Raleigh Technium 650b conversion

After my relatively successful third try into the world of 650b road bike conversions, I had to try out my new wheels on my 1986 Raleigh Technium. The Technium, as students of dead end bike technologies are apt tell you, has the three main tubes made of aluminum and bonded into steel lugs, which connect to a steel rear triangle and steel head tube. The hope was to get the lively feel of 531 steel with the light weight of aluminum. I can't speak to the weight--the complete bike has always felt rather hefty--but it is a lovely, flexy bike to ride. How would that match up with fat 650b wheels?

Very nicely, as it turns out:




38mm Pari Motos fit with great clearance at the front and rear brakes:


A bit tight at the chainstays, but still room for a fender:

These Pari Motos seem like a supple bargain. At around $35 per tire, they're about half the price of the Compass Loup Loup Pass tires. I haven't ridden them back to back, but they feel as good as my memory of the LLPs on my olde Trek 610. The rumor is their tread is thinner, so they won't last as long as the Compass tires, but this isn't a big concern for the meager mileage I usually do each year. The bottom bracket ended up at 10.75" tall, which seems just about right--it always felt a bit high with the standard 27" wheels.

I had some Tektro mid reach brakes in my parts bin, but I had to get a longer reach for this conversion. I chose some cheap Odyssey "1999" BMX brakes. For the princely sum of $18/wheel, I got brake calipers, a cable, an mtb style lever, and an end crimp. Conveniently, they also come with both long and short mounting bolts. They have kind a of weird, boxy shape, but I saw the merit in that when I pulled the lever and saw how the boxy shape keeps a good clearance around the wheel opening.

So, cheap and good clearance, but they flex quite a bit, the power is only adequate, and the feel is a bit wooden. Still, I don't have high expectation for caliper brakes, and these are good enough for flat Central Ohio. They also don't have a quick releases. That's a bummer, since my brakes levers don't have a QR either.

I set up my drivetrain with a lowish-Q Suntour XC Pro mtb crank, 44/34 gearing:

Eight speed friction shifting with down tube shifters. That's a nice reach:

I still need a bit more work on the drivetrain. I can't seem to get the right shifter tight enough to prevent slippage, or perhaps the frame is flexing enough to cause ghost shifting. It worked well enough with the original six speed index setup, so I can always work up something similar if I have to.

Strangely, when I ride it, one bike I always think of is my old ERB. It has the same flexy feel at the bottom bracket when I'm spinning, like the bike is winding up and releasing. Wind and release, wind and release... it makes for a fun, lively ride. In fact, as a proponent of frame flex, I will say the Technium is just about the flexiest bike I've experienced. More flex than my old Treks, even with their 1" top tubes on a big, open 65cm frame.  Combined with the plush Pari Moto tires, and it's a strong combination for general road riding.

The Raleigh has normal, mid trail road geo, so it gets one strike on Bicycle Quarterly's trinity of a flexible frame, supple tires, and low trail. But for normal riding, I prefer a mid trail geometry, and I expect I can manage on the odd occasion when I want a front load. It did OK on a ride yesterday back and forth to the library, with tools, books, and a big cable lock hanging off the front in my handlebar bag.

I think these old Raleigh Techniums are too often overlooked in vintage bike circles. Traditionalists want a lugged steel frame that was poorly brazed by a socialist somewhere, while people who want aluminum will hunt out old Kleins. These Techniums are fairly common, too, at least on my local CL, so you don't feel like you found a hidden gem when you uncover one for sale... but my advice is to jump on it, even if you have to spend a bit more than the $25 I did. It's worth it.

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