So I have thinking about getting the Performance Bike version of the GT GTR Sport as my first carbon bike. Performance has it with Rival for a great price, rather than the 105 GT mentions for the Sport model on their site. Link to Performance.
But I was looking at the geometry for the Sport on GT's site and it seems weird to me. I'm new, so I'm hoping to get input from others. Here's an image -
Rounding to the nearest half CM, the horizontal top tube of the -
XS - 53.5
S - 54
M - 55
Isn't that kind of a tight range?
My bike shop buddy says I should be on 54 frame, so I guess I need to just be looking at the Small size, but this is throwing up a concern flag for me.
Love that bike. I have had it for over a month now. Changed out the rival shifters to Red....changed the chain to Sram PC1071...changed the tires out to Ea90SLX....and am looking to change out the crank to Red as well. I love the blue/white/carbon theme of the bike. Although it is supposed to be around 18lbs or so stock, it feels lighter than that and is really quick IMO...especially after switching out the stock Mavic wheels.
Sorry, got carried away. As for size, I thought that was kind of strange as well. In the end, as most would say here, you have to just sit on the bike and see how it feels. I would use those posted numbers as a starting point only. I am 5'8" and went with the S. I like riding with the seat a little higher and felt more comfortable with the S 52 versus the M 54. I also liked the narrower bars and the shorter stem on the Small. The crank size of 170 also worked well for me.
For every degree of seat tube angle change, there's about a 1cm change to reach, so the XS with a STA of 74.5 and an ETT of 536.3 will have about the same reach as the S with a STA of 74 and ETT of 540.7.
One cautionary note about your friend suggesting you should be on a 54cm frame. Unless your sizing requirements have been determined for this bike or a bike of very similar geo, don't be misled into thinking everyone's 54cm frame is measured the same. There's no standard for measuring or determining frame size among manufacturers, so if you fit well on a 54cm Specialized Tarmac (as one example) you might take anywhere from an XS to a 56cm in some other brands/ models.
In terms of fit - checked out CC's fit calculator tonight, plugging in what good measurements I have and taking some rough solo ones myself for the rest. That resulted in these numbers for "The Eddy Fit"
That has got to be too small, so I need to get some help to get real measurements on the areas I did solo. With that done, I'll re-run the calculator. I'm hoping it pumps out something pretty close to the GT's small size.
I'm 5'9" by the way. 175cm tall, 84cm inseam, 64cm arm length, 56.5 torso - those are my trustworthy measurements.
In terms of fit - checked out CC's fit calculator tonight, plugging in what good measurements I have and taking some rough solo ones myself for the rest. That resulted in these numbers for "The Eddy Fit"
That has got to be too small, so I need to get some help to get real measurements on the areas I did solo. With that done, I'll re-run the calculator. I'm hoping it pumps out something pretty close to the GT's small size.
I'm 5'9" by the way. 175cm tall, 84cm inseam, 64cm arm length, 56.5 torso - those are my trustworthy measurements.
I have zero confidence in online fit calculators, so take what I offer with a grain of salt.
If you have a friend that works in a LBS, have him/ her fit you to a bike of similar geo to the GT. IME that's a far more reliable method that using the calculators because even when the correct values are entered, they recommend a range which is of little value to someone that's already 'in the ballpark' like yourself.
It shoudln't be that difficult to find a suitable 'test' bike, because the geo of the GT isn't that far off from (to name just three) Specialized Tarmacs, C'dale CAAD9's and Trek Madones.
you are 2 inches shorter and your CC measurements are 3 cm shorter than a buddy of mine who just bought this bike (size M). He fits on it well it is a truly compact geometry and the seatpost is laid way back, with no way of changing this compared to normal seatpost. The great thing about performance is that it is 100% guareentee, and they build it so throw on the wheels, seat and bars and give it a go. Had to adjust a number of things after about 60 miles. The Mavic rims are heavy and not great.
In terms of fit - checked out CC's fit calculator tonight, plugging in what good measurements I have and taking some rough solo ones myself for the rest. That resulted in these numbers for "The Eddy Fit"
That has got to be too small, so I need to get some help to get real measurements on the areas I did solo. With that done, I'll re-run the calculator. I'm hoping it pumps out something pretty close to the GT's small size.
I'm 5'9" by the way. 175cm tall, 84cm inseam, 64cm arm length, 56.5 torso - those are my trustworthy measurements.
The problem with on-line calculators is that the measurements need to be taken VERY accurately. Re-measure everything 2 or 3 times (have somebody help you) and re-run the calcs each time... my guess is you want a TT around 54cm BUT the other important parameter is bar drop, so if you want the bars high, pick the largest frame you can ride... if you want the bars low, pick the smallest frame you can ride.
Take the bikes for a long spin; try the small and medium. The geo on these bikes is very aggressive, steep seat tube angles and short headtubes...
I'm 5' 9 3/4" and ride a large (Giant TCR C) with a short stem but my bars are almost level with my saddle
My brother has the '08 version of that bike. They seem to run a little small. His is supposed to be the equivalent of a 56 (he's 5'10"), but it is almost the exact same size as my 54cm Fuji Team (I'm also 5'10"). The GT is a great bike though.
He does like the bike, but is new to road cycling, so nothing to compare it to. The wheels are fine ride them into the ground then upgrade.
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