Cadence drop with new TT bike

Hello. First post, been lurking on and off a while. Subscribed to TR in Jan 19 and have been using it as much as possible since then. I’ve just finished my first season of triathlon (2019), new to swim and bike (started both Jul-Aug '18), have been running for a few years (completely unstructured).

My tri season consisted of a HIM, Long Course Weekend (full distance spread over Fri, Sat and Sun), Olympic and Ironman. I intended two sprints first, but crashed my bike, broke my elbow (detached triceps, two surgeries) so missed them due to being in a cast. FYI I blame TR for my crash. My improvements from Jan to Mar made me go too fast into a sharp bend, lol.

Having completed my Ironman and been told “well done, couldn’t you have gone 4 mins faster” by the boss, I’ve bought myself a new TT bike. My plan is to leave the TT on the trainer all winter and use the road bike for the few occasions I go outside. My question, excuse the lengthy intro, relates to whether or not there should be noticeable differences between the two bikes?

When doing workouts on my road bike, my cadence sits in the 85-95 range as recommended. I can spin up to 110-120 before I bounce. My road bike has a 50-34t; 11-32t setup. My new TT has a 52-36t, 11-28t setup, both have 172.5mm cranks. My cadence has noticeably dropped on the TT rig. I can barely hold 85 doing sweetspot sessions, and usually end up with an average of 79-81. Is this expected? Is it normal? Is it the TT, or just the bigger chainring?

Also, VO2 sessions are harder on the TT. Again, is this normal? Is it something I just persevere with and it’ll improve?

I should note that my road bike didn’t have TT bars until my TT bike arrived (I bought the same bars and put them on the roadie). I am not flexible - I can only just about touch my toes after a run.


Hey - I would say that both i) cadence drop and ii) increased RPE/difficulty doing a VO2 are pretty standard when you’re new on a TT bike.

While both of these could be exacerbated by a bad fit, even with a perfect fit you would still probably experience both. In my own experience, I’ve found that cadence will come with time, in a new position your body needs to almost relearn pedalling efficiency. So try to do short periods at a higher cadence, and build up length until your comfortable again, but I’d say a lot of people have a slightly lower cadence on the TT bike anyway vs. road.

As for VO2, its a lot harder, which shouldn’t be surprising because a) you’re using a slightly different, potentially restricted set of muscles to the road position, and b) your breathing might also be compromised. This can take longer to balance out, but my advice is to do what Chad has recently said and do some of the interval in TT position, and then sit up to breathe - then try and build up time in position as you improve.

In short, don’t panic, both these things are fairly normal when new to a TT bike. Nevertheless, try and get some photo/video of you riding in TT position and maybe compare with some good examples to check you’re not miles out from a ‘good’ position (that at least then puts your mind at rest).

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Thanks. Great info. The first time I sat on the TT was during my fit. I had a fit on the roadie, left the TT with my guy who set it up for me and then he optimised the fit upon my return.

I’ll try and incorporate more spinning on the recoveries and easier sessions as well, and won’t worry too much about the intervals being harder. As soon as I sit up I can push the watts a bit more, so I’ll just keep plugging away in the aero position.

Are you using the same FTP for both the TT and road bike positions? Typically there is a 10%+ difference in your FTPs and you cannot get the same power out of your TT as your road bike. Typically this difference will narrow as you get more experience but in the end its usually harder to push the same power in a TT position versus in the road bike position. The trade-off is you are more aero in the TT bike, so you end up going faster. You may be pushing too high an FTP in the TT position and you are now doing, for example, threshold intervals when you should be in sweetspot zone. Obviously you will be having a bit more difficulty holding power in the TT position. This compounded with unfamiliarity and breathing reductions could be a reason why you are having trouble.

If you have not done so, FTP test in the TT bike in aero and keep that number “separate” from your road bike number. This might help you in your new position.

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I have not changed the FTP setting. It has remained unchanged since late spring, because it dropped due to my accident, then built up again. I redid the test just before I got the TT bike setup, using my roadie, but screwed the test so didn’t use the result (I eased off when I couldn’t go any further on the ramp test thinking it would automatically stop because I’d failed, but it didn’t - next time I know to hit pause/end as I fail).

I’ve got a cross country race on the weekend, so I’ll give it a week and then do the ramp test on the TT and see what happens.

I have a follow-up question for everyone though… Should I mix it up, swapping the TT and road bike for different sessions, or should I focus on the TT bike?

My goal is Ironman Wales in September 2020, however I will be doing a couple of sprint and olympic and a half before that. I know I won’t be using the TT for all of the races, as the half in particular is best suited to a road bike. I plan on using the TT for all the olympic and sprints, but only if I can recce the courses, as TT feels very weird at the moment and I don’t fancy being in the aero position on an unfamiliar course with twists and turns and hills. (I hope that makes sense and I hope both my confidence and ability improves, but that will only happen in the spring when I get outside on the beast!)

You will likely receive 2 contrasting opinions on this and IMO (hahaha) neither is wrong, but you should understand how to approach this and choose an appropriate plan based on what your goal is.

One camp will say to use the road bike to build fitness. Since you can typically push overall higher watts on the road position, getting your fitness higher means higher watts, and watts are watts. So you could do the majority of your training on the roadie, maximizing your watts and then closer to your goal races you focus on your TT bike, ultimately doing all your later rides in the TT bike for your race prep.

The other camp will say do all your training in your TT bike, as this is the bike you will be using for your goal race. If you get comfortable pushing high watts on the TT bike its obviously a positive, as this is the bike you need to be both comfortable with for long course and if you can’t hold aero, whats the point of using the TT anyways? Yes you might push lower watts when compared to the road bike, but you will trade off “higher wattage training” for TT specific training. You are not going to be racing in the road bike anyways (although you stated you will do some races in the roadie, if you are competitive, generally all races really should be in the TT bike as its faster)

Which camp is right? I duno. I don’t think theres a right or wrong answer; theres pros and cons to using either approach, but ultimately you need to put time into the TT bike regardless of how you train leading up to the race if you want to race on the TT and get the fastest time possible. Personally I ONLY use my TT/Tri bike unless I am doing a fun ride outdoors, as my races are all in TT position on the tri bike and I have been able to push pretty similar power numbers by training in my TT position over time. I am in the latter camp, train with what you race on and maximize your comfort pushing high power on the TT bike. However, if you plan on racing on the roadie and tri bike, it would likely benefit training on both. But understand that if you are not comfortable on the TT bike for 5+ hours (IM distance) you are going to have a BAD time. And 5+ hours on the TT bike is NOT easy.

This whole mentality would make me advise you to do all your training on the TT bike. Get comfortable on the bike so you can feel confident on descents and climbs. Unless its some serious switch backs and stuff, the TT is the way to go. If you need to switch up the position or dial it in, now is the time, not 3 months out from race day.

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