# 585 Sizing Help: 51 or 53cm?



## 1speed_Mike (Feb 16, 2004)

I'm hoping you guys can help. I've got an opportunity to get a brand-new 06 585 53cm frame/fork. However, I'm trying to decide if I should be on a 51 or 53cm. After reading through this forum, I've gone back-n-forth. 

I currently do not have a road bike, but my previous bike (a custom 1999 Seven Ti Axiom, which I sold 4-yrs ago to get a FS-XC MTB) has the following specs against the Looks [51/53]:

Seven Ti Axiom [Look 585s 51/53]
Seat Tube Length (c-ceff) = 50.5cm [A1 = 51.0/53.0cm] <-- this dimension looks wrong on Look's pdf
Seat Tube Length (c-t) = ~52.0cm [A = 47.6/52.1cm] <-- this dimension looks wrong on Look's pdf
Top Tube Length (c-ceff) = 54.1cm [B = 53.0/54.5cm]
Head Tube Angle = 73.0 [I = 72/73.0]
Seat Tube Angle = 74.0 [J = 74.5/73.75]
Head Tube Length = 9.9cm [K = 12.5/14.8cm]
Bottom Bracket Height/Drop = 6.8cm [HAV = 7.0cm]
Chain Stay Length = 41.0cm G = [40.5cm]
Stand-over Height = 78.1cm [73.1/76.4cm]
Wheelbase = 985mm [?]

There's something weird regarding the geometry numbers listed at Look: 

http://www.lookcycle.com/products/geometrie/585_2007_geometry.pdf

That is, in looking at the 53cm, how is it that A (521), which is shown to be the longest seattube dimension, is less than A1 (530)? Can someone verify these actual dimensions for A (c-t), A1 (c-ceff) and A2 (c-c) on a 51 and 53cm 585? I think that they should be A = 530; A1 = 521; and A2 = 495 for the 53cm, not as listed in the chart.

Stem on my Axiom was 100mm x 90-degree.

I'm 5'6 with a 30.5" cycling inseam. 

The 53cm gives me approximately the same TTeff (albeit, slightly longer 0.4mm). It also appears to have more standover than my Axiom. 

The 51cm would allow more exposed seatpost; however, the TTeff would be over 1cm shorter. And, the angles start to deviate from the Axiom's.

I'm not suggesting that the Axioms specs are the Holy Grail, but they are all I've got and should be an excellent baseline.

Unfortunately, I cannot find any Looks in my area in my size. 

The closest thing I've got now in my stable is my 53cm Empella Bonfire CX bike. It's got a 53cm ST (c-t), 49cm ST (c-c), 52cm Teff and I'm running a 110mm Ritchey stem. 

On my CX, I'm running the seat at 69.5cm (top of seat to center of BB) with 175mm cranks. So, I'd be ~70cm with a shorter set of road cranks (170-172.5mm). 

I like how my CX bike rides. But, with a 52cm TTeff, it's OK for CX, but would be too cramped for road. So, I'm definitely looking for something longer than 52cm. The 51s 53cm TT would give 1cm more in TTeff, while still running a 110mm stem. 

The c-t dimension on my Axiom ~52 and 53cm on my Empella. I gather the A dimension is actually 53cm, which would be the same as my Empella. If so, it's got enough exposed seatpost to be considered normal. 

Anyway, that's it in a nutshell....just trying to make sure I buy the right-size frameset.

Thanks in advance!

M.


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## C-40 (Feb 4, 2004)

*too big...*

The bottom line is the 53cm is too big for you. You need a 51cm. I'm also 5'-6" tall, but my saddle is 3cm higher and I ride a 51cm, with a 110mm stem.

The TT length on your Axion is obviously longer than you need since you're using a short 100mm stem.

Correcting for the difference in the the STA, the 51cm LOOK only has about 5mm less reach than your current bike. If you used a 110mm stem, it would still have more reach than your current bike.


As for the confusion in the dimensions, it's a problem with a "universal" drawing. The A1 dimension is the c-c distance for a horizontal top tube (traditional frame sizing). The A dimension is the actual length of the entire seat tube, which should be less, since the TT is sloped down. The A1 dimension would be well above the A dimension with a typical sloped TT frame. 

I have found some minor errors in the geometry chart however. The actual A dimension for a 51cm is about 484mm to the top of the seat post clamp.


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## 1speed_Mike (Feb 16, 2004)

C-40 said:


> The bottom line is the 53cm is too big for you. You need a 51cm. I'm also 5'-6" tall, but my saddle is 3cm higher and I ride a 51cm, with a 110mm stem.


Thanks, C-40...I was hoping you'd chime in!

I noticed your new red 585 and it's set-up. You run your seat on your 51cm about 2.5 (1in) higher due to your longer inseam (although, we are the same height). I don't have your flexibility, so I can't expect to get the 9cm drop you do. I typically have less than 2" (5cm). 



> The TT length on your Axion is obviously longer than you need since you're using a short 100mm stem.


With that said, what's the ideal stem length I should be looking at? 110mm? Rise? Number of headset spacers?

I typically don't run more than 2cm of spacers under my stems.



> Correcting for the difference in the the STA, the 51cm LOOK only has about 5mm less reach than your current bike. If you used a 110mm stem, it would still have more reach than your current bike.


By current, are you referring to my Axiom or Empella? I haven't had the Axiom for years and now only have the Empella Bonfire cyclocross bike as my closest bike to a roadie (I'm a MTB'er).



> As for the confusion in the dimensions, it's a problem with a "universal" drawing. The A1 dimension is the c-c distance for a horizontal top tube (traditional frame sizing).


Yes, this is the intersection of the effective TT (if the TT was horizontal) and the ST. This would be equivalent to the 50.5 c-c measurement on my Axiom (it had a horizontal TT).



> The A dimension is the actual length of the entire seat tube, which should be less, since the TT is sloped down.


This dimension should be the longest since it's the actual entire length of the seat tube, which is longer than A1 dimension. 



> The actual A dimension for a 51cm is about 484mm to the top of the seat post clamp.


Thanks....so, this compares to the 52cm on my Axiom (c-t). Almost 40mm diff!

M.


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## C-40 (Feb 4, 2004)

*more...*

By your current ride, I meant the Axiom. 

Since the initial setup of my 585, I've raised the saddle about 1cm, so I now have about a 10cm drop to the bars, using an 84 degree stem and 5mm of spacer. If your saddle height is 70cm, it's 3cm less than mine. That means you you need about 2.5cm of spacer with an 84 degree stem or only about 5mm of spacer with a 96 degree stem to get a 5cm drop. A 90 degree stem (not many of those made) would require about 1.5cm of spacer.

As for stem length, it could be either a 100 or a 110mm, since the reach is in-between stem sizes, compared to your axiom.


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## rensho (Aug 5, 2003)

While I don't know your true body dimensions, it sure does seem like a 53cm 585, and the geometry given for the axiom are both too big for you. From your dimensions, you seem to be very proportional, or at least not out of whack. I mentioned this in PM as well.

It is too bad you don't have a dealer/owner near you to ride either size.

I'm 67.5" tall (31.3" riding inseam). First, wow you guys run tall saddles. I'm at 70cm, and that comparatively seems high to me, looking at other riders, and the guys on the Tour. I'll leave it at that. I know it is more involved than that, as well as personal pref.

On my 53cm, I was on a straight post with a 100mm stem(tried a 110 and it was too long), and always felt the TT was just right or 5-10mm too long, provided the seat was in the middle of the seat rail. Even with this, KOPS was just right over spindle, whereas, I really would have like to run 5+mm behind spindle.

In the end, the 51cm sure fits me better by the numbers. I still need some seat time to get familiar with the new size.


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## scotbike (Dec 20, 2006)

With reference to the original query re the size chart being mixed up - yes you are correct the A1 and A are mixed up. I have a 585 53cm and the measurement c/c BB to top of clamp is 530, the the effective cc is actually 521. So A should be 530 and A1 521.

Re what bike fits you - I am 5'7" with a 31" inseam and have a 53cm bike - it is too big and I am changing it. The important measurement is the top tube and I need 530 effective length (B), I have 545 at the moment forcing me to use a 90 stem with the saddle railed forward and up to the stops. We have the same approx proportions and I am sure you will fit a 51cm. Go to the following link - http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO

Take 20 minutes to go throught this fitting process and use the 'competitive' result. I found it to be excellent and very accurate - even down to the stem length and saddle set back recommended. I am going with the Ultra this time around - same money and apparently 15% stiffer. The 585 is a great bike, althougth I have found it to suffer creak from time to time, but I guess this is carbon thing you need to work with. Best of luck, enjoy your bike!


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## 1speed_Mike (Feb 16, 2004)

Thanks for the reply.

Well, I guess I've got to the let the deal on the 585 go....I'm not going to compromise fit. And, based on all of the above, it looks like the 53cm would have been too big.

So, now I'm on the hunt for a 51cm!

M.


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## 1speed_Mike (Feb 16, 2004)

Well, 9-months later, I'm now re-looking at buying a 585 Ultra (07/08). I was still contemplating on sizing, but then remembered this cool site I stumbled across years ago: https://www.xcontario.com/bikeCAD.html. So, I plugged in the Small and Medium numbers and here are my virtual 585s...I'm going to be ordering a Small (51cm):

Small (51cm):









Medium (53cm):


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## rensho (Aug 5, 2003)

Cool site. Would you update the 53 with the trail numbers? Or did I miss it? Look has it at 58.2mm.

I'd like to know for myself why the 53 is so much more stable. By the above diagrams, a 73d should make the less stable.
I see on Look's site, the STA is different from what you have above.


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## 1speed_Mike (Feb 16, 2004)

rensho said:


> Cool site. Would you update the 53 with the trail numbers? Or did I miss it? Look has it at 58.2mm.


I updated the pic to show the trail. 



> I'd like to know for myself why the 53 is so much more stable. By the above diagrams, a 73d should make the less stable.
> I see on Look's site, the STA is different from what you have above.


The HTA/STA were inputted as per Look's data (HTA/STA = 72/74.5 on 51; 73/73.75 on 53), but were just shown rounded in the dimensions.

Edit: I've increased the decimal place to 1 and updated the pics.


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## Crit-Licker (Jun 14, 2007)

You never said just how good the deal on the 53 was. Although the 51 is obviously more optimal from a fit standpoint to a certain degree either would work. I rode a 50cm back in the racing days but sometimes raced on my son's 54 Merckx and it worked fine. Of course as old armchair punters we have the luxury of making our ride fit as exactingly as riders in the pro peloton. We can also purchase bikes just as exotic even if our abilities aren't so exotic anymore.

If you are going to get a Look I would recommend viewing the DVD enclosed with their 2008 products. Compares favorably to the material on the Cervelo website but has that particular joie de vivre of the French. A real class act. I ride a quiver of S-works but would love to transfer a kit to a 595 or 585 ultra. Cutting the seatmast would have to be precise of course.

- CL


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