you are welcome atmo.

we also must remember that we may not like marrying the same girl
we think we fantasized about as 14 year olds. well, i dunno how else
to phrase this. there were alotta girls along the way, and they were,
well - great for the time. but if one was delivered (read: redelivered)
to me now, i'd choose the girl i married over all the dates i had in my
going to the pistol range days atmo.

I, too, was going to try to reproduce the ride of my favourite bike, a TI Raleigh. It was stolen many years ago, but I remember the first time I rode it. It was just so quick and responsive. I bought it at the time because it looked so beautiful, not because of any particular geometry. But it seems some people MIGHT call it criterium geometry. See http://www.wooljersey.com/gallery/v/...ction/album94/. Mine was 22.5 inches C-T (57cm). This bike is 74/74 deg, and about 64cm bb drop (I calculate).

So the questions are:
Was it just me being (much) younger and more impressionable that it just seemed to handle so well?
Should I try to reproduce this? Or something more traditional like 73/73 deg?

I appreciate all your great insights, and I am in awe of people like e-Richie.

Not wanting to start another war.....

Thanks,
Dave

Quote:

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Originally Posted by tuz (Post 7663226)

That was a nice read :)
tigrrrtamer, I'd perhaps look into a Gios Compact frame. It has 74 deg ST and 39.5cm chain stays (with funky sliding dropouts... there is about 1cm of adjustement), a 26.6cm BB heigh (~7.8 drop). They don't specify the head angle but the fork has a 4.5cm offset, so I'd guess 74-73 deg for a 5-5.5 cm trail.
link
I just got a used 57cm one. Can't comment much on it since I did not ride it much yet, but I love it :). I have tried other road bikes (a 54cm Marinoni and a 55cm Ryffranck), and can't honestly say I felt an obvious difference. But I'm rather inexperienced, i.e. don't ride enough, only in TO and Ontario, and usually quietly :p. It's the best fitting one so far though.

---

I think they are trying to keep a "trade secret"... LOL If you are curious about it's geometry, you can do as I did, and order an inexpensive inclinometer on ebay. I'll be measuring my rides soon. Also ordered a scale...

But from the looks of the pictures on the link you gave, it seems like the head tube angle is rather slack. Looks like a stage race or bad-roads bike. May be a time trial bike... steeper seat tube angle, slack head tube for a more stable straight line ride (shortens the distance going from point A to point B).

Quote:

---

Originally Posted by e-RICHIE (Post 7665517)

we also must remember that we may not like marrying the same girl
we think we fantasized about as 14 year olds. well, i dunno how else
to phrase this. there were alotta girls along the way, and they were,
well - great for the time. but if one was delivered (read: redelivered)
to me now, i'd choose the girl i married over all the dates i had in my
going to the pistol range days atmo.

---

Bikes don't go crazy with time! LOL

I still have the bikes of my youth (except for a lightning fast and twitchy Faggin with rocket speed:D), and they don't ride like they did in the mid 80's.............

Dave, you are among the fortunate, that you can find the geometry because the bike was more popular.
Whether you should try to reproduce it or not, depends on what you are looking for. If you preferred it's handling, I'd say go for it! But don't expect something identical, because type of lugs, tubing, fork crown, all affected the rigidity and feel of the bike. You do have the opportunity, however, to change materials to favor rigidity or vibration dampering without changing the geometry. That's the beautiful opportunity offered when you want to recreate a ride that you loved.

We sometimes question ourselves (and quite legitimately so) as to whether we can trust an impression from days when we were less experienced. I remember when I tried other rides after my Cambio Rino crash, more standard racing geometries, and I was able to experience immediately the differences because I had the "body-memory" of my lost love.

When going back to a conventional wisdom geometry, you either like it more, or you like it less. I think that an immediate impression is something you can trust and go by. A more average racing geometry is definitely something to test ride to give yourself a baseline of comparison, to help make a decision of what direction to go in.

I think a good analogy for this thread is like being the only sober guy at party at 2am. :D

My 3TTT quill stem seems to point slightly downward, and those are set around 73deg right? On the other hand I didn't feel the bike to be super twitchy.

Just watch! We'll have the world's problems solved soon - pass the scotch!

Not necessarily. I have a stem on my track bike that does a nose-dive downwards.
Some of them had a radical down-sloping so you could set the handlebars lower than a conventional stem would allow, for a more aggressive / aerodynamic position. On the track it allowed you to be a bit more aerodynamic while still maintaining good arm extention and optimal bend in the elbows for a firm strong hold on the handlebars which was required in maneovering on the track. And on the road, well, in a time trials, these enabled you to go down even lower in that aerodyamic tuck.

What I meant is that the head angle is not really slack, since my road stem ends up pointing slightly downwards. If the latter is at 73deg (the Cinelli ones are), then the head angle is steeper. But I don't have a way to measure it so who knows really. Just to say it's perhaps the type of bike you're searching.

pic here. You'll notice the tight-ish clearance (25c mounted, with about 1/4" adjustment left fore and aft).

Tigertamer, check out this thread in C&V. I wonder if this is what you're looking for? Sounds close!

http://www.bikeforums.net/showthread.php?t=75660

Road Fan

Thanks for bringing that to my attention. Time-trial/triathlon/stage-race frames, and smaller 19" frames, tend to have slacker head tube angles. This bike meets both those criteria: it is a 19", and a time trial/stage-race focused* bike (hence it's "chronos" designation). However, I'd love to be proven wrong on that and would be open to getting measurements of a larger frame, in the 22" - 24" (56-60cm) range.

* I'd prefer to use the word geometry, but then another war would start, with people coming out of the woodwork to slap me over the fingers and telling me there is no such thing. ;-p

About the GIOS: Yes, I wrote my comment regarding the head tube looking rather slack after I saw a picture of one on the website. Now this was probably lens distortion from the camera (fish-eye effect as it is called) that made it look that way, as it was a 3/4 forward-facing view.

I looked at the picture you submitted, your yellow bike, and I no longer would make the same comment.
Your Gios looks quite nice! The angles too. I wish I could take it for a test ride. :-)

OK, what I was trying to say, is that I'm not hellbent on the seat tube angle, that if we find a nice handling bike with a STA that isn't ideal for the rider we can compensate in other ways. The STA is more fit-focused and not as much handling-focused as the HTA.

How I wanted it to be interpreted, is that we are paying more attention to the head tube angle and it's rake, in this particular thread.

There is a frame geometry database here. Perhaps it can be useful to you or others. I wouldn't say it's super accurate tough.

After looking at the spreadsheet, and assuming that every individual who contributed did a perfect (and not careless) job in measuring, the GIOS looks like the geometry that I am looking for. It looks like a bike that I would buy, definitely! Thank you so much for that! (OK, I admit I knew of the existence of this, and already had the spreadsheet on my PC, but it took your post to get me to actually take a more detailed look, look find the GIOS and discover what a nice geometry it has).

It has a very short wheelbase, shorter top tube relative to frame (seat tube) size, which is good for me because I have long legs relative to my total height and bikes are always too long for me in my frame size (with the exception of the Cambio Rino I had, which was very compact).

One last thing though... and I'm just putting this out there for discussion sake, is regarding the trail.
You can read in books like "Bicycle Science" that a bike's handling, "sluggish" steering, is much affected by human interpretation and misconceptions caused by erroneous theories.

My personal theory is that trail may actually help in handling, here's why: as you turn, the contact point with the ground is moved outward of where you are steering towards, thus helping the bike lean into the curve. But the fact that this is interpreted as "sluggigh", less neutrally responsive and requiring more effort to bring back into a straight line (and keep it there?), sort of casts some doubt on my theory. Maybe it is a bit a combination of the two, that you have to find the sweet spot.

Hey guys, I just took measurements off of my Cambio Rino track bike... this is one nervous b!tch, and I now understand why! LOL
Head tube angle 74.5, seat tube angle 76, wheelbase min38.5! max39.5 (the rear dropout is a long horizontal slot and you can adjust the fore-aft positioning/distance, in order to tension your chain or just shorten your wheelbase if you want to. This is a 24 inch frame (24" c-c ST (about 24.5 c-t), 23.5 c-c top tube).
And with it's Columbus Zeta tubing (low end but stiff as hell), it's pretty good at transforming energy into motion, and doesn't bend a bit while manoeuvering.
Just thought I'd add that for the fun of it, although it has nothing to do with the Cambio Rino road bike I'm looking for.

That IS a pretty tight frame! Can you measure the rake (aka offset) of the fork? Then we could calculate the trail, which is what really gives an indication of steering behavior.

Road Fan, I'll try. Yes indeed, and I was an agile monster on this on the track. Ahh the good old days...
I'll have to make some kind of insert to the steering column, and find a way to make sure it is co-axial, so I can be confident about the quality of my measurement. Otherwise, what would be the point right? I'll let you know when I do it.

Just get it as good as is reasonable. I only know one sure home measurement method, and it needs the fork off the frame, on a flat table ideally a reference plane, some precision tools, parallel blocks, et cetera. Find a method you can sight in with reasonable ease, do it about 5 times recording the numbers prob to the millimeter each time, and calculate the average. Or post all the numbers and I'll do the math, it's falling off a log for me (engineer with 30 years). Then I'll get you a trail value that's as good as the inputs are, look it up in my Talbot, and see what he said about that range, for what that's worth.

For a built bike, I fix the bike in a training stand and level it as well as possible. I align a meter stick with the stem center bolt and the center of the fork crown, and make sure the bottom of the stick is sitting on the floor. Secure the stick to the bike with tape. If necessary I mark key points on the bike with a fountain pen, which just wipes off of painted surfaces. Then measure the offset with a metric scale, perpendicular to the meter stick edge (which now represents the steering axis), to the center of the quick release skewer. That's the offset. You can see the setup is tricky. Sometimes I can reproduce the manufacturer's numbers.

I'm gonna guess it has a lot of trail. Short wheelbase usually means a front wheelthat's kind of close to the downtube, which implies not much offset. A small value of offset will compute out as lots of trail.

I really have a similar "re-create the past" project, my old mid-60s Rossignoli road bike. I think it was a great example of the race bike for not-so-good Italian roads of the day. I do wish I still had it (stolen!!!), or at least knew the numbers so I could work with a framebuilder to see if I should re-create it.

For the rationalists here, we are clearly beyond the pale.

Just a small note. Although the Gios has a shorter TT its effect may be cancelled out by the steeper ST angle: you may end up increasing the setback to keep your position wrt to the pedals constant, thereby effectively lowering the angle and lengthening TT.

But saddle setback, AFAIK, is mostly a function of femur length, so if your legs have longer tibia in proportion, it may be fine. Btw me too I prefer short TT and stems :)

Wow! Sounds complicated! Lots of trouble!

Here is how I did it:

I strung a thread through the dropouts, up to the headtube. (Because my track bike's stem extention slopes radically downwards, I've had the extra step of creating a support, in this case with tape, from the handlebars to the stem, over which to drape the thread.) I adjusted the thread so that visually, the two sides, and the part going through the dropouts, were all co-planar. Then looking at the thread, with both near vertical threads in my sights as aligned (co-planar), I set them to be parallel with the head tube. I did extra checks that the threads, after sliding them along the stem-extention (support below it), and readjustments, to make sure they were still co-planar. After I measured with a slide rule, one of the jaws parallel to the 2 threads, the other behind the head tube, subtracted half the diameter of the headtube.

Fork Rake: 38.5mm
Bottom Bracket Drop: 49mm
Chainstay Length: 390mm +/-12mm
(measured to intersection with seat stay, as there is about 12mm fore and 12mm aft adjustment on that)


I also made a trip to measure a GIOS that was up on eBay... frame too small for me. Nice geometry though.

Tigerrtamer, the trail is 51.6 mm.

trail = (radius *cos HTA - rake)/sin HTA