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1981 & 1982 Trek 610/613/614 Ishiwata Forks

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View Poll Results: 1981 & 1982 Trek 610/613/614 Ishiwata Forks
1. Own one of these models and the fork has no issues
2. Own one of these models and the fork cracked
Voters: 16. You may not vote on this poll

1981 & 1982 Trek 610/613/614 Ishiwata Forks

Old 01-03-16, 07:04 PM
smallpox champ
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Originally Posted by elboGreaze View Post
So to be clear, your 311 fork that cracked had the Trek logo stamped on the crown ? I'm asking because mine has the stamp , thanks !
Yes, it was stamped TREK.
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Old 01-04-16, 12:28 AM
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Originally Posted by elboGreaze View Post
So to be clear, your 311 fork that cracked had the Trek logo stamped on the crown ? I'm asking because mine has the stamp , thanks !
I've actually heard 2nd hand from master frame builder Mr.Yamaguchi who has built steel frames for US Olympic events (currently resides in Colorado) that in particular "... stamped seat stays by major manufacturers was an attempt to replicate one of his signature design style tricks, which in most cases was done incorrectly and led to many premature failures in the 80's-90's."

Because Trek only started in 1976 and my app tells me the 1981 613/614 forks were Ishiwata 0265 Hi-Ten I assume they were not high-quality forks and Trek was still figuring stuff out, possibly stamping them in the process to market them as 'higher value' feel.

That being said, I had a Taiwaneese 1983 Raleigh Olympian with stamped fork crown and seat stays ive run into many ditches/potholes during its 5 years of heavy use before giving it up due to sizing issues. It never actually failed as a frameset.
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Old 01-04-16, 09:54 AM
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Originally Posted by NukeouT View Post
Because Trek only started in 1976 and my app tells me the 1981 613/614 forks were Ishiwata 0265 Hi-Ten I assume they were not high-quality forks and Trek was still figuring stuff out, possibly stamping them in the process to market them as 'higher value' feel.
The forks with the "TREK" stamped fork crowns were actually made and brazed in Japan and shipped to Waterloo unpainted. The forks we built in Waterloo all used investment-cast crowns (e.g. Ishiwata SCM, Cinelli, Haden, Tange).
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Old 01-22-16, 06:49 PM
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Choices should have been Own or "Did Own" one of these forks so bumping this thread looking for more input.
Surely there must be more than 9 members (votes) who have owned one of these bike.
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Old 02-22-16, 03:05 PM
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Unfortunately I'm only able to vote once, but I have a fair amount of experience with the fork in question...

I had an '82 311 that I bought in 2010 and commuted on, randonneured with, and generally rode its wheels off until it was stolen last fall. I put more than 14,000 miles on that bike, mostly set up as a single speed, but eventually with gears and 650b wheels. It looked like it hadn't seen many miles when I bought it, but it had been stored in a fisherman's net locker for decades, so it had some rust. No fork problems ever.

I bought an '82 614 in 2012. I continued to ride the 311 as a single speed at that time, and used the 614 when I wanted gears. I rode the 614 for about 4,300 miles until I sold it a couple years ago (and I still can't figure out why I ever sold that bike). No fork problems.

This past December I bought another '82 614 to replace my stolen 311. It's been set up with 650b wheels and so far I've only put about 500 miles on that bike. No fork problems.

So, altogether I've ridden nearly 19,000 trouble-free miles on the dreaded Trek "death fork" in the past few years. Many of those miles have been on gravel roads. I've hit quite a few pot holes and even bunny-hopped a few curbs in that time. Yes, I check for cracks now and then, but then I do that with all of my bikes.

I'm looking forward to many more happy miles on my old Treks.

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Old 07-31-16, 01:41 PM
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My 1981 Trek 613, with less than 500 miles, has no issues in the fork area, does not have the Trek stamp, and I am the original owner. (I voted anyhow.)

Last edited by dklanecky1; 07-31-16 at 01:47 PM. Reason: grammar
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Old 08-01-16, 12:08 PM
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The steer tube on those forks is straight wall, no extra thickness at the crown. I replaced mine before I toured on a 510 frame and was surprised to figure out why the fork was so flexible. Not surprised to hear it has issues.
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Old 08-23-16, 08:26 PM
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Well, I finally decided to stop lurking and actually make an account on this forum, and I guess this will be my first post!

I recently helped my brother buy a 1981 Trek 610 that was manufactured in 1981 according to the Trek database (ser. 008335). But after doing some reading I discovered a few threads warning about potential fork/crown issues. So far, I can't conclude whether the Ishiwata forks on these bikes are inherently dangerous. Here are my observations:

I found an in-depth post by thebulls which talks about the crown design of these bikes:https://www.bikeforums.net/16898705-post23.html
My interpretation was that the inside of the crown needs to have lugs that are curved, or pointed in order to reduce the possibility of a stress fracture occurring along the tubes. So, to evaluate this claim I tried to find some other examples of crowns that look similar.

1981 Trek 610 Fork (my brother's bike):

Early 90s Trek 420 Fork:

These bikes were built about a decade apart, but both have the same lug design on the inside-facing portion of the crown (although the one on the 420 is slightly more rounded). The 420 was bought new by my dad and ridden thousands of miles across both road and trails and still exhibits no signs of stress fractures. However, this is just anecdotal information, so I decided to take a look at some new-production crowns: https://www.ceeway.com/NEWPARTSPAGES/...k%20Crowns.htm

Most of these indeed have deeply sloping or pointed lugs on the inside portion of the crown (LC-15, LC-16). However, there are also a few varieties that look very similar to the ones on the 610 (ELC, C-52). If this crown design was inherently dangerous, than it seems unlikely that companies would still be producing it, or offering it to builders. This leads me to believe that the Trek 610 crown design is not inherently dangerous or the instigator that leads to fork failure (although one could argue that it is less strong than other designs).

However, on this forum there are still three separate, documented cases of this fork failing. Is it a coincidence? Is there some defect in the fork that we don't know about? Was QC not as good as it was in other years? It's tough to say. One thing I DID notice was that the fit and finish of 610 crown was noticeably worse than on the 420, despite them both being stamped and welded units.


I kept digging around and found some useful links:
1981 Trek Catalog: https://www.vintage-trek.com/TrekBrochure1981.htm
Ishiwata Catalog: https://www.equusbicycle.com/bike/ish...%20opt%205.pdf

In short, the fork tubes are your basic hi-ten steel that you find on entry level bikes. I doubt this could be a potential cause for failure since this type of steel has been used for awhile and its properties are well-understood.


After looking though all of this again I'm feeling more confident that the forks on these Trek bikes are fine. I haven't found any concrete evidence that they would be prone to failure, and the bikes themselves are over three decades old, potentially with multiple owners and unknown histories (crashes, heavy off-road use, etc.).

Last edited by MrChubbs; 08-24-16 at 02:26 AM. Reason: Grammer
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