Wednesday, August 24, 2011

RM-20 Rides Like New

I took the newly-built Sekine out on a good 40km ride across town, and boy- this bike can fly. It's amazing how fast 30-year old steel rolling on 1 1/4" rubber can go. Power transmission feels solid, even though the ride seems cushy. The steering holds a strong line, almost to the point of unresponsiveness. Somehow, it's easy to set up a quivering speed wobble in the steering; but just as easy to snap out of it. The bike climbs a bit slow, but is very stable on the descent. And despite a bit of sun-fading, that red paint still looks great.

21" x 22" triangle.

Fit is the biggest issue; but I knew when I bought the bike that it was a size small. The seat post is raised to the max height (but still 2cm too low), as is the stem; which as a result, makes the bars feel flexy, and the bike looks a bit strange. Even with a 56cm top tube, the 60mm stem makes me feel a bit compressed; I notice that when I'm in the drops, I have to scoot my butt back almost off the seat to feel comfortable. However, I can probably ride short to moderate distances with no problems, and the small size makes the bike easy to whip around. I'd prefer handlebars wider than the 39cm c-c Road Champions, but feeling narrow can be nice on the streets.

Shifting with down-tube levers took some getting used to. Always reaching down, gauging cable pull by touch while keeping eyes on the road, ears listening for trim. The rear derailleur has a little quirk which could be termed "soft shifting". As the cable is pulled, a small spring-loaded arm on the derailleur body swings into contact to make the shift. This small, initial pull gives a mushy feeling at the shifter for a moment before engagement- I think I'd prefer a straight pull. Obviously, deft shifting will only come from practice, and the system is beautifully light and simple. Also, I will apply some thread-lock compound on the shifter adjustment screws, as they kept coming loose.

The gearing surprised me with its versatility. With a big 52/42 ring up front, the bike definitely likes speed, but this is balanced by a generous 14-28 range in the back. The big ring is actually useful around the city. Climbing the hills around Vancouver's bike routes, I definitely appreciated the 28T, and can see why old Sekines sold with this range may have been popular here. Long term, I'd probably switch the 42T for a 39T ring, just to add a bit more low-end for days when I'm tired.

Braking is probably the biggest concern with this bike. Going fast is thrilling, but it's more frightening when I know the brakes have a sluggish response. As mentioned in the re-build post, the brakes are Shimano Tourney long-reach side-pull calipers, which I have tried to augment with nice road cartridge pads and compressionless housing. Stopping is still more of a gradual affair that I'd like (compared to the disc brakes I'm accustomed to), however it's probably as good as it can get. Worst of all, after initial set-up, the rear brake caliper howled a painful vibration that travels up through the frame, buzzing one's genitals unnervingly. This is a clamorous problem, and I'm attempting to quell it by experimenting with the adjustment of the brake's center pivot nut (Update: setting the pivot a bit loose made a large improvement).

New tires, saddle, and bar tape make a big improvement.

On the initial quick test ride, the chain seemed prone to skipping off the rear cogs. Closer inspection revealed that this was probably due to insufficient chain wrap, caused by a weak derailleur pivot spring. My solution was to remove the dropout spacer inserts, moving the axle to the rear of the dropouts, and further past the derailleur pivot. So far this has eliminated the problem, although giving a 1cm longer wheelbase.

Overall, the bike is fun. It's exciting to ride something I've only looked at for so long, and it's strange seeing the bike parked in the house. It's red, chromed, silver parts, and pretty. I can't wait to take it out again tomorrow.

Sunday, August 21, 2011

RM-20 Rebuild

After stripping, cleaning, and rust-checking the frame, I moved to do the same with the components. Despite the Sekine's composition of a few relatively simple parts, a thorough cleaning took hours.

Dirty essentials in the parts box

The derailleurs looked the most interesting, so I started with them. A rag and screwdriver to clean off decades of accumulated grime, and a bottle of Phil Wood oil to re-lube pivots and screw threads. Repeat the procedure with the brake calipers. The crankset was pretty dirty. Pulled all the chainring bolts, and spent twenty minutes wiping old, dried-up grease from the chainrings. Some oil on the bolt threads, and it all went back together smoothly.
The wheels that came on this bike when I bought it were mismatched, and not in particularly good shape. I replaced them with some other wheels I had lying around- from another Sekine, incidentally. Araya 27x1 1/4" alloy rims, laced with 36 spokes to Shimano hubs, with some choice new Continental tires.

Shimano Altus LT derailleurs, date code EI; 1980/Sep

The re-build went rather smoothly. Packed the old steel headset with fresh grease, gave it a push and watched it twirl. The cup-and-cone bottom bracket, Takagi brand matching the cranks, was an easy overhaul. New bearings with lots of grease, shielded by an inner dust shield, spins almost like new. Throw on the matching Takagi Tourney cranks, tighten down the spindle nuts, install pedals. Add on the Shimano Altus LT derailleurs and down-tube shifters, followed by the Tourney long-reach brake calipers. Bars and stem go next, install brake levers and line them up. A nice Brooks saddle goes onto the seatpost, because I don't much like riding on anything else. Some brand-new cartridge brake pads onto the calipers, and install wheels into frame. Brake cables go into new Jagwire kevlar housing, to make those brakes feel as good as possible. A new Shimano chain to drive the machine. Then it's a matter of final touches; adjusting derailleur limit screws, cable tension, brake pad alignment, snugging down nuts and bolts. Last to go on is the bar tape, and I hum and haw over flashier colours before defaulting to the basic black.

Taking only a brief moment to step back and admire the new Sekine, I head out the door. The red machine surely looks a gem, but only a ride will tell; and that's the next post.

Monday, August 15, 2011

Model RM-20 Frame Details

The bare bones

Even before I bought my Sekine, I knew that any used bike would probably require a complete re-build. An overhaul would both ensure reliable long-term function of the bicycle, and bring it to a riding standard I'd be content with. Happily, a re-build is work that I enjoy doing, and I was eager to get into the details.

Tange 1" threaded fork, chrome-plated

Warning: bike nerd/mechanic stuff ahead!
As soon I had the chance I stripped the frame almost completely, leaving in only the press-fit headset cups and crown race. A bare frame is much easier to clean, although there were some thick streaks of hockey tape residue that required a lot of elbow grease to remove. A thorough cleaning gave me opportunity to look closely over the entire frame, and I examined where an old kickstand mount had slightly crushed the rear chainstays, and discovered a dent at the base of the downtube. Some quick sprays of Frame Saver into the 30 year old frame & fork tubes to slow any unseen rust seemed prudent.

Shimano LF dropouts, 130mm rear spacing

Frame laid bare (and leaking Rust Check) I took the opportunity to weigh it and get some photos. I present, for your Sekine-nerding enjoyment, specs for the RM-20 frame & fork:
Seat Tube: 53cm/ 21"
Top Tube: 56cm/ 22"
Chain Stays: 435mm
BB Drop: 60mm
Wheelbase: 1040mm/ 41"
Seatpost: 26.4mm
Brazed-on cable-guides and stops, DT water bottle bosses
Frame Weight (incl. steel headset cups): 5lb 10oz/ 2.56kg
Fork Weight (incl. steel headset race): 1lb 14oz/ 0.84kg (fork is chrome-plated)
I do not currently know the head/seat tube angles, nor the fork rake (anyone..?)

Inside the BB shell. Shimano cable guides brazed on top.

Friday, August 12, 2011

Prices from the Past

How much was that Sekine bicycle worth back in the day when it was new? I've managed to find a few retail prices scattered in old newspapers. Here's a listing from a Winnipeg bike shop in 1975:

SHS 270 - $250 - Deluxe cro-mo lightweight ten-speed
SHL 271 - $169 - Mixte hi-tensile lightweight ten-speed
SHC 270 - $160 - Hi-tensile lightweight ten-speed
SIA 271 - $130 - Hi-tensile
SIA 101 - $124 - Hi-tensile

Listings from previous and following years show that over time, prices climb (predictably) ever higher.
Now that we know how much they sold for back then, we can approximate what a Sekine would cost today using The Inflation Calculator. Of course, nowadays a lugged steel frame would probably cost a lot more, but you'll likely be getting a better product.
If you're buying a used bike, always subtract for wear, keep in mind the components you might have to replace, and remember that vintage does not necessarily mean good.

Wednesday, August 10, 2011

Joining the Owner's Club

I've never owned a Sekine of my own. I've worked on them, fixed one up for my girl, and looked at dozens of them on the streets over this past summer.
Haunted by dreams of riding my own Sekine machine, I've been browsing the used bike ads on Craigslist for the past while. The other day I finally saw something I wanted to buy, a red RM-20 lightweight:
The Sekine RM-20, with disembodied hand

Took it for a quick test ride down the street, and it seemed alright. A quick look-over to make sure there was nothing obviously wrong with the frame hinted the bike needed much work, giving me grounds to bargain down the price. The lady selling was the original owner; since buying the bike in 1981 she'd ridden it countless miles all over the west coast. I handed over a fistful of bills, and doubled off home on my new (old) Sekine.

Buyer beware, of course. As with the majority of used bikes bought off Craigslist, this one needed more than a few repairs. Some things were obvious, some weren't. Here's a list: The cables and housing (almost always) need to be replaced, handlebar foam is worn out, the chain is worn out, the tires were old and starting to crack, the rear wheel was a mis-matched 700c, the seatpost is a tad short for me, the front brake pads have hardened. Add to that all the labour required to tune this machine to my standards (basically, a full overhaul and detailing). Despite all this, I think I paid a fair price, and got a nice little bonus out of the deal (post to come later!).

It's mine to work on now, mine to ride and obsess over. My first Sekine!

Over the next little while I'll be posting as I tear down and re-build this bike.