Translate Old Dimensions to Stack and Reach?
 

The frame I raced on back in the day was measured before Stack and Reach became de riguer. I would love to be able to compare its stack and reach with what i s available in the marketplace. Does anyone know if there is an app online or a calculation that can be done with the old style specifications so that i can calculate the stack and reach of my old frame?

This was an old 2002 Bianchi SL Lite frame (59) and Bianchi provided measurements for the following:

1. Seat tube C to T
2. Top Tube (actual)
3. Top Tube (virtual)
4. Head Tube angle
5. Seat Tube angle
6. Stand Over Height

This might help:

https://geometrygeeks.bike/bike-dire...and/?b=Bianchi

Because you don't have the head tube height or the top tube slope, there is not enough information to determine where the top of the head tube is.

There are other methods to compare fit that are as or more useful. What are you trying to do?

Almost, but didn’t have that frame and the one they had was wrong size. They don’t have stack and reach anyway.

Unfortunately that frame is long gone as it was an aluminum frame and I “tore” the BB cluster like a soda can. It was the best fit I felt I ever had so was trying to use stack and reach to come close with a racing frame from today.

You have enough information to duplicate the horizontal reach, and then it is just question of playing with bar height until that fits. If you remember your stem length and how your setback was derived.

Post two geometries and I'll show you what I mean.

Not without a plumb bob, a protractor, and some trigonometry. Personally, I can't even remember my stack and reach preferences, but give me dimensions for head tube, virtual top tube, bottom bracket drop, and approximate seat tube angle, and I can approximate the stem height and length.

But he doesn't have all those dimensions.

If the original bike had a sloping top tube, which is suggested by the "virtual" measurement, then the seat tube length isn't super useful without the top tube angle. Assuming it's not a virtual seat tube length. However, I feel like I could reverse engineer it fairly well without that if given the actual measurements.

Kona used to label their bikes with actual seat tube length, even though they often had sloping top tubes. There was one bike they called a 58cm that I measured as a 65cm. Makes it really confusing, and I know it cost them at least one sale.

Without the frame still in my possession it seems the only way I can learn anything is if someone else has the same frame or 1 like it, or if the dimensions are published somewhere.

From the 2002 Bianchi catalog I found several frames with the same geometry as my SL Lite Alloy. These were:

SL Lite Alloy
Alloro
SL Aluminum Centaur
XL-Alloy EV4
XL-Alloy EV2

I think I stumbled on my answer. In the Geometry Geeks database there is a 2006 Bianchi Giro (59) with identical measurements and Bianchi even provides stack and reach. Now I can effectively compare a potential bike purchase with my current 2014 (59) Bianchi Intenso (endurance frame) with my old race frame, 59 Bianchi SL Lite Alloy.

https://geometrygeeks.bike/bike/bianchi-giro-2006/

Thanks for everyone's input!

Specialized had a line of crossover hybrids sized like that, too, around 2009-10. All the shops ordered as if they were normally sized, so there were a lot of 57s, 59s, and maybe even some 61s, on clearance. A tall guy, maybe 6'6", would walk into the shop and say, "I need a bike for casual riding, don't want to spend a lot." "I have the just the bike for you."