Looking for some help fitting my TT bike

I am just getting started with time trials and looking into fitting my bike properly. I know some of the local stores offer fit services, but at $200 a pop I just cant go there. Already spent enough on new carbon rims ($800) and tires ($300) and my wife would not appreciate me spending even more. I have been watching some You-Tube on the subject and have used measurements from my road bike that I had a 3-D image fit done when I bought it, but it is a road bike and I am aware there are differences. SO, what I am hoping is there is someone out there who would be willing to help me do some more fine tuning, things like seat position, not height, but how far forward or back should it be. I read UCI rules say the front of the seat must be a minimum of 5cm behind the crank case?. There are other measurements for the handlebar heights and on and on and on. so, would anyone be willing to help out?


Hey David,

If you send me a video of you riding on the trainer from the front and side I’ll take a look at it and see if anything jumps out.

Uci rules are silly and I’m sure Chris will chime in about those.



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Alex knows his stuff and I’m happy to help you out too :slight_smile:

What’s your height and how flexible are you?
What’s your road saddle height measured from the center of the BB up to the top of your saddle?

Rules for UCI events:

  • Tip of saddle 5cm behind centre of BB
  • Aerobar extensions max 80cm from tip of shifter to centreline of BB measured on the horizontal plane
  • Aerobar pad height to tip of shifter in most upright position 10cm

Couple of things to think about when fitting:

  • Is your crank length the same between road and TT bike?
  • Are you using the same saddle?
  • Gradually work your way into the fit. So start with the aerobar pads fairly wide and don’t have too aggressive a saddle/pad drop to start. Get used to the position, work on flexibility and core strength
  • Take note of your road bike saddle height and setback. It’s often not all that different on the TT bike with UCI restrictions in place. Many people (especially tall) won’t need to go right to the 5cm limit. Usually it’s in between your road bike saddle setback and the 5cm. Saddle height is very similar if crank length is the same.

Feel free to post pictures of yourself on the bike from the front and the side with leg at BDC on the bottom and at TDC. (Bottom and top dead centre)

Finally don’t set yourself up right at the edge of the UCI rules. They use jigs to measure fit and there is often variance between the jigs. Give at least 0.75 cm for the 80cm aerobar rule (ie: 79.25cm) and ~1cm on the saddle setback rule.

Easy way to measure is to back your bike up to a wall so your rear wheel is touching.

  • Measure from the wall to the center of the BB.
  • Then measure from wall to tip of saddle (needs to be at least 5cm less)
  • Measure from wall to tip of aerobar extensions and shifters. (Needs to be 80cm or less)
  • Measure floor to aerobar pad
  • Measure floor to tip of shifter in most vertical position. (Must be 10cm or less)

Hope this helps!

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Alex and Chris, Thank you both for the information and offer to help.
Chris to answer some of your questions, I am 5’11" and relatively flexible. I do stretch and do a lot of core work and go to karate a few times a week where we stretch a lot.
When I bought my road bike I had a re-tul fit which I believe does measure seat height from the BB, so I do have some confidence with the seat height. I have also used the TT bike in its current set up on my trainer and feel comfortable with the seat. I did play with its height, but not its forward/back positioning. The bike was set up for my buddy for triathlons so does not meet all UCI rules. I dont know how much I can change the width of the elbow pads, it is an older VISON bar system, but I do have some good flexibility in my shoulders, and can hold the current position for an hour on the trainer, may be different on the road where I know the closer the pads are the more squirrely the bike gets.
You can see from the photos how the bike is currently set up. The metal pole is at 90’ to the floor, so you can see how the front of the seat is in line with the BB. Also, looking at putting my new ALTO CC40 with 25mm tires on, just not sure if I will have clearance to the frame. Or if I keep the ALTOs for the road bike and put the ZIPP 404 23mm back on the TT bike.
Also, likely to take the bottle cage off the back of the saddle. Don’t like it there.

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Nice setup!

Your aerobar pad width looks fine and stable. You pad height to tip of shifter looks ok too but best to measure and verify. (Make sure the shifter is pointing straight up)

Your saddle is definitely illegal. I’d first slide it back all the way on the rails and recheck. (If you have a drywall square that’s convenient to measure with as it’s 5cm) :slight_smile:

If you’re still not legal you’ll need to move the seat to the rearmost seat post hole. (That’s actually specifically designed for UCI setback)

As a result of that change you might need to slide back the aerobar extensions slightly but I doubt that will be required. (Post pictures though and we can confirm)

Great to hear on the flexibility and core work. It’s really important for TT’ing.

I don’t believe that bike frame will support 25mm tires on wide’ish wheels…You can test them but it’ll be very very close. Probably best to go with the Zipps and 23mm tires.


Thanks again Chris!
A very good friend shipped it from Halifax for me this last Feb. He cant ride anymore so said its mine for a 5 star dinner, so heading east in Aug to take him for dinner!
I am excited about riding on the road for the first time this weekend. Going to ride Crowsfoot and see how that goes (weather permitting). Feels fast and comfortable on the trainer but it did take me 2 weeks to be able to stay on the pads for over 30 min and still get decent speed. I agree there is likely no room for the 25’s and will stay with the 23’s. I will move the seat to the rear setback post hole. Don’t have much room on the aerobars to move them. The bars are already fully extended and with my elbows on the pads my hands extend beyond the end of the bars.

You’ll likely need to choke up on the bars with them set at 80cm. With the bars UCI legal my wrists are past the end of the shifters. It’s terrible. :slight_smile:

My first tt bike was also a p2c, they are such a classic bike.

As you have found out the tt bars don’t give you a lot of adjustment as you can really only adjust the width. Like Chris said slowly move them closer as you get comfortable with the handling. The sign that you have gone to narrow is when you can’t “turtle” your head because the flexibility of the shoulder blades is to tight.

See how that saddle works for you but I would usually recommend trying a tt/tri saddle as they are designed to sit with more forward pelvis rotation and since you sit more on the nose it is easy to meet the 5cm setback rule.

Keep us posted on your progress and look forward to seeing you out at some of the club tts

I thought I should chime in on this subject…for the UCI rules. I am a road and track commissaire in Ontario, so am somewhat familiar with the TT setup rules. Yes they may be a little “silly” but are there for your safety and for a more level playing field (prevents people from getting into super aero “superman” positions).

  1. Nose of saddle must be 5 cm behind the center line of the BB. You MAY move the nose of the saddle forward of this position - but you may NEVER exceed the front of the BB Center line. You are also ONLY allowed ONE exemption per bike. (Rule 1.3.014)
  2. Saddle angle cannot exceed 9 Degrees from horizontal… this is a VERY large leeway, but it is checked… if the commissaire thinks it looks too far off horizontal. (rule 1.3.014)
  3. Tip of extensions (including the shifters in their most horizontal position) cannot exceed 75cm in front of BB center line. For morphological reasons this can be extended 5cm allowed… but this is an exemption – See above though… ONLY one exemption per bike. (If you happen to be a taller rider – 190cm+ or 6’-3"+ – the extension can be increased 10cm to 85cm. Rider must be measured in socks and no helmet to garner this exemption however. (rule 1.3.023)
    4.In addition, all extension and elbow rest assemblies must conform to the following :
  • Elbow rests must be made up of two parts (one part for each arm) and are only allowed if
    extensions are added ;
  • The maximum width of each elbow rest is 12.5cm ;
  • The maximum length of each elbow rest is 12.5cm ;
  • The maximum inclination of each elbow rest (measured on the support surface of the arm)
    is 15 degrees ;
  • The maximum dimension of the cross section of each extension is 4cm.
  • The height difference between the elbow support point (midpoint of the elbow rest) and the
    highest or lowest point of the extension (including accessory - that being shifters) must be less than 10cm. (rule 1.3.023)
  1. This one is often overlooked for younger kids, but for adults is a must… the MAXIMUM height for the extensions (including shifters in the most vertical orientation) CANNOT exceed the height of the saddle… see rule 1.3.023. The entire handlebar setup must remain within the box prescribed by the following limits: A - front of box is a maximum 75 cm in front of BB center (or the exemptions allowed). B - Top of box is a line drawn through the support point of the saddle. C - bottom of box is the top of the wheels. D - back of box is the back of the head tube.

That’s pretty much all the restrictions I feel are relevant for fitting purposes on your TT bike. Of course, all these restrictions ONLY apply if you’re planning on riding in a Sanctioned TT event - like provincial championships. These restrictions do NOT apply for racing in Triathlons. They are also not enforced for club / regional events (unless they are sanctioned by the OCA).

If you need any more info, feel free to talk to me at the TT’s we will be holding… or any club ride I’m at… or message me directly. Have fun and enjoy riding your speedy steed!!


Well definitely need work on my fit! Did 35km and while I felt fast I felt my legs and feet tingling and going numb. Shoulders and arms were worn out and left hip, which I have problems with anyway, was cramping. I think part of this was caused when my saddle unexpectedly tilted forward. But I need to figure this out. :thinking:

David what crank length is on the TT bike? It’s very common for master athletes to have some hip issues especially when starting in the position. Something a lot of TT riders do is to run a shorter crank on the TT bike and raise the saddle slightly. This gives you a surprising amount of additional hip angle.

For example I run 172.5mm on the road bike and have experimented with 165mm on the TT bike. (I’ve gone back and forth on this but tend to run shorter cranks early in the season and then switch back as I get used to the position and get lighter)

What will really help is to see your position on the bike from the side and the front. Any chance you can post pictures here?

Also when starting out on the TT bike don’t go really hard in the first few rides. It’s always best to gradually increase the duration and intensity over time.


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Chris, I have 172.5 cranks on the TT. my road bike is the same 172.5.
My hip issues are more from an injury I had years ago. I lost estimated 20% of the nerve and muscle function on my left hip and leg in an industrial accident. I am actually considered disabled. Had my pelvic rebuilt and lot of other things. I was in a wheel chair for 2 years and told I would never walk without an aid device. So, I need to be carful when I do things like biking, having said that, I am reconsidering having a proper fit done. I am not much of a fan of photos of myself, but my wife agreed that if it helps she will take a short video of me riding that I can share.
I know I should not go hard when I am just getting started with the TT bike, but its in my nature to push myself. As my wife says Nice boy not a bright boy

Go see @AlexV at Ziggy’s, he’ll get you sorted. Given your injury history I’d say it’s a must. Also would be a good idea to have your road bike fit validated.

the more I think about it the more I know I need to suck it up and spend the money, Im a very cheap sob. But there is just too much going on to do it myself. The road bike I had done at Racer Sportif in Oakville when I bought the bike, and went back after riding it for a year for refit. Im very comfortable on the road bike. Happy (but slow) doing 50-75 km on it, especially now I got a new saddle.

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