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Correct frame size?

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Old 09-25-25 | 04:22 PM
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Correct frame size?



Hi everyone! I just picked up this bike: Surly Midnight Special, 54cm (M). My height is 180cm, and I have relatively shorter legs and a longer torso. According to the official guidelines, I'm between 54M(170-183) and 56L(180-190). Before I start working on the actual fit, I just wanted to make sure I got the right frame size! Sorry about the messy background! It's raining outside. Thank you!!!
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Old 09-26-25 | 09:28 AM
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not looking at the actual specs... but just eyeballing the pic... we all have the option of using a number of difference frame sizes in any bike design/model.

you can make this size work for you.
but a couple of comments as to how you have it currently setup
1. Your saddle angle will cause you to slide forward on it, it will certainly cause a lot of your torso weight to be transferred to your arms and the bars, putting undo pressure on your everything from your back/beck to you wrists, hands...
Flatten the saddle to reduce that issue. Saddle fore/aft adjustment will also help balance your weight pressure between seat and bars - that's a bit more complicated - so with that std setback seatpost, just center the saddle on the rails adjustment, and work from there. Sliding the saddle slightly forward, move weight more forward but also makes it just a bit easier to 'spin' a gear - rearward does the opposite. Balance between the two opposites is usually preferred...
2. You'll likely need to lower your saddle to make a flatter saddle work well. DO that.
A good start point for saddle height placement is to put your heels on the pedals and pedal backward while moving - when you're not rocking your hips to maintain pedal contact - that's a good start point. Then ride for some days, making very, very small adjustments to that. The small adjustments will accommodate your foot/shoe size and your pedaling style...
3. Bend your elbows to a comfortable degree, so that weight, shocks can be properly handled rather than straight arms which just send shocks right thru your arms to shoulders and neck.

Ride the Bike for a while before fooling greatly with things.
If you're not riding your bike often over a week period, you'll likely find your will have 'butt ache'... - normal - it's a period of 'adaptation' for the butt... very often not a saddle problem, just time on the bike.
This is all under the assumption that your will ride for more than 20-30 minutes for a ride...
Ride On
Yuri

Last edited by cyclezen; 09-26-25 at 09:33 AM.
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Old 09-26-25 | 09:44 AM
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Originally Posted by cyclezen
not looking at the actual specs... but just eyeballing the pic... we all have the option of using a number of difference frame sizes in any bike design/model.

you can make this size work for you.
but a couple of comments as to how you have it currently setup
1. Your saddle angle will cause you to slide forward on it, it will certainly cause a lot of your torso weight to be transferred to your arms and the bars, putting undo pressure on your everything from your back/beck to you wrists, hands...
Flatten the saddle to reduce that issue. Saddle fore/aft adjustment will also help balance your weight pressure between seat and bars - that's a bit more complicated - so with that std setback seatpost, just center the saddle on the rails adjustment, and work from there. Sliding the saddle slightly forward, move weight more forward but also makes it just a bit easier to 'spin' a gear - rearward does the opposite. Balance between the two opposites is usually preferred...
2. You'll likely need to lower your saddle to make a flatter saddle work well. DO that.
A good start point for saddle height placement is to put your heels on the pedals and pedal backward while moving - when you're not rocking your hips to maintain pedal contact - that's a good start point. Then ride for some days, making very, very small adjustments to that. The small adjustments will accommodate your foot/shoe size and your pedaling style...
3. Bend your elbows to a comfortable degree, so that weight, shocks can be properly handled rather than straight arms which just send shocks right thru your arms to shoulders and neck.

Ride the Bike for a while before fooling greatly with things.
If you're not riding your bike often over a week period, you'll likely find your will have 'butt ache'... - normal - it's a period of 'adaptation' for the butt... very often not a saddle problem, just time on the bike.
This is all under the assumption that your will ride for more than 20-30 minutes for a ride...
Ride On
Yuri
Thanks for the great advice! I'll work on the saddle adjustment!

I understand that when it comes to frame sizes, it comes down to your preference unless it's far off from your size realm but subjectively speaking does the size of the bike look good on me?

Thank you!!
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Old 09-26-25 | 12:46 PM
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Originally Posted by cyclezen
not looking at the actual specs... but just eyeballing the pic... we all have the option of using a number of difference frame sizes in any bike design/model.

you can make this size work for you.
but a couple of comments as to how you have it currently setup
1. Your saddle angle will cause you to slide forward on it, it will certainly cause a lot of your torso weight to be transferred to your arms and the bars, putting undo pressure on your everything from your back/beck to you wrists, hands...
Flatten the saddle to reduce that issue. Saddle fore/aft adjustment will also help balance your weight pressure between seat and bars - that's a bit more complicated - so with that std setback seatpost, just center the saddle on the rails adjustment, and work from there. Sliding the saddle slightly forward, move weight more forward but also makes it just a bit easier to 'spin' a gear - rearward does the opposite. Balance between the two opposites is usually preferred...
2. You'll likely need to lower your saddle to make a flatter saddle work well. DO that.
A good start point for saddle height placement is to put your heels on the pedals and pedal backward while moving - when you're not rocking your hips to maintain pedal contact - that's a good start point. Then ride for some days, making very, very small adjustments to that. The small adjustments will accommodate your foot/shoe size and your pedaling style...
3. Bend your elbows to a comfortable degree, so that weight, shocks can be properly handled rather than straight arms which just send shocks right thru your arms to shoulders and neck.

Ride the Bike for a while before fooling greatly with things.
If you're not riding your bike often over a week period, you'll likely find your will have 'butt ache'... - normal - it's a period of 'adaptation' for the butt... very often not a saddle problem, just time on the bike.
This is all under the assumption that your will ride for more than 20-30 minutes for a ride...
Ride On
Yuri
Agreed, mostly. But: in addition to leveling the saddle, it'll have to come down significantly.

Also, the heel-on-pedal thing gives very different results, depending on the thickness of the heel. It's most reliable for the old-school racing shoes that had very thin leather soles and no heels. Using shoes like the pair the OP is wearing in his photos can and often does result in moving the saddle to a position that's still too high.

The OP might try making the changes per your suggestions, taking another set of photos, and then comparing those photos to action shots of professional road riders.

Somewhat counter-intuitively, many or most of the pros use saddle heights that usually show more of a bend in the knee (with the pedal at the bottom and the crank in line with the seat tube) than many amateur riders.

(I've never understood why amateur sport cyclists gravitate toward setting their saddles so high, or why casual.cyclists set theirs so low.)
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Old 09-26-25 | 01:00 PM
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If you like the lower bar height, then the 54 was probably the right decision. If you will rather have a higher bar height, then a 56 in that same model might have been better. But either way not a big deal unless you need the most extreme opposite position that the two could give you. For any upper body position in between, Either size can be made to get you the fit you want or need.

I'm 180cm with long legs. And I bought the smaller of two sizes for the model bike I wanted. Because I wanted the lower frame stack to have my bars lower than I could have gotten them on the next size up. And because I knew I wouldn't like the longer 175mm crankarms that came with the larger size bike. The 172.5mm crank arms on the smaller size bike I might have gotten use too. But I still decided to change them anyway since I already had cranks of the 165mm length I prefer.

If you don't have any complaints about numbness or pain. Or find yourself wondering if there is a better position for you to put out more power and be more aerodynamic, there is really no need to worry about fit. It looks okay. Though for longer rides you might get numb or sore hands and wrists with your somewhat straight arms. If you can't get use to keeping more bend in the elbow , then putting a longer stem and raising the bars might might stretch your arms out to a angle that will let more of your body share the bumps and other stuff that work on your hands and wrists.

I also think you should have your saddle fairly level with little tilt. To me, noticeably tilted saddles are a sign that other things about your fit need to be changed. Sometimes the saddles setback. Either more or less. You can experiment with where you put the clamp in the rails. If you were to have the saddle all the way to the extreme range on the rails, then that might suggest you need a different setback on the post.

Often, what is comfortable for short rides, isn't comfortable for long rides. So consider that when changing things up.

If you have a actual complaint, then let us know. Or someone local to you know. Numbness should be dealt with immediately. As should sores on skin that might be from your riding posture. It's not something you should think you'll get use to. Very minor pain, particularly a sore butt might be a indicator you just don't ride often enough or are too new to cycling.

Exercising your glutes, upper arms and shoulder girdle through their full range of motion when off of the bike will go a long way to keep you comfortable when on the bike. Particularly after you retire or when your physical activity for other things starts to slack off.

I'm not a fitter. But I have fit myself to all my bicycles very well since my first bike before kindergarten.

Last edited by Iride01; 09-26-25 at 04:58 PM.
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Old 09-26-25 | 03:21 PM
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Originally Posted by Lili1117
Thanks for the great advice! I'll work on the saddle adjustment!

I understand that when it comes to frame sizes, it comes down to your preference unless it's far off from your size realm but subjectively speaking does the size of the bike look good on me?

Thank you!!
Overall the size should be workable.
A longer torso person would be able to have a 'longer' frame, as long as the seat position can be met (large frames tend to have a lower, more angled Seat tube, slightly...
for some like me, v-short torso, v-long legs,arms a larger frame can create 'reach' issues (which don;t really bother me...)
so, what I see is a very 'race' type geometry for the main triangle - a quick compare with a Spec Tarmac SL7 (very much a race oriented machine) shows the 54 Midnight Special to be very close if not more 'race' (HT length) than the Tarmac.
How is that adapted to a more 'rec' type fit? The very up-angled, relatively short stem, and a bunch of spacers under the stem, which raises the 'stack' some.
If the current setup works for you, then great.
Can I tell you if it works ? No I can't ... that really depends on you, how you ride, you desires and expectations, etc...
Can a professional Fitter tell you how it will be/work? I don;t think so. What they can do is look at your body geometry and try to put you into a 'position' which their system recognizes as the optimum for performance and maybe comfort, from data gather in studies they ascribe to...
Can a Pro Fitter help? Sometimes... They might help where things are quite out whack for you.
What I think might work is also in question - which only you can answer.
You're asking BECAUSE you have doubts if the bike will 'fit'? Or have you already ridden it and have found things which don't feel 'right'?
my opinion is that the bike can 'fit', but is also on the very smallest of frame dimensions For someone your size.
Ride On
Yuri
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Old 09-27-25 | 04:22 PM
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Originally Posted by cyclezen
Overall the size should be workable.
A longer torso person would be able to have a 'longer' frame, as long as the seat position can be met (large frames tend to have a lower, more angled Seat tube, slightly...
for some like me, v-short torso, v-long legs,arms a larger frame can create 'reach' issues (which don;t really bother me...)
so, what I see is a very 'race' type geometry for the main triangle - a quick compare with a Spec Tarmac SL7 (very much a race oriented machine) shows the 54 Midnight Special to be very close if not more 'race' (HT length) than the Tarmac.
How is that adapted to a more 'rec' type fit? The very up-angled, relatively short stem, and a bunch of spacers under the stem, which raises the 'stack' some.
If the current setup works for you, then great.
Can I tell you if it works ? No I can't ... that really depends on you, how you ride, you desires and expectations, etc...
Can a professional Fitter tell you how it will be/work? I don;t think so. What they can do is look at your body geometry and try to put you into a 'position' which their system recognizes as the optimum for performance and maybe comfort, from data gather in studies they ascribe to...
Can a Pro Fitter help? Sometimes... They might help where things are quite out whack for you.
What I think might work is also in question - which only you can answer.
You're asking BECAUSE you have doubts if the bike will 'fit'? Or have you already ridden it and have found things which don't feel 'right'?
my opinion is that the bike can 'fit', but is also on the very smallest of frame dimensions For someone your size.
Ride On
Yuri
Thank you so much for taking time to break it down for me! It's been very helpful.

I was mainly asking because of my OCD haha I was between sizes and decided to go with the smaller one. I’ve done a short ride (around 30 km), and it felt fine so far, at least to my inexperienced eye.
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Old 09-27-25 | 04:41 PM
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Originally Posted by Iride01
If you like the lower bar height, then the 54 was probably the right decision. If you will rather have a higher bar height, then a 56 in that same model might have been better. But either way not a big deal unless you need the most extreme opposite position that the two could give you. For any upper body position in between, Either size can be made to get you the fit you want or need.

I'm 180cm with long legs. And I bought the smaller of two sizes for the model bike I wanted. Because I wanted the lower frame stack to have my bars lower than I could have gotten them on the next size up. And because I knew I wouldn't like the longer 175mm crankarms that came with the larger size bike. The 172.5mm crank arms on the smaller size bike I might have gotten use too. But I still decided to change them anyway since I already had cranks of the 165mm length I prefer.

If you don't have any complaints about numbness or pain. Or find yourself wondering if there is a better position for you to put out more power and be more aerodynamic, there is really no need to worry about fit. It looks okay. Though for longer rides you might get numb or sore hands and wrists with your somewhat straight arms. If you can't get use to keeping more bend in the elbow , then putting a longer stem and raising the bars might might stretch your arms out to a angle that will let more of your body share the bumps and other stuff that work on your hands and wrists.

I also think you should have your saddle fairly level with little tilt. To me, noticeably tilted saddles are a sign that other things about your fit need to be changed. Sometimes the saddles setback. Either more or less. You can experiment with where you put the clamp in the rails. If you were to have the saddle all the way to the extreme range on the rails, then that might suggest you need a different setback on the post.

Often, what is comfortable for short rides, isn't comfortable for long rides. So consider that when changing things up.

If you have a actual complaint, then let us know. Or someone local to you know. Numbness should be dealt with immediately. As should sores on skin that might be from your riding posture. It's not something you should think you'll get use to. Very minor pain, particularly a sore butt might be a indicator you just don't ride often enough or are too new to cycling.

Exercising your glutes, upper arms and shoulder girdle through their full range of motion when off of the bike will go a long way to keep you comfortable when on the bike. Particularly after you retire or when your physical activity for other things starts to slack off.

I'm not a fitter. But I have fit myself to all my bicycles very well since my first bike before kindergarten.
Thanks for the input! It's good to hear. I was starting to overthink haha. I took it for a spin but didn't feel any discomfort other than my sit bone but that's probably because I just haven't been riding enough yet.

I'm probably gonna size down the crank length from 170mm to 165mm as well since I have shorter legs.
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Old 09-28-25 | 10:10 AM
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Originally Posted by Lili1117
Thanks for the input! It's good to hear. I was starting to overthink haha. I took it for a spin but didn't feel any discomfort other than my sit bone but that's probably because I just haven't been riding enough yet.

I'm probably gonna size down the crank length from 170mm to 165mm as well since I have shorter legs.
54 is very small for someone nearly 5'11" tall.

The problem with going to a small size because of short legs is that you have the torso of someone 6' tall and you are trying to ride a bike with horizontal reach for someone 5'6" tall.


You have this bike so it is worth trying to get it to work. Start by moving the saddle all the way back to give you reasonable set back and use up some of your extra reach and use the .883 formula or equivalent to set the saddle height. Then see how the reachnis and if a longer stem or higher stem placement will work.
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Old 09-28-25 | 11:33 AM
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Originally Posted by Lili1117
I'm probably gonna size down the crank length from 170mm to 165mm as well since I have shorter legs.
Wait till you know they are a issue for you. I already had some previous experience that made it reasonable for me to change them out at the get go. A previous bike I put longer cranks on and couldn't get use to them. And that was in my early 50's. All my previous bikes were low cost Schwinn's from the vintage years with Ashtabula cranks that tend to be 165mm or less. So my knees were use to that. And there are other more common causes for knee pain on a bike than crank length. So investigate the other causes first before jumping to the somewhat expensive solution that may not actually solve your pain.

I'm actually again toying with the idea of putting those longer cranks back on an seeing for sure that there were or weren't the issue I felt they were.

Surly does size their bikes a tad differently than some others....

Surly Bike Sizing Chart

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Old 09-28-25 | 12:17 PM
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Originally Posted by Iride01
Wait till you know they are a issue for you. I already had some previous experience that made it reasonable for me to change them out at the get go. A previous bike I put longer cranks on and couldn't get use to them. And that was in my early 50's. All my previous bikes were low cost Schwinn's from the vintage years with Ashtabula cranks that tend to be 165mm or less. So my knees were use to that. And there are other more common causes for knee pain on a bike than crank length. So investigate the other causes first before jumping to the somewhat expensive solution that may not actually solve your pain.

I'm actually again toying with the idea of putting those longer cranks back on an seeing for sure that there were or weren't the issue I felt they were.

Surly does size their bikes a tad differently than some others....
That's true. I should keep the length for now until I ride it enough to see how I feel.

Yesh according to the Surly size chart I'm well within the M size realm and apparently their frame sizes tend to fit bigger that's why I went with 54 haha.
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Old 09-29-25 | 10:03 AM
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Originally Posted by Lili1117
Thanks for the input! It's good to hear. I was starting to overthink haha. I took it for a spin but didn't feel any discomfort other than my sit bone but that's probably because I just haven't been riding enough yet.

I'm probably gonna size down the crank length from 170mm to 165mm as well since I have shorter legs.
Since it seems that you're new to cycling on this type of bike, I suggest not getting into wholesale changes to components.
Get some miles under the tires, by many months.
Work on optimizing your posture and pedaling. A smooth, circular pedal stroke goes a long way making cycling fun and efficient.
Ride On
Yuri
EDIT: and having a good torso posture goes a long way to making the riding comfortable. That usually means riding with bend in elbows (not locked or 'straight')
and wrists held in a straight fashion (not allowing them to collapse into an L shape with the hand/palm and forearm...Allow the shoulders to 'drop' and not hunch up around the neck... riding posture will be 'habitual', so work on good habits for pleasurable riding...

Last edited by cyclezen; 09-29-25 at 10:35 AM.
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Old 09-29-25 | 11:08 AM
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Originally Posted by Kontact
54 is very small for someone nearly 5'11" tall.
This is a long-running Surly road bike thing. Their trademark styles are large tire clearance but also level top tubes. So to make an acceptable stand-over, they push the top of the frame (both seat tube and stack) lower. Nevertheless they quote the seat tube size. A size 54 on this bike is 55.5 long, would be a 56 for the large brands.


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Old 09-29-25 | 02:32 PM
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Originally Posted by Darth Lefty
This is a long-running Surly road bike thing. Their trademark styles are large tire clearance but also level top tubes. So to make an acceptable stand-over, they push the top of the frame (both seat tube and stack) lower. Nevertheless they quote the seat tube size. A size 54 on this bike is 55.5 long, would be a 56 for the large brands.

If you correct for STA of 73.5, it is a 55 TT which is normal for 54, and their 56 has a 56 5 TT which is also normal.

They seem to be sizing everyone down for no apparent reason.
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Old 09-29-25 | 06:41 PM
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another fun comparo - 2023 Spec Tarmac SL7 v 2024 Surly Midnight Special 54cm

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