Welcome to the forum. Here's a link to your photo gallery https://www.bikeforums.net/g/user/535355

Based on the logo style and the Shimano 105SC components, this should be a 1990 model. By that time the ATB trend had pared Nishiki's road line down to four models. The International was 2nd in the road line with an MSRP of $599 US. Tange #1 tubing is good and would have been 2nd in the Tange line at the time. The 105SC components were 3rd level for Shimano. I notice that it's TIG welded construction, which was just starting to take over from lugs as a more economical and flexible method. Taiwanese manufacture was becoming typical for the price point, taking over from the Japanese. It would be consisdered a decent, mid-range, sports model for its era.

hello mr da07079, i want to ask you what size of this sugino seatpost?
thanks for the answer

The seat post on the subject bicycle would be 26.6mm. However, I recently answered another inquiry of yours regarding the seat post size on a 1986 Nishiki International LD, which would be 27.2mm. These two bicycles use different versions of Tange #1. The Comp III uses standard, imperial diameter, Tange#1 and stock construction, while the International LD uses large diameter Tange #1 with internal lugs. Consequently, they use different seat post sizes.

To properly answer your numerous posts on the subject, we need to known exactly what you have. Given that you are in Indonesia and each market has different model names, photos would be helpful. At the very least, we need to know the outer diameter of the seat tube, the construction method and the tubeset.

https://cimg1.ibsrv.net/gimg/bikefor...7cfc6fc24e.jpg
Now i use 27.2 but seatpin is to tight like this, maybe the catalague is wrong?
https://cimg9.ibsrv.net/gimg/bikefor...1c14518b28.jpgouter seattube diameter is 31.8

I'm sorry, but I no longer own this bike

I don't believe the seat post is undersize by much, if at all. Looking at the picture, the problem appears to be overtightening of the cinch bolt, to the point where the mounts have deformed/bent and are touching each other. If you look at the cinch slot itself, there is still a very noticeable gap at the top, about 2/3 the width of the slot at the bottom. Typically, cinch slots are cut about 3mm wide, so this one appears to be about 1mm narrower at the top. Even with a correct size post, proper tightening will result in a cinch slot narrowing by about 0.6mm.


So, the frame might accept a 27.4mm post but it doesn't look like it would accept 28.6mm (and it definitely won't take 31.6mm), which are the most common sizes for oversize frames. 27.4mm isn't a common size, so it was most likely designed for 27.2mm. The current post might be slightly under its listed size or the lug may have been aggressively reamed.

Centurion le Mans
 

Hi T-Mar, many thanks for what you are doing here! I now have my two daily rides accurately dated, thanks to you. I picked up a very smart Centurion Super le Mans a few days ago in great condition but with a large frame, with the intention of swapping to a smaller one. Found the frame for a much older le Mans the next day and I am impressed with its smart brazed-on cable stops and chromed socks. There's one number, stamped on the seat tube, at the back and just below the pinch bolt B622. It was once a metallic red and bears the remains of a decal stating "Designed by Mitchell" and another "Guarantee". Might there be a clue? Photos below, and the Super le Mans that shares the same FD and RD is here: https://www.bikeforums.net/classic-v...l#post21980270

https://cimg1.ibsrv.net/gimg/bikefor...ad18a2f647.jpg
It once was red metallic.

https://cimg5.ibsrv.net/gimg/bikefor...33c242f0c0.jpg
Guaranteed?

Yes, those short alpha-numeric stampings on the seat tube are typically the only things reported on the Centurions with the Raleighesque graphics. As far as I know, nobody has been able to make heads or tails of them. Your best bet would be date codes on any components. The crankset might have dual letter date codes on the back of the arms. If it came with derailleurs, they should SunTour and also have date codes consisting of two letters.

Thanks so much!
 

Hi T-Mar, thanks for replying so quickly. I didn't see any date codes on the FD or DR, but both show 4532 as in the photo. The drive-side crankarm has 906 on the back, it's a Tourney. Hope this helps further - even if it's a rough date range.

https://cimg3.ibsrv.net/gimg/bikefor...862ac15041.jpg
https://cimg4.ibsrv.net/gimg/bikefor...66da165b98.jpg

Based on the cage style, the rear derailleur should be a circa 1974-1977 model. The rear derailleur date codes are typically stamped on the back of the rear parallelogram arm, while the front derailleur date codes were typically stamped on the back of the cage. During this period, the date codes were typically stamped inside a small circle. Here's an example of a rear derailleur with date code PG (i.e. 1973 July).

https://cimg5.ibsrv.net/gimg/bikefor...7cbd2ac6f2.jpg

And more!
 

Hi T-Mar, i am ashamed that I thought the circled numbers to be trademarks. So here they are!

https://cimg2.ibsrv.net/gimg/bikefor...36c99c8f9f.jpg
https://cimg5.ibsrv.net/gimg/bikefor...f4fda86c5a.jpg

So, the date code is QB, which represents, February 1974, which should make the frame a 1974 model. The 2nd photo says JIS, which is the symbol for Japanese Industrial Standards.

T-Mar, thank you so much, and apologies again for not knowing about the date letters. This is great to know and allowed me to determine more about the frame. If of use to your many readers, I found a recent website for Centurion enthusiasts here: Vintage Centurion Bicycles. Sheldon Brown's site has a contribution from one of his successors at https://www.sheldonbrown.com/centurion.html, which quotes you at length, something that will never, ever happen to me. Thanks again!

Extremely grateful for your post. It help me date my Nishiki Prestige! Sincere thank you bro.

I've had two of those Nishiki Internationals with the oversized tubing and both took a 27.4mm. The catalogue states they are 27.2 but I suspect some overly excited reaming in the factory has caused them to be too big. Both frames had cracking in the lugs/tubes from the clamps being tightened too much with the stock 27.2 in there. One I had repaired and later sold, the other I got used and fitted a shim right away so the cracks haven't spread far enough to weaken the clamps.

Would you like the serial no. of the second of my frames? I still have it hanging in the garage awaiting better days.

Thank-you for posting. Just to be clear, did the frames have a 27.2mm post when you rec'd them? Yes, I'd appreciate the serial number, though it probably won't cause any revelations. TIA.

No worries. First the serial, it's WF00969. The frame is one of those pink and dark-grey Internationals that came with Suntour Sprint, same as here
https://i.imgur.com/ytNy0Qq.jpg
The first bike I got was the blue and silver one, which had the 27.2 spec seatpost. I had problems with it slipping and probably should have shimmed it, but anyway ended up cracking the clamp area. When I took it to get repaired the frame builder (who did a nice job brazing a new lug up) said that the tube measured out much closer to 27.4 than 27.2 which would have caused the issue. I bought a 27.4 seatpost and rode the bike for a couple of years before selling.
I then found the current one on the facebook trader, cheap as it had no groupset. I bought it knowing the possible issues, and sure enough found that it was starting to crack by the clamps. I made a shim for a 27.2 seatpost and rode it for a while before buying a 27.4 seatpost which fits very nicely.
I should add that I am in New Zealand, maybe bikes for the Oceania/Asia market were finished differently in a different factory or it's just they were made on a friday afternoon just before clock-out time:)

American Eagle saved from the trash bin
 

Saving this old beast from certain death....

https://cimg6.ibsrv.net/gimg/bikefor...f923f54f9d.jpg
Old tank with bent front fork
https://cimg9.ibsrv.net/gimg/bikefor...ae2d99f15f.jpg
https://cimg1.ibsrv.net/gimg/bikefor...3b4f92b409.jpg
https://cimg4.ibsrv.net/gimg/bikefor...d741edef1e.jpg
KB -Kawamura Built

https://cimg4.ibsrv.net/gimg/bikefor...7e0982ff6c.jpg
Another serial number for T-Mar
https://cimg7.ibsrv.net/gimg/bikefor...0b68deec11.jpg
https://cimg0.ibsrv.net/gimg/bikefor...62c771042d.jpg
https://cimg5.ibsrv.net/gimg/bikefor...5987d6ae7d.jpg
https://cimg6.ibsrv.net/gimg/bikefor...b24bd0037d.jpg
https://cimg9.ibsrv.net/gimg/bikefor...dc28f23ccb.jpg

Went by our (usually closed) co-op to check on the dumpster this week and found this tall Backroads MTB from the '80s hanging out by the dumpster. I don't mind dumpster diving but this technically wasn't in the thing so I left it alone but posted about it. Another forumista inquired about getting it so I phoned the co-op and was told that stuff around and in the dumpster is fair game so I grabbed it. Originally sold by The Unicycle in Blacksburg VA the serial number looks like it has a misstrike.
https://cimg6.ibsrv.net/gimg/bikefor...2d8348a9b3.jpg

First character looks like a bad 6 (Maybe a C?) followed by 690003. Hope this helps.
https://cimg0.ibsrv.net/gimg/bikefor...60b214ef19.jpg

The very high five numeral serial number should place it circa 1971. Thxs for posting.

The graphic are indicative of a 1987 model, so I'm assuming the well struck '6' is the calendar year and that it was built in late 1986. Giant was still building the Nishiki entry level models at the time and I'm wondering if the intended S/N was Gx690003, where 'x' is an alpha character indicating the fortnight? Thxs for posting.

Nishiki Century
 

Serial# 4009466
Dia-Compe front brake caliper date code: 1283M
27” wheels
Frame is in very good shape. Red paint has nice sheen. I’m going to build it up with updated components and alu wheels for my daughter.

https://cimg0.ibsrv.net/gimg/bikefor...95ceae804.jpeg
https://cimg1.ibsrv.net/gimg/bikefor...5a05de6af.jpeg
https://cimg2.ibsrv.net/gimg/bikefor...6ce52483d.jpeg

https://cimg1.ibsrv.net/gimg/bikefor...ded262b59.jpeg

https://cimg6.ibsrv.net/gimg/bikefor...a0df9c454.jpeg

The subject bicycle appears to be a 1984 Nishiki Century, manufactured by Giant of Taiwan. There should be a date code on the other dropout, format Gmmyy, where mm is the month and yy is the year.

Bingo

https://cimg4.ibsrv.net/gimg/bikefor...d0acf5847.jpeg

I have seen this format and location of serial number before on USA Nishiki bicycles.

The first and last characters on this frame were not struck cleanly. I would suggest that the serial number reads as: G6900030.

This is a Giant of Taiwan serial number from later in 1986. This is the time when Giant was changing the format of serial numbers stamped onto the frames. Giant was no longer stamping a date code separate from the serial number.

This format has only one letter: G for Giant the manufacturer.
The first number, "6", is for the year of frame manufacture: 1986.
As stated previously this is a 1987 model Nishiki.

It appears that this format of Giant serial number was only used for a few weeks.
Later in 1986, Giant added a second letter into the serial number and removed a digit from the end.