# Geometry questions for small size



## gojita (Jan 25, 2007)

I'm 5' 7.5" with a 31.5" inseam but a longish torso and arms which puts me in-between sizes on the 595 that I am looking at. I can go with a medium which can easily duplicate the current setup of my 55cm bianchi 928sl (55cm top tube, 110 stem, 2.25" drop, no setback) but this would mean cutting the seat tube pretty short (saddle height is 71.5 cm from bb). 

Alternatively I could go with the small and a longer stem, but I'm a bit concerned about the geometry. The M/L/XL frames are reasonably balanced between the STA and HTA but the S has a big difference between the steep STA and slack HTA with more trail then the other sizes as well. Can anyone comment on the differences in handling? Would I even experience much of a difference once the saddle is setback to correct for the STA difference from my current bike (73.5)? Are there any problems I should anticipate going with a smaller size/longer stem than what I'm used to or does that not really matter as long as the reach works out okay?


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## C-40 (Feb 4, 2004)

*the small..*

Your inseam, at 80cm is 3cm less then mine, and you're only 3cm taller. I ride a size S (51cm) 585. My saddle height is in the 73-74cm range with a larger 10cm drop to the bars. The medium would be too large, IMO.

You didn't post the seat tube angle on your Bianchi, but each degree that the STA on the LOOK is steeper, effectively lengthens the reach by about 8mm and move the seat rail clamp forward about 1cm. The e-post seat rail can be moved back up to 1.5cm from it's nominal position, so the STA should not pose a problem. If by no setback, you mean that you use a non setback seatpost, then your seatpost clamp is probably a little more forward than the nominal position on the e-post.

As for the steering geometry, I find it quite well balanced. It responds plenty quick in tight corners on mountain descents.


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## rensho (Aug 5, 2003)

gojita said:


> I'm 5' 7.5" with a 31.5" inseam but a longish torso and arms which puts me in-between sizes on the 595 that I am looking at. I can go with a medium which can easily duplicate the current setup of my 55cm bianchi 928sl (55cm top tube, 110 stem, 2.25" drop, no setback) but this would mean cutting the seat tube pretty short (saddle height is 71.5 cm from bb).
> 
> Alternatively I could go with the small and a longer stem, but I'm a bit concerned about the geometry. The M/L/XL frames are reasonably balanced between the STA and HTA but the S has a big difference between the steep STA and slack HTA with more trail then the other sizes as well. Can anyone comment on the differences in handling? Would I even experience much of a difference once the saddle is setback to correct for the STA difference from my current bike (73.5)? Are there any problems I should anticipate going with a smaller size/longer stem than what I'm used to or does that not really matter as long as the reach works out okay?


I'm your exact height and inseam. I had a medium 585 and sold it for a Small. I run a 71cm saddle height.


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## gojita (Jan 25, 2007)

*what about head tube?*

Thanks for the replies.

rensho, did you have any problems with the short head tube? How much drop do you run, I tend to be somewhere between 6 - 7 cm. and am a little worried about the spacer stack. Also, what stem length did you end up with, a 12 cm? How do you find the handling?


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## C-40 (Feb 4, 2004)

*spacers...*



gojita said:


> Thanks for the replies.
> 
> rensho, did you have any problems with the short head tube? How much drop do you run, I tend to be somewhere between 6 - 7 cm. and am a little worried about the spacer stack. Also, what stem length did you end up with, a 12 cm? How do you find the handling?


Firguring out the spacer and stem angle setup should be simple. You have a bike now with a certain length from the base of the fork to the bottom of the stem. Measure that and compare to the LOOK. The small size has a 125mm head tube, plus a 15mm headset top section, for a minimum length of 140mm with no spacers. Up to 3cm of spacer can be added to that. There may also be stem angle changes possible, depending on the angle you have now. Producing a 6-7cm drop with the inseam you posted should be no problem, but an actual saddle height would be better information.

As for the stem length, the small 585 will require only one size longer stem than whatever you use now. Although the TT length is 2cm shorter, the steeper STA reduces the reach difference to only about 1cm.


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## gojita (Jan 25, 2007)

*have done the math*

Thanks C-40...

I actually had that info buried in the first post (71.5 cm seat height) and have measured the front end of my current bike, it looks like I can produce the same drop with about 2.5cm of spacers on the small, unless I move to a stem with a little bit of rise as I currently don't have any. I'm certainly leaning towards the small based on all of this feedback.


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## C-40 (Feb 4, 2004)

*spacers..*



gojita said:


> Thanks C-40...
> 
> I actually had that info buried in the first post (71.5 cm seat height) and have measured the front end of my current bike, it looks like I can produce the same drop with about 2.5cm of spacers on the small, unless I move to a stem with a little bit of rise as I currently don't have any. I'm certainly leaning towards the small based on all of this feedback.


I would recommend the very common 84 degree stem, like a Ritchey 4-Axis. Then you might need only about 1.5cm of spacer. The actual handlebar height would be about 88cm from the floor to the top of the bars. If you need an 89cm heihgt, 2.5cm of spacer would do it.


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## rensho (Aug 5, 2003)

gojita said:


> Thanks for the replies.
> 
> rensho, did you have any problems with the short head tube? How much drop do you run, I tend to be somewhere between 6 - 7 cm. and am a little worried about the spacer stack. Also, what stem length did you end up with, a 12 cm? How do you find the handling?


I run a 110 stem with a 50mm saddle drop. The handling is very fast, but not twitchy. The medium was more stable at speed, but the small is much quicker handling. I run a 20mm spacer under the stem.


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## protocam (Aug 14, 2007)

Hello Gojita - Don't your fit issues point to a 585 Optimum? I'm in the same boat - about
5 - 8.5 with a 32" inseam. I have a short torso and arms and find most bikes that accomodate my longer legs to be too long in the top tube. Bikes that fit in the top
tube (about 53-54) put me "ass high" with too much drop. I like about 2". The numbers
on the web page for the Optimum look like some one customized it for me and I'm
waiting for my local LBS to get one in. On another note, since you have long legs
and "longish torso and arms, shouldn't you be taller?


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## gojita (Jan 25, 2007)

*opposite problem*

protocam:

I actually have the opposite problem -- short legs with a longer torso and arms, though not dramatically so, I'm pretty evenly proportioned. Normally I would jump on the medium 595 but I don't want to cut the seat tube so short. From everything I've heard here, the small 595 sounds like the ticket and I've found a place with a small 585 in stock so that I can get an idea of how the 595 would work out. Smalls are tough to come by, everyone has mediums in stock but that seems to be about it.

Thanks everyone for all of the feedback!


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## bigtino (Nov 5, 2004)

*Fit is very important!*



gojita said:


> I'm 5' 7.5" with a 31.5" inseam but a longish torso and arms which puts me in-between sizes on the 595 that I am looking at. I can go with a medium which can easily duplicate the current setup of my 55cm bianchi 928sl (55cm top tube, 110 stem, 2.25" drop, no setback) but this would mean cutting the seat tube pretty short (saddle height is 71.5 cm from bb).
> 
> Alternatively I could go with the small and a longer stem, but I'm a bit concerned about the geometry. The M/L/XL frames are reasonably balanced between the STA and HTA but the S has a big difference between the steep STA and slack HTA with more trail then the other sizes as well. Can anyone comment on the differences in handling? Would I even experience much of a difference once the saddle is setback to correct for the STA difference from my current bike (73.5)? Are there any problems I should anticipate going with a smaller size/longer stem than what I'm used to or does that not really matter as long as the reach works out okay?


According to your height and inseam the Small( 51.7cm TT & 66cm SaddleMast) 595 will work just fine with the E-Post. It provides 7.5cm of height when inserted without any spacers. You'll be able to accomplish your desired saddle height. My measurements put your optimal saddle height at 70.7cm. If you think you will ever want to lower your saddle for any reason make sure to factor it in before cutting the seat mast. The E-Post offers 3 cm of upward adjustability with the use of spacers. It would be good to know the length of your sternum notch from the ground while standing with feet shoulder width apart. Then measure both arms from the inside of your arm pits against the rib cage out to the webbing of your thumbs. These measurements will help to see what your optimal cockpit length should be and from there we can asses what stem length would be ideal. I think you would want to run the E-Post slightly set back (1.0 - 1.25cm) with a 120mm stem to accomplish a similar length to your Bianchi. You will find that the smaller frame will feel slightly quicker to respond due to it's slightly tighter geometry. We can discuss all this further by email. I'm at [email protected].


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## rensho (Aug 5, 2003)

Someone asked for my bike measurements and pics.

Bar height is 91cm. Seat height from ground is 95cm.


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