Frankenbike question: 1.5" fork in an otherwise 1.125" headtube?

[Gummee]

So I've got a Frankenbike project going on with some 5800 stuff that I bought on a whim. ...but the fork's either going to be a carbon Fuji tapered (1.5 - 1.125) CX fork or an ancient Kinesis AL fork that's straight 1.125"

I'd rather use the carbon fork, but my google-fu is weak today for some reason.

Does anyone make a 1.5" crown race dia headset that fits a 1.125" head tube?

M

[PacNW2Ford]

Given that the outside diameter of a steel 1-1/8" head tube is about 1-1/2", I would say "no".

[oldpotatoe]

So I've got a Frankenbike project going on with some 5800 stuff that I bought on a whim. ...but the fork's either going to be a carbon Fuji tapered (1.5 - 1.125) CX fork or an ancient Kinesis AL fork that's straight 1.125"

I'd rather use the carbon fork, but my google-fu is weak today for some reason.

Does anyone make a 1.5" crown race dia headset that fits a 1.125" head tube?

M

No. You can do the opposite, of course but not a 1.5 steerer into a 1 1/8 head tube.

[Gummee]

No. You can do the opposite, of course but not a 1.5 steerer into a 1 1/8 head tube.

That's what I was thinking. I was *hoping* Acros came up with something, but they don't.

M

[ultraman6970]

No matter the adapter, the 1.5 steering tube wont fit in the 1 1/8 front tube :P

Probably in millimeters is easier to picture??

1.5 inches = 38.1 mm

1 1/8 = 1.125 = 28.575 mm


Then you hear that metric system doesnt make any sense :p

[Gummee]

I can picture the bottom cup in my head. Looks a lot like a pancake...

M

[oldpotatoe]

No matter the adapter, the 1.5 steering tube wont fit in the 1 1/8 front tube :P

Probably in millimeters is easier to picture??

1.5 inches = 31.8 mm

1 1/8 = 1.125 = 28.575 mm


Then you hear that metric system doesnt make any sense :p
I
31.8=1 1/4 In. 34.9=1 3/8 in. 28.6=1 1/8inch 25.4= 1 inch

But you know that!

I'm confused but not the first time.

[PacNW2Ford]

I can picture the bottom cup in my head. Looks a lot like a pancake...

M

The INSIDE of (The hole in) the head tube is 33.9mm, the OUTSIDE of the steerer tube is 38.1mm. The steerer tube has to go through the hole in the head tube. It can't do this if it is bigger than the hole.

Picture taking your pancake and making a hole in the middle that is bigger than the pancake itself.

[Cicli]

No matter the adapter, the 1.5 steering tube wont fit in the 1 1/8 front tube :P

Probably in millimeters is easier to picture??

1.5 inches = 38.1 mm

1 1/8 = 1.125 = 28.575 mm


Then you hear that metric system doesnt make any sense :p

Typo?

[ultraman6970]

Yup sorry, typo :/