Charliekeet

Hi,
I’m in the midst of disassembling my ‘85 Cannondale this winter in order to strip the beat-up paint, and I am looking forward to seeing that beautiful bare aluminum frame. What I hadn’t considered as much is the chromoly fork.

How does one know when it’s worth it to forget the old one and get a new (1” threaded) fork? Obviously I can’t see all of the rust yet, as I haven’t stripped it, but based on these pics can those with experience tell what I should look out for/what I’m in for?

Thanks for any thoughts

gugie 

Based on your pictures, strip it down, 100:1 odds that fork can be cleaned up and repainted with no issues. I've seen worse clean up nicely.

jet sanchEz

Looks like it is only surface rust to me

Reynolds 

I'd have it bead blasted, probably it's OK.

Charliekeet

Thanks, everybody! Welcome news.
So after the bead blasting, I can prime and paint, then clearcoat normally? And if I don’t have a blasting done, would I need to treat rust spots with a converter first?

cudak888 

That looks like a Ishiwata CCL fork crown.

See these discussions:
https://www.bikeforums.net/classic-v...ork-crown.html
https://www.bikeforums.net/classic-v...ata-forks.html

While it's not that likely that you'll have a failure after all these years, since you're bead blasting anyway, have a framebuilder braze in a pair of tangs on the inside. Just for peace of mind.

-Kurt

Charliekeet

Well, that’s interesting. It does look like that. And it does not look like the one on the SR900 in the 1985 catalog, which is supposed to be a Tange fork- see below. (I assumed this was the original fork, but then again, it doesn’t have its original headset either.)

So I’ll have to think about it some more, see what I see, get info on cost for blasting. Or maybe it’s a better idea to move on and buy a replacement, something like - -> THIS?

vintagebicycle

I worked at a Trek dealer back in the late 70's/early 80's and into the 90's. I do remember Trek supplying us with a bunch of forks but I only remember changing out one or two. None showed any signs of any cracks, but the customer's were offered a new fork if they so wished. I'm not sure if they were notified or if they read about it and it became a repair program of sorts.
In all these years I've never had my hands on one that was broken. I also seem to think that the forks they supplied were all chromoly, not mild steel. The fork crown wasn't very different on the replacement forks vs. the original forks. I seem to recall it was for one or two particular models, the colors were dark metallic blue, light metallic blue, white, and yellow. The white and yellow forks were 700c and the blue forks were all 27" forks. At first a lot of customers came in wanting new forks, so they were ordered by individual serial number, and in the correct color. Not many ever came back to get their forks changed over though and I don't think any forks were 'handed out' to customers.
I did end up with a few of them over the years.
I don't

Here's some pics of one of the unused replacement forks, its marked Only Ishiwatta Trek with the last few digits of a serial number on the label. I've used many of these over the years as generic replacement forks on my own bikes, I'm a big guy, I ride a 25" frame and have never had a problem with any of these forks. There is no Trek logo on these forks, and the inside of the crown lug has a seam down the center.
They look to be just another generic fork to me, that just happens to have come painted not chrome.
I do remember a few people wanted to dump their bikes after they got that notice, a few traded them in, a few went away mad not happy that they couldn't get their money back after several years had passed. None of us saw any problem with the fork nor could we see or find any issues with either the original forks or the replacement forks. We just figured that maybe one of two had been defective so they recalled the whole lot of them.
There's also the fact that some folks could break a crowbar in a sandbox too. If you saw the condition of some of the bikes that used to come in the shop back then, it was amazing that any of them every survived the first year. Rust was a big issue, it seemed that no matter what model bike people bought they must have rode it in saltwater and stored outside year round. Clean, well kept bikes were a rarity.
It seems to still be the case as most used bikes I find are pretty rough, finding anything half decent is a needle in a haystack these days.




Marked 1986 Trek Ishawatta on the bag, with the last four digits of the bike's serial number it was intended for.


The following light blue fork is a Tange cast crown, which looks a lot like the OP's fork, this is from a 1985 Nishiki Sport and was shipped as a replacement fork under warranty and never used, I think there was an issue with the fork blades being too short for the 27" wheels, we pretty much assumed they shipped a fork for a Prestige just painted to match the customers Sport.
At a glance its similar to the Trek fork but much better built.
I've seen quite a few of both of these forks floating around over the years, my take on it was that they freely distributed them to dealers so many got left on the shelves over the years. At one point I had 30 or more of the light blue fork and a dozen or so of the Trek fork above.


thicker than the Trek crown, plus Tange is clearly stamped on the steer tube.

Cast crown, no seam

recessed brake hole

Charliekeet

Hmmm I’ll pull the fork and see if we find the Tange stamp

scarlson 

Yeah I was going to say, I have an Ishiwata-crowned fork, and something about the OP's fork don't look quite like mine. @vintagebicycle has put a finger on it! The OP's fork crown looks cast, whereas the Ishiwata fork crown is stamped and welded.

Look for the weld bead on the underside. That should tell you.

Also I will say, I have been riding on an infamous Ishiwata fork all last year and it's been fine. But I took a good long hard look at it before I did so! Normally if they crack, the crack would start on the inside, by the crown.

cudak888 

Fair points. Given no similar history for the cast crown of the same design, it shouldn't be problem vs. the stamped Ishiwata crown.

I still think that this crown design, overall, could have had larger inner tangs to reduce stress risers, but that's IMHO.

-Kurt

Charliekeet

Well, it’s definitely a Tange. Says Tange 5G on the steerer, and no weld bead underneath. So the ‘85 Cdale catalog was accurate, though it does have a different lug design than the one they picture (in red above).

It weighed in at just under 27 oz (764 g) with the crown race on. Guess I’ll see about bead blasting, or will strip and treat it myself and repaint.

scarlson 

Now that I have a view from this angle, may I suggest taking a file or sandpaper and scraping away the rust and taking a good hard look right there where I've circled in yellow? If you can't see a decent bond with brazing filler present, but instead see a gap between the crown and the fork blade, it may indeed be questionably made, because you won't know how deep the gap is.

Not to say it's in dire immediate danger of failing if you do find a gap. I'm sure some would ride on it anyway. Just probably not worth repainting and you might want to look into a replacement.

Charliekeet

Hey- yup, I see what you mean, and I appreciate the clear explanation. I definitely wouldn’t want to spend tons of time and effort refinishing it unless I feel good about using it
I’ll check it out and post pics.

Charliekeet

Here’s what I see so far. I can also apply paint stripper etc, but I’m not encouraged yet; I do see/feel a bit of a gap.

scarlson 

Stick a needle or pin in there. Scrape it back and forth in the gap. Does it feel like it's touching filler metal? Or going deeper into an empty void?

I think I see filler metal (bronze or silver) in the gap, only a little below the surface, in that last picture.

Charliekeet

I see what you mean now. I scraped more in the gap itself, and there’s no void- bright metal. Just a gap at the corners of the lug/fork blade juncture, so I’m likely ok if I want to keep it?

unterhausen

Just a little under-filled

Don't bother with the tangs, if you were thinking about that. They don't do anything to stop cracking. That crown doesn't look cast to me.

scarlson 

Yep, seems like all's well!

Charliekeet

Thanks so much, you guys! I'll begin the laborious rehab of it, but at least I know when I'm done that I'll be able to use the same fork and also the headset, which is in surprisingly good condition.

thook

a friend of mine had (he's deceased) over a hundred vintage bikes of all kinds and conditions piled around on his property....many of which he'd ridden often (at one time or another) and hard around our rural area. long and short of it, i've seen some of those forks with less quality craftsmanship than yours....none of which had failed after decades of neglect and use