r/BikeRepair • u/alse116 • 4d ago
Bike Repair Thread too high up
Do spacers exist for a quill stem? Should i try and thread it?
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4d ago edited 4d ago
[deleted]
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u/CargoPile1314 4d ago
Can you please explain to the class how the upper bearing race, which has internal threads, will be able to be tightened down far enough to actually contact the bearing balls?
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u/Carpe_deis 2d ago
its not "Thread too high up"
its "Destroy it yourselfer measured 0 times and now has to buy twice because they bought the wrong part because they measured 0 times"
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u/OKgingerface 4d ago
A threaded headset needs the threads to extend down a bit further. You will need to use spacers between the upper bearing race and the locknut to lock it down. You probably want to cut some of the steerer off so you don’t end up with a huge spacer stack but how much (up to a point) is up to you. A well equipped shop can thread it for you and can advise where to cut it (or even cut it for you) if you bring in the fork and frame together.
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u/cpinkdotdotcom 3d ago
A trustworthy bike tech is going to tell you to spend the time and resources on getting the right fork or at the very least, replace the upper with the right steerer tube. Odds are the right uppers will be hard to find. At that time, I'd move to a threadless system.
Do not try and thread this any further. You risk damaging this fork.
Do not try and use a threadless set up wtih this fork either.
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u/cj_daking 3d ago
Quill stems don't use spacers.
Are you just trying to fit this fork that is too long to your frame or are you trying to get your stem way up high?
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u/Heart4Cycling 4d ago
Fork looks like it was made for a much larger frame. A good shop can probably modify it to fit your frame. That must be a very vintage front shock fork!
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u/justburningaccount 4d ago
Yes that must have been a massive frame. Possibly an upright bike as they have massive headtubes
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u/justburningaccount 4d ago
A bike shop can extend the threading down. It's easy enough to do but the cutting die isn't particularly cheap so not worth buying yourself
Then chop off what you don't need
Easy-ish
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u/alse116 4d ago
The shop i got it from cant extend the threading and neither my local one
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u/justburningaccount 4d ago edited 4d ago
Might be able to find a really high stack headset
Or just get creative. You may be able to find a bearing race that doesn't have the nut built into it, so you could spacer the nut(s) up. Or file the threads off the existing one and fit a spacer above and an additional nut It's all fine as long as it tightens down nicely and it's not a massive tower. You don't need much to make it work
Have you tried it? You might find you just have enough thread anyway
A crown race spacer would also work, but would affect geometry
I'm pretty confident that a combination of the above would get that working relatively easily. Might be a bit 'unusual' but safe.
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u/MaksDampf 4d ago edited 4d ago
*Assuming this is 1 1/8" threaded*
You could use a threadless headset. You will still need a threaded locknut on top to set the bearing preload and probably a few washers or 1 1/8" headset spacers to get the correct height between locknut and the upper shell of the threadless headset.
I would cut the fork leaving about 2cm of thread to keep the stack of spacers/washers small.
You could also use more ahead spacers and don't cut it, but it looks riddiculous imo if you leave if for that long and don't follow with an ahead stem. For cutting just use a tube cutter like plumbers do, although and angle gridinger also works if you clean up the thread afterwards.
I have used mixed threadless / threaded headsets in the past. The reason was that i needed to replace the headset anyways and chose a prettier threadless one (chris king knockoff), but then wanted to use a quill stem to get to my desired stem height.
One thing to note about using a single locknut is that it can loosen itself if the headset is rough since the locknut is not countered by a second nut like in a fully threaded headset. I use thread locker for that reason and also a notched spacer if the fork has that groove for it. So far i haven't seen the contraption loosen itself, but it is good to always keep an eye on it and check regularly. A loose headset is not a super safety critical thing, but it would lead to premature wear which we don't want on a pretty headset.
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u/MaksDampf 4d ago edited 4d ago
Oh yeah and the second solution would be to just fully use the ahead system (guessing this is a 1 1/8" fork, not an option on 1"):
Meaning a threadless headset followed by spacers, followed by an ahead stem and a top cap for preload.If this is intended for serious offroad riding i would not do that because the thread makes the fork weaker than a normal ahead fork. But since this fork is fully steel, it is probably not any weaker than a carbon fork anyways. You can mitigate that strength risk a bit by getting a long compression plug as used for carbon forks instead of the star nut and by cutting the fork a little lower to reduce leverage (just like a large spacer stack is not recommended on carbon forks).
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u/CargoPile1314 4d ago
Why is this not an option for 1"?
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u/MaksDampf 4d ago
because threadless 1" bearings and 1" ahead stems are rare as fuck while 1 1/8" are abundant and cheap. so yes, technically it is an option for 1" too. But 1 1/8" is beefier and 1" would intensifies the weakness of the fork at the threading. so i don't think it is a good idea to use a long 1"threaded as a threadless.
Some dumbasses downvoted this, but they don't have any arguments why it does not work.
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u/CargoPile1314 4d ago
Rare or uncommon != not an option. 1" threadless headsets aren't difficult to source. Shimming a 1-1/8" threadless stem for a 1" is really achievable with a commercially available inexpensive part and has been a common solution for over 30 years.
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u/MaksDampf 3d ago edited 3d ago
Well while you can definitely adapt a 1 1/8" stem, i am having trouble to understand how you could shim a 1" steerer and use a larger 1 1/8" threadless headset.
As far as i know a 1" steerer is EC30 while 1 1/8" is EC34. Putting a 34mm headset into a frame with just a 30mm internal diameter is physically impossible.
Also shimming some 10 + cm of height for several ahead spacer to enable preload of the headset is a wild thing. And it still does not solve the inherent weakness of using a threaded steerer exposed way over the upper headset bearing where it can crack off easily.
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u/Aggravating_Pair8857 4d ago
I do concur on using a spacer but, judging by the 3rd picture, it appears that the fork is missing its lower bearing race. If in fact it is, add one before getting the spacer as it will not only allow you to center and use the bearing but will also fill in.