In the beginning there was Metric Reynolds 753 tubing, and then later in 1982, a new Imperial Reynolds 753 tube was introduced. The new tube, called 753R, had different diameters, different gauges and was slightly heavier than the original Metric tube. And that’s how it was always known… Metric 753 before 1982 and Imperial 753 available after 1982. That seems quite straightforward doesn’t it?
There has always been lots said on the subject of Reynolds 753, and that doesn’t surprise me. This tubing had such an impact on the sport of cycling; the frames and their riders were breaking records before anyone even knew 753 existed! 753 frames are still sought after 40+ years following their introduction. You can’t go a day without the subject of 753 cropping up on the internet and the online debates and discussions mean that there are always stories and different opinions. But are these stories real and are the opinions accurate? What is truth and what is myth? What are these stories? Have I done enough research and accumulated enough data to either prove or debunk them?
Sometimes my frames come to me without any signs of originality meaning that I can’t accurately identify them. There is seldom a known history to accompany a 2nd hand frame. SB7121 was a classic example of this. I bought it on a whim, based on a basic description which indicated that it was probably a Reynolds 753 frame. The frame number dated it to 1985 and it had a hand painted finish with ‘Wheel Craft’ frame transfers, but underneath the paint, it was 100% an SBDU. I wrote an initial blog post on the frame but always wanted to come back and dig deeper and take a proper look into what it was.
This post isn’t necessarily about the SBDU, but I thought I’d write it as I get asked regularly to confirm seat pin sizes, or to try and decipher what an SBDU frame might be made from based on the seat pin and tube size. After collecting several SB frames over the years, I’ve seen lots of different seat pin sizes used in Reynolds frames. I have seat pins ranging from 26.6 to 27.4 – and 753 frames with 4 different size pins. That demonstrates just how varied their tube gauges were. So here is a little post that lists some of the most common seat pin sizes and the associated Reynolds tube gauge (wall thickness).
There are many stories about the SBDU and even more about Reynolds 753 tubing. Most of these stories travel the internet, changing and evolving each time they are told. Something as simple as which seat pin size should fit a 753 frame is one of those stories. It causes the most confusion and creates some of the longest discussions whenever it is raised. Everyone seems to have an opinion about what is right; few ever seem to agree. My latest addition, SB3800, means that I may now have a couple of frames that could finally settle the seat pin debate.
The search terms used by people who reach my blog are often connected to searching for information about the weight of a frame, specifically Reynolds 753 and Reynolds 531. So I thought I would write a little post to show the weight information I’ve collected on my own frames. I have frame weight data on several SBDU frames across a range of Reynolds tube sets. What I’ve found is that it isn’t simply a case of saying that every 57cm Reynolds 531 frame will weigh the same. Lots of factors influence frame weight.
This is the post I’ve been most looking forward to writing and also fearing with equal measure… Reynolds 753 was a tube set that took the bicycle world by storm. It had unrivaled strength while being ultra light and thin for a steel tube. It is probably the most mis-understood tube set and the one that has the most stories connected to it.
Frame details…, it is all about those little frame details… Frame details are hard to change. They are individual elements, fitted to tubes and formed into a frame when the torch melts the filler. Paint and decals are not the same, they can change over time, fooling you and misleading you with a different story… the frame detail should always tell the real story.
The SBDU at Ilkeston used a range of different frame and fork details over the life of the unit. The amount of different details they used means that this post may turn into an epic. I did consider splitting it into 2 smaller posts, pre and post 1980, but as this is ultimately a timeline post, I wanted it to be unbroken, and to start and complete in one go. Hopefully, it will be helpful for anyone doing research into their own SBDU frame. I’ll also try my best to fit dates and years in as I go. If you are a fan of the SBDU or simply need to know these details, then please stick with me. I learnt so much while researching and writing this post, hopefully I can pass this information on to whoever wants to read further!