I don’t ride my TT bike much at all and I’m not the most flexible fellow in my hips and perhaps the bike setup isn’t so great. I do a few duathlons and TT’s a year and did my first TT this morning after a couple years w/o a TT bike in the garage.
Sitting on my road bike in the basement, I can do a 20 mins test at about 340, Riding a 17 minute TT today, I was only able to muster 304. I think much of it is lousy position and just not doing the time on the tt bike.
My question though is, if I had been able to ride say, I dunno, 20 watts higher on the road bike road would it have been the faster choice?
My rough approximation is that you need to crank out about 25% more watts to make up for the aero difference. So, at 300w, that’d mean 75w more to go the same speed.
Obviously depends on position a lot, but 25% is a reasonable quick rule of thumb based off numbers I’ve seen from a bunch of different athletes.
To turn into practical terms, that’d mean going from a CdA of .25 to .31.
How do you Watts on a trainer? I would think that indoors your 20/17m power should be close, and your reference is to outdoors you need 100w more power to maintain the same speed. Also, if you play with weight variable, it’s negligible compared to the sensitivities of aeroness…
How do you Watts on a trainer? I would think that indoors your 20/17m power should be close, and your reference is to outdoors you need 100w more power to maintain the same speed. Also, if you play with weight variable, it’s negligible compared to the sensitivities of aeroness…
i used a powermeter on the rollers, same one I sued today. It comes down to my difficulty finding a comfortable position on the tt bike. I need to spend more time in that position to get my hips more used to rotating i guess.
i’m on a pretty small frame and have the seat well forward, but i’m still struggling with it. I may reduce the bar drop a bit, it’s not huge but my neck gets all sore.
I’ve thought about this as well. I look at my times on my Felt AR3 with aero bars vs. my Felt B12 Tri bike and they are only a few minutes apart (tri being faster). Now if it were just a few minutes, I’d probable dump the tri bike and get a road bike for tri’s. It’s not like I’ll ever hit the podium. However, the unknown is how much does the tri bike help my legs for the run. I didn’t have a PM on my road bike so I don’t know if I’m going faster at less watts. If there is a time savings and a wattage savings then it makes sense to have both bikes. With my run, I could have a motorcycle on the bike and still finish MOP.
Don’t suppose you could post a side on photo of your position on your road bike and your position on your tri bike could you -I’d be interested to compare the positions since you say you’re not getting that much time difference. I’m just considering getting a tri bike as I currently only have a road bike.
Don’t suppose you could post a side on photo of your position on your road bike and your position on your tri bike could you -I’d be interested to compare the positions since you say you’re not getting that much time difference. I’m just considering getting a tri bike as I currently only have a road bike.
Thanks. Looking at your positions I’d have expected you to go a lot quicker on the tri bike as your position looks waaay better. I’m surprised they’re similar.
Thanks. Looking at your positions I’d have expected you to go a lot quicker on the tri bike as your position looks waaay better. I’m surprised they’re similar.
no, my issue was I don’t make as much power on the TT bike, I’m sure it’s still faster than the road bike (based on what I gathered from above posts)
Looks like your saddle is too high (a cliche, I know) on your tri bike. Your nearest foot is bottom of the stroke on both pictures but the angle through your knee is wider on the tri bike. Is your effective saddle height BB > saddle top same on both bikes, different crank lengths, different pedals/cleats etc? Either way, you look to be over reaching on the tri bike and if you are having to rock your pelvis on the down stroke you will be less comfortable and probably struggle to produce the same power. Drop the saddle a bit.
I swap from TT bike to road bike a lot. Both with power meters.
For me it’s almost exactly 2 mph. If anything a bit more than that.
do you make about the same power in your aero position
almost no one does. you make the tradeoff that you get more speed as you sacrifice power. Even with a lot of acclimatization, you may still be 10-15 watts below your road position, but it doesn’t take a genius to figure out that to be 2 mph faster (say from 25–>27mph) on a road bike, one generally needs about another 70 watts. In your case, possibly much more.
you mentioned your problem in your first post: not enough acclimatization. the rest sounds like you are bargaining so that you can have your cake and eat it, too.
ICYC, I hope you never race in a jersey fitting that loose. It’s a full size too big. That’s costing you at least 15 watts right there. Jerseys are supposed to fit snug, the cooling effect of the jersey material is also reduced when it’s not against your skin, meaning it’s warmer when oversized.
Just my $.02…but I think you need to rotate forward for BOTH positions. On your road bike especially, you are basically sitting straight up and them leaning over at the waist. I would slide the saddle forward a touch and rotate your hips. That is probably one of the reasons you need an upturned stem on your road bike.
I’ve not done FTP tests in both positions, but I’d guess that I lose somewhere between 10-20 watts going from road bike to TT. It might be even less than 10.
For me riding at the same perceived effort I’m 2 mph or a hair faster on the TT bike vs. road.
Just my $.02…but I think you need to rotate forward for BOTH positions. On your road bike especially, you are basically sitting straight up and them leaning over at the waist. I would slide the saddle forward a touch and rotate your hips. That is probably one of the reasons you need an upturned stem on your road bike.
Great bike, btw…
I think that’s clearly true–my hips are pretty tight, i notice when i sit on the floor I can’t just pop back up, which suggests to me weakness or tightness or both. I need to keep working on it
