1" (one inch) headtube 1 1/8 forks Help please

[fireball_jones]

Hi guys.

Im going :cry: mAD. :shock:

i have had no luck getting a 1" fork with lock out for my montague biframe.

http://www.retrobike.co.uk/forum/viewto ... highlight=
http://www.retrobike.co.uk/forum/viewto ... highlight=

:cry: ....so ...

I'd like some adive from those expereience tinkerer's/inventors who have managed to fit a 1 1/8 (threadless) fork into a 1 inch (threaded) headset.

from my investigation so far there is enough room for the tubes to fit inside each other its just the hardware e.g. headset etc

i have seen it done on bmx but would like to see an example of thison a mtb due to frame differences. http://bmxmuseum.com/forums/viewtopic.php?id=40740 (this is just for those moaners who say it cant be done:roll: )

I reeaaaaaaly look foward to your responses and help.

i do have ideas of how it could be done but would like to hear what you have done before if you know of a existing product.

 

[pete_mcc]

Sadly it won't work on mtb. Bmx have a different 1" to mtb:

Head Tube Bore Size
1" Standard - 30.1mm
1" BMX - 32.7mm
1-1/8" - 33.9mm

So while bmx is only 1.2mm out, mtb is nearly 4mm different. Sorry fella, back to the search!

 

[fireball_jones]

cheers pete,

thanks for your info, do you think there is and other ways to solve the problem mate?

e.g. i thought that you may be able to fix 1 1/8 cups to the outside of the headtube. does that makes sense or is a diagram needed?

sorry mate i am a design student so creativity is my problem compounded by the fact i dont have sufficent tools just gets me fustrated.

thanks again

 

[PIGEON]

So instead of fitting the cup into the head tube, you want to fit the cup around it? I never thought of that, but I don't think it wuld work. Even if you would get an exact fit, there wouldn't be anything to keep the lower cup from sliding up the headtube.

Most suspension forks I have seen have the steerer fixed to the crown, and the legs are clamped to the crown. However there are also forks that clamp the steerer aswell (Marzocchi xc700 for example). If you can find a fork with lockout and a steerer clamp, I guess it should be possible to clamp a 1" tube with a shim onto the crown.

 

[pete_mcc]

Downside with trying it on the outside is that all materials have a different outside diameter, also it would require a headtube that extends 1cm at the bottom and top of the top tube and down tube for the cups to fit onto.

It really is a case of either getting lucky on eBay and finding a set of pace or zokes or butchering a set of rock shox together using a dremel and a judy 1" crown

 

[pete_mcc]

Can you guess that I investigated this as well........

 

[fireball_jones]

where theres a will theres a way

"Can you guess that I investigated this as well........ "

what have you done thats worked?

"butchering a set of rock shox together using a dremel and a judy 1" crown" what do you mean by this? have you done it? pics?

ok i just couldn't resist, please see attached drawing i think i may have solved the problem. it basically a shim which attaches to the outside of the headtube which allow the attachement of 1 1/8th cups (scale drawing dimension from sheldon brown). i really should be working

copyrighted to stop big bad corperations stealing it and becoming millionaires while my innertubes have more patchs than a tramps trousers.

 

[barry2017]

It would be easiest to replace the head tube. But to be honest, it may be a disappointing bike to ride after the conversion. The bottom bracket is already very high as a result of its design.

Have you considered a Girvin Flexstem?

 

[fireball_jones]

"Have you considered a Girvin Flexstem?" have heard bad things about them too often, and would like alittle more travel. cheers.

yeap thought about the headtube but was worried that it may not be as strong additionially i think the bb is low from the time i hit peddels on rocks etc what make you sya that have you ridden a biframe?

 

[barry2017]

Yes. In fact, I own one. It's a great design, but I couldn't think of anything worse than suspension forks for it.

To everyone that doesn't own one, it's a funny design; the seat tube extends below the BB shell, before finally meeting the down tube about 2" below it. As a result, it has quite a high BB; manageable but still high.

What bad things have you heard about Flexstems? Have you tried one?