Kabuto

Here's a question for cyclists who ride flat pedals and clipless, I realize there are multiple variables to consider (foot position, pedal thickness, shoe sole thickness etc. etc. etc.), but all things being equal, do you set your saddle height slightly differently for the two systems? If so, how?

Mojo31

As you raise the saddle, it may be appropriate to slide it forward on the rails. And, vice versa.

Iride01 

How scientific do you want to be?

Just measure the distance from the top of the pedal to the top of the saddle where you sit. I put my pedal at the bottom when I do this. Then transfer that measurement to the other bike or same bike after installing the clipless pedals, measuring to the top of the part you clip into.

Then several times after riding a time or two, you might want to adjust one way or the other. Might need to slide the saddle fore and aft too if you do change height.

Type of shoe and cleat will probably make something different in height, but for a first time setting, don't dwell too much on that. I don't know of any chart that tells how much extra to allow for brand x with z over brand y with w.

But if you got to be perfect the first time, well, that's not me.

Kabuto

Yes, one of the variables I mentioned, and I'm assuming that is unchanged.

Kabuto

Well, I didn't want to go into too much detail because it'll probably just complicate the discussion.
But the crux of my question is ... am I going to have enough seat post with the bike I'm looking to purchase...

My height is 183cm, my cycling inseam is 92cm.
I'm looking at buying a 2021 size 58 Domane SL5.
This bike's maximum BB to saddle rail length with the "tall mast" seat post option is 78.5cm.
I don't have the bike yet, nor do I have clipless pedals/shoes.

On the bike I'm riding now, I have the BB to saddle rail distance set at 78cm.
I'm currently using flat pedals, and will move to clipless pedals with the new bike.
My current crank length is 170mm but is 175mm on the new bike.

Am I going to have enough saddle height with the size 58 Domane SL5 and clipless?

The reason I ask is I've never used clipless pedals. If the move to clipless requires less, no change, or up to 1cm extra saddle to pedal distance, the size 58 Domane will work (bike is in stock and I can get it immediately). If the move to clipless requires more than an extra 1cm of saddle to pedal distance, a size 60 Domane will get me an extra 2cm over the size 58, but it's special order in Japan so a six month plus wait.

Unca_Sam

I personally don't expect the cleat attachment to add that much height, especially with you adding 5mm to the pedal to saddle distance.

The measurements you're providing are close, but still don't get the information needed to say yes or no. The measurement that matters is saddle surface to pedal surface, everything else is just a subdivision of that. I'm guessing that you don't know the girth of the saddle that will come on the bike, but in my experience it's usually around 5cm from the rails to the part you're sitting on. I'll also note that the cleat attachment can add some thickness to your shoe/pedal interface, but it's not likely to exceed 1 cm, especially if you aren't riding your flat pedals with minimalist 3-7mm thick soles.

My take is that you'll be fine on the 58, unless you like to ride frames as big as possible.

Iride01 

Likewise I wouldn't expect a big difference in saddle height due to going to clipless. It's not been anything I've ever been concerned with. Maybe at most a silly centimeter longer. Sort of like the old Chesterfield commercial long ago before they were banned. (only it was a silly millimeter longer)

I don't know how you should base choices you got and they don't specifically say online. These are for the 58 cm frame.

Saddle rail height min (w/short mast) 69.0
Saddle rail height max (w/short mast) 75.0
Saddle rail height min (w/tall mast) 72.5
Saddle rail height max (w/tall mast) 78.5

I sort of assume that with the they are the min max you can get measured to the BB then you have to add in the crank length and the height from saddle rails to top of saddle.

My 56 cm Tarmac is currently at 73.6 cm between the rails and BB. I'm 180 cm with 87.6 cm inseam. So that sort of makes sense what Giant is showing.

You can simply measure your current bike if the saddle height is to your liking from the bb to the rails. Since your cranks are 170, then for the bike with 175 mm cranks you need to take 5 mm off whatever you measure.

The issue I see is that if the bike comes with 175 mm cranks, then you might be better off with the short mast. If you are going to change them to 170 mm cranks later, then you might need the tall mast as shorter cranks mean taller saddle height.

How much is a mast if you find later on that you need the other size?

I wouldn't sweat the clipless/flat pedal thing though. I'd actually doubt it's the cm more I mentioned. Though again, I've never thought to concern myself with it.

caloso

I have a set of spd/platform pedals I keep on my CX bike during the offseason when I use it as a commuter/gravel bike. I notice that it feels "short" when I'm riding on the platforms with normal shoes but since I'm just doing short commutes and errands, I don't bother changing saddle height. If I were to ride for an hour or two like that my knees might start squawking, but it's really not an issue to be a mm or two short for a 20 minute ride. YMMV.

Kabuto

Thanks for the reply. Actually, I am riding my flat pedals with minimalist (7mm or so?) thick soles, and it occurred to me as I read your post that I should have just asked about stack height differences between flat pedals vs clipless.

I think I'll be fine with the 58 but its going to be close.

Mojo31

I recommend going and trying out the bike. My 2020 Domane SL5 fits quite differently than my Sirrus 4.0 despite very similar frames. My Sirrus is a 58. My Domane is a 56. The Domane fits “large” and the seat post range is more limited than on a bike with a conventional post. The Trek site said I needed a 58, but I could barely reach the pedals. I don’t think you will find the answer to your question until you hop on one.

I would expect that the store could put a pair of shoes, etc. on you and sit you on the bike to see how it would work out.

Great bike - love mine! So much I splurged on a carbon wheel set for it Saturday (Bontrager Pro 37).

Also, highly recommend the Ion Flare RT lights. Really integrate well with the Blendr stuff.

Good luck!

Kabuto

That's the thing. Compared with my current flat pedal setup, even with the tall mast at maximum extension (78.5cm) AND 175mm cranks, there's only a silly cm of extra extension available compared to what I'm riding now.
I noted the fourth number here (78.5) in my second post above. I will have the tall mast extended pretty much to the max, so the other three numbers are not relevant to my situation.

Yes, its BB to saddle rail. Confirmed this at a Trek shop yesterday.

As I noted in my second post above, my current bike is 78cm between the rails and BB. Compared to you, I have an extra 4.4cm of inseam and my saddle rails are 4.4cm higher. Lines up perfectly with your numbers, but I'm on flat pedals with thin sole shoes and still haven't factored in increased pedal stack height due to cleats.

I did measure my current bike. 78cm from BB to saddle rails as noted above. I'm probably going to need that extra 5mm from the 175mm cranks.

The short mast will definitely NOT WORK for me. Way too short.

That's the thing. Compared with my current flat pedal setup, even with the tall mast at maximum extension (78.5cm) AND 175mm cranks, there's only a silly cm of extra extension available.

I should have just asked about differences in stack height between flat pedals vs clipless. I know all the other variables but don't know these.

Kabuto

Thanks for the reply. I understand the difference won't be huge. The issue for me is "will it be within 1cm extra"?

Kabuto

Thanks for the reply. The integrated lights do look great! Will look into that!!

Re sizing, sitting on one before buying is not an option, unfortunately. I live in Japan where the average cyclist rides a bike about two to three sizes smaller than the average western cyclist. That means size 56 bikes are not very common, size 58 bikes are rare, and size 60 and above bikes are rare as hens teeth. The biggest Domane I could find in multiple shops in Yokohama (a city of 4 million people) was size 54. There's a 58 in a box in a Trek warehouse somewhere, but its yet to be assembled. Size 60 and above is not available in Japan except by special order (six months+ wait).

Mojo31

Gotcha.

Kabuto

Trek sizing seems a little on the small side compared to other manufacturers, so its interesting you went down a size with the Domane compared to your Sirrus. Can I ask what your height/inseam is? Thanks!

79pmooney

For me, bike fit is an almost sacred thing, especially seat height and placement. Buying a bike that might be close but not quite? Better not be one of my good bikes.

Again, for me, the key issue for seat height is knee bend. That is affected by shoe thickness, cleat height, pedal design, seat shape and my position on the bike. Yes, in theory, all this should be measurable and known. I draw up my bikes on the computer and estimate seat height and setback from that. But still, I am carrying the wrenches and am tweaking on my early rides. If I found I was at the limit and wanted a hair more, I"d be very upset. (Except that won't happen. I won't buy a bike that has anything "pegged" or "slammed". Well I might, but only if I knew I could easily have the part custom made that would rectify that issue. Slammed regular seatpost? Getting a custom post of whatever setback is just a matter of money. It is easily made. Seat masts? Count me out. My body or needs might change.)

Mojo31

6’ and right at about 32.5/33” barefoot.

Kabuto

Sounds promising for me. I think you couldn't reach the pedals on the 58 because of the tall mast, which comes standard on the 58. The 56 comes standard with a short mast. A 58 with a short mast might have worked for you?! How high do you have the short mast set on the 56?

Mojo31

That could be. At the time, I was not fully up to speed on those details. The one I tried was the first one I found. The store did not have a 56 for comparison.

Here is my mast/post. Not much extension.

Mojo31

A better pic.

caloso

It’s a good question. It might be depending on your shoes.

Kabuto

Brilliant!!! Thank you!! Could I trouble you to also post a pic of the seat mast from behind to show the height scale on the post?

Mojo31

hope this helps.

Kabuto

Perfect!!!! Thank you very much!!!! From that photo, I calculate that your BB center to saddle rail height is about 69cm or 27.2 inches. From your height and inseam measurements at that BB to saddle rail height, I think I'll be fine on a 58.

FYI for anyone wondering about the two types of seat masts, short and long below.

Kabuto

I think I'll be ok, especially if I stick with a low pedal/shoe stack height.