Classic & Vintage - Miyata Upgrade?

Hello, New to the Forum but suspect you can help with my questions. Circa 91-91 I bought a bike from a LBS in Atlanta. Was told at the time it was a Miyata frame, but had a "Karate" head plate on it. Appears quite similar to the Miyata's i've looked at. Bike was built up with Shimano 105 components, brakes, index shifters, FD, RD, and 6 speed freewheel. Alloy wheels, nothing great. Bike has been bulletproof. Upgraded to a 105 triple when in VA hills. Have been away from riding and recently got back into it. Question is, is the frame etc worth saving and upgrading to 8-9 speed STI components? Cost is probably less than new entry level bike, but kids and all, I'm looking at entry level $$. What's the concensis?? dump it and buy new, or begin an upgrade process.

Thanks in advance.
GSM

The frame is worthless. You should pack it into a box and mail it to me so I can dispose of it properly. ;)

Seriously, it would depend upon the model. What's the number on the top tube? I actually don't really know a whole lot about Miyatas beyond the one I own. T-Mar's your man. But if it's one of their decent bicycles (as opposed to a hi-tensile bargain basement model), then it may well be worth keeping. Miyata made its own high-quality, triple-butted cromoly tubing, and their lugged frames are some of the finest production bicycles ever built. You say it's a '91, however, so it may be after their glory days. As I say, T-Mar will likely know.

After I got home, I removed the CO2 holder and found the following info on decals "Tange 900 Double Butted tubes CR-MO" "Karate, Japan". Serial number is under bb, M7K01293. Original wheels are "Ukai",still have the front, but I lost the rear in a argument with a car, (rather large pot hole) and replaced it. RD bit the dust too, replaced with Shimano 600. As i said, the bike has been near about bullet proof, just don't know much about it or if it's worth keeping.
Thanks
gsm

Not a moment's hesitation after seeing the tubeset you've got there. I'd definitely keep it.

Question is, is the frame etc worth saving and upgrading to 8-9 speed STI components? Cost is probably less than new entry level bike, but kids and all, I'm looking at entry level $$. What's the concensis?? dump it and buy new, or begin an upgrade process.

Thanks in advance.
GSMDepends on how much money you want to dump into it. Bar end shiffters are alot cheaper and easier, as is staying with 7 speed, which works well enough with a triple. The assumption is also made you have the know how and tools to do this stuff rataher than relying on LBS.

Not a moment's hesitation after seeing the tubeset you've got there. I'd definitely keep it.Tell us all you know about Tange 900 DB cromo.

Grolby, thank-you for the vote of confidence, but I still have lots to learn on Miyata. That 750SR posting completely stumped me. Fortunately Dnalsaam and Miamijim had the answer.

In this case, I strongly doubt the frame is a Miyata. First, the serial number sequence does not match the known Miyata formats. Even when Miyata produced frames for Univega, it was possible to identify the Miyata frames via the use of their traditional serial number formats.

Secondly, Miyata had their own steel foundry to produce frame tubes. Once they had it up and running in the early 1980s, they phased out the other steel tubing suppliers and used their own steel tubing exclusively.

Tange 900 was designed specifically for high volume production and brought down the cost of butted frames to the point where they could be found on $250-$300 US bicycles. Many people derided the tubing, but from a weight and gauge perspectrive, it was essentially equivalent to Tange #2.

Honestly, I'm suprised to see a Shimano 105 group on this frame. Normally, I would expect a slightly more prestigious tubeset. This was probably an attempt to get a 105 equipped bicycle to a very low price point.

Whether to upgrade or not is a tough call and depends on a lot on what you are used to, how much you like the workmanship and ride quality, and your finances. The tubing is fairly light and there is nothing wrong with it, but for many cyclists, it would have a lower end stigma attached to it. Most would probably either keep it as is, or strip the frame for the parts. The frame would likely make a decent fixed gear, if you are into that sort of thing.