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-   -   Frame size (https://www.bikeforums.net/classic-vintage/1248614-frame-size.html)

swampyankee2 03-20-22 06:24 AM

Frame size
 
After doing alot of fettling on the Dawes Galaxy I finally got take it for a test ride. I may have underestimated the size of the frame, which measures about 23-24" crank-to-top of seatpost depending on how you look at it. The top tube is probably too high, as it just touches the crotch. I'm starting to think re-framing this project might be good, especially since this frame isn't the greatest shape anyways.
It would be good to stick with English so that most parts will swap over. If I'm looking for a new frame, how should I expect it to be measured?

Mr. 66 03-20-22 07:55 AM

That would depend on on the origin and or manufacture. Some would measure bb center to top seattube, others measure bb center to toptube center. Toptubes are always measured center to center(ctc). English bikes are in inches center to top, most French are metric center to top, a lot of Italian are measured metric center to center, but I see many Roma ctt. Also there is the standover height. On to of that there is the sellers measuring, that can be all over the board on how they record.

swampyankee2 03-20-22 08:43 AM

That's why I was limiting my query to English bikes. I know my selection would be limited, but at least the measurements might be more standard.
when I look for bikes online I generally look at the stem as an indication of frame size and assumed the Dawes would be about right.
https://cimg5.ibsrv.net/gimg/bikefor...018f6c956e.jpg
But in my excitement and naiveté I neglected to check standover height which turns out to be a bit high for me.
https://cimg3.ibsrv.net/gimg/bikefor...1dc2555728.jpg
The actual frame size seems to be 23". I would need a 21" as measured by this method:
https://cimg9.ibsrv.net/gimg/bikefor...6290f430c9.jpg

tkamd73 03-20-22 08:50 AM

When buying a vintage frame online, by vintage I mean horizontal top tube, I always look at the head tube only. Frame angles tend to affect the ride more then the fit. Too bad, nice looking bike.
Tim

John E 03-20-22 08:52 AM

Agreed. With a 30" trouser inseam, my ideal frame size is 55cm C-T, which is why I collected the three Capos and the Bianchi and why I gave my 57cm Peugeot PKN-10 to my elder son, who is 3" taller than I am. My 21" Peugeot UO-8 also fits me, by virtue of its proportionately long top tube.

I just barely pass the "crotch standover test" on my 55cm road bikes.

https://cimg6.ibsrv.net/gimg/bikefor...a283de0622.jpg
1959 Capo with Nervar Star crank and Campag. 980 derailleur upgrades and new Brooks Pro saddle.

Having said this, I confess to having bought a 23" Nishiki Competition and ridden it 40K miles until the frame broke at the bottom bracket shell. It was a bit tall for me, but compensated with an extremely short top tube. (It was so short that I bought a long-reach stem for it. In contrast, the PKN-10's top tube was so long for me that I needed a close-coupled, minimal-reach stem.) Many people have advised that top tube length may be even more important than seat tube length in frame sizing, although both obviously count.

Mr. 66 03-20-22 08:56 AM

I don't think you want a frame 2" smaller than the Dawes. Is the saddle position correct for you? How is the standover now? Are you actually on toptube in standover? Try standover and lift the bike to the pelvis how far are the wheels of ground? I would think that you would want about 3/4"- 1 1/4" clearance, I think 1/2" gap would be considered French fit.

swampyankee2 03-20-22 09:05 AM

Granted, I've only straddled the bike while in casual clothes (and commando) so the standover height might be better in cycling garb. The only other traditional frame bike I have to go by is my Raleigh Sports, which measures 21" C to T and has a very comfortable 31" standover height.

Aardwolf 03-20-22 09:17 AM

FYI, my 1982 Holdsworth Avanti is 22" top tube (centre to centre) and 22" seat tube (centre bb to seat tube top).
I just measured the standover at 31.5".

jdawginsc 03-20-22 09:34 AM

I would imagine your comfort zone should be around 54-55cm. Maybe someone has a frame to trade/sell on here.

23" is 58 cm, which for me at 5'11" is a no go.

52telecaster 03-20-22 09:49 AM

For my taste I prefer a frame that many would call too tall. I never actually stand over the bike so it's not an issue. I ride 23-23.5 usually and like 24. My take on it is that when you stop you have one foot on a pedal and one on the ground. Top tube length and stem reach + handlebars make so much difference for fit that seat tube length doesn't account for.

wrk101 03-20-22 10:16 AM

I have negative stand over on some of my bikes. I focus on top tube length instead. Plenty of top tube length sizing guides out there on Google. I always tell people "you don't ride a bike like the Flinstones drove their cars." I came from the era (1970) where a small Schwinn was 22 inch ST, medium was 24 inch ST, and large was 26 ST. Wow, those were the days.

I've had smaller ST bikes with super long top tubes, like a 52 cm CTT ST, 58cm TT CTC, that was too big due to the silly long top tube. I use stem length to fine tune TT sizing. I've seen XL bikes with short stems, and small bikes with long stem. I would not use stem length to represent sizing. Realize these bikes are 50 years old, so even if they originally came with a long stem, over the years, riders could have swapped them out to better fit them. Heck, sometimes they didn't leave the original dealer without a stem swap.

non-fixie 03-20-22 11:02 AM


Originally Posted by swampyankee2 (Post 22444770)

For a touring bike like the Galaxy this size is spot-on.

https://cimg6.ibsrv.net/gimg/bikefor...4a0bfe7c7c.jpg

swampyankee2 03-20-22 12:54 PM


Originally Posted by Mr. 66 (Post 22444779)
I don't think you want a frame 2" smaller than the Dawes. Is the saddle position correct for you? How is the standover now? Are you actually on toptube in standover? Try standover and lift the bike to the pelvis how far are the wheels of ground? I would think that you would want about 3/4"- 1 1/4" clearance, I think 1/2" gap would be considered French fit.

Saddle position is correct heightwise but after today's ride I shifted and tilted it forward, since I had to slide forward on it to reach brakes.
i can stand over the toptube but there is zero clearance between it and the tender parts. I'd consider that a French fit by your description.

Mr. 66 03-20-22 01:41 PM

On reach, you do have some minor adjustments that can draw your reach closer. I though your saddle set height and tilt looks great to the size of frame. Could pull that forward a tiny maybe. If you were to reposition the brake levers higher on the curve of the bar. Which will take pressure off your wrists. Another would be to rotate the handlebars up, both of those can put you a touring position as opposed to race. Other things can be done but this changes no parts. Experiment, back and forth, being comfortable makes so much difference.

SJX426 03-20-22 02:02 PM

[MENTION=550353]swampyankee2[/MENTION] - Your brake levers are waaaay to far down on the HB. If you take a straight edge and align it with the flats of the drops, the ends of the levers should be touching or slightly above the straight edge. You could also rotate yourbars.
https://live.staticflickr.com/7327/1...08ddd971_b.jpg1983 Colnago Superissimo on Flickr

Senior Ryder 00 03-20-22 02:20 PM

One issue that I've had with seat tube measurement and stand over is BB height. Acquired a few frames that had the "right" size seat tube, but the BB height made the stand over tight.
Cheers,
Van

Hobbiano 03-20-22 07:26 PM

Keep in mine that with a smaller frame you would not be able to raise your handlebars as high in relation to the seat. Adjusting your brake levers as SJX426 & Mr66 said will help shorten reach a lot. Judging by saddle height, I wouldn't call that French fit. French fit usually results in the top of the bars being almost level with the saddle, without the stem being too high (there should always be at least 2" of stem inside of the fork, 2 1/2" is better). You should check yours - it looks like it may be too far out of the fork. Once you adjust the bars & brake levers, if you still wanted a shorter reach, you could get a stem with less reach, and maybe more height.

Chuck M 03-20-22 07:57 PM

FWIW, one my most comfortable bikes to ride just touches my crotch. But I spend more time riding it than I do standing over it. I would take the suggestions offered above to correct the brake lever position before giving up on this frame. You may find with tilting the saddle that you still have issues reaching the brakes and now have another issue with sliding forward and thus having to hold yourself more with your palms.

nlerner 03-20-22 09:19 PM

IMO, stand over height is the least useful measurement you can use. How much time does one spend standing over the top tube with two feet on the ground, anyway? And I agree the OP’s brake levers are set up too far forward. I try to achieve a level surface between bars and the tops of the hoods.

albrt 03-20-22 09:36 PM


Originally Posted by nlerner (Post 22445494)
IMO, stand over height is the least useful measurement you can use. How much time does one spend standing over the top tube with two feet on the ground, anyway? And I agree the OP’s brake levers are set up too far forward. I try to achieve a level surface between bars and the tops of the hoods.

Standover height is important for beginning riders who are at serious risk of falling over when they have an unplanned stop. The more experience you have and the faster and further you want to go, the more you should go with what is comfortable.

jdawginsc 03-21-22 05:44 PM

Looking more closely now that it is not on a small phone, that is a perfect size bike for you if the seat is in the right position. A smaller frame is going to necessitate a significant jump (2cm) in seatpost height from seat tube. And then the corresponding stem (Technomic zone)

Maybe get a shorter stem reach, and I agree with everyone here, move the levers around and up until you find a comfortable zone, looks be darned. Neal has a nice rule of thumb I am going to use for quick adjustments...

squirtdad 03-21-22 05:44 PM

Remember a proper fitting bike will be one that you have to get off the seat at stops, typical answer to a close to uncomfortable top tube is to lean it over a bit when stopped.

how are you setting saddle height? My go to is to do an initial set based on heel on pedal axle with knee locked, from there if you hips don't rock when pedaling, keep raising until they do, and then lower a bit.

Looking at the amount of seat post you have, i thinks this is probably not a bad fit and you probably don't need to go down a size

repechage 03-21-22 06:52 PM

Top tube length and handlebar position also play a roll.
when I was young and 5'-7"
I bought a 59 ctt framed bike, everyone thought I would grow... I did but not eneough.
I sold it off for. 56 cm ctt frame when I was 5'-9". I gained some height but gravity struck back. I still have that 56cm bike but truthfully it is now a tad long.

if I wanted my bars level with the saddle a 58-59 cm would work.

but most often those bikes have a top tube too long.

I am not discussing seat tube angle or as some note "setback".

I think the Dawes is on the middle- longer side.
a 22.5" top tube might be what it has, if so, can be made to work with a shorter stem.

consider what you need and go from there.
Dawes I think went 19, 21, 23... maybe even add a 1/2" to each size.
Sometimes even the 21" frames had long top tubes... easier to avoid toe clip overlap.

spudly 03-21-22 07:10 PM


Originally Posted by tkamd73 (Post 22444775)
When buying a vintage frame online, by vintage I mean horizontal top tube, I always look at the head tube only. Frame angles tend to affect the ride more then the fit. Too bad, nice looking bike.
Tim

Interesting! Can you expand a bit? Thanks

Mr. 66 03-22-22 09:41 AM

Swampy, double check your rear wheel. It does not look properly seated in the claw and dropouts in the picture posted.


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