TT-Bike Budget Build

[cLs_elite]

My FTP is waaaaay lower than Dallas, and i wouldn't run a 52 on a TT bike. But obviously, if you're not going to ride it on the flat, then it gets complicated. There are useful online tools to figure out, based on cadence, gearing and so on, the speeds at which you can ride. I can tell you that i dislike high cadences, so at 80-85 cadence, i dont want to be doing tempo in the smallest cog on the flat, because it means i spin out as soon as i start pushing, which sucks. Also, the smallest cog should always be an emergency cog, not a "i'll be doing my hard efforts in that cog".

On crank arms, be careful, you might be throwing good money after bad. I'd get pedal based power meter and shorter cranks. I'd get 165mm, now that they're cheap from China. If you plot it trigonometric-ally (?) you see how big of an impact crank length has on how high your knees go up into your chest in TT position. So it's not a marketing trick to sell more bikes. It's just objectively more comfortable to be horizontal with short cranks. And sell your 172.5mm rig before nobody wants it

Hey, thanks for the reply. Great advice! I looked into the crank length topic, and it definitely makes sense now. I’ll try to find a setup with a shorter length (155-165mm) and sell my power meter.

Unfortunately, getting a setup with a spider power meter or power meter pedals will be more expensive...
I guess the cheapest option would be to go with 165mm crank arms. Will I regret not going shorter, like 155mm?

[Da11as]

Hey, thanks for the reply. Great advice! I looked into the crank length topic, and it definitely makes sense now. I’ll try to find a setup with a shorter length (155-165mm) and sell my power meter.

Unfortunately, getting a setup with a spider power meter or power meter pedals will be more expensive...
I guess the cheapest option would be to go with 165mm crank arms. Will I regret not going shorter, like 155mm?

You can buy spider-based option that will fit your current crankset interface and buy some cheaper crankset at shorter lenghts to experiment with it. Or you can go to bike fitter with the proper tools and see how much you can reduce hip to torso angle and how short should you go. I think today 165 mm cranks on TT bike is generally accepted (not by manufacturers) standard.

[Serge_K]

Hey, thanks for the reply. Great advice! I looked into the crank length topic, and it definitely makes sense now. I’ll try to find a setup with a shorter length (155-165mm) and sell my power meter.

Unfortunately, getting a setup with a spider power meter or power meter pedals will be more expensive...
I guess the cheapest option would be to go with 165mm crank arms. Will I regret not going shorter, like 155mm?

I am probably missing something, but i dont understand why pedal based power meter isn't the go to for most people. You can swap between bikes, you can travel with it, you can put in the home trainer and outside to get consistent readings, you can upgrade your bike and keep the same pedals. I've had the vector 2 from garmin since the great war of 1914. It's done dozens of thousands of kms, and well, it just works. The only thing i dislike is it uses coin batteries, but it's so old, rechargeable PM didnt exist then.

Bike tech does evolve. Quite fast, in fact. Discs, wider rims, shorter cranks, hydro brakes, and so on. Throughout all of this, the one constant has been my vector 2. I've probably used it on 10 bikes. And it wasn't that expensive to begin with (i have the single sided one, because unless you had an accident, you're probably balanced enough, and having one dummy side means there's one electronic thing that can break of malfunction instead of 2).
A friend bought the dual sided speed play power meter, for a literal fortune, and it never seems to work properly.

[etherealryu]

A plausible reason is how people underestimate the hassle when moving components from bikes to bikes. Pedal based powermeters are usually more expensive than crank-based powermeters but they are the price for at least a single-sided powermeter in addition to a pair of pedals. A lot of people don't realize it's a complete mess when they need to change crank length or just getting a new crankset while the crank-based powermeter is bound to the previous crankset. I started with 4iiii crank-based powermeters but once I realized that they are a huge hassle if changing bikes/components occur I immediately sold them and turned to pedal-based ones. Now I happily own rally SPD, rally SPD-SL and Assioma duo Shi on three different bikes. They work just as well as crank-based ones and I can easily transfer them if I will get a new bike.

[cLs_elite]

Yeah I see what you guys mean, it definetly makes sense to switch to the pedal-based power meters.

[klindsey00]

one thing that worries me about power pedals is possibly not being able to swap the pedal body when it wears out. I went with a sram rival crank because it was basically the cheapest power meter you can get. (maybe a stages 105 single arm might be cheaper but idk)

[etherealryu]

one thing that worries me about power pedals is possibly not being able to swap the pedal body when it wears out. I went with a sram rival crank because it was basically the cheapest power meter you can get. (maybe a stages 105 single arm might be cheaper but idk)

The powermeters in the pedal are usually the spindles so you can just purchase new pedal bodies if they wear out.

[klindsey00]

Right, I’m just saying if you aren't able to source a new pedal body it would suck.

[etherealryu]

Right, I’m just saying if you aren't able to source a new pedal body it would suck.

If you get Assioma duo Shi then you can always source new pedal bodies because Ultegra R8000 pedals are everywhere.

[Da11as]

The powermeters in the pedal are usually the spindles so you can just purchase new pedal bodies if they wear out.

While it is true, I think spider-based powermeter will work better unless you have more than two bikes and want PM on all of them as it will last forever and requires zero maintenance. I know several people that have Assiomas of different fitness levels, all of them managed to destroy pedal body or brick them during an accident within 3 years. Considering how cheap some options are, one can get some common mounting option (let's say Sram 8 bolt interface) and change cranks if necessary.