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Rivendell Design Theory(20 posts)

Rivendell Design TheoryGinz
Aug 21, 2002 6:19 AM
Ok, so I got myself a Nitto long-quill stem and the bars are level with my saddle. The extension is 7cm, almost as short as stems can get. I'm 5'4" and I ride a 47cm frame with 700c. The top tube is short...like 50cm short.

I'm STILL not comfortable with the reach. I feel ok in the flats and a on the first curve of the bar (where my knees can almost touch my elbows). But, my hands still hurt in the hoods. I CAN ride in the hoods, but it's just not comfortable for more than a few minutes. Strangely enough, I feel somewhat ok in the drops.

Should I just expect discomfort in the more aero positions and ride in the flats more? Am I a whimp? I'd go custom, bow much shorter could a top tube get?
Raise the hoodsAhimsa
Aug 21, 2002 9:25 AM
Roll 'em back a bit on the bar toward you. I'd play with that for a while and get it dialed in. I'd be surprised if that doesn't solve it.

It ain't freddish (not that anyone here cares) if that bothers ya.....ol' Lance rolls his back further than most.

Cheers!

A.
re: Rivendell Design TheoryMelMo
Aug 21, 2002 10:48 PM
Well, in truth Grant P. would say that the problem is that someone tried to make a 47 cm frame with 700c wheels, and your problems would go away (or be much resolved) if you had 650 or 26" wheels because then it would be possible to have a shorter top tube. Or that's what he concluded in an article a couple of Readers ago. I think Marinoni (Canada) makes a 650 wheeled bike, some English builders such as Thorn (SJS cycles), and a friend of mine has a very chic Mariposa, but I think it cost the earth. There are other, more mainstream builders who make small frames with smaller than 700c wheels, but I'm not enamored of the designs. The Fuji small bikes have stupid steep angles and I think they'd be brutally uncomfortable, despite the smaller wheels.

I had a similar set up problem on a 49 cm Fuji I owned---my hands always hurt, no matter what I did. I was forced to conclude ultimately that it was because the steep angles of the bike pitched my weight forward and put it on my hands. I noticed it the most on the hoods just because it's a small, intense contact point. I ride a bike now that's slightly bigger all around, but has much more relaxed angles and hence balances my weight better between my butt and hands.

Short of getting a different bike (and this group will certainly encourage you to go shopping, if you need encouragement) moving your hoods up might help, and seeking out a handlebar with flatter ramps might help too (like Rivendell's Nitto Dream bar, I think, though I think some older Sakae handlebars also have this shape, as do some Randonneur style handlebars). Best of luck.

Melinda
How about some of the Terry bikesscottfree
Aug 22, 2002 4:56 AM
with the 24-inch (?) front wheels? Don't know much about them, but was looking at my wife's catalog the other day and thinking they'd be good for someone who needs a seriously short top tube.
Don't do the mixed wheels!!Kurt H
Aug 22, 2002 7:51 AM
I thought about one of those for my wife a while back. I talked to the owner of one of our LBSs (whose opinion I trust to be VERY reliable) and he had absolutely nothing good to say about the mixed wheel size bikes from Terry. Aside from the obvious difficulty of carrying two tubes, his experience with the bikes showed the Terry claims of a wonderful handling geometry to be vastly overstated. In a nutshell, they are a mess!
YMMV
Kurt
Gonna disagree with that one.Spoke Wrench
Sep 12, 2002 12:06 PM
My question is: How tall is the LBS that didn't like the Terry? A bike that is well designed for a 5' tall woman isn't going to feel right to a 5'10" male. Small size women's shoes would probably make his feet hurt too.

For what it's worth, I never had a serious buyer test ride a Terry and not buy it. I've never talked with a woman who owned a Terry and wasn't in love with it.

Difficulty of carrying two tubes?
Gonna disagree with your disagreementAndante
Sep 13, 2002 11:56 AM
My wife suffered through a Terry. Besides weighing a ton (not exactly the nicest framesets), it handled like crud. She would never go down hills without riding the brakes, as the 24" front wheel is a squirrel. She will say the fit was nice, though. We got rid of it and she has a 46cm Litespeed now with 650's that fits as well or better (She is 5'1"). The Conti 3000 tire comes in a 650c by 23 size, so that ends the discussion on tires as well.
Thanks for the suggestionsGinz
Aug 22, 2002 6:26 AM
I agree that 650c wheels are probably the ticket. The scary part is that with 700c I have a bit of toe overlap and would probably still have some overlap with 650c.

Maybe it's a combination of relatively slack headtube, steep seat tube, small wheels, long rake fork, long stays, headtube extension... blah blah blah. I hope to find a builder who can solve this problem while still producing a recognizable, classic-looking road bike. I simply refuse to have a threadless fork or a sloping toptube. Call me stubborn if you must.
650 wheel and tire selection is poorChainstay
Aug 23, 2002 5:26 PM
The disadvantage of the 650B style is that wheels and tires are hard to come by and the selection is poor. Some builders go wth 26" wheels for the greater selection. Mariposa in Toronto will do this.
650 wheel and tire selection is poorSteve Bailey
Aug 25, 2002 3:04 PM
Ditto going to a 26" - Mt. bike size wheel.

For clarity, a 700C is 622mm, a 650C is 571mm and a 26" is 559mm.

Rivendell also sells an Atlantis frame, specifically designed around the 559mm rim. Note that the Atlantis use cantilever/V brakes, not dual pivot road brakes. The other issue is that slick road tires tend to be no smaller then 1.2mm wide or so, which is roughly a 27mm tire. The 650C's are very difficult to find in a 23mm. Nothing larger and the 23's tend to be VERY expensive.

SB
Why 26"?Ginz
Aug 26, 2002 7:00 AM
The Atlantis 47cm frame's top tube is no shorter than any other 47cm frame I've ever seen...about 51cm. The standover is no different, about 28.5-29.5".

The problem is top tube length; they are all too long. Average size folks don't ride with 7cm stems for good reason. Why must I?

When a frame is scaled down in size, the reduction in top tube length is supposedly proportional to the rest of the frame. Then why do all of the sizes all have the same chainstay length and BB drop?

My point is that most builders don't seem to realize just how small the smaller rider is. Most builders seem to think that toe-overlap is the main problem with small frames. Well, don't smaller riders have smaller feet, hence less overlap anyway? Cantilever brakes? Why not long reach calipers?

26" wheels are a waste of time unless all factors of frame design are considered. But that's just my opinion.
Why 26"?Steve Bailey
Aug 27, 2002 4:48 PM
Actually, you have valid questions and comments, which may well steer you towards a custom frame.

I cannot answer why Grant designs the Atlantis with a long'ish TT in the 47 size. To be honest, I've never noticed, not owning an Atlantis and using a 56cm frame myself. Why don't you call and ask ?. Knowing Grant, he'll either admit it's too long for the frame size, or have a good reason for the geometry. It may well be related to a limitation in lug angles and selection. Remember that in order to keep the price down, this is a bare bones design, which can limit choices somewhat. I'm sure he would be happy to build up a full blown Rivendell in 650C exactly to your spec's.

I do know that having long chainstay's is a positive attribute on a bike. As well as giving you a bit of clearance for things like panniers on a commuter bike (which the Atlantis is very good at) it also makes the chain angle a bit less steep, which often allows better use of gearing while in the middle ring. My Heron Road, with 42.5cm chainstays, is a typical example. I can use 7 of 9 rear cogs from the middle ring without chain rub on the large ring. I cannot do this on my Klein with it's 40cm stays. I happen to agree with Grants concept that road bikes these day's are not as useful as they could be, thus his design philosophy, which tends towards a longer wheel base, lower b-bracket, higher h-bar, long chainstay's etc...

As to 26" VS. 650C ?. On the Atlantis, it makes sense as most owners are building these up as all-round bicycles, thus the rim size gives them better choices in tire sizes and tread design. For a dedicated road racing machine , don't get the Atlantis, get a custom built with 650C. Just be aware of the limitation in tire sizes and price.

SB
Maybe not THAT bad a selectionKurt H
Aug 26, 2002 7:08 PM
I don't ride 650's, but saw this pop up on Sheldon's website a while back. Hit the link (which I hope works!):

http://www.sheldonbrown.com/harris/new.html

Look down at March 22, 2002 and you will find that Terry Bicycles has released a 28c tire in 650c size. However, they're not shown on the tire page of the site, so I'd call before I banked on them being available. In addition, Sheldon has a couple of options for Continental 650X23C tires in the $30-40 range. Sure, not cheap, but in line with his prices for 700c Continental tires.
Just a thought!
Kurt
650c X 23 Conti 3000's easy to get(N.M)Andante
Sep 13, 2002 11:59 AM
Having read the whole thread...Ray Sachs
Aug 29, 2002 4:17 AM
I think one of the things that needs to be stressed is seat tube angle. The problem with small frames using 700c wheels is partly top tube length, but largely seat tube angles, which have to be too steep to make the rest of the math work out. A steep seat tube angle will NOT let you get your weight back far enough, thus putting more weight on your hands and shoulders, thus making even apparently short top tubes feel too long.

Going to a slacker seat tube angle (the Atlantis has either a 72 or 72.5 degree seat tube in the smallest sizes) allows you to get your weight back and the slightly longer top tube than you want may feel just fine, since your hands aren't supporting as much weight. With my butt back, I'm comfortable stretching well out over the front end. With my butt too far forward, my hands are supporting too much weight and I keep wanting to move my bars back and up.

A slack seat tube angle often requires longer chainstays, but this is a good thing IMHO, for the reasons Steve mentioned and because with your weight further back, it evens out the weight distribution on the bike and adds to the stability of the ride.

-Ray
Well... I agree and disagreeGinz
Aug 29, 2002 5:59 AM
A slacker seat tube angle would ultimately result in a longer effective top tube. If your saddle is higher than your bars, I can see how a slightly longer top tube would be more comfortable.

I'm looking for a more upright position where the bars are near level with the saddle. So, I think a slack seat tube would just make the situation worse, lengthening the top tube as I raise the saddle to position. Eventually, I'll get a custom frame and lay down the law with the builder.
Right, but...Ray Sachs
Aug 29, 2002 7:12 AM
regardless of how high the bars, the farther back your center of gravity is (and the more weight on your butt), the less work it takes to hold your upper body up as it leans forward. This is somewhat dependent on where you carry most of your weight, but the basic principle holds true regardless.

Check out Peter White's article on fit (particularly the section on "fore-aft saddle position" - you'll have to scroll down a little bit) for a better explanation of this than I could ever give:

http://www.peterwhitecycles.com/fitting.htm

-Ray
The finer points of frame geometry...Ginz
Aug 29, 2002 7:59 AM
Ok, I think I get it. A slack seat tube angle, while maintaing the same effective top tube, would balance me a bit more by compensating for the bend in my knees. However, that would probably cause more toe overlap.

So the answer might be 26" wheels, slack seat tube, slack head tube and long rake fork to lengthen the wheelbase. I need to get out the protractor and see what this looks like on paper.
Not that I'm pushing it, but that sounds like an Atlantis (nm)Ray Sachs
Aug 29, 2002 9:05 AM
Sorry to keep going with thisGinz
Sep 17, 2002 6:14 AM
I've got one last questions that might clear things up. When Rivendell says, "most people ride bikes that are too big..." they don't mean that they should literally upsize their current frame. Instead, they are riding frames designed with handlebars too low and seattube and headtube too steep?

I just don't understand how a longer toptube is supposed to be more comfortable. Everyone says it, but won't that just make we lean forward even more?