Road Bike Frame Differences


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wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#1
How much different are Road Bike Frames vs Sit Up Bikes Frames? At a bike swap meet yesterday I test rode 2 road bikes that were clearly too short for me. I am 6' tall so I figure I need a 23" frame. These were 21" or a little shorter, perhaps. Instantly they were very comfortable to ride! No feeling of leaning over the bars and causing my hands to hurt. One bike was from the 70's and the other from the 80's. I could sure tell they would be hard for me to pedal very long so I passed, but I can't get over how comfortable they are. What I'm wondering is.....is this related to the size (height) of the bike or the geometry? I'm puzzled.
 

SirMike1983

Cruisin' on my Bluebird
Jun 27, 2008
3,061
2,712
United States
#2
It sounds like the frame reach was shorter. The height is only one measurement of the frame. You also have to consider the length of the top tube and how far forward you have to reach to get to the bars. How the bike feels is the product of several measurements beyond just height - top tube length, stem type, bar height, etc. Same as how you could not tell a tailor to make a suit by only telling him how tall you are - there are other measurements.

https://www.cyclingabout.com/understanding-bicycle-frame-geometry/

wpid-Photo-3-Oct-2013-1141-pm.jpg
 

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#3
It just felt like, and this may be part of the puzzle, that the upper half of me couldn't be more comfortable. I was at ease reaching for and shifting the downtube shifters on the one. I just wish I could figure it out and find that level of comfort on a bike made for my legs. Frustrating. I must have to try out several so I can find the one. I have noticed that on my Raleigh Sports bikes that I have turned into road bikes I can tolerate them if I slide the seat as far forward as possible.
 

dnc1

I live for the CABE
Apr 1, 2016
1,965
5,860
53
Wallingford, Oxfordshire, UK
#5
From what you've said immediately above @wrongway , and from what @SirMike1983 intimated earlier, top tube length in conjunction with paying close attention to stem reach length would appear to be your guide to achieving a comfortable ride.
You may have to swap a few stems around on any given frame to get where you want to be.
Bars may also need to be swapped, so many subtly different shapes, and widths available in the field of drops.
Oh, I second @juvela wholeheartedly!
 

Duchess

Wore out three sets of tires already!
Feb 14, 2014
560
1,002
Beverly, MA
#6
Different eras of road bikes brought fashionable changes in frame geometry, but as a general rule, a cruiser has a more laid back seat post and longer wheelbase. Fit is most difficult to achieve with a road bike because they aren't built for comfort as top priority and what works to transfer power efficiently does not often match what is comfortable. The idea behind them is also that you are powering enough that you don't support much of your weight on your hands, but the geometry makes that difficult to do unless you are heavily using your leg and core muscles as you would when riding fast (that you're not supporting much weight on your backside is why the saddles are so often recreations of devices used during the Spanish Inquisition). That's also the reason for the drop bars—to allow for more hand positions to relieve stresses, particularly on longer runs and to allow for different postures to match a change in topography. Cruisers are designed for comfort at the expense of efficiency and handling and are not generally expected to do long rides.

It sounds like you want the shorter reach and more upright stance of a cruiser, but something like the more efficient pedaling geometry of a road bike. I am much the same way. My favorite bike that I've ridden is my modified 93 Giant Innova, which is an early hybrid with a strong and reasonably light chromoly frame (mostly a rigid mountain bike with larger and thinner 700c wheels and tires). It's a hair on the small side for me, but I can easily dismount while moving. It is versatile, comfortable, and surprisingly fast—not as much to keep up with roadies, but I have to hold back whenever I ride with anyone else. These types of bikes are usually pretty cheap. Here's what it looked like originally (actually, this is a slightly larger one I picked up to electrify) and what it looks like now that I'm done with it (though, I might add a tow bar for my kayaks). Even with the added weight of the rack, fenders, 12V headlight and battery pack, and oak block pedals, it's only about 35 lbs.

1554934987045.png


1554935003401.png
 

49autocycledeluxe

I live for the CABE
May 29, 2017
1,176
2,096
59
fremont california
#7
on a road bike when you stand over the top tube you should have maybe 2" of clearance for your junk.

taller frames are also longer on the top tube. your reach can be changed with a different handlebar stem... longer or shorter or one that puts the bars higher or lower.

why were those bikes hard to pedal?
 

bulldog1935

Cruisin' on my Bluebird
Jan 21, 2013
3,766
5,529
Bulverde, TX
#8
Well, I'll do what I can. You definitely don't want a top tube taller than you can stand over flatfooted.
Racing bikes tend to be steeper angles in head tube and seat tube, to give you crisp steering and short wheelbase, and lower bottom bracket.
Upright bikes and touring bikes tend to have relaxed angles and longer wheel base, including longer top tube, and higher bottom bracket. Low trail is a particular advantage in a front-loaded bike (low trail can be achieved either with relaxed head tube angle or fork offset).
Low trail also rides really nice (the fork is a better shock absorber), and the French always preferred low trail forks even on their racing bikes.

Relative top tube length has grown over the years. The angled top tube is simply to make it easier to stand over the frame. Bars are getting taller, and bar reach shorter.
Mountain and gravel bikes are kind of a special case of touring bikes, with shorter frame, longer top tube, high bottom bracket clearance and long chainstays to give long wheelbase, all intended to keep you going straight when you bounce.

Carlton geometry ruled the racing world in the days of steel. Those steep angles I mentioned, low fork offset, with seat tube and top tube pretty close to equal lengths. People built like me, with long limbs and shorter than typical torsos for their height love Carlton Geometry. (People with shorter legs and longer torso are going to prefer shorter frames with longer top tube.)
The Italians grabbed Carlton geometry with fervor, and over the next decades made head angles slightly steeper. and shortened chainstays to virtually no clearance between tire and seat tube.
High trail or low fork offset on a racing bike gives you very solid on-center feel, still with fast steering when you do turn for that steep head-tube, but more often you lean to make the bike turn. An advantage to leaning when you turn the bike is that gravity is adding to your acceleration out of the turn.

Reach and height can be adjusted in seatpost and stem, but as you lengthen your body relative to the designed wheelbase, you can adversely affect handling.
In a racing geometry, while you still sit behind the crank, a greater portion of your body weight is on the front wheel, and relative to more relaxed geometries, you're much closer to being directly over the crank. Proper seat height on a racing bike is usually a little higher than the stem - you should be able to lock your knees, but not forced to lock your knees on every rotation. You also pedal on the balls of your feet, requiring a taller saddle. Proper reach on a racing bike, your hands should be right over the front axle.

Usually a bad idea to make an upright out of an aggressive racing frame - the steering is awful fast, and your weight distribution won't be great. Less weight on that steep head tube makes steering twitchy.
Seat height on an upright should never be tall enough to let you lock your knees - you should be sitting well behind the crank, and bar height is taller than seat height. You can also center your arches over the pedals, allowing you to sit shorter.

Raleigh is always a good benchmark. Their touring bikes are uprights. They built a few true sport-touring bikes in the International, Gran Sport, and Grand Prix, Carlton geometry frames with low trail forks, and the rest of their bike-boom 10 speeds were Carlton geometry frames with high-trail (low offset) racing forks.

Here's my International frame with a pretty good perspective - Carlton geometry frame with low-trail fork, and I have it built now as a semi-upright with tall stem - this bike is my benchmark in every respect, the most comfortable and versatile bike I own, and I begin any other bike project with reach measurements from this bike. I worked out this position over 40 years on my Grand Prix, with identical frame and fork geometry.
Note that with the moustache bar cockpit of this bike, the stem reach Must be 2" shorter than what normally fits you on a drop-bar road bike, because the bar reach is that much greater. My semi-upright riding position has the hoods about an inch behind the front axle.
hPkFYWX.jpg


here's the perspective on my road bike - I started with reach measurements from the bike above, compared top tubes, and measured out a stem length of 100mm to get the same reach to the hoods as above. You may be able to see this bike sits a little closer to being vertical over the crank, also requiring a taller saddle.
Both head and seat tube are slightly steeper, top tube length about the same, noticeable lower fork offset (high trail)
The bars I picked are Cinelli 64, the original compact Dream Bar from the 70s - shorter reach, much closer and usable drop position - you can find this bar new for $45 - do not pass Go.
1YGtXlj.jpg


Upright - seat way back, much lower, on the longest-rear-offset seatpost made, Nitto S84. The CX frame has a longer top tube and higher bottom bracket. I measured reach here to match the outside grab position on the moustache bars of the International. You'll note hand position here is not even close to the front axle.
6YY7fET.jpg
 
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MarkKBike

Wore out three sets of tires already!
Apr 17, 2017
858
2,003
Chicago Suburbs
#9
We all change over time as well. When I was younger I used to keep the bars pretty low. This comment does not have much to do with geometry, but as I got older I found that raising my stance a bit has eliminated much of the back pain I used to experiance, and has made for what I feel is a much more comfortable ride. I now perfer a bike that has the handle bar position at about the same height as the seat, while in my earlier years a bit of a drop never bothered me. I tend to choose comfort over max performance now a days. I also choose a slightly larger frame to what my height would typically indicate as ideal as my arm span is about 4 inches longer than my height.
 
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bulldog1935

Cruisin' on my Bluebird
Jan 21, 2013
3,766
5,529
Bulverde, TX
#10
two more views of the Cinelli 64 Dream Bar (Giro d'Italia) - as I said above, these are the original compact drops. I spend as much time on the drops as on the hoods.
Even touring bikes in the bike boom tended to have giant reach, giant drop pista bars. Don't know what they were thinking, but it wasn't comfort.
The Maes bend that Raleigh used was somewhere between, but greater reach, slightly greater drop, and not near as compact and cozy as this bar.
6Fw33Dy.jpg
hDVGDMM.jpg
 
Last edited:
Likes: dnc1

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#11
Different eras of road bikes brought fashionable changes in frame geometry, but as a general rule, a cruiser has a more laid back seat post and longer wheelbase. Fit is most difficult to achieve with a road bike because they aren't built for comfort as top priority and what works to transfer power efficiently does not often match what is comfortable. The idea behind them is also that you are powering enough that you don't support much of your weight on your hands, but the geometry makes that difficult to do unless you are heavily using your leg and core muscles as you would when riding fast (that you're not supporting much weight on your backside is why the saddles are so often recreations of devices used during the Spanish Inquisition). That's also the reason for the drop bars—to allow for more hand positions to relieve stresses, particularly on longer runs and to allow for different postures to match a change in topography. Cruisers are designed for comfort at the expense of efficiency and handling and are not generally expected to do long rides.

It sounds like you want the shorter reach and more upright stance of a cruiser, but something like the more efficient pedaling geometry of a road bike. I am much the same way. My favorite bike that I've ridden is my modified 93 Giant Innova, which is an early hybrid with a strong and reasonably light chromoly frame (mostly a rigid mountain bike with larger and thinner 700c wheels and tires). It's a hair on the small side for me, but I can easily dismount while moving. It is versatile, comfortable, and surprisingly fast—not as much to keep up with roadies, but I have to hold back whenever I ride with anyone else. These types of bikes are usually pretty cheap. Here's what it looked like originally (actually, this is a slightly larger one I picked up to electrify) and what it looks like now that I'm done with it (though, I might add a tow bar for my kayaks). Even with the added weight of the rack, fenders, 12V headlight and battery pack, and oak block pedals, it's only about 35 lbs.

View attachment 978370

View attachment 978371
Nice bike. I may have to go for something newer like that.
 

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#12
on a road bike when you stand over the top tube you should have maybe 2" of clearance for your junk.

taller frames are also longer on the top tube. your reach can be changed with a different handlebar stem... longer or shorter or one that puts the bars higher or lower.

why were those bikes hard to pedal?
They were hard to pedal because they were so short for me. I can see why the Motobecane Mirage would be a nice bike. it was sure smooth!
 
Likes: dnc1

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#13
These are the two bikes I'm currently playing around with. The one in the snow is a 'replica' of a 50's Raleigh Sports Model 21. I've gotten to where I can ride it in the drops. I am right at 6' tall and figure I need a 23" frame. This bike is a 23" frame. The other is a '51 Rudge and is a 22" frame. I also feel comfortable in the drops and maybe a little more so than the other. With the Rudge I can also have my legs fairly straight so the saddle isn't really too low.
NIGHTRALEIGH.jpg


NIGHTRUDGE.jpg
 

bulldog1935

Cruisin' on my Bluebird
Jan 21, 2013
3,766
5,529
Bulverde, TX
#14
on your bike just above, note sucky pista bars with giant reach and giant drop - your stem height doesn't look safe - be careful not to damage the fork steerer tube.
They were hard to pedal because they were so short for me. I can see why the Motobecane Mirage would be a nice bike. it was sure smooth!
You can try raising the saddle, and also try a stem that was made to be taller - Nitto Tecnomic or Dirt Drop.
Here's how Rivendell sets up a drop bar bike today - not intended to be a racing bike, but an all-road comfort bike (the Nitto noodle bars are still long reach for my likes).
(and the Nitto Technomic stem was made to be in this position)
b-sam16d-2_1600x.jpg


This bike has the same frame geometry (and probably size) as your bike just above - note how differently they're set up - this stem is at its safe limit, and saddle is higher for my 35" inseam.
z7AdSmu.jpg
 
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Likes: dnc1

vincev

I'm the Wiz, and nobody beats me!
Nov 2, 2008
12,636
10,669
crown point<indiana
#15
How much different are Road Bike Frames vs Sit Up Bikes Frames? At a bike swap meet yesterday I test rode 2 road bikes that were clearly too short for me. I am 6' tall so I figure I need a 23" frame. These were 21" or a little shorter, perhaps. Instantly they were very comfortable to ride! No feeling of leaning over the bars and causing my hands to hurt. One bike was from the 70's and the other from the 80's. I could sure tell they would be hard for me to pedal very long so I passed, but I can't get over how comfortable they are. What I'm wondering is.....is this related to the size (height) of the bike or the geometry? I'm puzzled.
I think you should have gotten the bike if it felt perfect for you.I always laugh when people ask "how can you ride on that skinny seat". They dont believe how comfortable a properly broke in seat feels.lol
 

PCHiggin

Cruisin' on my Bluebird
Jan 22, 2008
3,787
1,635
Ryderwood, United States
#16
Im 6'1" and the smallest oldie road bike frame for me is a 25"er 1974 Letour. I also have a 26" '73 Sports Tourer,It fits me well but the Letour frame geometry is more comfortable.
 

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#17
on your bike just above, note sucky pista bars with giant reach and giant drop - your stem height doesn't look safe - be careful not to damage the fork steerer tube.

You can try raising the saddle, and also try a stem that was made to be taller - Nitto Tecnomic or Dirt Drop.
Here's how Rivendell sets up a drop bar bike today - not intended to be a racing bike, but an all-road comfort bike (the Nitto noodle bars are still long reach for my likes).
(and the Nitto Technomic stem was made to be in this position)
View attachment 978607
I like that bike! Love that color, too! Is it a new bike? Important notes on the Rudge. I'll either change it or just occasionally ride it around town....maybe. I would like to find a road bike that is comfortable for many miles, but can also keep up with others.
 

wrongway

I live for the CABE
Apr 24, 2012
1,062
303
Pella, IA
#18
I think you should have gotten the bike if it felt perfect for you.I always laugh when people ask "how can you ride on that skinny seat". They dont believe how comfortable a properly broke in seat feels.lol
Well, I still could. I know where it's at. A friend has it. I could go over and adjust the seat and bars and see if I could make it work. It was the smoothest bike I've ridden so far and that was on 27x1-1/8 tires. Pair that with my Brooks B17 and I'd be set!
 
Likes: vincev

bulldog1935

Cruisin' on my Bluebird
Jan 21, 2013
3,766
5,529
Bulverde, TX
#19
I like that bike! Love that color, too! Is it a new bike? Important notes on the Rudge. I'll either change it or just occasionally ride it around town....maybe. I would like to find a road bike that is comfortable for many miles, but can also keep up with others.
yes, that Riv is brand new, with a discounted price tag of 2 grand
https://www.rivbike.com/collections...cles/products/sam-hillborne-complete-drop-bar

You also might want to review their sizing chart about measuring you and bikes.

As far as skinny saddle, you match saddle to riding position. B17 is for semi-upright. B15 (swallow) is for drop-bar road bike.
My Swallow is the most invisible saddle I've ever ridden.
Saddle break-in, though, is a myth. Need for break-in is picking the wrong saddle to begin with and/or maladjusting it.
Any Brooks saddle should always nose up, never nose down.
 
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bulldog1935

Cruisin' on my Bluebird
Jan 21, 2013
3,766
5,529
Bulverde, TX
#20
I like that bike! Love that color, too! Is it a new bike? Important notes on the Rudge. I'll either change it or just occasionally ride it around town....maybe. I would like to find a road bike that is comfortable for many miles, but can also keep up with others.
here's the correct stem if you want to swap it - not a lot of money nor a troublesome exercise (note the forward reach is 2-1/4", shorter than the photo shows)
 
Likes: dnc1

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