TT Bike Sizing?

[Hellgate]

A week ago I did a six hour TT on my road bike. Now I'm hooked and want to try longer distances, 200 miles.

While my road bike worked well, and I need to put away my road race instincts, and plan a bit more, a proper TT style bike will pay back in spades.

eBay is full of late model TT bikes for a song. My question is what are sizing rules of thumb? The internet is a bit sketchy.

Typically I ride a traditional 57/58. My 333fab has a 57.2 top tube c2c. For a TT bike, should I go smaller? Like a 56, or a medium?

Thoughts???

[Jcgill]

I ride a 54/55 top tube road bike and had a medium speed concept. It fit me well but was on the small side. If you are 57ish I would say you would be better off on a large.

[rinconryder]

I did triathlon and road TT bikes for years. Granted I only rode the cervelo P2

I ride a 55 and rode a 54 cervelo P2 so you would probably be a 56

What you really need to do though is get a proper fit - it makes a world of difference. There are also seat posts that can turn road bikes into a proper TT bike - they basically moved you up and forward on the bike.

Good luck.

[loxx0050]

I would recommend joining the slowtwitch forums if you are looking for used as there are always plenty of used Tri/TT bikes for sale on there. http://www.slowtwitch.com/ & http://forum.slowtwitch.com/

For reference I ride a 54cm frame road bike (SS Evo) and have a 54cm Felt B12 TT/Tri bike (previous gen). Both work although I have a self fit so the cockpit of my TT bike isn't exactly dialed in. But these days I only do short TTs, 10 miles out and back a handful of times a season or less, so it really doesn't matter too much.

[Hellgate]

Thanks for the input, it's very much appreciated.

I'm up in the air on the whole idea as so much is course dependent too.

For the 200 miler there a fair amount of climbing and technical decents so the road bike may be a smarter choice.

I'm thinking clip on's, move the saddle forward a cm may be all I really need. Then I can stay lower, longer, and have the benefits of a road bike when I need them.

[Jcgill]

This is the rest of my tt bike story:

I was doing triathlons and an ironman 70.3 back in 2013 and that is why i picked up the speed concept.
While it was a great bike and I enjoyed riding it, i too found that I prefer my road bike for most situations.
I found that unless you are going to wear a skinsuit, aero helmet with integrated sunglasses, shoe covers etc. and test in a wind tunnel, and constantly work on your form and stay down on the aerobars 99.8% of the ride then you will be better off on your trusty old road bike.
I did several 40 mile tt’s on the same course on the speed concept, a trek madone, and a cannondale caad 10 and they Were all within 58 seconds of each other.
I was always terrible at getting aero, i just wanted to grab the side handlebars and swing the bike around like climbing on my road bike. Plus all the group rides around here shame you if you show up with a tt bike.

I am looking to get back into tri this summer and am planning to do 2 ironman 70.3 events and i am looking to buy an emonda disc to ride for the tri’s

The guys over at slowtwitch will tell you you need a full on tt superbike with a solid disc in the back and a zipp 808 in the front or else it will add 2 days to your time on any tt you ride:p

[loxx0050]

I would also agree on the comments above to take it with a grain of salt the regulars who preach their advice on slowtwitch.

I also prefer my road bike for most of regular riding outdoors honestly over my Tri/TT bike. Initially I got back into cycling for the first time since I was kid because of a MTB trip with the guys and then decided to enter a sprint triathlon (buddy was on his 2nd year of Tri's who motivated me into it). Took up Tri's more seriously the following year but it wasn't until my 3rd year of doing short distance Tri's is when I decided to get a Tri bike. Eventually upgraded it to a deep front and disc rear (HED Jets 9 front and disc rear) but really I had issues with "upgraditis" and like to shop more than I admit for new things. It also helps that I won my current HED Disc+ rear wheel as a raffle prize at my local TT series. The Jet 9 front I got was a used deal off of another slowtwitcher too.

But my first couple of years of Tri's I used road bikes (first was a downtube steel-moly framed Giant Kronos bike) and then a full carbon Trek Pilot. Both I road with clip-ons until I got my Tri bike. But speed wise (Trek w/clip-on aerobars vs my Felt Tri bike) I wasn't that much faster overall maybe 0.5-1mph total at most but that was more due to having deeper wheels to go with the Tri bike (did have an aero helmet already once I bought the Trek).

Honestly knowing what I know now, if I had to keep only 1 bike I'd stick with my Evo since I enojy riding that the most. If I was in the market for a new bike and only could have 1 I'd consider an aero road bike that has a flippable seat post like a Felt AR that can mimic the seat tube angles of TT/Tri bikes. These days my Tri bike is old enough that I can't really get that much selling it so I keep it on parked on my trainer most of the year and bring it out for TT's. I'll eventually get back into Tri's once my kid grows older and doesn't want to hang out me as much. But I'll probably just train enough to do a full distance Ironman (not necessarily that brand though) and call it quits because I don't think I could keep that up for very long.

[echappist]

This is the rest of my tt bike story:

I was doing triathlons and an ironman 70.3 back in 2013 and that is why i picked up the speed concept.
While it was a great bike and I enjoyed riding it, i too found that I prefer my road bike for most situations.
I found that unless you are going to wear a skinsuit, aero helmet with integrated sunglasses, shoe covers etc. and test in a wind tunnel, and constantly work on your form and stay down on the aerobars 99.8% of the ride then you will be better off on your trusty old road bike.
I did several 40 mile tt’s on the same course on the speed concept, a trek madone, and a cannondale caad 10 and they Were all within 58 seconds of each other.
I was always terrible at getting aero, i just wanted to grab the side handlebars and swing the bike around like climbing on my road bike. Plus all the group rides around here shame you if you show up with a tt bike.

I am looking to get back into tri this summer and am planning to do 2 ironman 70.3 events and i am looking to buy an emonda disc to ride for the tri’s

The guys over at slowtwitch will tell you you need a full on tt superbike with a solid disc in the back and a zipp 808 in the front or else it will add 2 days to your time on any tt you ride:p

With all due respect, your advice should be taken with a serious grain of salt

If one is to purchase a TT bike, one should dedicate the necessary time on that bike to adapt adequately.

Once cruising, I do ~28 mph on 300 W on my TT bike. With the same get up (with a rear disc swapped for a 60 mm rim), I'd be lucky to average 26 mph on my road bike, and that's with most of the time spent doing the IAB. (I did the ITT on my TT bike first, then did the course on my road bike)

The point being, one absolutely should be going a lot faster on a TT bike, assuming equal power output. A good number of people will need to dedicate a signficant time to learn to generate power in that position, and that's just part of the process.


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As for sizing, that's a bit more personal, and anything you find on the internet is just a guestimate. That being said, I personally regret going with a smaller size down, as it places the handlebars too far away for me to handle the bike with as much confidence as I have on my road bike.

[redir]

Gosh I've not ridden my poor old TT bike in years. I should get that thing on the road again. Problem is some time ago most of the omniums and even some stage races went to the Eddie style TT events for some reason. SO a lot of bikes collected dust. I bet there are a lot out there for song.

But dang! 6 hours? I would be tempted to set up the TT bike like your road bike for such long events. In fact I would recommend just getting TT bars for your road bike. That way you will be more comfortable on such long hauls and still get 90% of the aero.

In any case don't be tempted to go super low and aero on the TT bike, you start to cut power when you do that.

[homagesilkhope]

But dang! 6 hours? I would be tempted to set up the TT bike like your road bike for such long events. In fact I would recommend just getting TT bars for your road bike. That way you will be more comfortable on such long hauls and still get 90% of the aero.


And OP's gonna be out there a lot more than six hours if he's doing 200 miles.

[Hellgate]

Indeed, ride time for 200 miles will be 12 to 14 hours. Assuming I can actually complete a ride that long.

The more I think about it, clip on's are probably the way to go, stick with what I know.

This is the my next target, assuming the foot surgery is on track.

The race is very interesting, 200 miles, drafting allowed, one planned pit.

http://www.raamchallenge.com/#courses