Thanks for the many replies ... Bob and Barrettscv identify the key issue for me in having a bike built that is both aesthetically pleasing and fits properly:

Bob says:

I'll be honest, I don't remember what those reasons were. (!) But the fact that he had compelling reasons for that design -- it's not like he only ever builds sloping toptubes, this was a specific consideration based on what he knew about me and what sort of bike I was looking for -- convinced me to put up with an aesthetic element I wouldn't have originally choosen.

And, Barrettscv says:

I base my selection on fit, not appearance.

Fit is the primary issue for me in having a new bike built. And, if there are no compelling fit issues with a level top tube, then that is my preference. But, as with Bob's experience, at least one builder I have talked with suggested a sloping/slanting/angled tt. Since he has built about 4000 bikes, my guess is that he knows a bit more about fit than I do and perhaps I should trust that advice, even though aesthetically, I like the level tt.

When I did a search for the reasons bikes are built with sloping vs level tts, I could not find much that was compelling from a fit perspective. But, since folks here in this forum have the experience and some of the age-related issues that sometimes influence bike fit, it seems a good place to gain from your experience as I plan the design of the next bike.

Thanks again for your help.
MH

Up until 2006, all of my bikes, even the MTBs had level top tubes and I had no intention of changing that. I felt that sloping tubes looked wrong. Then I got a Rockhopper with a sloping tube and later a Stumpjumper. I figured aesthetics didn't really matter as much on MTBs and the increased standover room was an advantage in the dirt. But road bikes needed to look right and that meant level top tubes and lugged steel construction. I even found a lugged steel level top tube MTB frame for less aggressive offroading to round out my stable. I was a proud traditionalist.

Flash forward and I now have a Salsa Casseroll with a sloping top tube and welded steel construction and a Specialized Roubaix with a swoopy sloping top tube and full carbon fiber construction. And the new bikes are just as comfortable (at least) and look just as good to me as the old school ones did.

I don't really see a functional advantage of either style. This is just how they make bikes nowadays. I do still like the look of the traditional bikes and would like to find a good lugged steel frame to build up to fill a niche in my lineup. I like all kinds of bikes. I appreciate traditions, but am not bound by them.

If I were to have a custom road frame built today, I would probably choose a slightly sloping top tube design. Not sloping down to the rear for clearance, but starting at the normal height at the seat tube junction and sloping upward slightly to the head tube to allow a higher handlebar without a stack of spacers or an upward sloping stem. Due to neck issues, I have to have my handlebars no more than 1" lower than my saddle or I can't see down the road.

Aesthetics do matter with my bikes, but ultimately, form must follow function.

A penny farthing wouldn't have worked with a level top tube. I'm not sure what a traditional bike frame style is.

I have never had a level top tube--Except for 45 years ago when Sloping tubes only existed on Girls bikes. This probably comes from using small frames where a frame with a level TT that fits me on Standover height would put the Head tube about level with my knees when sitting on the saddle. I know standover height doesn't matter but Some of my frames are termed Compact

http://bikeforums.net/attachment.php...hmentid=189228 http://bikeforums.net/attachment.php...hmentid=189229 http://bikeforums.net/attachment.php...hmentid=189230

And some are termed sloping top tube.

http://bikeforums.net/attachment.php...hmentid=189231 http://bikeforums.net/attachment.php...hmentid=189232

You tell me the difference

In the true spirit of a cycling forum, anymore slope that what MY bike has is unacceptable. ;)

http://bikeforums.net/attachment.php...hmentid=189233

I think a lot depends on what you are used to. I brought a custom frame several years ago. The builder asked about slope and said 85% of the customers at that time requested sloping top tubes. I went with a slight slope. I quickly got used to it and the slope is very minor compared with just about every new bike out there. Now I think that flat top tubes look dated.

Nope, and I am a 70+ rider..BTW, when I ride my motorcycle, I ride in the full tuck too, with rearsets set all the way up. Only speaking for myself, hitting the gym 5 or 6 times a week helps you along..;)

IMO, they couldn't give me a sloping tube bike, just like they couldn't give me a cruiser or even a touring motorcycle...:D

Traditions can be whatever you want them to be.

AFAIK, there really aren't any structural/functional issues in level vs sloping TTs, as long as your saddle and 'bar are in the right place. Go for whatever makes you happy - it's YOUR bike.

I've got both level and sloping bikes, and they all work and look fine. The ones that really get me are level top tubes with huge extensions on both the seat tube and head tube, usually on tig welded frames to boot!

(on a good day I can touch my fingers to my knees without bending the floor)

SP
Bend, OR

Same here but I'll make an exception for stupid tall people [that's stupid tall not tall and stupid] looking for a stiff raced bike. IF made mine without a huge head tube or 18" of seat post showing and I'm stupid tall and perhaps tall and stupid.

http://bikeforums.net/attachment.php...hmentid=189244
Sloping . . .

Long as you didn't say, "tall stupid people"...

SP
...not sure I qualify as "stupid tall", at only 6'3", but I do like "stupid-long" bike rides - aimin' for PBP (1200k) this year.
Bend, OR

6' 3" is very tall in Japan. ;)

Really? I mean, really?

Back in the late 60s/early 70s we were told to get our bars up as high as our saddles on our touring bikes for versatility and all day comfort. That was dandy advice on the bikes of the day if you used a North Road style handlebar - and many touring bikes back then did - but problematic if you wanted to use Maes bars for the multiple hand/body positions they afforded. The two ways to get drop bars up back then was (1) to search out a rare and ugly short reach "swan" stem or (2) ride a crotch-stuffing large frame size. Most tourists chose route #2 and rode what would be considered today huge frames.

So one day back during the bike boom (clap your hands if you remember the bike boom) I was reading DeLong's Guide to Bicycles and Bicycling and there was a picture (on page 55 - look it up) of a custom made, brass-brazed bike from a US builder with a sloping top tube. "That's brilliant," I said to myself, "Good stand over with high bars. Less unwanted flex in both the stem and frame."

I asked around and all anyone could tell me was "It can't be done that way." I researched and found a number of bikes through the last hundred years that had been built that way. I asked further and was promised that "It's just not done that way. Top tube are supposed to be level."

Finally Mike Burrows arrived and led Giant out of the wilderness, and nearly everyone else (including the master retro-grouch himself, Grant Petersen, crying, "The Hillborne isn't a compact frame! It's an expanded frame!") has followed.

I'm not clear on how this affects fit at all. In this photoshopped image of one of Stapfam's bikes, I've changed the slope of the top tube, but the position of the saddle/handlebars/cranks has not changed at all. So, that bike would fit exactly the same, independent of the TT slope.

Am I misunderstanding?

http://bikeforums.net/attachment.php...hmentid=189318

Horizontal top-tubes were common on lugged steel frame. The shape of the lug determined the position of the tubes on the bike. The designer did not have unlimited freedom since lugs were outsourced and lug manufacturers limited the number of designs supplied. Pictured below is a 1973 Schwinn Paramount with cromed lugs;

http://i289.photobucket.com/albums/l...HHH2010010.jpg

TIG welding of steel bicycle frames, which started in the 1980’s, allowed for the direct fabrication of frame tubes without the dependency on lugs. TIG welded frames are just as strong and durable as lugged frames. A TIG welded frame can be welded on an angle without any additional cost. Pictured below is a 2008 Soma Double Cross, this is a TIG welded frame;

http://i289.photobucket.com/albums/l...9handlebar.jpg

Designers started designing frames with a sloping top-tube for multiple reasons. One of the driving forces was to allow a wider range of cyclist to fit well on a smaller set of frames. The combination of shorter seat-tubes and MTB style stems meant that bike fit was more adjustable than before. Using a longer seat-post with a shorter seat-tube could provide a huge range of adjustability between the saddle and the crankset. Shorter or longer stems could adjust the reach.

Manufacturers like Giant could reduce the number of frame sizes available while still fitting most cyclists.

Fitting a bike is still as challenging as before, but a bike model needs fewer frame sizes to cover a broad range.

I've always complained that the "sportier" bikes are designed/outfitted for the jocks/ racers. That's for both the bar height and the gearing. I got tired of trying to convert them for me and my wife. My last store-bought (used) road bike had a huge frame where I could only put one foot down at a time other wise my voice pitch changed.

I started to build ours. More $'s but more useful for the more casual/older cyclist.

The last several years has seen some manufactures leave an extra long steering tube with spacers which one can trim to his needs. That's at least the case for mountain bikes. I still prefer to build them as I even gear the mountain bikes lower.

I saw the other day that even the 2011 Shimano XTR crankset now comes with a 42 big ring vice the 44. I've been using 42 for years and 21 for the small ring. The older XTRs used 46 as I remember.

Now they've gone to two rings for mountain bikes even for the 29ners which are already geared low due to the wheel size. The jocks again. A good way to blow a knee in the mountains. A 65 year-old friend who has raced for decades did exactly that on a 29ner with a tripple.

Al

Don't forget fillet brazing. It pre-dates TIG by about as much as lugged, and also allows unlimited angles.

http://www.kirkframeworks.com/blog/w...2/DSC_1845.jpg
"Naked" fillet photo stolen from Kirk Frameworks.

You are not misunderstanding but it is that funny thing called standover height. With the sloping tube I do have standover height- wheras on a Level top tube- if I forgot myself- I could have PAIN.

But it does come back to Sloping tube V. Level top tube frame Characteristics. With the sloping top tube the frame is stiffer- Smaller triangles and less flex- unless the manufacturer makes the tubes thinner- alters the angles- or does other things to make the frame more flexible. Of course you then have the more flexible parts like a longer seat post - so I don't think the frames differ much in stiffness transmitted to the rider.

On talking to various riders- you either like sloping tubes or you don't. The ones that I have found that prefer the sloping top tube are mostly the shorter riders.

Not necessarily misunderstanding, but perhaps presuming: a framebuilder would not necessarily make all the other tube dimensions identical -- iow, it's not always an "all other things being equal" scenario -- just to get the contact points in the same place. As tcs mentioned (channelling Grant Petersen) sometimes a sloping toptube is employed not to make the rearward part of the front triangle smaller, but rather to make the forward part of the front triangle larger.

Although there may be some other reasons for sloping top tubes, the following reasons were repeated in one way or another by various posters (my apologies for not crediting the original sources, which I can no longer find):

•compact frames have a smaller triangle, which some claim improves handling, requires less material for greater stiffness and lighter weight
•compact frames are a good fit for many shorter riders because they increase the standover clearance and give them more adjustability than traditional frames
• because of the increased adjustability, stores don't have to stock/offer as many frame sizes (usually s, m, l)
• Lower center of gravity

And, there is this summary

But in short, the advantages are that it 1) slightly lowers the bike's center of gravity, 2) stiffens the rear triangle, 3) decreases standover height, and 4) uses slightly less frame material, so less weight. #1 helps when you're pedalling standing, moving the bike back and forth to quickly build up speed. Less top heavy, less effort to move the bike back and forth underneath you. #2 helps mainly when accelerating, especially uphill. Less rear frame flex = more power transfer. It also means you can incorporate more flexible structures or material (hourglass seat stays on the Merlin XL Compact, carbon/ti seat stays on the Litespeed Sienna, or full Titanium frame) and have less flex than you would on a traditional frame, giving a more comfortable ride to a stiff bike. #3 just means less chance of squashing your crotch on the top tube when you jump off...

"If I forgot myself"! Stapfam-Some lessons are, or should be, learned early and never I repeat never be forgotten!:injured:

Luckily I have never put myself into the position of being able to forget myself---But as my cycling experience improved- I learnt what I like a bike to feel like. One of those is Crutch clearance- but the other is a certain length of top tube. If I were to ever ride a level top tube Bike- it would a small one with a long stem sticking out the front. Now that would be wierd and probably have an adverse affect on the handling. Or even wierder- The lowest point of the top tube would have to be the same as the rear end of my current ride and to get a level top tube- the head tube would have to be lower- A lot lower.

But on sizing- Compact frames can fit a multiple of size riders. In Giant I ride 3 sizes of road bike. XS-S and M- But there is only one Size I have not had to change parts on- That is the one that fits me and is the S. The XS I have put a slightly longer bar stem on and the M has the saddle as far forward as I can get it. All 3 ride well but The S sizing is the one I like- Fits the same as Boreas that is a 51cm frame.

I know some manufacturers say that a Compact frame will cater for a size difference on riders and only supply small- medium and large and they will. It is when you want to get that final fit in that you "Wish" there was an intermediate size- or a larger one or that smaller frame.

All it boils down to is that you "Eventually" settle into a style of frame you like and the reason for that is you feel comfortable with it and it fits. I was lucky and did that 20 years ago.

This is not an advert for Giant- although I ride them but this is their sizing Chart- Don't take it as gospel for you though

http://www.giant-bicycles.com/en-us/...ompactroad/45/

S/M/L/XL frames.

One size fits none.