Between Sizes, Which Way to Go?
 

Hi all! So I'm pretty set on the Trek Domane SL6 but between sizes. Also, I don't really have options for test rides and a fit in my area. I could drive an hour to see more inventory but really don't want to waiste a shops time and then buy local.

About me, 55, 5'11", 33.5" inseam, not great neck and kness can get weird, back on the bike last year after some years off with health issues, got up to 30 miles at 17 mph avg. I will get the fit worked out, have done it many times, but being right in the middle of sizes kinda stinks. Goals this year, improve to max 60 mile rides and 19 mph avg.

Looking at Trek I fall exactly at the top end of a 56 and the bottom end of a 58. One thing I notice is the 56 comes with a 170 crank and the 58 a 172.5 crank, my current bikes are 175 cranks. I'm leaning towrd the 58 cause I figure I can always shorten the stem from 100 to 90 for a bit reduced reach if needed. Thoughts please and thank you!

Patrick

I thought the rule of thumb was to always go smaller. You can always pull stuff out, but you can't push it in more than it goes. You can change cranks all day until you find what works.

I'm 5'11" with a 34.5" inseam. The sizing guide for my Tarmac gave me the choice of a 56 or 58 cm frame. Since I knew I wanted to have a lower and more aero body position, I went with the smaller size.

Frame stack, which affects the height of the handlebars is lower as the bike size gets smaller. Reach is also affected. But not to as large of an extent. And that can more easily be dealt with by shorter or longer stems.

Without going to weirdly angled stems, riser bars and steerer tube extenders that to me will make the pretty bike a fugly bike, your choice of handle bar height is more restricted and only the 40 to 35mm or so of spacers that they give you with a new bike. So for certain, get the size that puts the handle bar at the height you will want.

And realize that the new bike is usually set to the max handlebar height the designers intended. And should only go lower from there.

Thanks for the comment.

Thanks for the input, I'm not looking for that extra aero we can get from lower bar, my neck just isn't good for it anymore. I'm looking for comfort allowing me ro cover longer distances. Your comment was helpful, thanks.

What size does your dealer recommend?

I've always found larger to be more comfortable and smaller to be faster. Decisions decisions...

I guess thats part of my issue, they really aren't committing either way. My local shops, only two, don't get bikes in this price range except on order. The other local shop isnt even ordering in carbon framed bikes this year at all, they have Speciaized, Cannondale and Giant. They also don't do test rides or even have the two sizes in the aluminum frame for me to throw a leg over. I'm probably going to have to go outside the area for better info. Thanks for asking.

Not all that concerned with faster anymore, just happy to be out biking again. Thank you.

58cm...more comfortable considering your physical description

Thank you Kai, that's the way I am leaning.

Took a ride to a dealer an hour away, think the 58 is the better fit for me. The bar being that .75 inch higher was better on my neck. Didn't really notice the bit of extra reach tbh. Thanks for the info and opinions all.

Not surprised that you didn't notice the reach much.
Gen 4 Domane' frames have really short effective top tube lengths and reach numbers when compared to a lot of competitors and older Domanes as well.

Glad you like the 58.

I am a little surprised that you are able to size up though.
Gen 3 and Gen 4 Domanes tend to be taller than the size chart would have most believe.
I am 5'10" with a 33" inseam.
Trek's size chart puts me squarely onto a 56cm Domane SL, but when I tried one out, I had to nearly bottom out the seat post in the frame.
I purchased a 54, removed 10mm of stem spacer to keep the bars from being higher than the saddle, swapped the bar down to a 40cm, and swapped the stem up to a 120mm (still -6 degree). It's a pretty normal looking road bike now, and I have replicated the fit from my Made-to-measure 55.5cm Waterford.


Glad you were able to find your own preferred position on one. It's a perfect example of why you really have to get yourself onto one in person when shopping for a mass production model bike.