Hi, I am looking @ a 2018 QR PR6. It is a 52cm. My BMC road bike is a 51. I am 5'7 1/2"; inseam 30.5"; my road bike seat height is 28.5" from BB and 36" from center of pedal. I have never had a tri bike before or been measured for X, Y, and Z. The QR site indicates 50 or 52 for 5'7", and 52 for someone 5'8". I am trying to confirm if the 52 is right for me, and if I get it maybe a good plan would be to take it to a fitter to dial in seat height, bars, pads, and crank. Do you have any thoughts on this? Thanks.

I would recommend getting a proper fit before buying a bike.

allblacks,
I have very strong thoughts on this....
The absolute best way to buy a tri bike is to GET FIT FIRST. And this is one of those things where you either do it right or not at all: go to a fitter who checks off these three boxes: they are educated in tri fit, experienced in tri fit, and they MUST own a dynamic fit bike*. Then you do fit, pay them whatever they ask, give them all your money because you'll leave with your exact Pad Y and Pad X telling you what will fit and what wont. Have them prescribe this bike you're interested in and 3 others. And you'll have all your fit coordinates (seat height, set back, cockpit detials, etc. etc. etc). The fit is done, you were part of the process, it's perfect - and you don't even own the bike yet!!!

*the dynamic fit bike is a critical piece of tooling. It's expensive and committed fitters purchase them becuase you simply cannot nail, dead-on a prescriptive fit without one. There are only really 5 of 'em: Shimano, Guru DFU, Purely Custom, Exit, and Muve. You need to interview the fitter, quiz them about where they tri fit education came from (they need to say Slowtwitch, Guru, Retul), ask them which dynamic fit bike they use (they need to name of of the previous), and ask 'em how many tri fits they do.

What I'm about to do it good but not as good as the above. Imma take what you've given me (morphology) and what you've left out (you didn't mention some catastrophic accident that left half your vertebrae fused or some such extreme thing) and I'm going to plug that into a formula, season with experience as a long time fitter and bike fit instructor, and over 2 decades of coaching triathlon full time and shazam... I've got some info to share. Again, it's good, it's not as good as the above...

I think your Pad Y is in the neighborhood of 600mm and your Pad X is roughly 460mm. A 2018 Quintana Roo PRsix size 50 will fit you and here are the options (because there's a few ways to arrive at these numbers).
To get our Pad X of 460...
You need either the 90mm stem or the 110mm stem. 2018 was a near year for a proprietary QR stem and they only made three lengths: 75, 90, 110
If it's the 90mm stem the bracket that holds the arm pads needs to be set rearward and then use the rear armrest hole.
If it's the 110mm stem then bracket goes rearward and use the middle armrest hole
To get your Pad Y of 600...
The stem has this clam shell system inside the base bar clamp. You should put one half of the clam shell on top the base bar and the other half below so you're in the "middle" setting. Then you only need you only need 10mm of arm pad pedestal to get to 600. Now this is a Profile-Design aerobar so it's easy to find bits you need to dial to perfection (bits= spacers and screws).

Some other notes to consider for your first tri bike. You must have a saddle that allows you to sit, in comfort on the front half of the saddle (look at any an all profile view pics of anybody at Kona and you'll see a lot of saddle behind their bum). You should ride 160mm cranks at the longest and prolly 155s so find our how long the cranks are on that bike and if they are longer, work the price down as you're gonna want shorter cranks.

Ian

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

Dear Mr. Murray,

I'm not sure if my recently purchased PRFive2 has enough clearance for 28mm tires.
Your help on clarifying this point will be enormously appreciated.

Thank you,
Rodrigo

Rodrigo,
Typically, I keep this thread to fit related issues but, I have some knowledge and opinion about this subject so I feel confident answering. 25mm tires will work in any and all cases. If you have a carbon rim that's wide... say inner width of 20mm+ and you put a 28mm tire on there.. the width of the rim + the width of the tire + the rim flex when out of the saddle and putting down heavy power can result in some rubbing of the sidewall of the tire on the chain stays of the frame. If you've got a narrow rim or an alloy rim with lots of spokes that typically won't happen with a 28mm tire.

Ian

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

Hi Ian,

I'm hoping to get some sizing advice on a PRsix2. It seems to be one of the only bikes that I might fit on...maybe.

Pad stack is 555
Reach to back of pad is 483

Thanks!

tpark,
For the QR PRsix2 you'd ride a size 48. To get the Pad Y right (very close) you'd set the stem, clam shell clamp in the low position; meaning the two halves of the clam shell would be on top of the base bar to push the base bar down and therefor your front end lower. And you use zero arm pad pedestals. You're slammed and the result is 560.

To get the Pad X right (or extremely close) you'd need the 110 stem, bracket forward, and arm rest hole mid-rear. That would yield 480.

Most fitters agree that 2-3mm is acceptable even in seat height (that's the difference between a bib short pad and a tri short pad). You're cockpit will be 3mm off and that's not a real worry. Your pad height would be 5mm higher...well, that's as low this bike will go.

Ian

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

Yeah, there's not much out there that fits those coordinates. 5mm is close...

Appreciate the response.

tpark,
While you're not a total outlier you're still long and low. Fewer bike makers are getting down there like they used to. Take a look at where you sit on this graph, it's interesting.
https://www.slowtwitch.com/...ld_Example_6852.html

Ian

---

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

That's interesting. When I plug in my coordinates (550 and 461) from a fit from 9 years ago, I'm just at the the "band of orthodoxy".

In any case, the reach is easier to solve for in most cases it seems. Stack, less so. It sounds like I might be best served to search for a bike with a conventional cockpit where I can swap in a lower rise stem.

That would mean a PR5 or PR4 but looking at the QR charts, the stack height is even taller even with the negative stem orientation. I'm guessing there are some repercussions to going with a stem that's even more negative and longer?

 

tpark,
If you go to a "mortal" bike - I use this term to describe a bike with a regular stem, one that can be swapped with hundreds of variations anywhere in the world... then you have more flexibility. A "super" bike has an proprietary design stem and you're a bit more limited there. So, for a Quintana Roo PRfive you could go beyond the Profile-Design stem -17 degree steam at 110 and get to or pretty close to your position. Frankly, I think 3-5mm off and being on the super bike is just so good that you make gains in other areas.

Ian

---

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

Hello Ian,

Pointed to this thread from Dan and hoping for some specifics on what QR bike may fit me and what "shopping list" I'd need for the surrounding components to hit my desired pad x/y coordinates.

Rider: 6'4" ~205lbs

Saddle: ISM PN 4.0
Crank Length: 165mm
Wheels: HED Vanquish RC Pro RC8/RC Disc 28mm tires

Fit Coordinates:
Saddle Height: 835 mm
Saddle Setback: -54 mm
Saddle Angle: 6.4 degrees
Arm Pad Stack: 660 mm
Arm Pad Reach (back of pad): 565 mm
Arm Pad Reach (middle of pad): 604 mm
Arm Pad Angle: 25 degrees
Saddle to Arm Pad Drop: -180 mm
Extension Reach: 900 mm
Extension Stack: 860 mm
Arm Pad to Extension Reach: 400 mm
Arm Pad Width: 160 mm c-to-c
Base Bar Reach: 600 mm
Base Bar Stack: 630 mm

Thanks in advance!

Hi LOW2000,

While I'm not Ian, I was trained by him a few months ago and just noticed there hasn't been a response yet, so I thought I'd take a stab at it and practice what he taught me!

You're clearly a tall rider, and achieving that PadX/PadY of 565/660 is proving a bit challenging. I went through all of QR's frames for you here.

I think the PR4/PR5 are out of the question. On a 56cm, you can achieve PadY of 660, but you'd need something like a 140mm, -17° stem to get to PadX of 565. On a 58.5cm, the lowest you can get is 682, then a 130mm, -17° stem would get you to ~561.

The V-PR also seems out of the question. While your PadY 660 is achievable, the PadX can only reach 533 with the Vision PRO and 522 with the Vision TFA cockpits; 30mm+ too short.
The X-PR with 1/Seventeen stem won't work either. Much like the PR4/5, you'd need an excessively long 140mm stem or something like that to get long enough.
The X-PR with QR Aero 110mm Stem and Aeria Ultimate Wing can only achieve PadX of 542; too short.

A PR6, 58.5cm with 110mm stem clamped in the lowest position (two half moons on top of the handlebar), zero spacers under your armrests, the armrests mounted all the way forward, and bracket orientation in the "forward " position can get you the closest to your measurements, within 5mm of each coordinate. This gets your PadX/PadY to 560/665.

One other thought is that these numbers were likely generated with 0° tilt to the pads. So your 25° tilt may actually correlate to a PadY 10-15mm higher on QR's coordinate charts.

Hope that helps! Ian, feel free to correct me if I missed something! =]

Once you add tilt (my calculator maxes at 20deg) none of the options get close

Hello Ian,

I am ordering my first triathlon bike and I am questioning which size X-PR. I had a bike fit with the below measurements and apparently am between sizes of 50 and 52. My fitter said either would work but that he’d go 52 because less risers would be needed. This will be my second year doing triathlons and I don’t have the greatest flexibility yet. I am 5’ 8” with a longer torso and shorter legs. What size would you recommend?
Thanks for your help,
Chad

Saddle height- 686mm
Saddle setback- -26mm
Handlebar reach- 466mm
Arm pad reach- 385mm
Arm pad drop- 12mm
Arm pad reach BB- 359mm
Grip reach- 718mm
Grip drop- 123mm
Arm pad to grip reach- 333mm
BB to grip reach- 692mm
Arm pad width- 264mm
Handlebar Stack- 630mm
Handlebar reach- 440mm
Grip angle- 26 degrees

do you have a video or photo in profile of you on a fit bike in your final position?

---

Dan Empfield
aka Slowman

Sorry I don’t.

What crank arm lengths were you tested on?

155mm, I did get confirmation from QR that 52 seems the best. Here’s hoping it fits like a dream!

honuvibe, okay firstly.... how can you be in your second year in triathlon and have the handle honuvibe - that's some veteran selection right there. Only the oldskoolers refer to "Ironman Hawaii 70.3" as Honu. I hope that's what your name links to and if so, I'm impressed!

We might need to go back and forth here a few times - be patient with me, work with me, I want to make sure you get the right bike.

You had fit done before you purchased - so great, thank you. I really only need three numbers from the fit to prescribe the bike. I need Pad X... and I think that number is represented here as "Arm Pad Reach BB - at 359mm" (sidebar - I'm betting this is from a Retul form). I need Pad Y and it's prolly in the neighborhood of 635mm and if I'm right about the brand name on your fit sheet it might be phrased as "arm pad stack BB".

Here's why Dan Empfield (Slowman) and the inventor of the triathlon bike, inventor of the terms Stack and Reach, responsible for the terms Pad Y and Pad X, father of Slowtwtich... If I'm a Master Bike Fitter, he's what? Godly Bike Fitter?... here's why Dan and now me are asking things like... can we see a picture of video of your fit?... is because some of the numbers are suspect. So I want to confirm some things first....

Based on your morphology (5'8" and shorter legs, longer torso) I'd expect your Pad X to be ~465mm. You're at 359. I wanted to confirm that so I took "Arm pad reach- 385" (I'd sort of expect that to be from tip of the saddle to the back arm pad) and mathed out your "saddle set back- 26" + "Arm pad reach BB- 359" = 385mm. So that does seem to be your Pad X from this fit. I have to ask myself.. why is the Pad X on a guy with a long torso so incredibly short. And just so you don't think that I'm grabbing at straws here... you've been recomended the size 52 the QR XPR - that item will not get to 359, not with any version of front end offered. It doesn't go that short (heck, the size 50 barely makes 359).... and if we go to a size 48 to meet this Pad X then the Pad Y wont go to above 653. And it's not QR, I don't know of a tri bike that'll meet those numbers. Take a look at the graph in THIS article and you'll see how litterally "off the charts" these numbers are. So, something is up here and I want to help.

Now, I don't see Pad Y listed but I can sort of guess... "saddle height - 686" - "Arm pad drop 12" would yeild a Pad Y of 674mm. That's a guess mind you.

If you can find a term on the sheet that resembles "Pad Y or "Arm pad stack BB" and is in the neighborhood of 635mm to 675mm. I'd like to hear about that AND I want to figure out what's going on here so...

What type of saddle were you on?
Where were you sitting on the saddle during the fit - back, middle, nose?
Did you ride easy the whole time or hard for a bit?
Was this fit done on a fit bike? Do you recall the name of that fit bike?
Did you feel powerfull - like you could really push down hard on the pedals or a little restricted?
Were you comfortable in the position reflected by the numbers above?

Let's say for example you wrote in and said "first tri bike, 5'8", short legs, long torse, not very flexible". I'd say.. okay, I think your Pad Y is roughly 635 and Pad X is about 465. You should get the QR XPR with the Profile Design 1-Seventeen Stem and Profile 35a aerobars, and the prescription is this... Size 52, 110 stem in the -17deg position with 15mm of spacer under the stem and 15mm of aerobar pedestal, and arm pads 1 hole forward of center. The reason why this works is because we are all far more alike than we are dissimilar- and there's room to move if I'm off by a bit. This set-up would allow you to go longer in your cockpit 20mm or shorter 40mm. This set up would allow you to go up 85mm higher in arm pads or down 30mm in arm pads - all with the prescribed hardware.

Get back to me when you can.

Ian

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

The arm pad stack BB is 683. You are correct this was done on a Retul. I unfortunately don’t know what seat was on it. There is a handlebar reach of 466mm? I believe I was sitting in the middle of the saddle. I only rode easy. I honestly couldn’t tell you if I felt like I could push down hard on the pedals, maybe restricted just a little bit?, I felt comfortable I guess but I wasn’t on it for a long time. He did recommend 155mm cranks. I’m sorry I’m not much help in explaining the feel. I also just think my torso is a little longer and legs are a little shorter but don’t have that verified. Thanks again for your help.

honuvibe,
If you're insistent with - "show me the bike that's right for me, my Pad Y is 683 and My Pad X is 385".. Then here's my answer.

Option A) QR XPR size 50 with a 110 stem in the +17deg position with 25mm of spacer under the stem and 30mm of aerobar pedestal and pads back 100%. That's it, that's the perscription.

Option B) QR XPR size 52 with a 90mm stem in the +17deg position with 30mm of spacer under the stem and 15mm of aerobar pedestal and pads back 100%.

Here's why I'm okay with you buying either of those bikes: I know this is not your ultimate position. You're most comfortable spot (that's always top priority), your most powerful spot (that's alwasy #2 for me), and your position with less drag - is lower and longer than 683/385. I'm betting it's closer to 660ish/420ish. It could even be 620/450 - and I'm okay with this because both of these bikes will go to those positions with all the same hardware when and if you're ready to make those changes.

I'm still deeply suspicious of your numbers for one, basic reason - you are normal. You're not weird enough to have such an unusual position. You would have stated the major, life-affecting thing in your post. Something like "I'm 5'8", short legs, long torso and......I have 7 fused vertebrea from a plane crash"... or "I was born and raised in that chemically soaked town that made Erin Brokovich famous and have deformaties"..or... "I was abducted by aliens, tested on, and returned to Earth forever changed". You're not saying any of those - and yet, 683/385 is abnormal. Again see where 683/385 lies on this graph https://www.slowtwitch.com/...ld_Example_6852.html

But, again, I'm okay with it becuase here's what I think will happen... you'll get the bike, ride it for 3 weeks and then go... "damn, I think I can pull some spacers and move the pads foward". That's 20 minutes of alteration with a micro multi-tool and boom, you'll be happier. Then 5 weeks later you'll think..."I keep creeping foward, my shoulders get sore from holding myself back. I think I could go lower still and a bit longer". You'll spend another 20 minutes with your multitool flipping the stem into the -17 degree postion, moving the pads foward another hole" and Shazam! Now you're loving it. So buy either the 50 or the 52 - seriously, in this situation both can meet you where you are now and go to where I think you'll want to be. And if the advice your fitter gave you "get the 52, fewer spacers" well, technically they're right the 52 has 10mm less in "upness".

One last, critical thing... the XPR can come with some super fancy front end options. You have to get the Profiel-Design, 1-Seventeen stem (it's a mortal stem, not a super stem) and the Profile-Design 35a aerobars. If you get any other version of this bike then your starting numbers are not possible and the ease of chaging position in the future will be harder and, becasue they will likely be done by a mechanic in shop, more expensive. Get the basic bar set up please.

Get back to me here anytime with more quesitons.

Ian

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

Were you tested with a noseless saddle?

I'm finally ready to buy a Triathlon Bike and i'm hoping you can help me out.

I have no idea where to start as i'm kinda pinched for time between work and raising two little kids. The QR website chat person told me i'd fit a 52cm X-PR, my local bike shop said i'd probably fit a 54cm Felt IA or B. Is this close enough to make a purchase?

I'm 45yo, pretty fit, 5 foot 9 inch 148 pounds living in north/central NJ. 79cm inseam. 95cm saddle height from floor.

My current bike is a 54cm 2009 Trek Madone with clipon aero bars which i had to buy a longer seat tube for because the original one it came with was just over the maximum safe height. I ride this bike about 4-6hrs per week and did IMMD and IMLP on it in 6hrs and then ran a 4hr marathon so i'd say my current fit is pretty good for a road bike.

Any help is appreciated. Let me know if you need more info.
EDIT, if you click the link to my bio i added some pics of me on my current bike.

What are your fit numbers?