# 585 sizing question, don't give up... :-)



## ilan_a (Aug 13, 2005)

As usual...I'm 173 cm high end 80 cm insem what frame size i need.
I'm totally confused from the drawing in LOOK site

Thank's in advance

Ilan


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## C-40 (Feb 4, 2004)

*a 51cm...*



ilan_a said:


> As usual...I'm 173 cm high end 80 cm insem what frame size i need.
> I'm totally confused from the drawing in LOOK site
> 
> Thank's in advance
> ...


Based on your short inseam of only 80cm, you need a 51cm. I assume that this is a cycling inseam, not a pants inseam, so your saddle height is about 70cm, as measured from the center of the BB to the top of the saddle, along the center of the seat tube?

The drawing may be confusing, but it's really quite simple. The A1 dimension is the conventional (horizontal TT) center to center frame size. The A dimension is the total seat tube length, which will be less, since it's a sloped TT frame. On the 51cm frame, the A dimension should be 486, not 476mm, although is makes no difference in the fit of the bike.

The B dimension is the standard horizontal TT length. The other important dimensions are the head tube length K and the seat tube angle J. When comparing to another frame, keep in mind that the HT length does not include the 15mm top section on the headset, so the total length of a 51cm frame's HT is 140mm, without any spacers.


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## ilan (Nov 27, 2006)

ilan_a said:


> As usual...I'm 173 cm high end 80 cm insem what frame size i need.
> I'm totally confused from the drawing in LOOK site
> 
> Thank's in advance
> ...


Hi ilan, nice to meet you! I decided to get a Look frame after much study of various frame geometries. The point is that the Look 585/595 geometry in size 51 is the best for my size: 77.5 inseam and 1.77 height, that is Look is best suited for people with short legs and long torsos. In particular, the 51cm Look has a 53 cm top tube but with a 74.5 seat angle, which converts to a 54.5 cm top tube, if the seat tube had a 73cm angle. As you can see, this is quite a long top tube, e.g., if you compare with a Cervelo 51cm frame with has a 73 cm angle and 53 top tube. Most of the other bike manufacturers will have a slacker seat tube in that size, but with 53cm top tube, yielding a shorter effective top tube than Look. An exception is the Colnago 52cm frame, which is almost identical to the Look. (I am ignoring the fact that headtube angle also comes in to the equation). I therefore suggest you consider other companies with otherwise quite similar products, e.g., Time, which has a 74 degree seat tube with 53 top tube, so a shorter effective top tube. 

Just so things are clear, I will briefly explain the importance of effective top tube. The basis is that your saddle setback (horizontal distance between saddle and bottom bracket) will be the same no matter what frame you choose, so what counts is the length of the top tube section in front of the bottom bracket. This quantity can be measured directly (the "reach" as described on the Cervelo website) or can be compared indirectly with a fixed seat tube angle, as I did in the previous paragraph. Thus, you would need a bike with a short reach, whereas I would need one with a long one. This is explained quite well on the Cervelo website, in the section on their philosophy of bike fit. 

Thanks,

-ilan


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## ilan_a (Aug 13, 2005)

*Great answers great thenks*

I must add 2 parameters to the equation

First I have a big refund in a bike shop that importing Look & specialized.......

Second I'm not at all a racer ,I ride more for pleasure & fitness 
with this 2 parameters I need to find the best for me
yours answers are graet, if u have more advice I will be more then happy
and is my plesuer to meet you !

Ilan


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## ilan_a (Aug 13, 2005)

thenks = thanks...


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## ilan (Nov 27, 2006)

ilan_a said:


> I must add 2 parameters to the equation
> 
> First I have a big refund in a bike shop that importing Look & specialized.......
> 
> ...


I'm pretty sure that the Specialized Roubaix will be a better choice for you than any of theLook bikes. It has more comfort elements, like a lower bottom bracket (4mm), longer chainstays (1cm) and a longer headtube, and I think it has shock absorbers (so does the 595, but...). I looked at the Specialized geometry briefly, it's not clear to me whether you should used the smallest size or the next one up. I didn't mention that your effective top tube length is also dependent on your femur size (the longer the femur, the more your saddle setback), so that should be taken into consideration. In any case, no matter what bike you pick, I think you will need to get a short stem, on the order of 9cm. 

Good luck biking in Israel, from everything I've heard, it either extremely dangerous, or downright illegalne triathlon champion was killed by a car even with a support vehicle, and one olympic team member, Leah Goldstein, was stopped by the police for illegal riding, that is, riding a bicycle for pleasure or sport. 

-ilan


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## ilan (Nov 27, 2006)

ilan said:


> It has more comfort elements, like a lower bottom bracket (4mm),
> 
> -ilan


I wonder if people realise that a higher bottom bracket results in a longer effective head tube. In other words, given two similar bikes, the one with a higher bottom bracket will require a higher stem height, since you are sitting higher from the center of the wheels.

-ilan


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## ilan_a (Aug 13, 2005)

ilan said:


> I'm pretty sure that the Specialized Roubaix will be a better choice for you than any of theLook bikes. It has more comfort elements, like a lower bottom bracket (4mm), longer chainstays (1cm) and a longer headtube, and I think it has shock absorbers (so does the 595, but...). I looked at the Specialized geometry briefly, it's not clear to me whether you should used the smallest size or the next one up. I didn't mention that your effective top tube length is also dependent on your femur size (the longer the femur, the more your saddle setback), so that should be taken into consideration. In any case, no matter what bike you pick, I think you will need to get a short stem, on the order of 9cm.
> 
> Good luck biking in Israel, from everything I've heard, it either extremely dangerous, or downright illegalne triathlon champion was killed by a car even with a support vehicle, and one olympic team member, Leah Goldstein, was stopped by the police for illegal riding, that is, riding a bicycle for pleasure or sport.
> 
> -ilan


Hi Ilan

I know that the Roubaix us more comfort bike, I just wont to upgrade my tarmac that have factory defect (and not comfortable for me) to European frame...

About dangerus in our roads I think living in Israel is quite dangerus without biking  
but we definitely have serious problem with mentality of drivers in Israel. most of my rides is in early saterday morning, for the police I can say more or less I'm working in the police...

And again Grate Thanks for your opinions 

Ilan


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## ilan (Nov 27, 2006)

ilan_a said:


> Hi Ilan
> 
> I know that the Roubaix us more comfort bike, I just wont to upgrade my tarmac that have factory defect (and not comfortable for me) to European frame...
> 
> ...


OK, if you are set on the KG585, then be careful about getting the Look seatpost (Ergopost) with it, because it has a lot of setback. In other words, get another non-setback seatpost, if you don't need setback. 

Good luck with cycling in Israel, be careful of religious extremists on those Saturday rides 

-ilan


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## ilan_a (Aug 13, 2005)

ilan said:


> OK, if you are set on the KG585, then be careful about getting the Look seatpost (Ergopost) with it, because it has a lot of setback. In other words, get another non-setback seatpost, if you don't need setback.
> 
> Good luck with cycling in Israel, be careful of religious extremists on those Saturday rides
> 
> -ilan


By the way, I saw the Roubaix geometry (size 52) the TT is 53.7 with 74 seat angle almost like 585...the smaller size certainty small. I'm not set yet, I hope to take a decision soon.

For the religious extremists u should know that I ride very fast when a stone follow me (good sprint training) ... 


Ilan


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