Yes, you read that correctly… an SBDU Ilkeston frame with Nervex Professional lugs. I’ve never seen one before. Even though I’ve viewed over a 1000 SBDU frames, spanning the entire period of the SBDU, I’ve not seen a frame with these lugs. That meant I really wanted to add this frame to my collection.
Like so many other blog posts I’ve written, and bike purchases I’ve made, this story also started with an email; an email tip-off!
That email gave me a link to an eBay listing of a bike described as a possible Mercian, but notably with an image displaying an SB frame number, SB662. The bit of the email I wasn’t expecting was the reference to Nervex Professional Lugs. I clicked the link and there it was. Clearly a repainted frame with some additional top tube cable guides, but the 4 slot bottom bracket shell and SB number were clear. I gulped when I noticed it was all the way down in East Grinstead and it was collection only!
Buying
eBay Auction
I didn’t ask any questions. The seller had already received a tip off that the bike he was selling was probably a special build Raleigh. There weren’t too many clear details to verify what it was, apart from the BB shell, but there were other subtle SBDU touches that made me confident that the Nervex Professional lugs were original and that this was indeed a very unique frame.
I really don’t like buying from eBay. The listings are often shared across multiple sites and pages and bidders can run out of control. However, this listing was quiet, and I hadn’t noticed any internet chatter about it. The final couple of minutes came along and I placed a cheeky bid… and won.

Collection in Person Only
The seller had a few other frame and fork listings and it looked like he was using a courier to send these. So I asked if he could just send the frame but the answer was ‘no’. He had no tools and was on a very tight timescale as he was leaving the country. The only spare day I had to drive down to collect SB662 was 12 days after the end of the auction. Thankfully that was a couple of days before he was leaving. It was my only chance to collect it.
The drive from Newcastle to the far side of London would be a round trip of 650 miles and a minimum of 11 hours. More like 13 hours with a stop and probable traffic delays.
The Drive
I’ve done these long drives before. Sometimes if you want it you have to make the effort.
Three days before my drive, the UK went into a bit of a melt down because of a reported fuel shortage. Fuel was difficult to come by because of some weird panic buying. Long queues were building up at filling stations. My car can get approx 450 miles on a tank of petrol but the drive was 650 miles!
Two days before my drive, we stuffed a car tyre and put a huge hole in the side wall. I started to wonder if this drive was ever going to happen.
One day before my drive, and with a new tyre fitted, Karen was asking me if I was sure I wanted to drive to the other end of the country in the middle of a fuel crisis.
The Sunday came and I was on the road at 7am. Driving along the road and making calculations in my head of miles per gallon, distance travelled, distance to filling stations and making sure I had enough fuel if I had to stop and just turn around. I stopped at a motorway services and managed to fill up without much problem and set off again, but still needing to make those mileage calculations on the go as I was still short of possible miles. One last stop just short of the M25 and a 30 minute wait in a queue and I was topped up again, now with plenty of petrol to finish the first leg of my trip and get all the way home too.
From then on, every motorway overhead sign announced ‘No Fuel at Next Services’ – I think I had been very lucky.
SB662 Was in the Car
After 6.5 hours, I had SB662 in my car and after 5 minutes chatting to the seller, I was setting the Sat Nav for the return journey. I quickly checked the frame number and also noticed that it was my size of 57cm. The eBay images hadn’t been great, so when I dropped the wheels out to get the bike in the car, I also checked to see if the ends were drilled, and the frame ends were.

The Sat Nav was showing that I’d be home at 18:45, it was actually 19:30 when I got back home, a total drive of 12.5 hours. But the 80s music on the radio and cruise control, together with the amazing weather and a worry free full tank of petrol got me home ok.
SB662 on my Workbench
Nervex Professional lugs
I’ve owned and also sold lots of frames with these lugs. They appeared on so many frames. So they’re not rare at all. They aren’t actually a favourite lug of mine, they are too ornate and often lug lined to show off the various cut details. Lug lining is also not something I’m personally into – however, lug lining does suit some bikes and these lugs especially.
But, and it’s a big but, I’ve never seen these lugs on a Raleigh SBDU frame before. I have over 1000 records of SBDU frames and I’ve used these records to write a few timelines on dating and details. The SBDU had regular build patterns and an SBDU frame is easy to read, but one thing I regularly say to people trying hard to identify an SBDU, is that you cannot 100% say for certain if a detail is correct or not – the SBDU were a custom build unit and sometimes a non standard detail slipped through.

Standard SBDU Lugs
In this period, early 1976, the typical lugs used on SBDU 531 and 753 frames were Prugnat S and S4 respectively. The ‘S’ was a plain lug and the introduction of Reynolds 753 brought in the use of the window cut S4, to reduce the amount of lug metal. Reynolds 753 required less heat, the build detail of SBDU 531 frames changed to accommodate 753 frame building requirements.

Prugnat S above displayed on SB9 and SB518

Prugnat S4 displayed on SB632, SB1500 and SB1995.
Occasional SBDU Lug Changes
The SBDU did occasionally deviate from their standard patterns. A deviation sometimes seen on 1976/77 was the use of a heavily modified Carlton Capella lug, seen on SH377T below.

SB498, which was a frame built for Bob Jackson, also shows a deviation. This frame uses Bocama Super-Professional R3 lugs.

SB662 Appearance
The appearance of these bikes can often be ‘changed’ by different owners over the years, and SB662 is no exception. The beauty of an SBDU can be hidden in plain sight.
SB5084 is a rare SBDU Cyclo Cross frame but was masquerading as a holiday caravan bike.

HK.2.76, a Tour de France stage winning bike, was an ex Raleigh manager’s daily commute.

SB662 was leading a life as a single speed.

When you look past the Velo Orange bars and BLB wheels, you see those Nervex lugs.


Parts
There’s a real mix of bits and pieces; BLB hubs, sealed bearing headset, SR Royal 165mm Pista cranks, Cinelli stem, badly fitting Velo Orange bars, a Mavic bottom bracket, Rolls saddle and Cane Creek brake levers.

Are Those Lugs Original?
A major question that needed an answer was “are those lugs original to the frame”. SB662 has been renovated, it has top tube cable guides that wouldn’t have been an original feature. Lugs can also be changed, so is it possible to tell if these are original?
As I keep saying, SBDU frame details can be read. The builders shaped and modified certain frame features. One type of feature was the shape of the seat lug. And it’s the Nervex Pro seat lug on SB662 that proves they are original.
SBDU Seat Lug Point
The front of an SBDU seat lug is shaped into a definite point. Any roundness or curve that the original form had is shaped into that distinctive point. That ‘point’ can be seen in the examples below.

That same shaping of the front of the lug can be seen on SB662.

SBDU Seat Lug Side Profile
The side profile of an SBDU lug is also shaped. The images below show how the side edge of an SBDU seat lug comes down from it’s front point and continues flat. The high point on the back of the standard lug is removed, making the side appear flat.

The side of the seat lug on SB662 has the same profile.

Normal Nervex Professional Seat Lug Profile
When you compare the seat lug on SB662 to standard Nervex Professional seat lug, the difference is clear. The following image is from an old (non SBDU) frame I once owned, a Reynolds 531 Mercian. You can see the rounded front and curved side profile. The SBDU take the round front profile and shape it into a point, and the curved side profile is flattened.

SB662 Fork
Unfortunately, the fork doesn’t appear to be original. I’m not even sure they are Raleigh. The fork ends aren’t drilled and there is no vent hole on the fork blade. However, they are a very good fit in both looks and geometry.
One point to note is that, although probably not original, they are stamped with a ‘662’ to match the frame number. Why was that done?

Is there a link to SB664?
SB664 is another SBDU frame with distinctively different lugs.

Yes, SB664 is built with Carlton Capella, but they are almost intact, and very different to how the SBDU treated other Capella frames. Only the front point on SB664 has been trimmed, and even then, only by a few millimetres. The majority of the original Capella lug has been used on SB664. So is there a link between SB662 and SB664, only 2 frame numbers apart? Did the SBDU build a set of frames with ornate and decorative lugs for a reason? If they did, how many? I’ve not seen SB663, but would that also exhibit different lugs?
What Next?
Is SB662 another early Imperial version of Reynolds 753? Are there any signs of an original colour? Is there anything else unique about the frame? What colour and lug detailing would suit such a different SBDU frame?
There are, as usual, loads of questions to answer!
