open topic, for anything cycling related.
I am trying to choose which frame size of the 2013 Bianchi Infinito (61cm vs 59cm) and ask for your help....
I am not wanting to go down the Sempre Pro route.
I have also reviewed numerous bike-fit sites....
I want to ride distances of 100km and beyond in an aggressive low profile riding position.
My body dims:
- Height 188.6cm
- In-seam 87cm
- Torso length 69cm
- Arm reach 70cm
- Total reach or top tube + stem ([(Torso Length + Arm Length) / 2] + 4") 79.6cm
The following differences in bike dimensions between these frames exist:
effective top tube - 57.5cm
effective seat tube length - 59cm
head tube length - 205cm
front centre - 607cm
effective top tube - 58.5cm
effective seat tube length - 61cm
head tube length - 225cm
front centre - 612cm
Your thoughts on which frame size to suit my application??
I'm 188.5 cm and went for a 61 cm frame with a 58.5 cm top tube when I bought mine, and the end result was having to fit a 90 mm stem to make the bike fit comfortable.
I really wish I had gone for a 59 cm frame instead of the 61 cm.
It’s much easier to make a frame that is slightly too small fit comfortably, than a frame that is a fraction too large.
Thanks very much guys.
- How do your other body dims noted in OP compare to mine?
- What is the impact of going to a smaller head stem at 90cm?
- How do you find the longer head tube in long rides?
- What stem would you have fitted if you had the 59cm frameset?
- How would the shorter Front Center dimension on the 59cm benefit (if at all)?
probably quicker handling and more responsive turn in to the corners. Chain stays are the same length,and the HTA on both is 72.5 (and I would assume the fork trail is the same on both), according to the geo charts, so wheel base is slightly shorter with weight distribution pushed slightly to the front because of the front centre dimension.
I guess I now need some clarification on reach between these 2 framesets.
Greyhoundtom states the increased HT increases reach. You have stated the reach is the approx. same due to slightly different seat angles....
Also - What is an optimal saddle - handlebar height for low profile aggressive riding to take advantage of the lower HT on the 59cm frameset?
I'm a fledgling bike fitter and sports physio by trade. My thoughts and questions for you;
How flexible is your lumbar and thoracic spine?
How do you quantify such a thing?
Are you a strong, mild or neutral heel dropped under load? Or the more rare toe dropper? This will affect seat height drastically and as such, bar drop and whatnot.
Are your legs "functionally long" on the bike? That is, do you have any idea when your seat height is too high? Measuring angles on a computer doesn't count here unfortunately. If your neural or mechanical length of hamstrings prohibits you from tilting your pelvis anteriorly on the seat, it will cause a shorter effective torso length and vice versa.
I'm not trying to be an ass about it, but the simple fact is - the way you interact with the bike can NOT be determined in any meaningful way by measuring yourself with a tape. Vast differences exist in terms of functional reach depending in large part on how your pelvis sits, how easily it rotates forwards and how well your spine flexes.
Your best bet is, quite simply, to go and sit on each one, pedal on a trainer for a while and see how you feel. An even better idea is to get a quality bike fitter to assess you on your current bike and then match the geometry to whichever frame suits best. For an expensive bike that may last you for five years, this is a good idea!
Reach is the amount of top tube in front of the BB. Maybe Tom and I are describing different things. You have probably seen this stuff, but the Cervelo site has a good description of stack and reach. Given that we generally position our saddles relative to the BB, this wont change on either the 59 or 61. You would have you seat further forward by some amount on the 61 to achieve the same relationship to the BB (you dimension are constant in all this) as the extra cm of TT is accounted for behind the BB in the frame set back, which is the proportion of the TT behind the BB.
http://www.cervelo.com/en/engineering/t ... d-fit.html
Anyway, I think Neill has the right idea, first you should establish if you are designed to ride a low, aero, and aggresive set up.
Unfortunately, no Bianchi dealer in Australia will stock the 2013 Infinito.
They will only supply the frameset after you order it, so it is impossible "to go and sit on each one".
I ride 550km per month and so I do not have a need to "pedal on a trainer for a while and see how i feel". I have core strength, I stretch well and I am flexible.
I do understand what you are saying and your ideals are fine in an ideal world.
TDC - Thanks for the link! I currently ride the 2007 928 bianchi in the low aggressive, aero setup with a 60mm height gap between the saddle and handlebars, 155mm Head Tube without any spacers and a 100mm Head Stem. Been doing this now for 2 years.
Last edited by Krank on Sun Dec 02, 2012 8:09 pm, edited 2 times in total.
ok - thanks TDC.
Can you give me the link showing the 928 dims of this HT? I cannot locate it.
My 57cm frame measures to the published 57cm frame with the other members. Perhaps the 55cm and 57cm frame share the same HT for the 928?
I feel that my current 57 frame is too small for me.
Last edited by Krank on Sun Dec 02, 2012 8:07 pm, edited 3 times in total.
Sorry - This is the bike I have - 2006 928 RC - 57cm.
http://www.bianchiusa.com/archives/2006 ... gedchorus/
are you able to calculate stack and reach on both my current 2006 RC 928 and my proposed 59cm 2013 Infinito?
it would be interesting to observe the differences...
mmm perhaps I may look at the 57cm frame on the infintio?
or just keep my existing bike??
but, i am real keen on having EPS and SR 11 speed gruppo.
My existing bike just feels too small.
Last edited by Krank on Mon Dec 03, 2012 8:16 am, edited 1 time in total.
You are currently riding a 57 cm framed bike and yes that would feel too small for someone with your body dimensions.
Because you are used to riding a relatively small frame going to a 59 cm frame will make a difference, and it certainly will feel larger, more comfortable, and slightly less aggressive due to the reduction in the top of saddle to top of handle bar dimension.
Going to a 61 cm frame would IMHO be too big a jump in size, and may actually feel a bit too large considering you are used to a 57 cm frame.
In your shoes my choice would be the 59 cm frame.
Yes, I know my back is not angled correctly when I am on the current bike and my arms splay out too much.
Do you actually own the 2012 infinito or another bike in the 61cm frameset?
No mate my bike is an old model Fuji, a 61 cm 2007 Team that I have since upgraded with an Ultegra groupset, CF handle bars, and a CF seat post.
However the geometry is very similar in regard to seat tube angle and effective top tube length.
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