Frame size uncertainties (Giant Propel)

MikeJD

Active Member
Hi all,

I’m currently looking to purchase my second road bike, a Giant Propel, something closer to a TT bike (once aero bars are fitted), but something I can still use on the roads.

I’m 6’4” and fall right between the Giant frame sizes L and XL. My current bike is a Giant Contend SL1 2018 in size XL, and the reason I doubt the size of the frame is my saddle is slammed all the way forward.

I’ve visited a Giant store, but they don’t stock any bikes in XL, so it’s difficult to sit on both and get a definitive answer. Although they did say from ‘looking at me’, I’d be better with an XL.

I’m conscious with the Propel, the custom stem won’t allow for shortening, which makes me cautious about purchasing the XL model. I know ideally I should shorten the stem on my Contend to allow my saddle to assume a more central position.

Does my seat being slammed forward mean my current frame is too long for me?

I know ultimately a bike fit would resolve these issue, which I do plan to get in the not too distant future, I just wanna grab this 2019 frame while it’s on sale at present.

Any other advice would be great.

Thanks
 

DCLane

Found in the Yorkshire hills ...
At 6' 4" you're an XL.
 

MichaelW2

Veteran
The seat forward shows that your body proportions are not close to average or the frame geometry is bodged. If your upper leg is long in relation to lower leg, you have to put the saddle back. Conversely if your upper leg is relatively short to move the saddle forward.
In addition you have to factor in crank length, which for tall people is always too short, so designers usually slope the seat tube back more.
If you already have a bike that fits, compare the points of contact to any new bike and replicate.
Angles can vary and are hard to measure.
Try using [x,y] coordinates with [0,0] at the bottom bracket. Mark x=0 on the top tube. Measure up and across to saddle nose and bars.
 
Poor effort from the Giant store.

I can understand they can't offer you a test ride on the bike for fear of making an expensive bike 'second hand'.

I can understand they don't want to stock XL - large bikes sell like stones.

But they ought to be able to get one in for you to swing your leg over in the showroom.
 

vickster

Legendary Member
Poor effort from the Giant store.

I can understand they can't offer you a test ride on the bike for fear of making an expensive bike 'second hand'.

I can understand they don't want to stock XL - large bikes sell like stones.

But they ought to be able to get one in for you to swing your leg over in the showroom.
All assuming the local shop is where the OP is planning to buy (and not an online bargain at the other end of the country)
 
OP
M

MikeJD

Active Member
Thanks for the prompt responses.

The store in question only had the L size available, but there is another store in the UK which has an XL.

Others have told me to go for the size L as small bikes can always be made large, but not vice versa.

The seat forward shows that your body proportions are not close to average or the frame geometry is bodged. If your upper leg is long in relation to lower leg, you have to put the saddle back. Conversely if your upper leg is relatively short to move the saddle forward.
In addition you have to factor in crank length, which for tall people is always too short, so designers usually slope the seat tube back more.
If you already have a bike that fits, compare the points of contact to any new bike and replicate.
Angles can vary and are hard to measure.
Try using [x,y] coordinates with [0,0] at the bottom bracket. Mark x=0 on the top tube. Measure up and across to saddle nose and bars.
Thanks for putting that process into detail, however it’s still quite confusing for me with limited bike measuring experience. Are you aware of any videos or other recources which show this measurement being taken?
 

vickster

Legendary Member
The OP says he has visited a Giant store, which suggests he is a customer in person.
Doesn’t mean he plans to buy the bike from them....he says it’s on sale but clearly not on the floor of that shop in XL

The Propel is a race bike, those seem to sometimes be ridden in a smaller size (at least by pros)
 

vickster

Legendary Member
Thanks for the prompt responses.

The store in question only had the L size available, but there is another store in the UK which has an XL.

Others have told me to go for the size L as small bikes can always be made large, but not vice versa.
Why not contact that store for their advice?
 

Soltydog

Legendary Member
Location
near Hornsea
Where abouts are you? I have A TCR on order in XL, if you're in East Yorks, you are welcome to come & try mine for size once it arrives :okay: Stack & reach measurements are about the same, so It'll give you some idea. Not sure when it's due though, delivery was put back a couple of weeks, but it should still be here by now. I'll ring the shop tomorrow :blush:
 

MichaelW2

Veteran
Thanks for the prompt responses.

The store in question only had the L size available, but there is another store in the UK which has an XL.

Others have told me to go for the size L as small bikes can always be made large, but not vice versa.



Thanks for putting that process into detail, however it’s still quite confusing for me with limited bike measuring experience. Are you aware of any videos or other recources which show this measurement being taken?
All the measurements are either vertical or horizontal.
Use a weighted string to get the vertical line to the bottom bracket . Mark this on the to tube for convenience and measure this vertical distance. You are just locating a convenient reference point on the bike. Measure forward to the grip of the bars, back to the nose of the saddle. Measure up to the grip if the bars and nose of the saddle. Sketch the points of contact out on a grid
 
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