Skikick

Hello fellow Sekine bike enthusiasts!

Looking at some local Sekine bikes on kijiji in Thunder Bay (can't post links because I am still a newb)

Anyone have any advice on how to tell a chromoly version from "just" a hi-ten version? Besides just holding weighing them side-by-side...
Appropriate frame sizing for someone 5'11'ish?

Cheers!

T-Mar

Welcome to the forums. The only one of those Sekine models with a CrMo frame is this one:

https://www.kijiji.ca/v-road-bike/th...ike/1566400171

Unfortunately, it is only the 21" frame size. Assuming you are of average proportions, I'd be looking for one with a 23" frame.

As the models varied a bit over the year, the only definitive rule for determining whether it is a hi-tensile or CrMo frame, is via the seat post diameter. The Sekine CrMo frames used 26.6mmt posts. Hi-tensile frames used smaller diameter seat posts. However, this doesn't mean much if you don't own precision measuring calipers

As a general rule of thumb, any Sekine model whereby the rear derailleur attaches to the frame via a claw shaped adapter that sandwiches between the axle nuts and frame dropout, is a hi-tensile frame.

Sekine1974

There is also a small Champion decal on the seat post tube that will indicate Chro-Mo Steel - If it is still intact. Mine is full Chro-Mo and I will try to get a picture here for your reference

BikeCrazy24

Greetings Sekine1974,

The only pictures I have of my chrome Sekine are the one I posted about 7 years ago. They are pretty bad pictures because chrome doesn't photograph indoor very well and it was -40 at the time, so wasn't going outside. Like yours, mine has the decals on it and the chrome and decals have aging. I've also had it for at least 20 years, so I really doubt it is a re-chrome or re-decal. Unfortunately, due to health order restrictions in my area, I can't currently visit it to take pictures.

If you find any more info than I did, let me know. I spent about 200 hours trying to find out something about them and was not successful. The plant in Canada has been closed for almost 40 years now and these chrome bikes are 40 plus years old. Probably have to contact someone in Asia to find out info about them now.

BikeCrazy24

Sekine1974

If you want to find out more about what I learned about these chrome frame bikes and look at some of the places I looked at, I suggest searching this forum with my user ID. That seems to be the best way to find out what I uncovered. There are links to other sites that may have been updated since I looked 7 years ago. Yes, it does seem like a rabbit hole when it comes to these bikes. That was my experience as well.

Skikick

Thanks all!
Going to pepper a few more questions here:
1) how can you tell the frame is a 21" vs. a 23' from photos?
2) Pretty happy to use 27 1/8 if I can find a bike with a good set of rims, but any luck moving to 700c (maybe with 35-38c?) wheels in these if not? Fork and rear look reasonably spacious.

Cheers!

T-Mar

1. You can tell the frame size by the length of the head tube, specifically the distance of the gap between the top and down tubes. Sekine offered frames in 21", 23" and 25" during this period. These correspond to head tube gaps of roughly 1", 3" and 5" between the top and own tubes. The top tube diameter is 1" and can be used to gauge the size of the gap.

2. 700c rims have an 8mm smaller bead seat diameter that requires the brakes pads to be lowered by 4mm.That doesn't sound like much but I've seen cases where the OEM brakes have had insufficient adjustment range and the longer reach brakes were required. I haven't tried it but I think 35-38mm tyres would be really pushing things, if it works at all. For both tyre diameter and width, you have to look at each case separately, as there a lot of variables that come into play and you can find cases of two bicycles of the same year and model where one works and the other doesn't.

bikemig 

If the bike is designed around a 27 x 1 and 1/4 tire (like the Sekine SHS 271 for example), I think you can fit a 700 x 35c. There are a lot of variables so you need to try it out. I know with my Sekine SHS 271, I'm running 27 x 1 and 1/4 tires that measure out closer to 1 and 3/8 so I'm confident I could get a 35c to fit.

Skikick

Thanks all!

BikeCrazy24

Greetings Skikick,

The other issues with going to 700 wheels is frame spacing and component incompatibility. The 700 rear wheels typically have more speeds (more gears) and then one will need to pretty much upgrade all the other components to get it to all work properly. I've seen people basically replace the whole bike and spread the rear section of the frame taking that approach. The other option is to find a rear 700 freewheel wheel that is as close as you can find to what was on the 27" wheel bike in terms of speeds, use the original freewheel from the 27" wheel, re-space the 700 wheel hub, and then re-dish the 700 wheel. I've helped people go in both directions, so it is possible, but like many things, it is not as easy as one may think.

Hummer

And yes, Y does mean 1974 year of frame manufacture.

Sekine1974

This is amazing!!! Another Chrome Sekine! 👍

If it’s Ok, please let me know as much history about this as possible! 🙏

BikeCrazy24

And now there are three!!! They are just popping up everywhere this year.

Any documentation regarding the history of the bike Hummer? We are all stuck on exactly why these bikes exist. Lots of speculation but no hard documentation like build sheets or at least accounts from people that worked at the factory or people that worked at or owned bike shops back in the day when they were built in the 70s.

Spellscape

Any idea what is year of this bike, is it Japan or Canada made?


I know it's saying Canada but maybe it's still Japan made initially

T-Mar

Assuming the Shimano Altus ST derailleurs are OEM, it's no earlier than 1979 and it would be a Sekine RM-30 model. It could extend into the early 1980s. We should be able to narrow that down, based on the serial number and/or derailleur date codes.

Spellscape

T-Mar

My personal interpretation is February 1979 but I know that there are others who hold a different view.

Spellscape

is it Canadian or Japanese made after all(at least frame) ?

Skikick

Throwing another one in the mix here: https://www.kijiji.ca/v-view-details...dId=1569187433

Do I see a chromo sticker there? Is this somone's conversion to flat bar and shifters? Year/model?

Interested in this bike as I would probably make similar conversions for commuting (flat bar and pannier rack).

T-Mar

That's a Sekine SHS, converted to flat bars. It employs Tange Champion double butted CrMo tubing. Circa 1973-1977.

Skikick

Thanks T-Mar. Appreciate it! Browsing through here - seems you have a quite a lots of answers I have about these old bikes.

One more for now: assuming these are freewheel hubs and not cassette hubs?

If so, could I move to a 7-speed 34t freewheel and use drop bar shifters? If that's where I wanted to go - would I start getting to the world of spreading the rear chainstays for a newer wheel setup to accommodate that - or would it be a straight swap and just a matter of indexing with a hypotethetical new 7-speed shifter?

Love these frames and the story... but maybe need to realize what I am potentially getting into in terms of tinkering, swapping, adapting. I like fooling around with this type of thing but have only done it with 00's and newer machines. New territory.

Skikick

Answered my own question: https://www.sheldonbrown.com/harris/freewheels.html

BikeCrazy24

Greetings Skikick,

I took a look at what Sheldon said. Yes I have done that. To avoid re-dishing the rim, I added washers and both sides of the hub or if you have access to hub locking nuts, I often just use wider locking nuts on both sides of the hub. This also basically makes the whole assembly wider, so what people often do is just jam the wheel in the frame. This adds extra stress on the frame when riding, which could cause frame failure. So it is recommended that you spread the frame so the wheel fits properly. This can be difficult to do properly.

The other option is to re-space the hub and re-dish the wheel to work with 7 speed free wheels or cassettes and fit the wheel in the frame as it is. I have done this as well.

Hummer

Hello @Sekine1974 and @BikeCrazy24,
sorry I missed these posts. I am only on bikeforums.net periodically so I do not see everything when it is first posted.

I cannot tell you anything more about that chromed Sekine. The pictures were taken several years ago and I think the bicycle has changed ownership.

I have seen this model and year of Sekine in blue and red, both with half chromed stays and fork. The paint was coming off the stays and fork and it looks like chrome underneath the paint. I could not tell if the main tubes and lugs were also chrome underneath the paint.

Hummer

Some people have questions about what years are represented by the letters in Sekine Canada serial numbers.

Here is a brief timeline of Sekine Canada. This timeline is based on contemporaneous newspaper articles from the Winnipeg Free Press.

See this excellent website for details: Rivers & Area Heritage

1972 Bicycles from Sekine Industries of Japan are imported into Canada by H.C. Paul Company.

1973 April. Joint venture Sekine Canada Ltd. is formed by three partner companies:
Sekine Industries, Nagase and Co. (and import-export company), and H.C. Paul Co.
Sekine Canada operates along side the Oo-Za-We-Kwun Centre at the former Canadian Forces Base Rivers.

1976 June. The frame manufacturing facility is added to the Sekine Canada operation.

1979 Sekine Industries withdraws its personnel from Sekine Canada. Many return to Japan.

1980 February. Sekine Canada financial restructuring. Sekine Industries reduced to 25% ownership.

1980 June 30. Oo-Za-We-Kwun Training Centre closes.

1981 August 31. Sekine Canada goes into recievership. The factory does not open the next day.

1982 January. Receivership auction of Sekine Canada assets.


The serial number of Sekinie Canada. The letter F is the last letter used for the year. 1981 was the last year of production.
One can deduce that F = 1981. Counting backwards, A=1976.
The first year of Sekine Canada production was 1973, X=1973.

There is a big change in the format of the serial numbers after the 1980 financial restructuring.
There was also a change in the Sekine Canada model line after the restructuring.