# Scott Geometry observation



## skygodmatt (May 24, 2005)

I've noticed the Scott Geometry Seat Tube angles are a little different than other manufacturers. It's interesting to note that they use steeper angles than say Giant for instance. Their geometry effectively lengthens the usable cockpit length. Think about it. It's all about getting the Bottom Bracket to go where you want it, so effective top tube length is actually a combination of top tube length combined with seat angle. With Scott, you would usually use a little setback in your seatpost to get your leg positioned properly over the BB. So, with this in mind, you gain a little TT length...usually works out to be 1cm for every half a degree of seat tube angle. 

For example:

The Large 56cm Scott CR1 has a steep seat angle of 73.5 degrees with a top tube of 56cm.
The M/L Giant TCR has a shallow seat angle of 72.5 degrees with a top tube of 57cm.

Which of these bikes have a longer overall TT for you? Well, looking at the numbers you would think the Giant right?...it's 57 not 56. On the contrary for a lot of riders however. 

If you know the desired seat angle for your leg is... say 73 degrees to make the BB position right, then you would need to move the saddle back 1 cm on the CR1 effectively giving you a TT of 57cm. On the TCR, you would have to move the saddle forward 1cm decreasing the effective TT to 56cm. 

By doing this, your leg is in the exact position relative to the BB on both these bikes, however, now *your upper body senses the GIANT as being 1cm shorter than the SCOTT!*

So, the point of this post is that you can't always fit a bike by the TT length. I found this out by riding different frames with different seat angles but the same TT length. They all fit differently when my lower body was positioned properly. 

Thats why I find Cervelo to have an interesting approach regarding Geometry. They use a fixed seat angle for all size frames. It happens to be 73 degrees which is most common among a demographic of riders. It makes logical sense---just find out where your leg needs to be...then select your desired stem length for your personal preference in handling characteristics and then select your top tube length in the frame. Sounds like this works. 

Enough rambling it's time for my ride.
For what it's worth.

Matt Potter
Fresno,CA
:idea:


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## climr (Sep 29, 2005)

Matt,

This is great stuff and as I've been researching different bikes I'm realizing just how important the seat tube angle is when comparing top tubes. The 74 deg seat tube angle on the size M CR1 explains why the bike feels bigger than other bikes with a ~54.5cm top tube. 

I did some quick calculations based on my leg length and found that the CR1 will feel (for me) about 1.33 cm longer than a bike with a 73 deg seat (assuming the measured top tube length is the same). That is quite significant (i.e. a 54.5 TT becomes equivalent to a 55.8 TT !!).

BTW, does anyone have full geometry info for a CR1 that includes wheelbase? 

Brad


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## skygodmatt (May 24, 2005)

*Scott fit*



climr said:


> Matt,
> 
> This is great stuff and as I've been researching different bikes I'm realizing just how important the seat tube angle is when comparing top tubes. The 74 deg seat tube angle on the size M CR1 explains why the bike feels bigger than other bikes with a ~54.5cm top tube.
> 
> ...





Hey Brad,

Most bike manufacturers manipulate the seat tube angles with different size frames to accommodate different femur length's. However, everyone does not have a proportionate femur length to go along with their height. So, you get all kinds of fits. 

I don't know the wheelbase, you just have to measure. Scott's run long. The 56cm has 100cm and the 58cm has a 101cm wheelbase. I measured them. They have semi-high bottom brackets for cornering clearance listed at 67mm drop. A lot of other frames have 69mm drop.

All in all, they are great frames. I am 6'2" and I can actually ride a 56cm. I fall directly in between the 56 and 58. 

later,
Matt


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## toyota (Sep 4, 2006)

Besides the 73.3 SA on size 58 and 61 on the CR1 the rest of their seat angles are right in line with everybody else. For example a 74 seat angle on a bike with a 54.5 top tube is pretty much the norm. In fact the Addict has pretty laid back angles on its smaller sizes. Its the Giant with its very laid back seat angles that makes the Scott seem steep. I cant even ride a Giant anymore since they revised their geometry and went with a way too shallow 73.5 SA on a freaking size small.


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## skygodmatt (May 24, 2005)

*true angles*



toyota said:


> Besides the 73.3 SA on size 58 and 61 on the CR1 the rest of their seat angles are right in line with everybody else. For example a 74 seat angle on a bike with a 54.5 top tube is pretty much the norm. In fact the Addict has pretty laid back angles on its smaller sizes. Its the Giant with its very laid back seat angles that makes the Scott seem steep. I cant even ride a Giant anymore since they revised their geometry and went with a way too shallow 73.5 SA on a freaking size small.




True...true...I was mainly looking at the larger sizes since I am a tall dude. Scott is 73.5 and Giant is 72.5, That's a big difference. I guess you need to know how long your femur is. I still think everyone should be like cervelo and make one seat tube angle in the middle of the range ( 73 ) and then just play with the top tube. 

Matt


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## toyota (Sep 4, 2006)

skygodmatt said:


> True...true...I was mainly looking at the larger sizes since I am a tall dude. Scott is 73.5 and Giant is 72.5, That's a big difference. I guess you need to know how long your femur is.* I still think everyone should be like cervelo and make one seat tube angle in the middle of the range ( 73 ) and then just play with the top tube.*
> 
> Matt


 Im glad youre not in control of geometry then. Maybe you being tall has made you unaware of different size riders needs. A 73 degree seat angle on a small bike(48-52cm) would mean that most riders would not get a decent position over the bottom bracket without shoving the seat very far forward. For instance theres no way I could ride with anything less than a 73.5 degree seat angle with a normal straight seatpost and even then the saddle would be pushed a little forward. Moving the seat forward would also throw off your weight balance on the bike. Most short riders need a 74 to 75 seat angle.

Also something else you havent considered is the effect on front center. Most short riders already have toe overlap with traditional seat angles. A 73 degree seat angle on a small bike would make for a SCARY time if the rider had to weave on a hill or turn around in a parking lot. It would be impossible for the tire not to hit the riders foot. For example my bike has 57.2 front center and I have a little toe overlap. On a 51cm Cervelo the front center is 55.8. Thats an additional 1.4 cm of toe overlap on a bike that actually has a 1cm longer top tube than my Cannondale. Cervelo has the most illogical and unrealistic geometry for short riders.


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## skygodmatt (May 24, 2005)

toyota said:


> Im glad youre not in control of geometry then. Maybe you being tall has made you unaware of different size riders needs. A 73 degree seat angle on a small bike(48-52cm) would mean that most riders would not get a decent position over the bottom bracket without shoving the seat very far forward. For instance theres no way I could ride with anything less than a 73.5 degree seat angle with a normal straight seatpost and even then the saddle would be pushed a little forward. Moving the seat forward would also throw off your weight balance on the bike. Most short riders need a 74 to 75 seat angle.
> 
> Also something else you havent considered is the effect on front center. Most short riders already have toe overlap with traditional seat angles. A 73 degree seat angle on a small bike would make for a SCARY time if the rider had to weave on a hill or turn around in a parking lot. It would be impossible for the tire not to hit the riders foot. For example my bike has 57.2 front center and I have a little toe overlap. On a 51cm Cervelo the front center is 55.8. Thats an additional 1.4 cm of toe overlap on a bike that actually has a 1cm longer top tube than my Cannondale. Cervelo has the most illogical and unrealistic geometry for short riders.



Yes...I see your point. Riders that aren't super tall need to be placed forward more. 
But what if a shorter rider has a long femur? Then it's way too steep. In your case, you are talking about a 48-52cm frame. Well, with very small or very large frames, the cyclist falls out of the range of any common generic seat angle number. I have a size 11 foot and a short femur. Your frame size angle of 74 degrees would be awesome for me too. But, then the head tube and top tube would be too short. I have overlap due to my foot size and 175mm crank on all frames. I guess we can both agree on something---Giant has some weird geometry numbers

---Matt


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## climr (Sep 29, 2005)

toyota said:


> Besides the 73.3 SA on size 58 and 61 on the CR1 the rest of their seat angles are right in line with everybody else. For example a 74 seat angle on a bike with a 54.5 top tube is pretty much the norm. In fact the Addict has pretty laid back angles on its smaller sizes. Its the Giant with its very laid back seat angles that makes the Scott seem steep. I cant even ride a Giant anymore since they revised their geometry and went with a way too shallow 73.5 SA on a freaking size small.


I agree the giant does seem to be extreme (maybe that's why I never feel stable on mine?) but the scott is the steepest of any bike that I've compared it too so far (lynskey, litespeed, klein and giant). I think Matt's point is that alot of people don't take ST angle into account when comparing frames and they obviously should! I know I sure was surprised to find that the scott 54 would feel larger than my giant M (55.5) with the seat in the same place relative to BB.


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## woodys737 (Dec 31, 2005)

My 56 CR1 TT measures 55. A friends 54 measured closer to 53.5. Just a FWIW.


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## climr (Sep 29, 2005)

woodys737 said:


> My 56 CR1 TT measures 55. A friends 54 measured closer to 53.5. Just a FWIW.


You are measuring along the TT (not horizontal to ground) I assume?


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## woodys737 (Dec 31, 2005)

Correct.


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## Pedal_Power (Nov 28, 2006)

Also on Scott bikes the headset is raised well above the seat tube height.So a 54 Scott
would have an effective set tube height well over 54cm


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## skygodmatt (May 24, 2005)

*Yes..long head tubes*



Pedal_Power said:


> Also on Scott bikes the headset is raised well above the seat tube height.So a 54 Scott
> would have an effective set tube height well over 54cm



That's a cool thing. I like the longer head tube. Since most of us here are not pro riders, we ride with a couple of centimeters of stack height. The longer head tube allows the spacers to be taken away thus lessening the amount of steerer tube flex and adds to the bike aesthetics as well.

Scott knew what they were doing.

Matt


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