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Picking from two similar sizings on the same frame(5 posts)

Picking from two similar sizings on the same framecollinsc
Jun 20, 2002 4:19 PM
So the LOOK KG361 has caught my eye as of late, but Im having some trouble figuring out which of two sizes I should be looking for. They are identical (or nearly) in most aspects, except for seat tube angle and I imagine, though it is not stated, stand-over height.

The 55cm has
Top Tube: 561
HT angle: 72.5
ST angle: 74
C to C: 550
C to T: 570

and the 56cm has
Top Tube: 559
HT angle: 72.5
ST angle: 73
C to C: 560
C to T: 580

I guess the biggest question would be whats the real difference between the seat tube angles? If it makes any difference for comparison purposes, my current bike has a 73 degree STA.

I imagine that the 56 would be the tallest of the bikes, made for the people with longer legs, but either of these lengths would work for my 32cm inseam and perfered high seat positioning.

If all those points are moot, would the only difference then be that the 56cm has 1cm less seatpost showing for a given leg length?

Thanks for any insight you can offer.
I always heard that....tronracer
Jun 21, 2002 4:55 AM
for racing, go with the smallest bike you can fit on.

Just my two bits,

Marco
both are too large, STA is the same....C-40
Jun 21, 2002 5:53 AM
If your inseam is 32 inches (81.3cm). Neither frame will provide sufficient standover clearance. A 53cm c-c would provide the proper vertical fit. A 54cm would be the tallest that you should consider(the standover height would be about 80.3cm). Your geometry figures also do not agree with the tables that I have looked up.

http://www.competitivecyclist.com/bike_look.htm#Geometry

The geometry table on this site shows that all sizes have the same 72.5cm STA, which is typical of LOOK frames.

To compare a frame with a 73 STA to one with a 72.5 STA, subtract .6cm from the TT length of the frame with the 72.5 STA to make an accurate comparison.
Are you sure?djg
Jun 21, 2002 6:34 AM
I'm not really a Look buff, but my impression was that they all had relatively slack STAs, which suggests that your 74 degree figure for the 55 is incorrect. Also, it would be curious for Look to provide both a steeper STA and a longer top tube on the nominally smaller frame.
oh duhcollinsc
Jun 21, 2002 7:42 AM
Youre right, i was looking at LOOKs own incredibly unhelpful geometry chart which requires you to flip back and forth between the picture and the numbers. Guess I stopped paying attention somewhere.