for slightly lighter hubs but the rest of the wheel components are about as light as it gets. Kinda silly to spend serious money making a Transonic SL light though cuz there's lighter aero framesets if you're looking to spend $3000 more.

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Lelandjt
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by Lelandjt

This thread reminds me that I've been meaning to ask:
What is the lightest frame with some attention paid to aero? It needs to do noticably better in the wind tunnel than a bike that was designed purely for lightweight. I think I saw that the Super 6 Evo has some aero shaping?
What is the lightest true aero frame? This has to give up little in aerodynamics to the class leaders. I'm thinking Dogma F8 X-light or whatever it was called. Maybe thay one doesn't count though cuz you can't buy it. Maybe the Scott Foil?

crux
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by crux

Lelandjt wrote:This thread reminds me that I've been meaning to ask:
What is the lightest frame with some attention paid to aero? It needs to do noticably better in the wind tunnel than a bike that was designed purely for lightweight. I think I saw that the Super 6 Evo has some aero shaping?
What is the lightest true aero frame? This has to give up little in aerodynamics to the class leaders. I'm thinking Dogma F8 X-light or whatever it was called. Maybe thay one doesn't count though cuz you can't buy it. Maybe the Scott Foil?


The F8 and Foil are two of the lightest aero frames out there.

F8 frame (54cm) 860g fork 360g total = 1220g
Foil frame (54cm) 945g fork 335g total = 1280g

by Weenie


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