Originally Posted by Jrasero

As a short king and OP being 5'7", SOH probably will start to make a difference in which size they take. A 52cm 746mm SOH a 54cm 768 SOH. That .86" of a difference for shorter riders like us might be one of the determining factors.
At 5'5" Specialized puts me on a 52cm but the 746mm/29.37" SOH is above my 29" SOH clearance. Also while a 52cm would work reach wise for me at 377mm that's really at the upper range for me, thus even if SOH was not an issue it would come down to running a smaller frame with a larger stem which IMO looks more pro and contributes to more stable steering, or running a slightly larger frame with a smaller stem which IMO doesn't look as pro and can be more twitchy

Originally Posted by Kontact

These are sloping TT bikes. SOH should never be an issue when these sizing guidelines go back to level TT bikes with higher SOHs.

Originally Posted by Jrasero

Sloping compact frames help but they still can be too tall. Short people people problems. Either way I would personally always get the smaller size if in-between sizes because swapping a stem is pretty easy unless you are dealing with integrated cockpits and too, a smaller frame will have slightly more compliance with more seat post showing

Originally Posted by Kontact

Stems are easy to swap. Head tubes are not. A 45 year old purchasing a bike for the next decade should be thinking about not limiting their stack height. That 17mm of head tube is much impactful than 10mm of reach.

Originally Posted by Jrasero

True but that's negated by the fact that Specialized and most companies ship with 50mm worth of spacers now. So I'd rather have a much shorter headtube and adjust accordingly via the spacers

Originally Posted by Iride01

IMO, stand over height should be one of the least important things for selection of a bike. Anyone riding a unloaded road bike for pleasure or exercise can simply lean the bike over when stopped. Which is what I did for most all my younger life when I rode bikes that were way oversize for me. Still to this day at stops, I'll stay in the saddle and just lean the bike with one foot on the ground.

As mentioned by several members, the smaller frame will have a lower frame stack. Which means the height of the bars will be lower than the next size up. And reach to the bars going to the next size up doesn't increase very much at all. And that can easily be made the same with a stem change.

Originally Posted by Kontact

The SL8 comes with 35mm below and 5mm above. Where are you getting this information?

Originally Posted by Jrasero

Whether it comes with 50mm or essentially 40mm worth of spacers is mute, the point is that that amount of spacers is above average and even with the shorter headtube on the 52cm, a full stack would be more than enough to make that bike comfortable to ride

Originally Posted by Kontact

I have seen so many riders that need the limit of 40mm of spacers on bikes like the old Cervelo R5s with tall head tubes. Riding a short bike is not easy. Replacing a long stem takes minutes.

Originally Posted by Jrasero

One I doubt you are of the size to give advise on what a shorter rider needs, but IMO if OP is looking at a Tarmac they kind of know or should know it's one of the more aggressive race bikes to begin with, thus if they truly can't fit on a shorter bike there are plenty of really great bikes, granted the Trek Madone Gen 8 is even shorter so I would steer clear of that. Point being it's like going to buy a Ferrari and then complain about how it hurts to get in and out of a low to the ground sports car. I truly think a 52cm at there height unless they have a long reach is a better pick.

Originally Posted by Jrasero

True but that's negated by the fact that Specialized and most companies ship with 50mm worth of spacers now. So I'd rather have a much shorter headtube and adjust accordingly via the spacers

Originally Posted by Jrasero

Interesting to see what OP decided. I just picked up a 49cm Tarmac SL Fact 10r frame size 49cm w/ a 90mm stem. I am 5'5.5" for reference

Originally Posted by eduskator

And it looks weird. The only reason why companies are doing this IMO, is because they want to sell their products. People want race bikes, but not the race position. I don't get it. It just looks so odd. ''Not the right frame size'' is what comes to mind when I see these stacks of spacers.

Originally Posted by Kontact

That's a rather short stem for that frame's reach. Do you have rather short arms for you height, or are you reaching more down than forward?

Originally Posted by eduskator

And it looks weird. The only reason why companies are doing this IMO, is because they want to sell their products. People want race bikes, but not the race position. I don't get it. It just looks so odd. ''Not the right frame size'' is what comes to mind when I see these stacks of spacers.

Originally Posted by mLuMaN83

I currently have a 2016 Tarmac Comp and I am wanting to get a new bike to get me through the next 10 years+. My bike is fantastic, but the new tech is calling my name. Florida rider so most rides are on the flats with some occasional hills in the Gainesville area. I have my eye on the SL8 Pro.

I currently ride a 54 frame and shops have told me that this is the correct size. However, I have had to move my seat pretty much as far as it will go forward to feel comfortable. I am thinking a 52 may be a better option. I use the stock stem with the 16 Tarmac Comp and a slightly narrower bar and it feels good with the seat all the way forward.

I am about 5'7 with a shin length of around 16-16.5 inches. My current seat height feels good at 28 inches. There is a 54 and a 52 to look at, but they are 3.5hr+ drive from me.

What are your thoughts on this? I am leaning toward 52. What are the main differences in frame sizes? Length? Height? Ever since I bought my tarmac in a 54, it just felt a tad large to me. I am not a serious racer. I just love to get out by myself and push it for 20 miles or an occasional group ride.

Here's a photo of my current setup where things feel comfortable.

Originally Posted by Jrasero

Whether it comes with 50mm or essentially 40mm worth of spacers is mute, the point is that that amount of spacers is above average and even with the shorter headtube on the 52cm, a full stack would be more than enough to make that bike comfortable to ride

Originally Posted by jnbrown

I have 54cm SL8, I am 5’8” with 30.5” inseam.
saddle height is 26.5” so your legs must be longer. I have short legs and long torso.
i also have my saddle all the way forward with a set back seat post and stock 100mm stem.
they do have a zero set back post but it only comes on the 52cm and smaller frames.
In most bikes I ride a 52 because of the standover, but the SL8 has a sloping top tube so I am able to ride a 54 and the taller stack is better for me. You could certainly ride a 52 cm but it will be lower stack.

Originally Posted by choddo

Your saddle looks like it’s sloping down in that photo, just an effect of the bike not being square against the garage door?