rousseau

Is there anyway that a fork with a 1 1/8" steerer could be mounted on a bike with a 1" head tube? Is there any sort of special headset out there that would allow for this, or am I just dreaming?

I've forayed into the world of threadless forks. My mid-1990s steel frame (Bianchi Thron) has a threaded chrome fork, but today I picked up a 1" Alpha Q carbon fork and a 1" threadless headset to go with it, and went to work.

I'm learning as I go. I'm now aware that my bike, with its 150 mm-long head tube, requires at least 230 mm of steerer to be viable. The used Alpha Q I picked up had 207 mm of steerer available, bringing the top of the steerer just barely to the middle of the stem bolt. I might have considered trying to go with that, but the cap bolt wouldn't reach the star nut, so I took that as a sign. The fact that none of the hardware stores in my town had a longer bolt was another sign. So I'm giving up on this fork.

Does the 1 1/8" steerer simply not fit inside the 1" head tube? Or have people finagled these to work somehow?

Apologies if this is a stupid question.

mrblue

Think about what you're asking...

You're asking if a piece of metal can fit into a hole, that is 1/8" smaller than it. Logic would dictate, no. Then again, maybe I'm missing something and not understanding your question.

rousseau

I'm fully willing to admit that it's a stupid question!

But just to prod the issue a bit: the 1" steerer can't be too snug inside the 1" head tube, right? Otherwise it wouldn't rotate freely. I'd go out and measure all this stuff, but I put my chrome fork back on the bike, so I don't want to take it all apart.

It just seems to me that the 1" steerer is a somewhat loose fit inside of the 1" head tube, i.e. the internal diameter of the head tube is slightly larger than 1". Isn't it? So, erm...what if i's actually large enough to allow a 1 1/8" steerer to fit inside and move freely?

Or would it simply not fit?

mrblue

Use a set of calipers and measure the inside diameter of the head tube. It may be slightly larger than 1". However, I seriously doubt the headset, meant to fit the 1" head tube," will accomodate a 1-1/8" steerer. In the world of bikes a small amount, like 1/8", is a HUGE difference. As far as I know there is no special headset for this.

Then again, I've never tried to get that creative with my bike components. I'd just buy a fork with the proper dimensions and be done with it. Who knows? It just might work.

FBinNY 

Can you put 10#s of potatoes in a 5# bag?

It's always possible to use reducers to adapt a smaller diameter tube to fit in a large one, but the reverse isn't possible.

OTOH a 1-1/8" (28mm) steerer is slightly smaller than the 30mm ID of the 1" frame's head tube, so it's possible in theory. But it leaves no room for the wall of the part pressed in. If you could adapt a zero clearance headset that could securely sit on a head tube with ends possibly machined conical or a thin step, but it's not an easy job, and I don't believe anybody offers anything along those lines.

hueyhoolihan

the outside diameter of the steerer tube on the fork that came with my 1985 steel framed trek with what is commonly referred to as a 1" headtube is exactly 1". the inside diameter of the fork;s steerer tube is about 7/8". that means that the head tube's inside diameter is slightly larger than 1" and the outside diameter of the head tube could be as much as 1/8" wider still. this is all easily, and more accurately, referenced on wiki. with an emphasis on accurate.

JohnDThompson 

Frames designed for 1" steer tubes generally have 1.25" head tubes. Is that what you're asking?

rousseau

This is what I was wondering. You've clearly explained why it's unlikely. Thanks.

Next question: Where can I find a good wood extender? I need a 16-foot 2x6 for my back deck, but I only have a 15-foot cast-off available. It doesn't seem to stretch very easily by hand, but surely there must be a professional tool out there for the job?

dabac

I've put a 1 1/8" steerer fork in a frame intended for an 1" once.
It was made "easy" through the bike being intended for an integrated headset. So I cut some shims and mounted a set of regular external cups. Changed the steering geometry a little, but nothing critical.
I've toyed with the idea of doing some "sleeves" which would press on to the outside of the head tube to possibly allow the use of 1 1/8 " steerers in 1" head tubes. Haven't quite needed it yet.

tomacropod

It can be done you just have to remove the pressed part of the cup from the equation Chris King rekindles an old flame - BikePortland.org

- joel

rpenmanparker 

Actually, no it isn't such a stupid question in this sense. FSA makes a 30 mm diameter spindle crank like for BB30 bottom bracket shells that just fits inside the standard BSA bottom bracket shells intended for 24 mm diameter spindles. Just like the OP is asking except for bottom brackets, not head tubes. Bad news is that unfortunately it doesn't work that way for head tubes and steerer tubes. Sorry. But a good thought.

fietsbob

Chris King (Because he can) has machined complete headtubes for his (Cielo) frames , with the ends like their press in bearing parts sold in thousands.

But since there is no need to slip inside the head tube the steerer Tube clearance inside the head tube could be smaller ..

So, head tube looks thinner, It is, but fork is still 9/8".

So it is possible , If you start with a New Custom Frame from Him..

wedgeSG

look around on You Tube...there is a guy that restores old BMX bikes, (possibly for a museum somewhere), that has a very detailed video of the process. There are a lot of custom machined parts involved, but he may be offering this as a kit by now. It basically runs a thin sealed bearing outside, above, and below of the original headtube. The steerer must be cut to the new longer than original dimension, but it does fit thru the head tubing. Seems like there may have been a similar Cane Creek product available as well many years ago. Somebody should make this product available. Would be a nice complement to the bottom bracket sealed bearing conversion parts that are available from a number of suppliers.