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-   -   Frame sizing on vintage bikes (https://www.bikeforums.net/showthread.php?t=1256663)

madpogue 08-11-22 09:19 AM

I've never worked in a bike shop, but the OP's Radio Flyer is cool.

Lbxpdx 08-11-22 09:29 AM


Originally Posted by Trakhak (Post 22606562)
Frame angles of 74 degees parallel for a 21" touring bike? Seems unlikely. That's '80s Italian criterium bike/track bike territory.

In the original Craigslist ad the guy had a scan of the geometry page for the Voyageur’s of that year. The larger frames were 72 ht 74 st if I recall, though I do recall the the 21” be 74/74 as my other bike is a 73/73 and I was wondering how much of a difference the steeper angles would make. That is also the reason I bought a VO seatpost with more setback to get my butt behind the BB. I messaged the guy, so hopefully he still has the images, which I will post if/when I get them.

Lbxpdx 08-11-22 09:33 AM


Originally Posted by Century Bob (Post 22606597)
I agree with Steel Charlie. I would address the seat first by leveling it. That would also require adjusting seat height. Then the reach to the bars would be improved allowing the rider to drop the stem further into the head tube. This set up looks very uncomfortable and the bar position is compensating for poor saddle position.

I did adjust the saddle a touch on the ride, bringing the nose down, though that must have been after the pic. My other bike, rando 650b, has the nose up higher too and I find it comfortable particularly when pedaling up hills.

smd4 08-11-22 09:39 AM


Originally Posted by bikemig (Post 22606193)
Good, then you know that your post was nonsense. A super tall stem is not a sure fire sign that the bike is too small since you have to see someone on the bike but it is often a sign that a bike may be too small. Of course you have to see the rider on the bike since dimensions do vary. And obviously as you wrote that setting up a person correctly on a bike involves proper leg extension as well as having the proper stem length, etc.

Personally (and clearly your mileage does indeed vary), I would never initially judge stem height as an indication of frame size, as you did ("That bike looks on the small side to me given how high the bars are"). Seat post height is a much more reliable and accurate indicator. What if the OP was using gorilla hanger bars that place their hands at shoulder height? That wouldn't tell me anything about frame size. To suggest otherwise is nonsense.

Without seeing the rider on the bike, if the saddle as shown is properly adjusted, I'd have to say the bike is a good size. If the saddle was sticking up 30 cm, then yeah, the frame might be too small. We had a guy here like that recently. But he too thought he was riding the correctly-sized bike. If the saddle was sitting on top of the seat tube, I would suggest a smaller frame size.

To each their own. If the first thing you look at is stem height to judge frame size, who am I to suggest otherwise?

smd4 08-11-22 09:42 AM


Originally Posted by Century Bob (Post 22606597)
I agree with Steel Charlie. I would address the seat first by leveling it. That would also require adjusting seat height. Then the reach to the bars would be improved allowing the rider to drop the stem further into the head tube. This set up looks very uncomfortable and the bar position is compensating for poor saddle position.

The bar height could simply be a factor of the rider preferring a more-upright riding position.

bikemig 08-11-22 10:07 AM


Originally Posted by smd4 (Post 22606722)
Personally (and clearly your mileage does indeed vary), I would never initially judge stem height as an indication of frame size, as you did ("That bike looks on the small side to me given how high the bars are"). Seat post height is a much more reliable and accurate indicator. What if the OP was using gorilla hanger bars that place their hands at shoulder height? That wouldn't tell me anything about frame size. To suggest otherwise is nonsense.

Without seeing the rider on the bike, if the saddle as shown is properly adjusted, I'd have to say the bike is a good size. If the saddle was sticking up 30 cm, then yeah, the frame might be too small. We had a guy here like that recently. But he too thought he was riding the correctly-sized bike. If the saddle was sitting on top of the seat tube, I would suggest a smaller frame size.

To each their own. If the first thing you look at is stem height to judge frame size, who am I to suggest otherwise?

You of course to misread my comments (as well as only quoting part of them).

Here is what I am confident that you know. If a customer came into a your shop to buy a bike and needed a tall stem to fit a bike (say a Nitto technomic), you would have suggested that the buyer look at a somewhat larger bike since that would avoid the unnecessary expense of the stem and labor involved and the fact that the customer needed such a tall stem suggests that perhaps a somewhat larger bike makes sense for the buyer. So that is just common sense from your experience as well as mine.

I agree with you that this is one piece of evidence and you have to look at the person on the bike to get a better idea of the right size.

To state that a tall stem is absolutely not an indication that perhaps the OP could use a somewhat larger bike is non-sense in that it runs contrary to how I am confident you sold and fitted bikes back in the day. It might be but that also depends on all the other factors you pointed out.

It is deeply puzzling to me that you took such a crazy hard line against this common sense observation. The bottom line is that I doubt we are very far apart in our observations and how we fit bikes.

bikemig 08-11-22 10:19 AM


Originally Posted by smd4 (Post 22606132)
snip . . .

Worked as a wrench, also selling and fitting, 10 years, 1985-1995.

In those 10 years, when a customer needed a very tall stem such as a Nitto technomic how often did you tell that customer to go ahead and pay the expense of the labor involved in installing the stem? Or did you suggest that perhaps the bike might be on the small side and a larger one might work better?

I'll bet that you had the customer try the larger bike first which is precisely my point. So you are making a point (that a very tall stem could be a sign that the bike is on the small side) that is contrary to your 10 years of experience.

And of course one can get a good fitting with a tall stem (which I suggested in my initial post). That is just a duh observation on your part. Just take a look at the long thread of all the MTBs converted to drops.

Here is my conversion on a 90s Specialized Stumpjumper. I used a Nitto technomic to get the bars up where I needed them.

https://cimg8.ibsrv.net/gimg/bikefor...b895a2f567.jpg

smd4 08-11-22 10:56 AM


Originally Posted by bikemig (Post 22606776)
You of course to misread my comments (as well as only quoting part of them).

Again, I don't understand the necessity to quote entire posts, when I am addressing only parts of them. Am I not allowed to only address parts of posts?


Originally Posted by bikemig (Post 22606776)
Here is what I am confident that you know. If a customer came into a your shop to buy a bike and needed a tall stem to fit a bike (say a Nitto technomic), you would have suggested that the buyer look at a somewhat larger bike since that would avoid the unnecessary expense of the stem and labor involved and the fact that the customer needed such a tall stem suggests that perhaps a somewhat larger bike makes sense for the buyer. So that is just common sense from your experience as well as mine.

Your presented scenario makes little sense to me. "A customer comes in to buy a bike and needs a taller stem?" Why would they think they need a taller stem right off the bat, without even having bought a bike? But whatever. After drilling down to find their preferred or hoped-for riding style and circumstances (for this exercise we'll say they want a road bike, as opposed to a MTB), I would have first properly assessed what I believe the proper bike size would be for them, using available bikes in the store to get them on a frame that I believed would be the best size, explaining to them my reasoning along the way. I'd adjust the saddle height for proper leg extension. I'd then let them take a test ride on an appropriately-sized frame. If they said the size felt fine, but they felt too hunched over (or something like that), then I would tell them that taller or longer stems are available. I certainly wouldn't suggest, initially, that a taller frame was a solution, but if they insisted, I would of course let them test ride a larger frame, with my caveat that it was likely the incorrect size for them. I'd leave the final decisions up to the customer. So no, the way you suggest things be done would certainly not have been my way.


Originally Posted by bikemig (Post 22606776)
I agree with you that this is one piece of evidence and you have to look at the person on the bike to get a better idea of the right size.

It's a very small, to me almost insignificant, piece of "evidence."


Originally Posted by bikemig (Post 22606776)
To state that a tall stem is absolutely not an indication that perhaps the OP could use a somewhat larger bike is non-sense in that it runs contrary to how I am confident you sold and fitted bikes back in the day. It might be but that also depends on all the other factors you pointed out.

I did not size or sell bikes based on stem height.


Originally Posted by bikemig (Post 22606776)
It is deeply puzzling to me that you took such a crazy hard line against this common sense observation. The bottom line is that I doubt we are very far apart in our observations and how we fit bikes.

Don't be puzzled. You and I see things way differently.

smd4 08-11-22 11:15 AM


Originally Posted by bikemig (Post 22606797)
In those 10 years, when a customer needed a very tall stem such as a Nitto technomic how often did you tell that customer to go ahead and pay the expense of the labor involved in installing the stem? Or did you suggest that perhaps the bike might be on the small side and a larger one might work better?

My assessment of frame size was always, ALWAYS (at the time) based on stand-over height and proper leg extension when sitting on the saddle. My recommendations /suggestions on stem height were based on customer's comfort wants or needs as they expressed them to me, based on a properly-sized frame. Stem height suggestions were separate and apart from frame size. Did customers want to ride bikes that I deemed too tall or too short? Sure, all the time. If they were unconvinced after my explanations, that was fine, and their decision. If a buyer was "between sizes," I'd always recommend the smaller size.


Originally Posted by bikemig (Post 22606797)
I'll bet that you had the customer try the larger bike first which is precisely my point. So you are making a point (that a very tall stem could be a sign that the bike is on the small side) that is contrary to your 10 years of experience.

Ummm...no. That's a mighty big assumption that I would have the rider try a taller frame first. In fact, it probably would have been the opposite. It of course would come up in discussing the bikes that there were different frame sizes, and of course the customer was free to request to try a taller frame, but that certainly wouldn't have been my go-to suggestion out of the box.


Originally Posted by bikemig (Post 22606797)
And of course one can get a good fitting with a tall stem (which I suggested in my initial post). That is just a duh observation on your part. Just take a look at the long thread of all the MTBs converted to drops.

I would phrase it thusly: Once you have a properly-sized frame, there are stem options, both in height and length, that can be used to place the customer into a more comfortable position, if that is what the customer was looking for.


Originally Posted by bikemig (Post 22606797)
Here is my conversion on a 90s Specialized Stumpjumper. I used a Nitto technomic to get the bars up where I needed them.

https://cimg8.ibsrv.net/gimg/bikefor...b895a2f567.jpg

OK? What's your point?

bikemig 08-11-22 11:21 AM


Originally Posted by smd4 (Post 22606881)
snip . . .

OK? What's your point?

Your posts are up there with some of the weirdest, argumentative posts I have read in some time. Congratulations.

bikemig 08-11-22 11:23 AM


Originally Posted by smd4 (Post 22606850)
snip . . .

Don't be puzzled. You and I see things way differently.

Actually we don't if you took the time to think about a post rather than engage in a weird fight. I don't disagree with anything you wrote and if you were honest, you really don't have an argument with what I posted.

Edit: it is time though that I put you on my ignore list. That way we won't clutter up the OP's thread with a nonsense discussion. It's too bad because there are no doubt things I might learn from your posts but you misrepresented my post to pick a silly fight.
Edit: Also my apologies in that no doubt I contributed to this as well so it's best to just walk away.

smd4 08-11-22 11:28 AM


Originally Posted by bikemig (Post 22606893)
Actually we don't if you took the time to think about a post rather than engage in a weird fight. I don't disagree with anything you wrote and if you were honest, you really don't have an argument with what I posted.

I've read your posts, word for word, over and over again. And then again.

I totally disagree with how you would size a bike for a customer. No argument there.

Lbxpdx 08-11-22 12:45 PM

If any of these numbers matter.
I’m a hair shy of 5’10”
PBH is 31.5”
30.5” stand over
top tube is 21.5”
seat tube is 20”
bb to ground is 10.5”
seat post is 5.5” from tube to seat rails
170mm crank
stem is 5.75” above top nut
center of stem/handlebar to seat nose is exactly elbow to tip of middle finger.

It would seem the frame fits me correctly, though my back and hands do not desire to a low stem.

Trakhak 08-11-22 12:47 PM

The posts by bkemig and smd4 are very interesting to me as a former bike store manager, mechanic, and salesman (on and off in the mid-'70s and through the '80s and early '90s). Shame that the anonymous forum format seems to promote friction somehow. Were they talking over a couple of beers after finishing a 50-mile ride together, they'd probably have found themselves 95% in agreement and would have moved on to telling each other customer horror stories by now.

By the way, I'd love to see a thread where (current and former) bike store employees compare notes on their various approaches to sizing bikes for customers.

Trakhak 08-11-22 01:20 PM

The owner of the bike shop where I worked in the early '80s came back from the New York Bike Show in (I think) 1983 having signed up as a Torpado dealer. I'd never heard of them at that point, despite having started bike racing in 1964.

This was probably the distributor's first foray into importing bicycles, since he brought in Torpado's whole size range, in 1-cm increments (!!!), in all models, top to bottom.

Most importers would have gone for the customary 5-cm size gaps that Americans were used to. (Back then, almost all racing bikes below the top one or two models of any given European brand used those size increments for the American market.)

Those Torpados were beautiful bikes, and nicely spec'd, with spot-on racing geomethry and various levels of Columbus tubing, partly or fully chromed frames and forks, and a variety of mixes of Italian components.

But it was the sizing that made them easy to sell. All you had to do is look at the customer, guess the size that would fit best, and have him or her ride that one, one 1 cm smaller, and one 1 cm larger (adjusting the fit of each appropriately beforehand, of course). Half the time, the customer would say, "Why should I ride three bikes that are almost the same size? I won't be able to tell the difference." We'd just say something like, "Please just take a short ride on each and let us know what you think."

I still remember the reaction of the customer the first time I sent one out on the three test rides. He said, "I was sure they'd all feel the same. Boy, was I wrong. The small and large ones were okay, but the middle one is perfect!"

It's a shame that the distributor stopped bringing in Torpados after only one season. Not surprising, though. Most bike shop owners and employees in the early '80s knew next to nothing about racing and would have been confused by the idea of carrying what would have seemed an unnecessarily large inventory of bikes in so many sizes. Too bad.

bikingshearer 08-11-22 01:42 PM


Originally Posted by Lbxpdx (Post 22605745)
My recently purchased Schwinn VSP is a fun ride. Nimble with nothing in the bags, yet planted and comfortable when the bags are filled with groceries. It is a 21”, 21.5” top tube, 170mm cranks, 74 degree head/seat and 27” wheels. With the amount of stem and seatpost showing, it looks like the frame is too small for me, but when I bought the bike I also tried a 23” version and it was too big for me. My nice bike is 56/56, 73/73 with 650b and it fits quite nicely and looks proportionate.

I’m trying to figure out why this bike looks small though it fits perfectly the way it is set up. Would a dirtdrop stem make the bike look more proportional?

Your bike looks small because it is small (says the 6'3" guy who rides 63 and 64cm frames).:D

More seriously, from your description, the bike is comfortable, it's fun to ride, and it does everything you want it to do. That sounds like a big ol' win to me. It ain't broke, so there's nothing to fix.

I do agree with the observation about the saddle angle - I would hate that on my bikes. But this isn't my bike, it's your bike, and if you like it, stick with it.

smd4 08-11-22 02:25 PM


Originally Posted by bikingshearer (Post 22607074)
I do agree with the observation about the saddle angle - I would hate that on my bikes.

You're of course not the only one to mention this--just using your post to start the conversation:

I'm sort of surprised to see the comments on the OP's saddle tilt. From what I've seen, very few folks on this forum ride with a perfectly level saddle (which--tilted fore or aft--looks quite odd and uncomfortable to me). I thought this was almost a given as to personal comfort. In photo after photo in other threads, however, I see folks with tilted saddles, and yet no one mentions it in these other threads. Surprised I guess that this one thread has generated so much opinion on it.

Trakhak 08-11-22 03:16 PM


Originally Posted by smd4 (Post 22607131)
You're of course not the only one to mention this--just using your post to start the conversation:

I'm sort of surprised to see the comments on the OP's saddle tilt. From what I've seen, very few folks on this forum ride with a perfectly level saddle (which--tilted fore or aft--looks quite odd and uncomfortable to me). I thought this was almost a given as to personal comfort. In photo after photo in other threads, however, I see folks with tilted saddles, and yet no one mentions it in these other threads. Surprised I guess that this one thread has generated so much opinion on it.

The saddle looks a bit swaybacked/stretched to me, which might mean that the only level section is the rear third of it. Tilting the nose down to any significant degree from its current angle might then result in his having to push back the handlebars to prevent his sliding forward.

rgvg 08-11-22 07:58 PM

I wonder if you don't have your saddle up too high. I have a 19" Trek where the seatpost is also about 14cm from top tube to rail. On my 21" Centurion the seatpost is about 10cm from tt to rail, which kind of makes sense. I know I'd hurt myself on a 23" frame as well. What I mean is, I don't see how you could have 14 cm of seatpost and yet not be able to go up a size. Was the other frame really a 23"?

smd4 08-11-22 08:09 PM


Originally Posted by rgvg (Post 22607437)
What I mean is, I don't see how you could have 14 cm of seatpost and yet not be able to go up a size. Was the other frame really a 23"?

5.5” on a 21” . Seriously? The frame size (based on the seatpost length, assuming it’s correct) is fine. To go up a frame size would be stupid.

tmnguuyen 08-11-22 08:18 PM

And there is the french fit option. I'm a short guy and it is hard to find nice vintage bikes in small sizes What's a good rule of thumb for a french fit as far as seat height, I read some where in the earlier posts, 1 hand or a fist (4-5 in) above the top tube may be ok. I think more clearance on stand over is more for a mountain bike fit.

French fit discussion in link below:

https://www.bikeforums.net/road-cycl...rench-fit.html

rgvg 08-11-22 08:25 PM


Originally Posted by smd4 (Post 22607450)
5.5” on a 21” . Seriously? The frame size (based on the seatpost length, assuming it’s correct) is fine. To go up a frame size would be stupid.

Well, 14 cm - 5cm (2 inches) = 9cm = 3.5" (average hand width) which kind of leaves you a hand's width of seatpost. Why would that be stupid?

Just wondering if the other frame wasn't larger than he thought it was or if maybe his seat on this one might be too high. Do you know if he's rocking his hips on it or not?

Lbxpdx 08-11-22 09:04 PM


Originally Posted by rgvg (Post 22607467)
Well, 14 cm - 5cm (2 inches) = 9cm = 3.5" (average hand width) which kind of leaves you a hand's width of seatpost. Why would that be stupid?

Just wondering if the other frame wasn't larger than he thought it was or if maybe his seat on this one might be too high. Do you know if he's rocking his hips on it or not?

i think the slightly shorter crank arm of 170mm is contributing to the height of the slightly extra height of the seat post. My other bike which is 56/56 with 650b’s has more French fit with a hand of seat post.

the I don’t recall the stand over on the 23” but if the stand over on the 21” is 30.5” and my inseam is 31.5”, it makes sense that the 23” wouldn’t fit. I recall my taint pressing up on the top tube when trying to stand over it with shoes on.

rgvg 08-11-22 09:13 PM


Originally Posted by Lbxpdx (Post 22607496)
i think the slightly shorter crank arm of 170mm is contributing to the height of the slightly extra height of the seat post. My other bike which is 56/56 with 650b’s has more French fit with a hand of seat post.

the I don’t recall the stand over on the 23” but if the stand over on the 21” is 30.5” and my inseam is 31.5”, it makes sense that the 23” wouldn’t fit. I recall my taint pressing up on the top tube when trying to stand over it with shoes on.

Well, if you've tried it then there's not much more for me to say, other than nice bike. I wish I had one like it.

smd4 08-12-22 07:03 AM


Originally Posted by Lbxpdx (Post 22607496)
i think the slightly shorter crank arm of 170mm is contributing to the height of the slightly extra height of the seat post. My other bike which is 56/56 with 650b’s has more French fit with a hand of seat post.

the I don’t recall the stand over on the 23” but if the stand over on the 21” is 30.5” and my inseam is 31.5”, it makes sense that the 23” wouldn’t fit. I recall my taint pressing up on the top tube when trying to stand over it with shoes on.

Yeah, I'd say you've got the correct size frame. What you do with the saddle and bars is just whatever works best for you at this point.


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