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GT and Trek geometry...how similar or different?(8 posts)

GT and Trek geometry...how similar or different?MVN
Jul 17, 2002 5:52 PM
Bear with a newbie question. I'm looking at a GT ZR 3.0 frame in 54cm. I am currently riding a Trek 1000, same size. I'm curious as to how different the geometry's are. I know the GT is a racing bike and the Trek is entry level sport/recreation. I just got properly fitted on the Trek (had saddle set too far back for a while) and it feels fine now. So I'm wondering how close (or how different!)the GT is to the Trek. What is the seat tube angle and what is the head tube angle? How long is the top tube? On the trek it's 53.6 cm. I know I'll probably have to play with stem length and the height of the bars. GT owners or more knowledgeable people than myself, can you help me out? Thanks.
look harder...C-40
Jul 18, 2002 1:58 PM
The info that you want is readily available on the web.

Trek has a geometry chart for the 1000 on their web site. I assume you are riding a 54cm. The TT length is 54.6 (not 53.6) and the seat tube angle (STA) is a steep 74.5 degrees.

The GT geometry is posted on the Supergo site, where they are still selling 2001 models. The 54cm GT is a larger frame, due to the difference in the way that they are measured. It compares to a 56cm Trek. The STA is 73.5 degrees and the TT length is 55cm. The 73.5 degree STA on the GT reduces the TT length by 1.2cm, when compared to the Trek, making it effectively 53.8cm or .8cm shorter.
look harder...MVN
Jul 18, 2002 3:09 PM
Thanks for the info, but I have a copy of the Trek chart, and it says 53.6 for the TT, and 74.0 for the Seat angle for a 54cm. I got it from their web site. I wasn't able to find the GT chart, but didn't think about SuperGo. I'll check there and see what the specs are.
website chart says 54.6cm TT....C-40
Jul 18, 2002 4:00 PM
Don't know what chart your are looking at, but the chart from the Trek website says 54.6cm for a 54cm frame size 1000 model. I just printed it today.

The GT site doesn't even list the ZR 3.0 model as far as I can tell.
maybe they changed the geometry...mine's a 2001MVN
Jul 18, 2002 4:50 PM
The chart I have is from their archive page. My 1000 is a 2001 model and that chart says 53.6. I seem to remember reading that this year's 1000 has race geometry, so maybe that's the difference. Thanks for your info, I've learned a lot from this site.
yep, Trek changed the 1000 geometry, I just checked...MVN
Jul 18, 2002 4:58 PM
You're right, it is 54.6 but for the 2002's. I just posted that I have a 2001 and my info is from that year's chart. They did change the geometry.
re: GT and Trek geometry...how similar or different?cking17
Jul 18, 2002 5:00 PM
Your 54cm GT ZR 3.0 top tube is listed in inches by GT - 21.7 inches which is roughly 55.5cm cm. The full specs from the old GT website are below. As another person mentioned, the GT road frames run larger than other bikes.

You will be pleased with the ZR 3.0 (see my review on this site under Road Bikes from 2001). I've had mine for 6 months, have raced it and it is an excellent bike. -------------------------------------
Available Sizes: 48cm • 50cm • 52cm • 54cm • 56cm • 58cm • 60cm

Frame Size 48 50 52 54 56 58 60
Head Tube Angle 72.0 72.5 73.0 73.0 73.5 74.0 74.0
Seat Tube Angle 75.0 74.5 74.0 73.5 73.0 73.0 72.5
Top Tube Length 20.5 20.9 21.3 21.7 22.2 23.0 23.4
Bottom Bracket Height 10.6 10.6 10.7 10.7 10.7 10.7 10.9
Chainstay Length 16.1 16.1 16.1 16.1 16.1 16.1 16.1

Available Colors: Lotto Yellow

Frame ZR-Road, double butted aluminum
Fork GT CR2.0 carbon fiber 1-1/8" threadless alloy steerer
Crankset Shimano 105 52/42/30
Pedals Ritchey Pro Road
Bottom Bracket Shimano Hollowtech
Front Derailleur Shimano 105
Rear Derailleur Shimano 105
Shifters Shimano 105 STI Flight Deck compatible
Freewheel Shimano 9 speed 12-25
Chain Shimano HG 72
Rims Mavic CXP-21
Tires Panaracer 'GT Racing'
Front Hub Shimano 105

Rear Hub Shimano 105
Spokes DT 15 gauge stainless steel
Nipples Brass CP
Front Brake Shimano 105
Rear Brake Shimano 105
Brake Levers Shimano 105 STI
Handlebar Syncros Ergo bend
Stem GT aluminum forged, front loading
Grips Black cork
Headset Tange Seiki DX-8 1-1/8" threadless
Saddle Sella Italia SPX
Seat Post GT aluminum alloy
Seat Clamp GT integral clamp

ZR chassis with custom-machined and butted aluminum tubing

New GT CR2.0 carbon fiber fork

Shimano 105 group

Selle Italia SPX saddle

Syncros ergo-bend handlebar
---------------------------------------
Maybe you can help with this question...MVN
Jul 19, 2002 6:25 AM
Thanks for your reply. I really don't know much about sizing, stems, etc. I just recently got properly fitted at my LBS. My inseam is 31.8in (81cm). I'm wondering since I'm comfortable on a Trek 54cm w/53.6 TT, would I be better off with a 52cm GT (54cm TT) since it has standover height of 30.4in as opposed to the 54cm GT which has one of 31.31in? The Trek's standover is 30.1 (mine is a 2001). ANy info you could give would be most appreciated.