Retrobike Forum Index

It is currently Sun Dec 04, 2016 9:30 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Thu Jun 09, 2011 11:47 pm 
Dirt Disciple

Joined: Tue Jun 07, 2011 12:26 pm
Posts: 86
Location: Lincolnshire
I'm a bit puzzled. I found a comment in one of the threads on this site saying that people used to ride bigger frames, and that therefore smaller frames in older (50s/60s) bikes were hence uncommon and hard to find. Is this true? Was the height of the crossbar somehow lower on older bikes? I am currently riding a 1980s Raleigh Gran Sport in 21.5", and would not want a crossbar higher than on this bike. I had assumed that in looking for an older more interesting bike (50s/60s) that I should be going for the same sort of size frame. Is this correct?
Andrew H.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 10, 2011 2:50 pm 
retrobike rider
retrobike rider

Joined: Fri Jan 29, 2010 11:57 am
Posts: 308
Location: Devon
You are lucky to have a 'small' Raleigh, as most bikes from that era are bigger, just look at ebay and you'll see that most bikes like Raleigh Bananas or Team Cadets are 23" frames. The smaller sizes like yours are vey uncommon, I've been half looking for a 54cm retro frame for ages.
I guess parents bought their kids something that they 'might' grow into rather than something that fitted them and was therefore safer to ride. Alot would depend on the advice of the bike shop, and I still see people buying bikes where the seat is at it's lowest poistion and thus giving a different riding position than the manufacturer intended.
If you go back further in time, you'll see big bikes seemed to be the norm, I guess they thought they were small after a penny farthing.

If you are looking at a modern sloping frame, I'd say go small. A guy that has joined the informal cycling club that's kind of come togther in my village has a large Giant defy or similar and he's only about 5"11. He gets off the saddle and is not comfortable standing across the top tube even though it's sloping. Also the length of the head tube doesn't look like it belongs on any bike. Apologies to anyone who has one of these, If you are really tall enough to need a large frame then I doth my cap in apology
:oops:


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 10, 2011 3:10 pm 
Dirt Disciple

Joined: Tue Jun 07, 2011 12:26 pm
Posts: 86
Location: Lincolnshire
Thanks for the reply. I'm looking for a much older bike than the raleigh, which is nice but feels like a new bike to me. A looking for a genuinely retro bike, really 50s or 60s. My dad (5' 5' in those days) rode a 22" record ace in 1955, and he tells me that he could easily stand both feet on the ground while standing astride it. My mother, who was maybe 5" 1' road a 19" Hetchins Nulli Secundus. My father was measured for a new bike in 1990, and he was told he needed a 19" frame, ie 3" smaller than in 1955! I think something happened to stepover height after the 60s. The horizontal style crossbars from the 50s seem to have been lower than on an equivalent 80s bike. Maybe the bottom brackets were closer to the ground???

Getting back to your search, I think you might find that a bigger older bike actually fits you better than you'd think. I wish more people would specify the step-over height as well.

Anyway, good luck with your search.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 10, 2011 4:05 pm 
retrobike rider
retrobike rider

Joined: Fri Jan 29, 2010 11:57 am
Posts: 308
Location: Devon
Don't forget that your dad will have shrunk ok hopefully not by 3 inches, I used to ride a 57cm in my late teens so I've got 4 race frames that I made my way through. I find they are not the most confortable size anymore. They are not bad, have to lower the seat a tad, but now would only consider a 54cm like your yours. I'm also of the opinion that clipless pedals allow your foot to get closer to the pedal axle than convential strada or pista pedals. Lastly crank lengths are generally longer as 170mm was the norm back in the 80's, but 175 is common now. So 3 factors that would mean your dad could get away with a smaller frame.

Agree with what you say though about stand over height, I have a 54cm that I have picked up just as a frame set, but as the bottom bracket is higher than my 4 raleighs, it's not quite the standover height I was expecting. As it happens I like it, coz I probably can get away with 55/56cm frame in Raleigh sizing/geometry.
In the 80's when I started out on quality frames, the advice was to get a frame about 10" off your inside leg measurement, so for me I with a 32" inside leg went for 22 and half frame as the top tube length of the 21 and half didn't suit me as well.

Good luck with your search. what are you after an old 531 or something?


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 10, 2011 4:24 pm 
Retro Guru

Joined: Sun Aug 03, 2008 12:31 am
Posts: 585
Location: London
I suspect when he says he can put both feet on the ground, there's firm contact between the top tube (crossbar) and him, whereas the current fashion is for a large gap. As long as the saddle top is about 13cm/5in above the top tube, you can put both feet on the ground. I think standover height is quite a recent thing when sizing a bike.

Top tube height can vary a bit for the same frame size. A frame with a shallow seat tube and low bb height will have a slightly lower top tube than one with a steep seat tube and high bb. I don't think small frames are actually rare, they're just less common than an averaged sized frame, in the 80s that would be 22in/56cm.

There's frame size and there's riding position set up. Frame size is largely arbitrary in regards to fit as long as the bars, pedals and saddle are in the correct position. The current fashion is for a very low top tube with very long exposed seatpin. But the "problem" with this is it doesn't work on a frame with a horizontal top tube, unless perhaps you're setting up a time trial position with upturned bars. There's nothing worse looking than an old frame with the saddle half a mile out of the frame and the stem at its max height.


Last edited by fiks on Fri Jun 10, 2011 4:28 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 10, 2011 4:27 pm 
Dirt Disciple

Joined: Tue Jun 07, 2011 12:26 pm
Posts: 86
Location: Lincolnshire
He's a bit shorter now, but not that much shorter. I'm going to see if I can track down a few 50s bikes and compare the standover heights with frame size. I'm really looking for something that will spark my dad's interest from his old cycling days, but unfortunately that means the expensive hard to find ones, like Hetchins/Bates/Galibier etc. I'd also really like to find a complete bike, rather than encouraging the "buy-and-break" mentality that ebay is engendering.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 11, 2011 2:23 pm 
Devout Dirtbag
User avatar

Joined: Tue Jul 21, 2009 5:27 am
Posts: 100
Location: Sydney
Lots of factors to consider here.

The last decade has seen frame manufactures redesign the geometry of frames. The compact frame with a sloping top tube is not a performance enhancement. It's actually a way for frame manufacturs to make no more than 4 frame sizes for all size riders. It is much cheaper for a manufacturer to produce 4 frame sizes than a full range of frames in 1 or 2 centimetre increments ranging from 47cm to 62cm. For most people, riding a compact frame is a compromise in frame geometry, even though they probably don't realise it.

Compact frames have greater clearance over the top tube due to the shortened seat tube, which allows shorter riders to fit on a bigger frame without it being apparent to them that the frame is too big. Big riders have a whopping amount of seatpost showing. The mrketers will have us believe that a smaller frame is stiffer and lighter. This is true, but the longer (heavier) seatpost, which is not part of a triangle, is free to flex all over the place.

This new frame geometry has resulted in frames being measured in all sorts of new and interesting ways. Whereas historically, a frame was measured by the length of the seat tube, from centre-centre, they are now almost always measured by the length of the top tube, or, sometimes, the effective top tube length, which is an approximation of what a traditional frame's top tube length should be.

Now the truth is, that top tube lengths on traditional frames are much less variable than seat tube lengths on traditional frames, so, statistically speaking, a person who is an outlier when sized using the seat tube measurement, is likely to appear much closer to the mean frame size when sized using a top tube measurement. These days though, the top tube length is a function of its slope, and many newer frames also have a curved top tube, so the measurement cannot be compared from one brand to another. See the trickery going on here? I'm certain that frame builders these days are deliberately trying to make it harder for people to know what frame size they fit, since it can vary from brand to brand, and even model to model. Once you find a bike you like, it is much harder to compare it with other brands.

Next, I would say that overall, bikes that are from the 50s and earlier, have a tendency to have noticably different geometry to later bikes. They have longer wheelbases, flatter headtubes and slower steering. I put this down to the fact that riders spent as much time riding on unpaved roads and trails as riding on paved roads. The motorcar was a luxury back then, and almost no-one had them, so there wasn't the same road infrastructure we have today. Anyway, the point I am making, is the more relaxed angles (including the seat tube angle) meant that the seat tube needed to be longer to raise the rider to the same vertical height. You can confirm what I am talking about if you can find one of those old bikes with the "Major Taylor" style seatpost, where the saddle can be slid forward along the flat section of the seatpost to bring the rider back to a more upright riding position. In those days, setback seatposts were unheard of, and everyone had "set forward" seatposts (and by corrollary, longer seattubes), which equals bigger frames, even though the rider is in pretty much the same riding position.

The next thing to consider is wheel size. These days 700C is the norm, but bikes in the 50s ridden by sports clubmen were more often than not built with 26 x 1 and 1/4 inch, which if memory serves me right is 590mm in ETRDO sizing, and quite a bit smaller than 622mm of 700C rims. This may not make much difference to frame angles, but is likely to increase the standover clerance. Incedentally, when traditional bike frames were the only option the bike shops all told me that I should have about an inch clearance above the top tube when standing in relaxed fashion over a road bike.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 11, 2011 5:54 pm 
Dirt Disciple

Joined: Tue Jun 07, 2011 12:26 pm
Posts: 86
Location: Lincolnshire
Thanks Toff, thats really helpful. I now think I may get away with a 60s 23" touring type frame if I dropped down to 700 wheels, which would really open up some new possibilities for me. There are many more 23" frames for sale than smaller sizes. Thanks again


Top
 Profile  
 
 Post subject:
PostPosted: Tue Jun 28, 2011 4:20 pm 
Dirt Disciple

Joined: Sat Jun 11, 2011 5:56 pm
Posts: 15
I'm sure I read somewhere that bottom brackets on modern bikes are further from the ground than on older bikes - wouldn't this have an effect on the suitable frame size?


Top
 Profile  
 
 Post subject:
PostPosted: Tue Jun 28, 2011 5:07 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8202
Location: New Forest, UK
You are absolutely right - this was done to prevent pedals hitting the ground during hard cornering. In the old days pain was nature's way of saying you had done something stupid. Nowadays we all live in fear of compensation claims. Result: higher bottom brackets.

Much of this is due to bikes being designed and made in Taiwan for the US market with its predatory lawyers. As European manufacture collapsed we acquired US design norms along the way.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: 47p2, Big Block, Theoldfm, Yorkey and 37 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group