Ride Quality>> Trad vs. Oversize vs. Double Oversize

[Adam Eldridge]

Is there a quick answer to the difference in bike handling and ride characteristics between the tube sizes?

If your building with DO what type of crown and blades are you using to keep the fork from looking anemic?

Are your DO customers most always going with carbon forks, I would assume this..?

85 with 98% humidity and getting ready to fillet braze in a warehouse. Time to sweat it out.

Thanks gents.

[e-RICHIE]

i've ridden and raced on the first two options for a long time, and trained on the third, too. according to my opinion, it's a style/fashion thing and what you perceive, if anything at all, comes from the frame design. keep that consistent, and vary the diameters/shapes, and it "feels" like the same bicycle. well it does for me. but as eras changes and visuals do too, folks get used to different things. i can't look at modern parts and shapes on frames made with your first choice. when i went OS full time in the mid 1990s it was for this reason alone. bicycles with "trad" dimensions looked wrong with ergo, and concealed cables, and deep(er) rimmed, low spoke count wheels, and with short stack saddles replacing the rail geometry from the era before - and let's not forget thread-less. the beauty of waiting long enough is that the technology these days allows the frame dimensions to grow with the eras yet not penalize the end user with unnecessarily added avoirdupois. data point: my opinions are only about the ferrous materials. i embrace the look of the bicycles the same way i love to use them - fully. but when my eyes are shut and i'm in the pain cave, as long as the contact points are correct, and my center of gravity is positioned where it should be, i have no clue which tube set the bicycle is made with. the ideal is to take the best characteristics of the past and bring them along with you to the future. in my book, that means frame design and construction quality trump material choice every day of the week. that's been my message going back decades before bin laden's left eye was vaporized. and, all this from a guy who's in the business of selling materials too atmo...

[Dave Kirk]

I see this a bit differently than Richard does. While it's true that the larger tubes have a different look I don't see that as a compelling reason to use/not use them. I see it more of a way to match the bike to the rider and less of a way to match the look of the frame to the wheels or components.

When the diameter of a tube changes the bending stiffness of the tube changes too and in a fairly dramatic way. If one considers a pair or top tubes, both with a wall thickness of .6 mm (.023"), and one has an O.D. of 1.125" and the other has an OD of 1.250 (the change that the tubes go through from OS to XL or D.O. tubes) the larger top tube will have 140% the stiffness of the smaller tube. That is a pretty big number that I think most folks would feel. When you go from a 1.250" down tube to one with an OD of 1.375" the larger tube will have 133% the stiffness of the smaller one. The seat tube going from 1.125" OD to 1.250" will give the same results as the top tube - so all three main tubes gain a minimum of 33% in bending stiffness. These numbers are just for simple bending and doesn't factor in torsional resistance. I'd calculate it but for some reason I can't find my spread sheet for it. As I recall the numbers will be even more dramatic but someone smarter than me will find a calculator and post the numbers with any luck.

I own bikes with old school 1" top tubes, new school OS with a 1.125" top tube and a grad school 1.250" top tubes and while I like them all I would say that they lend themselves to different uses and feel a good bit different from one another. They all work well but they work best in different circumstances and certainly have much different flavors to me.

All that said and more to your question of how the tube diameters will affect handling. Generally speaking the larger tubes will of course deflect less when hitting bumps and will not give as smooth a ride. This is not to say that they give an unduly harsh ride but it isn't as buttery smooth as the smaller tubes. At the same time the larger tubed bike will have more torsional stiffness which makes the bike feel more precise on turn-in and it will better hold it's line on rough surfaces as it will not be deflected off it's line as easily.

I see the ride and handling differences being one of degrees. Both can work very well but no doubt some will prefer one over the other - as with all things some will like the change and others not so much.

As for the fork difference and the aesthetics. I build my XL bikes with steel forks and do not offer carbon forks. The steel fork has a 1 1/8" steerer along with it's bigger crown and headset and the only thing staying the same in size are the blades and I don't see the smaller blades being a problem aesthetically - but your taste may be different.

I think there are many ways to make a good bike and tube selection is just one of the many tools the builder can use to truly fit the bike to the rider and the end use. I offer bikes with 1" top tubes to smaller riders, 1 1/4" top tubes to larger riders and 1 1/8" tubes for those in between and it's all good. Goldy Locks had it right IMO.

Dave

[e-RICHIE]

i agree with dave - the numbers exist and are part of an equation. my reply answers the question
related to ride quality, etc. i can't tell the difference between the options listed in the first post atmo.

[jerk]

i agree with dave - the numbers exist and are part of an equation. my reply answers the question
related to ride quality, etc. i can't tell the difference between the options listed in the first post atmo.

it'd be really tough to make a bike that felt "underbuilt" to an athlete richard's size. personally, i can tell you that geometry trumps everything and determines how a bike will ride and also how it will feel. in my experience- you simply need the tubeset to be stiff enough that it doesn't wiggle torsionally- that it won't break in to a million pieces if you eat shit on it, that it's stiff enough that it'll hold its line over crappy road conditions and that it's light enough to be built up to the uci weight limit with normal parts, metal stems and bars and fancy wheels.

the rest of it is gravy and i am not of the opionion that you can make a bike "too stiff" except when "too stiff" means "too fucking heavy"...but there are plenty of bikes that are too wiggly and underbuilt for many riders.....but it's really tough to do with modern steel tubing.

craig/jerk

[e-RICHIE]

it'd be really tough to make a bike that felt "underbuilt" to an athlete richard's size.

it's not size, it's ability atmo. the bicycles are made to order, labeled and all that, too.

ps material has improved exponentially through the years. and better yet, folks who are
still in the game are better at it than many predecessors whose bicycles, the batch built
ones particularly, became the baseline for discussions like this one.

[jerk]

it's not size, it's ability atmo. the bicycles are made to order, labeled and all that, too..

i don't get this.

ps material has improved exponentially through the years. and better yet, folks who are
still in the game are better at it than many predecessors whose bicycles, the batch built
ones particularly, became the baseline for discussions like this one.

i know. what i am saying is that if the wheels are in the right place- any modern steel tubeset is going to be plenty torsionally stiff enough for something 54cm or smaller for most athletes.

you said you don't notice a difference based soley on tubing diameter. i was agreeing that you shouldn't....how could you unless you were flexing the fuck out of it? if you're not, there's no difference to notice. the bike stays in plane and rides right.

[GrantM]

When the diameter of a tube changes the bending stiffness of the tube changes too and in a fairly dramatic way. If one considers a pair or top tubes, both with a wall thickness of .6 mm (.023"), and one has an O.D. of 1.125" and the other has an OD of 1.250 (the change that the tubes go through from OS to XL or D.O. tubes) the larger top tube will have 140% the stiffness of the smaller tube.

I probably shouldn't be posting here 'cause i'm not a builder,
but hey, the mod powers let me, so forgive my indulgence....

How common is it to have the same wall thickness in std size tubes as oversize tubes?
I was under the impression most frames built from OS tubes are thinner wall than "std" tubes.
For example, I think a Columbus Spirit Top Tube is 0.4 and say an 'ole SL top tube is 0.6.

This is what I presume E-Richie is saying, the functional differences between tubes of different
diameters has mostly been offset by making the larger tubes thinner.

Is it fair to say the OS tubes commonly used negate most of the change in diameter?
- OS ends up a bit lighter, and that's why it gets used?
This of course leaves the builder the option of larger, stiffer tubes for those who need it.

I'm also a lighter weight rider, and I can say that there is much more "smoothness"
that comes from properly matching the tubes with the rider. I own a steel bike
I would describe as "overbuilt" for my needs, as it is noticeably less enjoyable to ride
over rough surfaces. It's a custom build, so obviously the builder chose the tubes thinking
he was matching them to my needs.... I'd say he missed.

So what does all this mean? I guess it says put me in the camp that says tubing matters...

-g

[Dave Kirk]

.................
How common is it to have the same wall thickness in std size tubes as oversize tubes?
I was under the impression most frames built from OS tubes are thinner wall than "std" tubes.
For example, I think a Columbus Spirit Top Tube is 0.4 and say an 'ole SL top tube is 0.6. ....................

So what does all this mean? I guess it says put me in the camp that says tubing matters...

-g

For the most part the walls of all high end steel tubes are about the same now. It used to be (before the new stronger materials) that the thin walls were left to the bigger tubes and that a larger diameter tube ended up weighing about the same as the smaller tube due to it's thinner walls.

This changed when the material became strong enough to use thin walls even on the smaller dia. tubes. So now the tube wall thickness is more driven by what the tubing maker can make and less about what is needed to be safe. This ends up being about .5 - .6 for the thick part of the tube. This is why I left the tube wall the same in my example above.

dave

[suzyj]

ATMO the chainstays are the main determinant of whether or not a bike feels stiff. When you're out of the saddle flexing the frame, it's the chainstays that are doing most of the work to resist that.

So even though the rest of the frame might be considerably stiffer (as it will be, because stiffness increases with the third or sommat power with increase in diameter), unless we scale the chainstays proportianally, there will be relatively little perceived difference. Not to say there isn't one, but just that it won't be as much as you might otherwise imagine.

[Dave Kirk]

ATMO the chainstays are the main determinant of whether or not a bike feels stiff. When you're out of the saddle flexing the frame, it's the chainstays that are doing most of the work to resist that.

So even though the rest of the frame might be considerably stiffer (as it will be, because stiffness increases with the third or sommat power with increase in diameter), unless we scale the chainstays proportianally, there will be relatively little perceived difference. Not to say there isn't one, but just that it won't be as much as you might otherwise imagine.

I agree. The real difference/benefit in using the larger tubes is making the frame torsionally more rigid. The extra torsional rigidity will make the bike feel/handle better on rough surfaces that might knock a less rigid bike off line. But as you so well said - the big main tube will do little to stiffen the drivetrain.

dave

[progetto]

So if a lot of perceived stiffness comes from seatstay- chainstay combinations, should we see a much larger variety in available tubing options or is the variation only subtle. I find that wheels, tyres and tyre pressure can play just as big of a roll in ride perception. As Craig said, if you are on the shorter, lighter side, you can pretty well get away with anything, on a larger size frame I would imagine the differences could be exaggerated.
Bill

[Dazza]

Dave has explained well
for me
I had this settled 20 years ago
circa 1991.
I have been using XL sized tubes (the term Double over size and any other silly terms are to be banned) since 1991.
(Columbus MAX and Mega tubes)
Big or solid riders like them!

I have been using XL tube with lugs since I designed and produced the first ever XL Compact lugs in 2003
World's First compact angled road bike lug set. The LLewellyn "XLCompact" (Formerly known as "Slant 6")
Album: World's First compact angled road bike lug set. The LLewellyn "XLCompact" (Formerly known as "Slant 6")
"The need for compact angle over size tube lugs got me going. So I set about hand making lug patterns, CAD drawings, with ye old French lug maker "Bocama" influences on the shorelines. My Llewellyn compact angled over size lug set has been a hit with exports around the world. 36 HT 34.9 DT 31.7TT 31.7ST 60* & 79* HT lug angles, 79* ST lug angle"



then in late 2009 (not Feb 2009)
a XL lug set with horizontal top tube
read the story here
The Framebuilders' Collective | Cadenzia Lug Set

and also a prototype XCr for XL lugs tube set in Jan 2010. (I made and took this frame to NAHBS, see FNL #51)
After 16 months the production sets have arrived. (see FNL#112)
This Columbus tube set is driven by Dario Pegoretti with some small inputs from me.

oh and the 30.60mm (which is the correct size for 31.7 .5 tube) seat posts to fit the Columbus 31.7 Life, Cyber, Genius and XCr seat tube with out a sleeve have existed since 2003

So this stuff has been around and well established for TIG and lug builders for many years despite the perception being presented.
and I and others have actually been making frames with these XL tubes for many years.

In my mind it is about correct selection of materials and dimensions for the rider.
One tube set for every size rider and weight of rider is not always going to give the correct result.

This may be of interest
Bici da corsa | bdc-forum.it - Visualizza messaggio singolo - Llewellyn...ditemi un po'
there is no definite line to cross from OS (Custodian) to XL (Cadenzia) size tubes.
I think XL tube sizes are best when the rider
a: the rider is more than 75kgs
and or
b: The frame size is bigger than 58cm seat tube.
c: If the rider is very powerful
d: Some riders want stiffness in the frame to feel confident.
e: Some times the rider's pedaling style and technique is an influence

It is important to match the fork to the rider
The fork blade thickness selection will vary to suit the rider's weight.
I use .8mm for light riders (-65kg) and .9mm (normal) and 1.00mm for heavier riders. +80kg
For very stiff forks I use Columbus MAX fork blades. (+ 95 kg)

It is also important to match the seat stays (posteriore verticale) to the rider and the ride feel desired.
I use 16mm, 17mm and 19mm diameter for the very big riders and track frames.

XL tubes (Cadenzia) is approx 20% greater stiffness then OS tubes (Custodian)

I explain to the client the direction and rational and we confirm so all understand the desired result.

[Jonathan]

I've got a datapoint in the garage that's been under my own ass. I built it with Dazza's compact lugs, ubersized tubes unfortunately with most of the butts cut out to make it my size, Dazza dropouts which build a stiff rear triangle and 19mm stays that are fastbacked to the seatlug. Matched with a max fork I or another traditional sized steel fork I can tell a difference in ride. I can't tell a difference in performance, but I can tell a difference in ride. My opinion is that if there is any tube matching going on it should be to match what the client likes. 2/3 of what I've been building are cross bikes and frankly its pointless to discuss what i do when we are talking about bikes that often have less than 35lbs of air in the tires.

[e-RICHIE]

i have read all the stuff since day one, i make the things, and also use them daily and hard. i'd like to say it's equal parts technology and technique, but i have to draw the short straw and play the alchemy card too atmo. if you guys can feel the numbers and not just quote them, your fingertips are a lot more sensitive than mine. and i mean it with no hint of negativity or sarcasm at all. i've never been on a frame (of mine) and thought, "now this steel (or tubing, or dimension, or shape) really does make it better." the quality of its manufacture* is another subject altogether. some combinations are lighter, some are not. round. oval. seat stays of every known shape. imperial and/or continental blades. cast parts. pressed steel parts. i don't feel it. if the position is correct, the design rational, the center of gravity in the right place, and the paint red, i'm down the road on it.

design > assembly > materials > atmo



* the material's, that is...

[Dazza]

i have read all the stuff since day one, i make the things, and also use them daily and hard. i'd like to say it's equal parts technology and technique, but i have to draw the short straw and play the alchemy card too atmo. if you guys can feel the numbers and not just quote them, your fingertips are a lot more sensitive than mine. and i mean it with no hint of negativity or sarcasm at all. i've never been on a frame (of mine) and thought, "now this steel (or tubing, or dimension, or shape) really does make it better." the quality of its manufacture* is another subject altogether. some combinations are lighter, some are not. round. oval. seat stays of every known shape. imperial and/or continental blades. cast parts. pressed steel parts. i don't feel it. if the position is correct, the design rational, the center of gravity in the right place, and the paint red, i'm down the road on it.

design > assembly > materials > atmo

* the material's, that is...

I agree with you

but

Richard, how tall are you?
How heavy are you?
Yes, of course you rode lots of bikes hard
the key point is YOU
You are a good test pilot for a frame that is designed to fit YOU and well assembled with materials selected for YOUR frame.

I raced at 60kg and I am 172 cm tall
my frame was typically 520 x 545
saddle height of 720mm
If I used XL tubes it will be over kill
the bike would shake the fillings out of my back teeth
and rattle any kidney stones loose

but I am not 200cm tall
and weigh plus 90 kg
and have a thresh hold at 400 plus watts

Not many of my clients are built like me
I also will not make a good test pilot for an XL tubed frame

The feed back from tall and heavy riders to all the frame builders I know well is that increasing the rigidity of the frame to match the size and weight and power of the rider yields a frame that is pleasing for them to ride. Maybe not faster, but pleasing, nicer handling, inspiring confidence.
Of course
"design > assembly > materials >" all this has to be in the recipe.

I do plan to make myself an XL frame one day soon with Cadenzia lugs and XL XCr tube set and Dario's new carbon fork when it becomes available , totally just for my own kicks. I do not expect it to handle better or feel faster than my normal OS bikes, it may return negative feed back for a small and feeble rider such as myself. It may well test out my dentist's expensive work in my back teeth For me it will be interesting and fun project just to find out what it really feels like to a whimp like me

I do not build XL tube frames for aesthetic reasons, I use XL tubes when they are appropriate choice for the client's frame.Llewellyn Custom Bicycles History

[Dave Anderson]

I do not build XL tube frames for aesthetic reasons, I use XL tubes when they are appropriate choice for the client's frame.

I agree with Dazza here and also will add that I've been building XL or DO tubed lugged bikes since Dazza first introduced his Slant-6 lugs (sorry Dazza I still prefer the old name :-) ) way back when...they make for a great bike for the right rider, but frankly these bikes are overkill for most riders (for example...those under about 6'+ and/or 200 lbs IMO). All you are doing is adding weight for very little, if any, performance gain for most, while increasing rigidity to the extent that it can make for a long day in the saddle. Pair a DO tubed bike to a MAX bladed fork and the issue is compounded substancially. Talk about shaking your fillings out! Of all of the "road" forks I have tested (and I do deflection tests on nearly every fork that goes through my shop), none are more stiff longitudinally (front to back, as opposed to side to side), than a max bladed fork....to the extent that there is almost no deflection under normal riding conditions. I suspect some folks will cry foul here, but its true.

Dave

[Dave Anderson]

For the most part the walls of all high end steel tubes are about the same now. It used to be (before the new stronger materials) that the thin walls were left to the bigger tubes and that a larger diameter tube ended up weighing about the same as the smaller tube due to it's thinner walls.

This changed when the material became strong enough to use thin walls even on the smaller dia. tubes. So now the tube wall thickness is more driven by what the tubing maker can make and less about what is needed to be safe. This ends up being about .5 - .6 for the thick part of the tube. This is why I left the tube wall the same in my example above.

dave

Yes, but most tube diameters are still available in multiple wall thicknesses, so if I wanted to build a standard tubed bike, I can still use an 8/5/8 or even a 9/6/9, 28.6mm diameter down tube, for example. It's up to the builder really to select tubes that are safe and that's likely going to mean thicker walls on a bike with smaller diameter tubes...all other things, including the rider, being equal. (At least when it comes to a Standard vs OS frame)

To Grant's question (if I understand it correctly)....in general, yes, thinner OS tubes are used to maintain (increase actually) stiffness, while also reducing weight. However, there is a point of diminishing returns, after which, depending on the rider and the application, you're just adding weight (and stiffness) for no appreciable gain....

[Dave Kirk]

Yes, but most tube diameters are still available in multiple wall thicknesses, so if I wanted to build a standard tubed bike, I can still use an 8/5/8 or even a 9/6/9, 28.6mm diameter down tube, for example. It's up to the builder really to select tubes that are safe and that's likely going to mean thicker walls on a bike with smaller diameter tubes...all other things, including the rider, being equal. (At least when it comes to a Standard vs OS frame)

To Grant's question (if I understand it correctly)....in general, yes, thinner OS tubes are used to maintain (increase actually) stiffness, while also reducing weight. However, there is a point of diminishing returns, after which, depending on the rider and the application, you're just adding weight (and stiffness) for no appreciable gain....

I agree Dave.

I simplified (over simplified?) to make the point easier to make.


Dave

[timto]

Put me in the camp that believes diameter does make a big impact on ride feel.

I've ridden exclusively OOS bikes and only recently, after connecting with a lot of what DK has written about re:" too much stiffness" and yes I'll admit even some BQ articles !!! I put my money on the line to experience std dia tubing (22.2 chain stays) for the first time. I currently have no shop but had Erik at Alliance build me a STD dia bike for my 155 lbs. The ride behavior of this bike is simply night and day in terms of 'fit' for my weight considering same contact points. I now understand what it feels like to have a bike that works 'with' me. It is more smooth, responsive and enjoyable than ANY OOS tube bike in ANY material that I've been spoiled enough to own.

I think though big tubing is popular for looks (nothing wrong with that!), essential for the right athlete (big dudes), but us lighter dudes should give a skinny tube bike a try. Clients should communicate what they want in terms of performance/feel and not tubing diameters and geometry and leave those two, plus construction of course, to the builder.