| I was working on the Miyata - cleaning and polishing.....It has braze-ons for a rear rack.....and eyelets for front rack, or front fenders......tells me it's a touring frame. There are braze ons for 2 water bottle cages. But, it has this braze-on on the underside of the down-tube. What could that be? It's about mid-way between the shifter bosses and the bottom bracket. It can't be for a water bottle cage. I had a Schwinn Passage.....it had braze-ons for 3 water bottle cages - the third was on the underside of the down tube - but it was 2 holes...just like the regular water bottle holes. But this one on the Miyata......What's it for?|
| Is it a tapped boss, like the water bottle mounts? Same threading? Just a single hole? Maybe a mistake?|
| It's just like the water bottle ones.......but there's just one. Surely it's not a mistake! But, what else could it be?|
| An unconventional braze-on for a very long front wheel stop?|
| Could be for one of those flip down things that holds the front wheel and fork from turning when you lean the bike against something.|
| The third "water bottle cage" on bottom of the down tube on the older touring bikes was for a fuel bottle for your camp stove. Where it was located, if it leaked, it didn't get fuel all over the rest of your camping gear. A little bit of trivia from the golden era of loaded touring.|
| This threaded hole was used for storing a spare rack/water bottle mounting screw. How many of us have lost one of these screws during a ride and wished we had a spare to get us home?|
| Flickstand was what those gadgets were called.You could mount it on the down tube,usually with the supplied clamp.I had an asian Raleigh touring bike with a braze-on,with one mounted to it.If this braze-on is fairly high on the bottom side of the down tube,I'm pretty sure that is what its for.|
| Jack's explanation is the best so far.|
| The Raleigh "flick stand" things were pretty close to the shifter bosses. Within a couple of centimeters. How far down the tube is the mystery boss on the Miyata? I have one of the Asian Raleighs, a Kodiak, and have ridden it since 83 or 84. I'll keep it until I can find an old Bob Jackson in my size at the bike swap.|
| The boss is about midway between the shifter bosses and the bottom bracket. I had a Schwinn Passage with water bottle mounting screws on the underside of the down tube - but they were closer to the bottom bracket....and of course, there were 2 of them. I have also seen a single boss on the underside of a Raleigh Technium - at the shifter location - of course, it had stem mounted shifters - and the single boss was for the shifter cable stops. |
.....but again....this one is mid-way.......What could it be?
| Thank's David...and yet my response was tongue-in-cheek, although not entirely in that that's what I would use it for in lieu of a "flickstand". Hmmm, that sounds a little bogus too. At any rate, you need at least a screw there to keep gunk out of your tube and bottom-bracket. I did get a chuckle from this thread though...|
| I have a screw in there - of course, to protect the threads and keep dirt and stuff out of it........but still.....I don't really know what it's for.|
| this is for a compressed gas, tire filling system. two co2 cartridges screwed into the side of the adapter and rode until you needed an emergency fillup. i still have the system.|
| Well, I've been checking the local thrifts to no avail until today. Went to the Goodwill on Saurday, nothing. Went today and picked up an older Fuji Royale ($10), and a Centurion Accordo($20). They're still on the car so I can't go into details but they look to be in pretty good shape. Should keep me busy a few more weeks. |
| A good day just got better. Taking apart the Fuji and I find out it isn't a 12 speed as decalled on the chain stay. The last owner upgraded to a triple chainring. Don't know why I didn't notice it in the store. Also noticed the Centurion has Wolber 27in wheels drilled for presta valves. I'm tempted to keep them in case my commuter needs new wheels. It has been a very good day in deed!!|
| Isn't it great when you pick up one of these old bikes - then get it home and find a nice surprise - that you didn't realize whenever you picked it up!|
| For the second time I am having an older steel road bike wobble in the front-end with increasing intensity when I take my hands off the bars. The first bike, one I have since retired, was made of a fork and frame that I matched together, so I thought there was some kind of incompatibility. |
I am now riding a lovely old lugged Columbus tubed bike, I believe a Gieppeme (?-decals missing-?). It is the original fork for the bike. It does the same thing with the wobbling. I have good wheels and tires, and I have even swapped wheels, same thing.
Why do frames do this?
| Hi Tim,|
The issue of oscillation arises frequently, and various folks have suggested a wide range of possible causes and potential solutions. Since you have already ruled out wheels (loose spokes and mis-dishing are two extremely common culprits), you may want to check your headset and the rear triangle's overall alignment. It has also been suggested that certain rider-frame-wheelset combinations are simply subject to resonance at some speeds. I know I sometimes have to rest a knee against the top tube when coasting fast on my 1959 Capo. It will be interesting to compare notes when I get my newly-acquired 1960 Capo cleaned up, overhauled, and reassembled.
| Speed wobbles belong to a dynamic class called "self-induced vibrations". Notable examples include the collapse of the Tacoma Narrows Bridge, tool chatter on a lathe, drawing a rosined bow across a violin string, and the infamously wobbling shopping cart wheel. Well into the early 1960's many motorcyles came equipped with steering dampers to combat speed wobbles. Typically these were a knob atop the steering head that tightened a friction disk against the bottom of the head tube. A more sophisticated design employed an oleo-pneumatic damper analogous to the damper that prevents a screen door from slamming closed. Evidently the engineers got control of the wobbling phenomenon because the problem and the corrective hardware have long since disappeared from motorcycles. If you are of an experimental temperment, try (1) a larger diameter front wheel (or smaller rear wheel) which would effectively increase the rake and trail, (2) swap the head bearings eliminating any retainers. Associated with self-induced vibrations like this is a "negative friction curve". This is nerd-speak for the fact that the static coefficient of friction is higher than the dynamic coefficient of friction. This in turn allows energy to be pumped into the system as an increasing amplitude vibration. (More than you wanted to know .... huh!)|
Keep us posted; two bikes with speed wobbles is more than bad karma.
| download a 200-page Cornell engineering thesis on bike stability at|
There's some other cool links here also
| Oh my, that all sounds terribly complicated. I love working on my bikes, but don't much like the sound of reading a 200 page technical treatise :o) I'll try swapping out the headset bearings, but otherwise I'll just have to learn about riding with my knee against the top tube when I'm zipping my jacket or whatever two-handed task I have. Thanks all.|
| Some people report that they get wobble from a change in the weight distribution on the bike, for example adding a front rack or bag. Another cause can be a change in stem length or style of handlebars, again changing the weight distribution. Maybe when you take your hands off the bars, enough of your weight shifts to the rear to induce the wobble.|
| I'd thought head bearings, but I'd go along with Dick's various ideas; remember, only do one thing at a time, then take the bike for a ride. That way you can find out what's causing it.|
| Hello all. |
In a town about an hour's ferry ride from here I know about a "funny bike" with the downsloping top tube, I guess a time trial bike (?). I learned about it chatting with the proprietor of a small bike shop while away for a B&B weekend.
I forget now for sure, but I think its a Pinnarello. Its for sale for a very reasonable price, but not being actively advertised. This sounds like its in excellent condition, and I'm tantalized with the idea of going back to get the bike.
I am wondering what year this bike would probably be made, and what groupo I should expect to find. Has anyone seen a bike like this on e-bay? Thanks for info.
| I'm going just on memory here so the info is probably not precise.|
"Funny" TT bikes were an innovation of the mid-later 1980s and I don't think they lasted that long into the 90s. The reason being that the UCI decided that all bikes needed conventional double diamond geography. Pinarello wasn't the only maker of these bikes but they may have been the most widely marketed as the majority of such bikes I've seen are Pinarellos.
Gruppo? Top of the liners would be C-Record (buy it if your bike has it!) or perhaps Croce. Shimano wouldn't be impossible. I'd expect DuraAce, maybe 600EX.
Again while I'm pretty sure about the UCI killing "funny bikes" my chronoligy could be off.
| You're right, the UCI did indeed kill them off. Most of them had a 700 rear/650 front wheel combination and they legislated thatbikes should have same-sized wheels front and rear. I'm sure there's more to it than that, though. I have a Welsh-made TT frame/fork, curving downtube and toptube, which I bought from ebay for £45 (including 3TTT aero stem and Campagnolo aero seatpin). It's tiny, amazingly short wheelbase.|
| just bought another rusty bike to fix up for another ride|
a raliegh, made in the republic of Ireland serial# DB526610, steel cottered cranks, CB stem, simplex derailers and wienmann brakes. I got it cause I thought it would be a good frame to play with and ride on this years BAK, but got to looking at it and the brazing and lugwork just look sloppy. does any one think that these frames were any good at all? I want to put new everything on the frame cause it fits like I like but don't want to have it break on me. thanks for your opinions jason.
| If the fork crown (including steerer tube and blade attachments), the front dropouts, and the head lugs are sound, you are probably safe. I would be much more concerned about breaking a handlebar stem or handlebar, or even a crank (been there ... done that ... not fun) or a chain.|
The workmanship on my 1980 Peugeot is nothing to boast about; the head lugs are clean, but there are big brazing voids on the rear dropouts.
| went to the bike shop today and the guys basicaly said that its been around this long, its gonna be ok. It just looks like they were really hitting the guinness when they made this one.|