Team Marin Rockstar 750g Spinner Forks - A tale of woe...help needed

[Obi-Juan]

Other colleagues have already commented, quite accurately, on how to rethread a fork. Basically, it requires a lot of patience (1/4 turn forward and 1/2 turn back), proper lubrication, cleaning off the shavings, and drilling a few millimeters. It's very important that the die, like any cutting tool, is in good condition. And above all, when you see that things aren't going well, STOP!!! It's better to have 2 millimeters damaged (with 1 spacer washer, you could still use the fork) than to throw the whole thing away.

There is a solution, I've seen it once in my life, but I don't recommend it: Solder brass over the damaged thread and rethread it over the brass solder.
Brass is very soft, so I don't recommend it.

Certainly, looking for a new one is the best option. Durotec had great forks for just over 700 grams, and they're cheap (people only look for Spinners, and that helps find good, affordable alternatives ). I found a Durotec for €10.
I only had to spend a lot of time removing the black paint, but since it was spray paint, it came off very easily with thinner. I leave you a photo with the weight

 

[trezize]

Other colleagues have already commented, quite accurately, on how to rethread a fork. Basically, it requires a lot of patience (1/4 turn forward and 1/2 turn back), proper lubrication, cleaning off the shavings, and drilling a few millimeters. It's very important that the die, like any cutting tool, is in good condition. And above all, when you see that things aren't going well, STOP!!! It's better to have 2 millimeters damaged (with 1 spacer washer, you could still use the fork) than to throw the whole thing away.

There is a solution, I've seen it once in my life, but I don't recommend it: Solder brass over the damaged thread and rethread it over the brass solder.
Brass is very soft, so I don't recommend it.

Certainly, looking for a new one is the best option. Durotec had great forks for just over 700 grams, and they're cheap (people only look for Spinners, and that helps find good, affordable alternatives ). I found a Durotec for €10.
I only had to spend a lot of time removing the black paint, but since it was spray paint, it came off very easily with thinner. I leave you a photo with the weight

Great recommendation and advice. Thanks

 

[attitudeadjuster]

A little while ago I picked up a 95' Team Marin. It came with an assortment of non original parts and a fooked, very heavy suspension fork. https://www.retrobike.co.uk/threads/marin-team-issue-info-and-suggestions.490538/

I have set about sourcing a replacement rigid fork as I wanted to lighten the bike up and use it for some up-coming touring.

I was able to locate a Marin 750g Spinner fork. It fit perfectly in terms of axel to crown and the rake was exactly what I wanted geometry wise the paint was also good, the colour was a nice accent. The only issue, the steerer was too long.

View attachment 970712 View attachment 970713

Enter the local bike shop; they attempted to shorten the steerer and messed it up, totally cooking the thread. They have been very good after the mistake and will help fund a replacement fork.

View attachment 970714 View attachment 970715

So I am now asking for the following help please:

1. Is there any possibility of salvaging these forks? The steerer will be too short if the affected thread is cut off. Has anyone had any success with cutting and welding? Is this an economical or even a possibility? Any other solutions?

2. How rare are these forks. I have seen lots of the standard Rockstar forks but the 750g version seem to be rare. Did the Team Marin and other higher end Marin frames come with these forks as standard if a rigid fork was optioned?

3. Does anyone have a similar fork available? I am not necessarily precious about it being Marin branded, it was more the shape and weight I am after. My head tube length is 120mm.

4. The bike shop said that their Park Tool cutting die wasn't suitable for CRO-MO steel? Is this possible?

Thanks for all your help. I hope my disappointment can be the source for some interesting discussion.

Cheers

Paul Brodie extends a threaded steerer in this video -

- so it can be done if you have the kit/knowledge or know somebody who does?

 

[Obi-Juan]

Interesting video, very illustrative, I love it.
Although it's beyond my skills and tools, lol.

 

[Wolverine1094]

Well I must say this has been an interesting read for sure! I have a nice collection of Bridgestone MTB’s and they all run rigid forks. I also have a 1990 KHS Montana Team (Ritchey Logic bi-directional, 670grams) and a 1991 Main Team Issue with an original Rock Star fork. With all of this said rather than attempting to add threads why didn’t you or why don’t you just use some spacers and a threadless headset? I did this on my MB-1 that came with an older Koski /durotrack fork from a larger framed bike. You need to file off the top of a threaded headset nut and use it for your lower nut and then just lock it down with a regular threaded headset top nut…Cutting threads into a fork headtube has really become a lost art these days…finding a LBS that was in business 40 years ago with the right sized dyes is next to impossible.

I was looking at this because I also need a rigid fork for a 1990 42 cm MB-0 zip that I am building for my nephew. My impression of the forks from the late 80’s - early 90’s is that the Koski design was the heaviest but basically the standard that Tange used to develop / design their logic forks that came out in 1990. Spinner of Taiwan was also contracted by Bridgestone to produce a fork for their MB-3 in 1989….but BS used the Koski designed duro-trac made by either Koski or Tange of Japan for their more premium MB-1 and MB-2. Around this same time Klein was also using Spinner for the rigid forks they used in their lower modeled bikes with 1” head tubes (Rascal, Fervor).

For production bikes offered in 1990 the fork of choice was the Ritchey Logic regular or bi-directional that Tange made after they learned about using different diameters and wall thicknesses from the Koski design…and they made it about 200 grams lighter the Koski/ duro-trac. From my own riding experience the Koski fork is definitely more rigid than the other two but that sort of makes sense since it’s also about 20% heavier. The spinner and Logic forks are more similar…

So in short if anyone on here located in the US has a Logic or spinner or Koski fork in any size, any condition….as long as it’s not twisted and it’s cheap I’m interested….the headtube is only about 4.5” on this frame…

Thanks!