What is the exact distance from the center of the bottom bracket to the top of the saddle?

30"

Hi, thanks for reaching out.

Looking at your numbers, I'm estimating a Pad Stack of 700mm and a Pad Reach of 420mm... with those numbers you are "upright" or "slack", and might explain why you couldn't make the reach of the size M Trinity bike. Upper left quadrant sort of fit coordinates.

Actually, your fit numbers are sort of off the charts depending on the bike... you have the reach numbers of a 51cm bike and the stack numbers of a 58cm bike. At your height, 5'10", I'd never be thinking size 51cm for you, or even 54cm, and probably not 58cm either (the stack you're presenting), so something is off. My first instinct is your relationship with your saddle, and your ability to rotate your pelvis forward in order to properly sit on your saddle, which makes the effective length of your body longer and would put you into a more orthodox time trial position. Second, have you ever had a bike fit before? I want to get to the bottom of what's going on and prescribe a bike size for what you really need instead of making a Frankenbike work for you the way you are now.

Can you do me a favor? How far is the nose of the bottom bracket horizontally from the front tip of your saddle? What saddle are you riding? What size is your current cd0.1 bike now? They are notoriously long and low bikes. A picture of you riding in the TT position might help.

thanks,
Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

hi, thanks for reaching out.

I suspect that at your height you'd be a size 58cm Cervelo P-Series bike... nothing about your measurements indicates anything out of the ordinary. The Zipp cockpit on the P-Series bike is very adjustable in such a way that you can raise the pads and extensions independently of the stem so as not to incur an aero penalty by putting spacers under your stem to gain stack. Lots of fore/aft and width adjustment too.

Make sense? You might get away with a 56cm too, but without some more traditional fit coordinates I'd go with the 58cm.

thanks,
Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Hello Eric. I could use some advice. I'm looking to purchase two bikes- Cervelo P-Series and Cervelo Caledonia. I'm on the boarder between a medium and a large, and trying to decide which one to go with.

My height is 70.5". I have long legs and a short body. If I go medium, I need to make sure I can adjust the saddle up to the correct height. If I go large, I need to make sure I can adjust the saddle forward enough so I'm not too stretched out.

Pad X=425
Pad Y=610
Saddle Height=790
Seat Nose to Aero Bar Extension=825
Arm Rest Width (center to center pad)=230

Thanks in advance!

Yeah I know my fit is way off but it is comfortable for me and I dont have any hip angle issues in this position with the shorter 165mm crank. Saddle is certainly a huge part of it I usually ride an old Cobb 55 but I certainly need to experiment more with that and was looking to put the new sell watt saddle on whichever bike I get. I attached a pic of the current fit, my pads are high but they I can easily go lower than what I have them at. I did do a "bike fit" but it was super basic and was just to at least get me comfortable. Was going to do a full real fit whenever I got a new bike.

Nose of BB to tip of saddle ~ 1"
CD 0.1 is their M/L size

Is the tip of the saddle 1” behind or in front of the BB?

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Just want to confirm you’re interested in the P-Series and Caledonia, which come in numbered sizes and not S, M, L. etc.

Regardless of what your morphology is like and regardless of your bike or bike size, you move the bike parts to meet your position and not the other way around which you sort of alluded to in your post.

I just wanted to confirm this because with your fit coordinates of a pad stack of 610mm and a pad reach of 425mm (to *back* of pads) you’re in the range of 48cm or 51cm a Cervelo time trial bikes, not a medium or large like you’re thinking.

Make sense?

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Sorry, I was looking at the wrong number and should have stated a Pad Y of 670. I also should have said that based on my height, I'm on the border of sizes 54 and 56.

With this correct pad stack dimension, what do you think about which of the 54 or 56 will be a better fit to ensure I can get the saddle height I need without being too strung out?

Thank you

1” in front of bb

OK, so let's say your reach is 430mm based on a saddle 1" or 25mm in front of the BB. That makes more sense and confirms my suspicion in my original reply to you that something was off.

Looking at this pic, your fit is pretty good, you look really comfortable. What I'm really noticing though his how "vertical" your pelvis is, and how rounded your back is because of that. That effectively shortens your torso, which explains why your reach is so short for your stack or vice versa. The reason for this, IMO, is you're not on the right saddle or your sitting on the right saddle wrongly if that makes sense. I don't say this to criticize, so don't take it personally, but you're contacting the seat with your sit bones, which are way back, rather than your pubic bones which are more forward. IOW, you should be sitting off the edge of a good TT or triathlon saddle and you're not.

All of that to say that with the new reach number of 430mm you're at the back end of a 56cm bike and also within range of a 54cm. For the 56cm, you'd have to come down 20mm to hit the upper left quadrant of the fit range. You'd have a similar situation as your current bike, in that you'd have a fair amount of Zipp Vuka spacers below the pads. Conversely, you're only 20mm of reach from the back end of a 58cm.

Does all that make sense? We need to process this a little more before I can give you a hard prescription for bike size. Out of curiosity, what size CD0.1 are you on now?

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

OK, with those numbers you're slightly off the charts and also in between sizes. Pad stack 670mm and pad reach 425mm you're a little too high of a stack for a 54cm and not quite enough reach for a 56cm. For either bike, your saddle height is within range.

Any chance you could post a pic?

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Yes, This has always been my problem. You can see in the pics that for my Fuji TT bike (size M/L 56), I have the saddle adjusted as far forward as possible, and for my Scott road bike (I think size 54) (set to duplicate my TT fit), I have a Profile Design Fast Forward seat post.

Ok this makes sense to me! My saddle has always been an issue for me. The CD0.1 is their M/L size (thats what it says for sizing on sticker). In this pic I’m actually riding on an old school style tri saddle with no split. Just the long narrow saddles that used to come stock with tri bikes. I usually ride a bright green cobb 55 which you could actually see in the back of the pic on the other bike. On that one my hips are less vertical.

OK, this makes sense. With a better saddle you'll have a "longer" torso, and perhaps more reach.

At any rate, all this to say you're between bikes. You're just slightly taller than a 56cm and just slightly not long enough for a 58cm. I feel like it's a toss-up. You don't look like you *need* to get any lower, and the reach depends on you learning how to sit properly on the right saddle. I'd try a bunch to figure out which one is yours.

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

I think, all things considered, that the 56cm P-Series would be best for you, both now and any potential future fit you might evolve to.

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Thanks so much for you time!

Thanks for your time and help! Think im going to get a 56 p-series soon then, another question I had was if you knew what crank length the 56 came with? I cannot find it anywhere on the site, most likely going to order through my LBS and was wondering if the lack of info meant you can order whatever length you want but not sure.

I'm not sure but I'm reasonably certain it's not 165mm, which is the longest crank you should be using. See if your LBS can do a swap.

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Hi Eric,

I'm looking to buy a Cervelo P-series and would hugely appreciate some advice. I have had a bike fit for a road bike (see image below) but the fitter now seems unresponsive.
Height: 190cm
Inseam: 86cm
Wingspan (saw someone else post this, so maybe it'll help): 192cm

Thanks!

The numbers from your road bike fit have almost nothing to do with a fit on a tri bike.

Sure they do. A tri fit is just a road fit rotated about 20 degrees around the BB, with contact points readjusted based on new orientation of gravity.

E

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Unresponsive? There are four ways to get ahold of him right there on the bike frame!

Just kidding. OK, so you're tall. You're evenly split between inseam and torso. The max reach on a 58cm P-Series is about 525mm. The 61cm P-Series is a little bit longer, and a good chunk taller, 25mm. You might also fit a 61cm, but most likely you're a 58cm. Even if you have a "slack" or "upright" position, or a "long and low" position, the adjustability of a P-Series cockpit is excellent.

I mention the 525mm of potential reach for a 58cm because you've got about 600mm between the tip of your saddle and the bars on your road bike fit, which would be about 525mm of reach on a tri bike plus 75mm of saddle setback with a split nosed saddle that you hang off the end of, which is about what I ride and I'm also 190cm. If you can ride the "invisible aero bars" on your road bike with that setup that's a mildly good proxy for what will be going on for you on your tri bike.

I'm leaning toward a 58cm P-Series. Any pics of you riding in a TT position on a previous bike?

Eric

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”