Good stuff.

I’m curious the. Why the 54 recommendation for the Five, but 52 for the Six? Should it be the other way around? If the 54 in the Six would get me down to 620, that’s a full 30 lower where I am now, which I doubt I’ll ever got that low (I’m not exactly high now either).

Whereas the 54 in the Five would only get me down to 637 if I’m understanding correctly.

If it further helps I’m 6’1” with a 32in-ish inseam when measured by a tailor (I wear 34” pants, which aren’t leggy at all. 32” pants end up being borderline high water pants).

SBRcanuck,
Let's start with something simple... Pad Y of 640 - okay. Pad X of 485 to center is ~445 to the back of the pad. If that's correct then.... Those numbers can fit on a 54cm PRfive but only just, you're right on the limit. Far better to be on the 52cm and that's with the stock stem/bar set up.

Oh wait.. I've just gone over to TriRig to play with their calculator and they measure to the center. So if I plug in a 52 QR PRfive and use your Pad X to center of 485.... it would be "monopost 4.5, 20mm of stem spacers" and "pads -20mm". I put that stuff in quotes because I have not yet personally built the bar so I can only trust that their are accurate. I'm sure they are or we'd hear about it endlessly here on the Forum. Now for some opinion...20mm of spacer under stem.. I'm good with that all day long. Pads back 20mm, fine. 4.5 monopost...Hmmm...I see 6.5 exposed in some gallery pics so it's good to know you're not near the limit. Keep in mind that your aero position (arm pads and extensions) and your "pursuit position" (hands on bull horns, descending turns, corners, accelerating hard) will be 45mm apart in elevation. That's a preferred position for pro cyclists and their TT positions and it's near the edge for most age group triathletes - not terrible, it's acceptable.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

blueapplepaste,

Pad Y of 650 to 630 - I didn't consider that a "little lower". I should have asked for a definition of terms. I'd be super curious to know what length crank you're riding currently.

Here's my though process...

In terms of Pad location I'm good with 3mm too long or too short, and I'm okay with 2mm too low or too high. I feel like those are acceptable variables. To that end...
The 50cm and the 56cm PRfive cannot deliver the 645 Pad Y so they, along with the 48 and 58, are not in the consideration.

The 52 PRfive can give you a 645 Pad Y with a 70mm & 90mm stem but that set up isn't long enough.
The 52 PRfive can give you 645 in Pad Y with a 110 stem but then the 500 is X is the longest the bike will go. Yes, if you go lower, you essentially slide down that 73 degree angle and buy a couple more millimetres.

The 54cm PRfive offers the best combo of your Pad Y and Pad X. You ride pretty long already and you say you want to ride a little longer...okay, the 54cm PRfive is your bike. If you want to go a lot lower (635 or below) then you need to go to the 52 but it'll limit you a bit on the length.

Now the PRsix.. that bike will deliver on your Pad Y and Pad X in a size 50, 52, 54, 56. The 50 and 56 don't offer that much wiggle room.
If you go with the 52, it's the script I wrote in the previous post:

If you go with the 54, it's this set up: 110 stem. Stem/bar clamp in the low position (meaning the two clam shells are atop the bar within in the clamp) and 25mm of arm pad pedestal. Pad bracket in rearward position and pad mounted in mid-rear hole.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

I threw that out more of a "I can't imagine going any lower than that" down to 630. Is that "a lot lower" in your view? I'm honestly super comfortable where I am now, the going lower was more of a "I want the option" just to futz around with things.


For the reach, lately I've found myself scooting my elbows just a hair forward as I settle into the ride. So again, when I say a "little longer" it's just a hair to get my arms back into being better supported by the cups.


I've been avoiding messing around with my fit on the SC just because it's such a process. I used to love wrenching on it, but now with a toddler and busy job, not so much (hence the change to a QR).


I'm currently on 172.5 mm cranks.


I attached a picture of my current position (forgive the bad head position - going through some bike traffic so had my head up a bit to better see).

pic didn't come through, would love to see it. When you order your QR ask 'em to put 165 cranks on there. Your seat height will need to change to go up 7.5mm and your drop will increase by 7.5mm so that's a little lower right there.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Let's try again.

Looks pretty good. I can see that you find yourself creeping forward. And, yes, the shorter cranks thing is a must.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Thanks! Anything obvious you'd recommend?


Curious about the definitive suggestion on the 165mm cranks? I've read so much and seems theres a camp that's hardcore in favor, and another that says it doesn't matter.

Certainly open to experimenting with it. Mostly I haven't because I have a Quarq on there, and didn't want to lose my PM to play with crank sizes.

I'll be brief...
Many riders can be comfortable, powerful, and a bit more out of the wind when they ride a lower arm pad elevation (AKA more drop). The factor that has limited this for....well, forever... has been this: at the top of the pedal stroke the hip flexor become impinged. That means as the foot approaches 11 o'clock the flesh starts to bind up, the leg circle slows, and there's a bit of delay getting over the top and back towards the start of the power phase (at...1:30? 2?).

There are two ways to solve this
1) lift arm pads
2) shorten cranks

You're 6'1"...normal morphology... 160s might be better but your options are fewer = 165s.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Cool - makes sense. Will go for the 165 then.

Now just gotta wait for them to go on sale again...

My wife has a PRSix Disc Size 48 and is very confortable on the bike, but after riding it for some time she wants to go lower. Her aero/basebar is the Profile Design Aeria Ultimate Carbon, she is currently using it with out any spacers and can´t go lower. Any recommendations? I'm attaching a pic.

Thanks

Hello Ian,

I’m 5’10” and “was” riding a 54cm PR3 until I got schwacked by a car in a race, so I need to replace the frame. So I’m looking to go to a disc brake PR5 or PR6. I was pretty comfortable on my 54 cm PR3 but may want to try a little lower and longer than my current fit. According to the QR fit tables it looks like I can go with a 52 or 54, so I am curious as to your recommendation.

Here are the numbers from my 54cm PR3 fit:
Pad X 622
Pad Y (back of pad). 483
Saddle 749
Tip of saddle to back of pad 521

I’m considering going with a 52cm, but concerned about going too small as I felt cramped on my first tri bike which was a QR Lucero Lite size M. I welcome your recommendation on the size frame I should consider.

Here are some pictures of me on my PR3. I had dropped the front end about 1 cm since those pictures were taken to get to the numbers I provided you. Thanks in advance for your help!

https://imgur.com/tme5l3Y

https://imgur.com/ybbfJEj

Crash-Davis, Sorry to hear about the schwacking, glad you're okay and ready to get back on the horse.
Great pics, great info - makes it easier.
For the PRsix... a Pad X of 483 and a Pad Y of 622 (I see that reversal, happens all the time) you'd have to do it on the 52. The prescription would be: PRsix size 52 with the 90mm stem, the stem/bar clamp in the low position (meaning, both clam shells on top of the basebar), 20mm of arm rest pedestal, the arm rest bracket set rearward and the arm rest mounted in the rear hole. You're thinking of maybe going longer and longer - you can do both with this set up: you can drop the pads 20mm by just removing the pedestal, and 25mm longer by just mounting pads in different holes or flipping the bracket forward or a combo of both. The lowest the 54 goes is 620.

For the PRfive it's the 52 as well but now with the 110 stem, no spacers under neath that stem and only .5mm arm rest riser, and then mount the pads offset -2.50 (meaning 1 hole fwd of center). With this set up you can only drop to 5mm lower but if you tilt the aerobar you can drop another 5-7mm, and you can stretch out another 22mm.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hello Ian!

I'm hoping you can help me figure out a frame size for a PR5 OR PR6 from my fit measurements off of a 48cm 2010 Cervelo P3 built on 650c wheels with 170 cranks.

To note, I absolutely want to go with 700 wheels AND 165 cranks this time around. Prior to owning the 48cm P3, I was on a 2009 51cm P2, which also fit. I don't have fit coordinates for that and I can't remember why I went down to the 48cm (probably to get more drop since my inseam is a bit short). It was a tiny bike under me with those little wheels but it sure was a fun and fast ride! I used it for all distances from sprint through iron.

I am 5'5" tall
Cycling inseam 770mm

Arm pad reach: 430mm
Arm pad reach BB: 396mm
Arm pad stack BB: 580mm
Saddle height: 685mm
Saddle set back: -33mm
Arm pad drop: -87mm
Handlebar reach tip saddle to bar top: 471mm
Handlebar drop: -114mm
Handlebar reach BB to bar center: 438mm
Handlebar stack: 537mm
Frame stack (2010 48cm P3): 465mm
Frame reach (2010 48cm P3): 390mm

Saddle: ISM road (I hated that saddle and do not plan on using an ISM again - not sure if this matters)

Other bikes currently owned that fit well: 2020 52cm Tarmac Expert (I could def ride the 49 here as well but lots 'o drop) & a 2018 51cm Ruby Expert

Thank you so very much for your help! Please let me know if there is anything additional information I can provide.

Looking at getting a PR5 I'm just shy of 5'9", 31" inseam. Pad X is 487 and Pad Y is 622 on my current bike. What's your recomendation?

 

Shellabree,

If you get a PRsix... it's a 48 with a 90mm stem, the bar clamp in the "mid" position (meaning one half of the clam shell atop the base bar and one half below), 10mm of arm pad pedestal, the arm rest bracket set up in the forward position and the arm rest itself in the mid-front hole. That gives your exact Pad Stack (580) and exact Pad Reach (430).... and it gives you tons of room to take the cockpit longer or shorter and about 75mm of pad raise and pad drop. So you've got plenty of time to move in the future if you like.

If you get a PRfive...it's a 48 again but there are a couple of options on the front end config...
- 110stem, slammed, with only 5mm of pedestal and arm pads mounted 1 hold back of middle.
or
- 90mm stem, 10mm under stem and arm pads slammed, arm pads one hold forward of middle.
This both give you your numbers with a +- of 2mm.
There's not much difference in those too positions. I guess, for me a 90mm stem on a "48" bike makes more sense but it truly doesn't matter in this case.

BTW, I put "48" in quotes because QR sizing is VERY logical and therefore odd in terms of bike sizing. This is a 48 because the frame stack is 48cm not because the measurement from the center of the bottom bracket to the seat post collar or the top-tube/seat-tube or to some place in space if the top-tuber were level, etc. etc. It would be just as logical if this bike was called an Extra Small. At 5'5" you're not short but you ride pretty low with an arm pad elevation of almost 9cm so you need the smaller bike.

Get back to me here if you have questions.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hi Ian! Thank you so very much for that information. A couple of additional questions:

1. So pad reach is measured using the measurement from the saddle tip to the rear of pad (430) and not the BB to rear of pad (396)? I always thought both stack/reach and pad stack/reach coordinates were measured from the BB. So a bit confused here.

2. If I went to 165 cranks on this, I'd still be OK with the 48cm? I know that saddle height would have to come up a bit (which would increase drop), but I'm really not sure I want any additional drop. I'm not getting any younger and would probably move towards less drop if I moved in a certain direction. LOL!

3. The fit coordinates taken from above were at a 77 degree seat tube angle. I always felt like I could ride a bit steeper of an angle than that and not close off the hip flexors so much. Heck my road bikes are set up at 77! With the 48cm bike, I'd still have room to move forward, correct?

Thanks again for your help on this! This is all very educational and education is power! I'm super excited about getting a new bike!

shellabree,
Good gravy, thank you for keep an eye out for my error - yes, let me redo this under the Pad X of 396 rather than 430. When I teach bike fitting I'm adamant about specific terms of art to reduce confusion. I much prefer "Cockpit Distance" to identify the nose of saddle to the back of pad over Pad Reach to help reduce the error I just made :)
For the PRsix - still 48, still bar clamp in mid position and 15mm of spacer but now the 75mm stem with bracket rearward and armrest hole mid front.
For the PRfive - still 48, still 90mm stem, slammed with 5mm of pedestal under the aerobar and pads mounted one hole back from the closest the pad will go.

Regarding crank length and drop.... yes to 165s but you'd be even better off on 155s (JCobb, Rotor). Regardless - for every mm you lift the saddle height to meet the new crank length you can raise the bars (on both the PRsix and PRfive). Your saddle height is currently 685 w/ 170 cranks. That changes to 690 w/ 165 cranks - to sustain the drop at 87 you'd just bring the bars up 5mm. On the PRfive you can either put a 5mm spacer under the stem or 5 more mm under the aerobar for a total of 10mm. For the PRsix you can either switch the bar clap to the high position (both clam shells under the base bar) or, my preference here, to go 20mm of arm pad pedestal. All this same, easy math can be done for 160 cranks, or 155 cranks too. AND there's room to move in the future if you want to reduce your pad drop from 87 to 82 or 77, etc.

Lastly, about seat angle - your body angle is the real issue and not so much where the seat is - and you've spoken to that with the mention of your hip flexor being shut off. The shorter cranks will help with that but you should probably be riding steeper. The saddle, its comfort, and where you sit on it is so critical. If you're at 77 degrees but the saddle is on the long side and you're perched way off the nose of it - okay, fine. But if the saddle's short and you're sitting in the middle of it (or, heaven forbid, at the rear) then there's no way this fit optimal. This then makes me think that if you move forward in terms of hip over bottom bracket then you're gonna want to move the arm pads and extensions forward and both bikes as prescribed here have lots of room to go forward.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Ian,

That was such awesome information! Thank you SO very much!

Super grateful!

crujones#33,

487 is pretty long, is this to the back of the pad or the middle of the pad? I'm gonna proceed as if it's to the back but be sure to get back to me if it's to the center.

For the PRfive..... the best bet is a 52 with a 90mm stem in the -17deg position. The stem should be slammed and with only 5mm of pedestal under the arm pad. Then push the pads 100% out as far as they will go. The result is 622/486. If you went with the same size bike (52) and the 110 stem (again slammed with 5mm of pedestal) and then you pick your arm pad hole to result in either 484 or 491. With the 110 stem you can still elongate or shorten the cockpit but with the 90mm stem you are maxed on cockpit distance.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hi Ian,

I'm currently riding a 2013 CD01 Medium.
I'm a hair below of 5'9" and around 160lbs.

Measured by current bike's Pad X and Pad Y:
Pad X: 475
Pad Y: 665
Crank Arm: 165
ISM PN 3.1(if this matters)

I'm looking at getting a PRFive frameset (was originally thinking a size 52).
I have a Profile Deisgn Aris stem (90mm / +-7 deg) and a Profile Design Pro Svet base bar.
Thinking of eventually getting a TriRig Alpha or a 51Speedship Mono Riser.

But on to the frame for now. Is 52 the right size for me? Given the current cockpit that I have.

Thanks

Hi Ian,

My height is 180cm, (however one leg is 2ish cm shorter so I never know if that's my actual height or if when standing shoeless I drop off to my shorter side appearing shorter)
my inseam is 84cm,
my saddle height on my road bike is 793mm.
my saddle tip to hoods is 750mm. (if this helps)

Apologies for the lack of data!

Tommy

jeyps11_c,
Your Pad of 475 is exactly what I'd expect for you based on the info you provided. The Pad Y of 665 however is higher than expected - I'd think 620-630 far more logical and that's the number that's keeping you out of consideration of a 52.

If you had to live with these number (665 & 475) then the bike is a 54cm with a 90mm stem in the -17deg position, 20mm of spacer under that stem and 15mm of aerobar pedestal, and the pads mounted 1 hole forward of center.

If you have more questions please get back to me here.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hi Ian,

addition I should have made to my original post, I currently use draft legal tri bars on my road bike for a tri position, and although the position is far from perfect (restrictions with draft legal etc.), if it may help gain a picture of where I am as well as the aforementioned height, inseam, saddle height etc I thought I should add it here.

cheers,
Tommy

Tommy,
Let me just check in on two things...1) you're 180cm tall, your inseam is 84cm, and your saddle height is 793? This is a moderately unusual combination of numbers and I want to confirm before I proceed. 2) You are looking to acquire a Quintana Roo Tri Bike - are you thinking a PRsix or a PRfour/PRfive?

I'll get back to you quickly.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan