Size advice for a Giant TCR owner

Discuss light weight issues concerning road bikes & parts.
devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

Hello,

Sorry for another sizing post.

I currently have a Medium-Large Giant TCR race bike with the 110mm stem that came with the bike.

I am 5"10.5 / 5"11 (179cm) with an inside leg of 33.5" (85cm). The size chart puts me on the corner of the blue shaded area on the Giant size chart. I am guessing my legs are proportionally slightly longer than my torso as I am on the far right of the normal zone.

https://images.giant-bicycles.com/b_whi ... gsheet.jpg

I have slammed the stem (well, have 12.5mm spacer between headset and stem) and have no back pain and feel comfortable on the bike. My saddle is 76cm high from the BB centre to the top of the saddle. However, I do feel slightly stretched with my hands on the hoods when climbing seated. Downhill feels just right. I can't adjust my saddle fore-aft more forward as this gives me pain above my knee when pedaling hard. It's already 3/4 forward, and this feels right for me.

My problem is, the general consensus appears to be go down a size and run a longer stem if in the middle of two sizes, but my inside leg measurement alone would put me beyond the medium and onto a ML.

The measurements of the medium TCR are top tube 550mm + 100mm stem. ML is 570mm + 110mm. Therefore the reach is another 300mm on the ML with the stems that come with those sizes.

Do you think I will get used to the stretch over time, or should I really be running a 100mm stem, or even consider getting a Medium with a 110mm stem for my next bike purchase?

And what are the pros/cons of downsizing a stem? I like do a lot of climbing standing up and short stems put me more upright, which I prefer. But downhill, I prefer the more relaxed steering of the longer stem. I have both stem sizes but can't decide which one to settle on to best complement the type of riding I do (I am naturally a better climber).

Thanks in advance.

GothicCastle
Posts: 234
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

I’m your height, but my BB to top-of-saddle is 73cm. I’m riding a medium TCR. The M/L would have had me too stretched out. The downside is there is a bit more saddle to bar drop than I’d prefer.

Some people will say that 110 to 100 won’t influence the handling much, but I disagree. The longer stem mellows out the steering.

by Weenie


BagelMaster
Posts: 140
Joined: Fri Aug 10, 2018 11:13 pm

by BagelMaster

I'm in a similar situation, although my legs are somewhat shorter so I'm on a Medium. There is quite a bit of saddle to bar drop, with my saddle being around 75cm from the BB. I run quite a few spacers and a 100mm stem, and I'm happy with the changes I made with a bike fitter a month ago. I dislike being stretched out more than the saddle to bar drop, as one I can work on my flexibility and comfort if I want to slam my stem, but I can't lengthen my torso or unclench my shoulders when riding a longer bike.

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VTR1000SP2
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Joined: Tue Nov 05, 2013 8:21 pm

by VTR1000SP2

Wait for the next iteration to come out, there may be some geometry changes

alanyu
Posts: 100
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

Go down a size: a lot of people have said that it can make things much easier to go down a size, as you can use a longer stem, a longer seatpost, and pull back the saddle. However, lots of dynamic fitters would seldom suggest one size smaller, as many people don't have good flexibility and good strength, which usually results in "spacerman" on a smaller bike. On the other hand, one can also use a shorter stem and less spacers, a shorter seatpost, and push forward the saddle on a larger bike.

The question is: Why stick with Giant?
The reach of M is 383 but that's 398 of ML, quite a lot difference. Finding another bike with a more suitable geometry is a much better way. As you've (nearly) STS, you need a shorter reach, for example, Merida reacto CF2 S/M = R 385 & S 558 or M/L = R 390 % S 575

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naylor343
Posts: 174
Joined: Sat Aug 30, 2008 1:46 pm
Location: Haute-Ariege, Midi-Pyrenees

by naylor343

Question to the OP, what is the age of your current frame? I ask, as the older models were not as long as today's tcr. I am exactly the same measurements as you, and ride a fully slammed 110 -10 degree stem on a M/L. Mine is a 2010-13 team adv sl. Previously giant did not give the stack and reach, but I have measured mine to be 563x383 approx. If I was getting a new tcr today, the m/l would be too long and I would have to go M with spacers.
Last edited by naylor343 on Fri Jun 14, 2019 3:43 pm, edited 1 time in total.

devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

GothicCastle wrote:
Fri Jun 14, 2019 2:40 pm
I’m your height, but my BB to top-of-saddle is 73cm. I’m riding a medium TCR. The M/L would have had me too stretched out. The downside is there is a bit more saddle to bar drop than I’d prefer.

Some people will say that 110 to 100 won’t influence the handling much, but I disagree. The longer stem mellows out the steering.
What’s your inside leg measurement? 3cm saddle height difference is quite a lot. I adjusted mine so I could just about pedal backwards with my heels on the pedal without rocking my hips, which for me was 76cm.

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onemanpeloton
Posts: 283
Joined: Wed Jul 12, 2017 11:30 am
Location: Edinburgh, UK

by onemanpeloton

VTR1000SP2 wrote:
Fri Jun 14, 2019 3:28 pm
Wait for the next iteration to come out, there may be some geometry changes
You might be waiting a while. The 2020 disc version is already on the website and it's exactly the same as last years
2017 Giant TCR Disc
2015 Giant TCX
2016 Cube Stereo 140

GothicCastle
Posts: 234
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

devonbiker wrote:
Fri Jun 14, 2019 3:42 pm

What’s your inside leg measurement? 3cm saddle height difference is quite a lot. .
I don’t know my inside leg measurement, but 3 cm in saddle height isn’t unusual given differences in leg length and the fact that I’m riding speedplay pedals and you might not be.

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onemanpeloton
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Location: Edinburgh, UK

by onemanpeloton

There's lots of things to consider in bike fit. The solution doesn't necessarily have to be anything as extreme as a new frame.

Maybe post some pictures of the bike/you on the bike?

It might be that your hoods could be rotated on the bars to slightly adjust the reach, or that you could opt for a bar with less reach. You should also experiment with stem length. I know one poster said that 10mm will make a difference, and for some it might, but you might not even notice it. Or you might decide the change is worth it in the pursuit of comfort.
2017 Giant TCR Disc
2015 Giant TCX
2016 Cube Stereo 140

devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

naylor343 wrote:
Fri Jun 14, 2019 3:39 pm
Question to the OP, what is the age of your current frame? I ask, as the older models were not as long as today's tcr. I am exactly the same measurements as you, and ride a fully slammed 110 -10 degree stem on a M/L. Mine is a 2010-13 team adv sl. Previously giant did not give the stack and reach, but I have measured mine to be 563x383 approx. If I was getting a new tcr today, the m/l would be too long and I would have to go M with spacers.
It’s a 2018 Giant TCR Advanced Pro 1.

The current set up is in my ballpark and feels great for short rides, but on a climb or when I’m fatigued on a longer ride I feel like I am reaching out a bit too much on the hoods. I don’t think I’m going to find an perfect fit with the frame I have. Ideally I want a slightly shorter top tube and keep the 110 stem instead of going to the 100 stem. But I am stuck with the frame so I could try lowering the saddle and put a 1cm spacer under the stem. Or switch to the 100 stem and accept the fact that it doesn’t look as cool 😎

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naylor343
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Location: Haute-Ariege, Midi-Pyrenees

by naylor343

I recently changed my saddle to a pro stealth. Other than increased saddle comfort, another upside has been the abilitliy to get lower and longer with my body. This allows me to continually stay on the hoods when climbing if I want to, and to comfortably stay in the drops for as long as I want on the flats. Maybe one if these shorter saddle could help, pro stealth, specialized power, etc. If you have a friend who has one ask to try it, it could help.

DJT21
Posts: 318
Joined: Sun Mar 27, 2011 7:35 pm

by DJT21

Try lowering your saddle, the Lemond formula puts you at a 75cm saddle height.

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fa63
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Location: Atlanta, GA, US

by fa63

DJT21 wrote:Try lowering your saddle, the Lemond formula puts you at a 75cm saddle height.
I have the exact same inseam as the OP, and comfortably run a 76.5-77 cm saddle height. The Lemond formula is just a rough guideline.

As for sizing, my preference is to size up and use less spacers and shorter stem. You will not notice the shorter stem after a couple of rides.

by Weenie


DJT21
Posts: 318
Joined: Sun Mar 27, 2011 7:35 pm

by DJT21

fa63 wrote:
Fri Jun 14, 2019 9:48 pm
DJT21 wrote:Try lowering your saddle, the Lemond formula puts you at a 75cm saddle height.
I have the exact same inseam as the OP, and comfortably run a 76.5-77 cm saddle height. The Lemond formula is just a rough guideline.
Of course, it's only a guideline. But half the people I see appear to have their saddles too high. It's difficult to run a slammed stem/aggressive position if your saddle is too high. It's always better to err on the side of caution with saddle height.

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