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GIANT bike sizing (S-M-L)(5 posts)

GIANT bike sizing (S-M-L)Gunn
Mar 20, 2001 6:19 PM
Looking to get a Giant road bike...they sell three different frames, sizes small, medium (50cm), large (55cm). Has anyone sized and bought one of these bikes and let me know if I'm in the right ballpark?

According to the Colorado cycling website sizing, I have a 84cm inseam, and a calculated saddle height (BB to top of saddle) of 74cm. I used this for Giant seat post sizing.

I currently have a Specialized Rockhopper 19". Using that as a reference, and measuring the center of seat tube to center of handlebars (for Giant stem size calc.) I got 27" or 686mm.

So, from these, it seems I should get a Medium sized frame (50cm), with a 330mm seat post length, Size 4. This falls within the 740-760mm range for BB-to-seat measurement, mine being 740.
Then, I'd want a Size #3 stem, which falls in the 680-690mm range of center of seat tube to center of handlebars measurement (686mm). This stem adjusts from 123-135mm.

Do those seem like I read the chart right? Appreciate any feedback into those numbers.

just S-M-L? no Giant size? NMMade in Taiwan
Mar 20, 2001 8:17 PM
sorry had to do it :)
Giant sizing - my experienceMass Biker
Mar 21, 2001 6:10 AM
I'm 6'0", with a 32" inseam. Short torso. Long arms. I ride a size L Giant TCR Team. The top tube is fairly long. I have to run a 105mm stem with 5 degree rise (determining this took some trial and error). The bike fits me fine. FYI - I ride an 18" mountain bike. I'd also recommend that once you figure out what stem reach/rise works for you, to swap out the flexible (and heavy) adjustable stem and go with one that has the exact measurements you need. Good luck.
re: GIANT bike sizing (S-M-L)cyclopathic
Mar 21, 2001 8:06 AM
No you goofed with seatpost!

They use BB to seat rails vs to seat top, so 740mm is not the right size for seatpost sizing. Thing is that "aero" SP cannot be pushed down much.

I am 31 (787mm) instem and I ride small frame with standard SP. My BB to seatrail is 604mm (on 170mm cranks) and I am ok on standard Size 1. Judging from your 840mm instem your BB to rails will be 665mm and you should be OK on Size 1 seatpost.

With respect to stem adjustable stem is very flexy, so you wouldn't wanna keep it anyways, upgrade it. Reccomend ITM Millenium. It is light (130g) and only 69$ @ Performance Bikes.

PS. make sure you have enough steer to run spacers, dont let LBS to cut it short
re: GIANT bike sizing (S-M-L)Gunn
Mar 27, 2001 6:51 PM
Hey cyclopathic, thanks for the correction! That's exactly what I was looking for by posting my info. I'll take the advice on the stem too and once I get it figured out, upgrade.