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Bewildered by Frame Geometry(4 posts)

Bewildered by Frame GeometryGeekRoadie
Jan 6, 2002 12:47 AM
Question for those of you who are familiar with Lemond frames (or others for that matter).

How can some of the 2001 and 2002 models have different standover heights with seemingly identical geometry? I've double-checked their catalogs and various places on the net and it doesn’t compute...

Same frame sizes (c-t), TT, head angle, seat angle, fork rake, and BB drop. I am also assuming that a 23-622 tires are used, yet there is difference of 1/2 and inch in standover in most of their steel frames.

Could it be that head tubes are longer? What else could it be?

Any ideas?
simple mistake??C-40
Jan 6, 2002 7:10 AM
The Lemond website only shows 2002 geometry. Do you have another site with 2001 geometry? Perhaps the info on the other sites was copied in error. The listed standovers appear to be pretty normal for the sizes listed. Lemond frames are measured center to center. For a given size, the dimensions that affect standover height are the seat tube angle, bottom bracket drop (or height) and the diameter of the top tube. None are likely to have changed significantly from last year.

I just compared the Lemond numbers for a 53cm, which compares to my 55cm (c-t) Colnago. In this size, the Lemond chart lists a standover height that is 1cm lower than my Colnago, even though the advertised bottom bracket heights are identical. If you calculate the Lemond standover height you get 79.4cm, assuming a 33.5cm tire radius and adding 1.5cm to convert from c-c to c-t. This is about 1cm off the 78.4cm listed in the chart. The 55cm Lemond calculates to an 80.5cm standover, compared to the advertised 80.3cm.

What's the problem, though? Unless you're selecting a frame that's the very largest that you can straddle, standover shouldn't be a big issue. The critical numbers are the seat tube angle, top tube length and head tube length. You want the nominal saddle position to be correct, a top tube length that allows some stem length adjustment and enough head tube length to avoid using a lot of spacers.
simple mistake??GeekRoadie
Jan 6, 2002 9:19 AM
Thanks C40. I got the 2001 info from their catalog. I'd agree that standover height is important but not as important as other factors you mentioned. If the TT can be straddled comfortably, the other factors determine fit and "character" of the bike. The 51cm (c-c) version have listed 75.4 cm and 76.7 as standover height but the geometry seems identical.

My LBS says that the frames are the same. I'm contemplating getting a 01' Zurich and now wondered if the 02' have different frames. The difference might be inconsequential, but I am just curious "where" the additional height comes from. Has anyone ridden both and compared?

Regards
m
76.7 should be correct...C-40
Jan 6, 2002 1:56 PM
Simple calculation shows that the 76.7cm figure should be very close to correct. I wouldn't assume that there really is any difference between the '01 & '02. More likely it's someones error in measurement, calculation or typing.