kraftwerk 

There must be a way to do this elegantly, right? I bet someone.... one of you, has done it. How easy is it ?
Must be a cheater-tube-thing which slips over the 1" fork tube acts like a spacer, making it into a 1 1/8 fork, maybe.....


"What could possibly go wrong?"

bboy314

Problem Solvers makes shims that press into your head tube to make this work. Elegance probably depends on the particular frame/fork combination IMO.

https://www.jensonusa.com/Problem-So...adtube-Reducer

BCRider

The "elegant" option would be to just buy the fork that fits. Sorry, but that's how you'll gain the most out of the fork and frame combo. There would need to be something pretty special about the 1" fork and the furniture that fits onto it to justify this sort of mismatch I'm thinking.

TiHabanero

I did this conversion two months ago and it works perfectly. Just looking at the bike it is not possible to discern the headtube has been shimmed down to 1". Very elegant solution to an uncomplicated problem. Using a Cane Creek threadless headset on a threaded fork and it, too works just fine. I have used this arrangement twice before without any issues. Jensen had just one shim set left after I ordered mine two months agz28o and I just looked at their site and they are no longer listed.
Edit: I just looked again at the Jensen website and they show 3 available. Item # HS409Z28

alcjphil

My question is, what is so special about this fork that you want to use it on a frame that it wasn't designed for? Is it threaded or threadless? Threadless 1" forks are quite rare for good reason, by the time threadless became the standard the majority of forks and stems were designed around 1 1/8" steer tubes. If your fork is threaded, is it the right length? Threaded steer tubes have to be the right length for the bike's head tube within a pretty small range of millimetres.
More information about the fork in question and why you want to use it on that particular frame would be useful

kraftwerk 

Thanks people, just what I was thinking of, its cool something exists for this.
Of course I wish it cost $12 instead of nearly $50. The whole point of this build is to make a bicycle with parts I already own, to do a build out of what was left over from other builds... it is a personal journey I am on.
This should be a 700c gravel-type-thing , metallic-brown US built Trek 990 MTB frame.
The fork I was thinking of using : a 1" CARBON cyclo-cross w/canti-brake's, beautiful, but really not much lighter than quality steel canti-forks.
It is just something that is here already.
I do have a second option, which I will probably go with, since it is 1 1/8" : an old Surly cross-check, purple and white...
Thanks to the brain trust I learned something new today and gave me another possibility.

BCRider

I gotta say that this sounds like a fun build now that we see the list of options you are looking at using. And a pretty good reason for the adapter after all.

This should work out fine since while 700C forks are long enough that it should be pretty close to the shorter travel suspension fork that the frame was designed to use.

What about the rear though? The Trek 880 pictures I found online only show V brake bosses. And that's consistent with the 800 series at the time. That won't work with a 700C rear wheel. I know that because I thought long and hard before I decided to sell off my 870 when I wanted to go to discs and 700c wheels for my main commuter.

kraftwerk 

This is a TREK 990 ( sorry for the typo earlier )
As you my have gathered by now, I haven't really thought this thing through....all the way.
For the rear brake: I was contemplating adapting / fabricating an existing canti-brake to work on 700c
Again, I have the feeling something already exists to make work ...possibly...no? Otherwise calipers might work as well.


Hey, this is probably the subject of my next post!

BCRider

I think you led me down the garden path too... I'm pretty sure that my Trek was the 970 at reading your last post. And looking up pictures online proved that by seeing the same "Singletrack" named 970 with the same dark amber frame and yellow Rock Shox fork. That was a great riding bike......

One of my way too many hobbies is having a small machine shop. Trust me that I considered long and hard a lot of flights of fancy that would let me convert that 970 to disc brakes before I sighed and decided that a new modern bike would be the better answer. All the rest is just going to be a kludged up mess that will never look right. But if you really want to make it work then one option I considered was to make a plate up that looked like a booster arch. It would mount to the old posts and have new posts located out further. But as mentioned it's bound to end up looking like a Rube Goldberg botch up any way it's done. Same for an add on disc mount if it's not a properly done brazed on effort. Actually the ideal way would be to heat and remove the original drop out on the non drive side and make up a new drop out with disc mount and braze that to the stay. And a brace between the two stays. Disc brakes frees us from what fits or not. But now we're talking about a new paint job too. And while I slept on the idea in the end I didn't want to do that much work to the frame and get involved with the paint work.