There has been a bit of online chatter about the geometry of the new 40th Anniversary TI-Raleigh Reynolds 753 frame. The speculation relates to the geometry of the frame, and specifically, about Raleigh UK’s marketing images showing a sloping top tube. Raleigh UK claim that they have followed the spec of Joop’s original frame specification, so as I’ve got the same size 56cm frame, this is a perfect opportunity to check.
My Setup Ready To Measure
I’ve successfully measured the geometry on lots of my frames. All you need to do is get a couple of things setup correctly before you start.
When a frame and fork are designed to work together, they must connect correctly. The lower head lug doesn’t just sit on the fork crown. Something has to maintain the relationship between fork and frame in order to ensure the correct frame geometry. I’ve used a standard 1″ Campagnolo headset which has an approx. 14mm lower section. It’s an ideal height and should put the frame in the correct position on top of the fork crown.
They were in the room and were a great fit for a period TI build… the wheels from SB2476 were perfect. Small flange hubs on Mavic sprint rims and Clement Criterium tubs help TI40-192 stand upright in the correct position to check geometry.
I have to be very careful to position myself properly. Although I set up the workbench level and zero my digital angle gauge from the workbench to keep angle measurements relative, a bike can easily be made to look skewed if I’m stood in the wrong place or slightly off centre/perpendicular to the bike that I’m photographing. Most of the time I’m taking photos for the blog and the image is more important than the setup, but when I’m reporting geometry, I try to ensure I’m representing the bike as ‘square on’ as possible.
What Exactly am I Looking For and Comparing?
I’m not doing a full geometry check in this post. So there won’t be any chain stay lengths, bottom bracket heights, head and seat angles etc. I’m only checking this frame against the information that Raleigh UK gave during their marketing campaign specifically to do with Joop’s seat tube size, and to investigate the sloping top tube. Does this frame match the data and information Raleigh UK provided; I’m looking to see if they have interpreted the data they used correctly. Have they correctly built a frame to Joop Zoetemelk’s dimensions, or even close to it?
Sources of Data
Source 1: Raleigh UK’s Marketing Campaign
My first stop off is the post titled “The Making of the Raleigh TI 40th Anniversary Bike“. In this post they have a section called “Step one: it’s all in the design”.
The frame geometry for this project was our next challenge, but fortunately the original measurements for many famous cyclists for who had ridden a Raleigh SDBU frameset, were still in the archives. Many of whom were measured by the legendary Gerald O’Donovan. In these files were Joop Zoetemelk’s 56cm frame measurements, so as a central size we entered these in to Solidworks & upsized/downsized accordingly.Raleigh UK
I’ll cover what Raleigh UK mean when they say the “original measurements” in the next section.
In the same post, Raleigh UK give a geometry sizing chart. The 56cm option (Joop’s size according to the quote from Raleigh UK), has the following details
- Seat Tube (mm) 560
- Top Tube – Horizontal (mm) 560
- Head Tube (mm) 143
- Fork Length (mm) 370
Those measurements don’t give a reference to how they are measured, especially important for the seat tube.
The size options given are 50, 53, 56, 59 & 61cm.
On the 20th August Raleigh UK published the following post on Facebook.
Just to be clear, that post reads as…
Our anniversary TI Raleigh is based on the original geometry chart from Joop’s 56cm tour winning bike, developed with absolute precision, following the specs as closely as possible and the dimensions too.Raleigh UK
The discussion on geometry is all based on that original geometry chart (the one out of the archive). The question asked was…
Is the geometry the same as the original?Managing Director Raleigh UK
The answer was specific and said the geometry was based on Joop’s 56cm geometry which came out of Raleigh’s archive. Every frame was geometry correct as it should be (discussing varying frame sizes). Most significant of all is the sentence…
If you buy a 56cm you are basically riding what he would have been ridingProject Manager for the TI-Raleigh 40th Anniversary Bike
So to sum up this section, Raleigh UK had original geometry details for Joop which gave his frame size as 56cm. They then scaled up and down from that 56cm baseline to create the smaller and larger options. These frames were geometry correct. They were developed with absolute precision, following the specs as close as possible. The 56cm on offer was the same as Joop’s 56cm Tour frame.
Remember that for later…
Source 2: “Some Successful Designs”
What is that heading all about?
Well it is all about three pages that have floated across some Public Facebook groups for a couple of years. I first saw this in August 2016. I’ve never published any content from it as it isn’t mine, but I have referenced it on occasion. It appears to be from a larger document.
The details come under a a section called “Section 8 Appendix C – Some Successful Designs”. It is a 3 page list of rider frame geometry details – you will see it previewed at 1:40 during the launch event video, with Joop’s frame details highlighted.
Joop’s details are on the second page of this section (what appears to be page 17 of the document). However, on that actual page, there is no context telling the reader how to interpret those measurements. Joop’s seat tube is listed as 560.
The context, the important key to how to read the measurements, is on the previous page. It clearly states “all dimensions are in mm’s and centre to centre…”
So to sum up this section, an appendix to a document gave some reference to Joop’s frame dimensions. His seat tube is given in that document as 560mm. But if you read the document fully, the measurement should be read as centre of bottom bracket to centre of top tube (CTC).
Remember that for later…
Source 3: “Team 80 Specification”
In my post about Joop’s Team 80 Specification, I give a couple of different sources of information. One is from the appendix above, 56cm (CTC). The other is from narrative from Gerald O’Donovan talking specifically about Joop’s tour bike. It gives the seat tube length as 57cm. The 57cm will be centre to top.
To sum up this section, Joop’s frame size is given as 57cm – this would be 56cm CTC.
Remember that for later.
Source 4: My Own 56cm SBDU Frames
My collection is perfect for this, it is one of the main reasons I’ve strived to make it as comprehensive as it is.
One aspect of the 40th anniversary frame is the long head tube! The head tube on TI40-192 is 143mm (as per their spec above). So I compared that to my own SB5464. This has the same size seat tube as TI40-192 (CTC) but only has a head tube length of 134mm. That is almost a centimetre shorter?
The head tube on TI40-192 is much longer which puts the frame much higher at the front in relation to it’s seat tube length.
The fork length of a 56cm anniversary frame is given as 370mm but you can see the fork length of SB5464 is 366mm. To give you an example of how fork length works against head tube length, here is SB2692. This was built with a longer brake drop – to do this the fork blade is cut longer to give a bigger gap between rim and brake bolt. This lifts the front of the bike. To accommodate a longer fork blade and stop the frame from rising, keeping the top tube horizontal, you shorten the head tube.
You can see that the fork blade is longer (for longer brake drop), but the head tube is much shorter (for a 56cm frame), which retains the horizontal top tube.
If the SBDU had not shortened the head tube on SB2692, the frame would be higher at the front and would present a sloping top tube. So my 3 examples of exactly the same size seat tube frame are…
- SB5464 366mm Fork 134mm Head Tube
- SB2692 375mm Fork 122mm Head Tube
- TI40-192 370mm Fork 143mm Head Tube
The fork blade length of 370mm on TI40-192 should have a corresponding head tube length in the region of 130mm in order to retain a level top tube.
Fork Blade and Head Tube Link
There is a link between fork length and head tube length.
This link can be seen on Track frames. Track frames have no brake clearance so the fork is shorter. However, to compensate, the head tubes on Track frames, for a given seat tube size, are longer – to maintain a horizontal top tube.
You can see this link demonstrated perfectly on my Stayer frame which takes a 24″ front wheel. To keep the horizontal top tube the head tube is much longer.
The Stayer has a seat tube length of approx. 53.5cm but the long head tube (due to the short fork) gives the impression of a much larger frame.
There are other factors affecting the height of the front end, but I need to double check. The measurement concerns the brake drop on the fork. Most SBDU frames I’ve measured have a 45mm drop front and back. Here is SB3505 demonstrating this.
I agree, it’s not hugely accurate but you get the idea, 45mm from centre of brake bolt to centre of rim. Here is TI40-192 as a comparison…
The rear is approx. 45mm while the front is approx. 49mm
Does this mean the fork is 4mm too long?
So to sum up this section, there is a link between fork length to head tube which keeps a frame in proportion and maintains a horizontal top tube. A longer fork requires a shorter head tube.
Remember that for later…
Source 5: SBDU Road Geometry Information
Several years ago, the previous workshop manager of the SBDU, Mike Mullett, published some ‘stock’ geometry charts to the Yahoo group. The table below is for Road specific frame geometry. It gives information about how a ‘stock’ SB numbered frame was built. It goes further than most other geometry charts that I’ve seen for SBDU frames, and lists the head tube length for frames used with ‘Piccolo’ brakes.
Note the head tube length for both the 560 and 570 frames, both shorter than the 560 TI40-192.
Remember that for later…
TI40-192 Basic Geometry and Stance
Here’s a short video I recorded about the basic geometry and look of TI40-192.
Seat Tube Length
From the centre of the bottom bracket to the centre of the top tube, TI40-192 measures 54.5cm. From the centre of the bottom bracket to the tip of the seat lug, TI40-192 measures 56cm.
Top Tube Height
The distance between the level surface of the workbench up to the top tube/head lug tip is 81.5cm. The distance between the level surface of the workbench up to the top tube/seat lug tip is 80cm. This creates a slope from head tube to seat tube of 1.5cm.
Head Tube Length
As per the Raleigh UK geometry chart, the head tube is 143mm.
The images above show approx. 5mm difference between front and rear. 50mm front and 45mm rear.
- The document used by Raleigh UK – the section titled ‘Some Successful Designs’, list’s Joop’s seat tube length as 560mm. However the preceding page tells anyone reading this information that they must read this as Centre to Centre.
- The narrative from Gerald O’Donovan confirms this CTC sizing of 560mm when it quotes his seat tube as 57cm.
- The Raleigh UK Product Manager, during the launch event video, described the replica as the same as Joop’s original…
- Raleigh UK have clearly translated the seat tube data incorrectly. Instead of applying the 560mm as centre to centre, they have applied it as centre to top (creating a 545mm CTC).
- My TI40-192 shows this mistranslation. I bought a 56cm replica, knowing that Joop rode 56cm centre to centre According to Raleigh UK, this is the same size as Joop. Sadly it isn’t, it is 1.5cm too short.
- The data Raleigh UK have used for Joop does not include a head tube length measurement. But actual SBDU data does. Based on the SBDU data, the 56cm anniversary frame head tube is too long. With the head tube on TI40-192 measuring 143mm and the extra 5mm on the front brake drop, this has created a sloping top tube.
every frame is geometry correct as it should be with the original based on his 56cm frame. If you buy a 56cm you are basically riding what he would have been riding.Raleigh UK Product Manager
What do Raleigh Say?
I wanted to include an opinion from Raleigh UK. So who better to respond than the Managing Director, who also headed the Raleigh UK 40th anniversary launch video. This is the specific question I asked about geometry, and the answer I received.
Please let me know your opinion of how you have used Joop’s 560mm seat tube measurement? It should have been centre to centre but you have used it as centre to top. The length of the headtube is an additional problem. It was claimed in the launch event that anyone buying a 56cm frame would be riding the same as Joop – this isn’t correct – they are riding a smaller frame.Neil McGowran
Raleigh UK Reply
We obtained the original frame geometry from a member of the Ti Club which out previous product manage Terry presented the concept to them. The feedback we received was all positive at this event. We created the frame design in solidworks using the angles/measurements from Joop’s frame. Agreed we used C-T method of measuring.
On your question from the brake drops, these had to be amended to suit as the brake shoes would have been very extreme with their rear, especially on the rear which would have dramatically restricted the wheel positioning and adjustability.MD Raleigh UK
My Geometry Conclusion
Raleigh UK have the geometry wrong. It is not the same as the original, the seat tube is 1.5cm too short and the head tube is too long, with differing brake drop between front and rear.
They haven’t followed the geometry document, they agree that they have measured centre to top. They haven’t produced the same frame that Joop rode. The detail and precision that Raleigh UK have claimed just wasn’t there.
In their Facebook post, they claimed…
Our anniversary TI Raleigh is based on the original geometry chart from Joop’s 56cm tour winning bike, developed with absolute precision, following the specs as closely as possible and the dimensions tooRaleigh UK Facebook August 2020
I personally don’t believe that the statements Raleigh UK made in their marketing about geometry were correct. However, every one is free to draw their own conclusion.
A final round up of the 40th Anniversary TI-Raleigh frame, it’s appearance, geometry, more from Raleigh UK and even Reynolds Technology.