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Technical & Reference Section => Tech and Restoration => Topic started by: monkeybat on January 04, 2012, 05:12 AM

Title: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 04, 2012, 05:12 AM
Found some looka-like forks for my Mongoose DMC but they are 1" thread type and need to be 1 1/8.
Anyone every converted theres to a 1 1/8 steering tube ?
Have some old 1 1/8 forks to use the parts for this and also need to put bosses on them.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: ozone on January 04, 2012, 08:41 AM
Buy a headset reducer like this one...

http://www.sourcebmx.com/product/bmx-racing-products/bmx-racing-components/stems-headsets/headset-spacers/sinz-headset-reducer/2103.shtml
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Discostu on January 04, 2012, 09:13 AM
This can be done by fitting a small 1"1/8th top headset cup and loose bigger bearings greased up. Most 1"18th headsets such as Fsa pig had a smaller top cup compared to a Bottom one. The outside dimensions of the cup are the same as a 1" but the inside is an 8th of an inch bigger. So that is why bigger bearings are needed. You may be able to find some that fit complete in a race. But to be honest unless you have shed loads of spare headsets your probably better of putting loose bigger bearings from the lower part of a FSa pig in as they are bigger.  Or you can use a headset shim like the sinz ones in the post above.

The only other thing I need to say is "why are you doing this" !!!
You already have a frame that accepts an 1"1/8th headset which is a far better set up than the old threaded 1" version which comes loose. That's why all bikes have moved on in that direction. I can understand riders converting there 1" frame to accept a 1"1/8th forks/headset/stem set up for a bike that's going to be ridden as the steering is super smooth. Without coming loose. Why anyone would want to fit 1" forks into a 1"1/8th frame is beyond me. Having said that I suppose if you had one of those retro quads/rippers you could deceive some people if it had an old type 1" headset and the brake mounts removed. But it wouldn't be as good to ride. However your frame isn't a retro frame. I would just find some nice chrome or painted forks that are 1"1/8th and fit them to it until some correct ones turn up. There must be someone that can help you out with some. To save yourself a lot of bother and effectively making your build worse. I hope this helps. Cheers stu :daumenhoch:
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: TwoBobRob on January 04, 2012, 10:56 AM
Got to agree with Stu, you're on a hiding to nothing there buddy.

They're not going to be very lookalike up at the stem eh? The steerer tube isn't long enough for a clamp on stem is it?

Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: john4130 on January 04, 2012, 11:44 AM
i did this years ago with my standard sta, 1 1/8" frame and gsport 1" forks. my solution was to get a piece of aluminium sheet 0.7mm from work and cut it to the same length of the headtube, roll it so it fits in the headtube with a tigh fit and the ends of the rolled piece butted together, then just use a regular 1" threadless headset for the gsport forks. never had a problem with it for years. i originally bought the headset reducers that fitted the frame but they would not fit a regular 1" headset, i think they may only fit the 1" roadbike or mini bike headsets. worth finding out if you go down that route, or just do what was said and use bigger balls in an 1 1/8" headset.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: ED209 on January 04, 2012, 11:46 AM
jus bumped this upped for you mate  :daumenhoch:

http://www.radbmx.co.uk/forum/index.php'topic=136475.0
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Discostu on January 04, 2012, 12:17 PM
A good link there ed. but monkeybat wanted a conversion the other way round. Old school 1" forks fitting into a mid school 1"1/8th frame. I think it would be good to pick up all the info from both threads and put it under headset conversions. Then it can have a sticky on it. As it does pop up now and again. All the info on all the conversions in one thread.  :daumenhoch:
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Dannywhac on January 04, 2012, 12:29 PM
If you need to weld bosses on the forks as well, I'd just hold off till you can find the 1 1/8" forks for it :) Or as a temp measure shim like John suggested to save on having to pee around with h/s cups etc :)

One of the major reasons that we went 1" to 1 1/8" was strength, not that the h/s kept coming loose (beartrap 2 put paid to that). Bigger bearings, larger solid steerer leading to less bends where the forks (cos the forks legs are bigger) meet the steerer etc. Far more likely to rip the headtube off that bend the forks after 1 1/8" :)
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Discostu on January 04, 2012, 12:40 PM
This is true the forks were much stronger in 1"1/8th as the stem clamps on to the outside of the stem the fork head tube could be a lot thicker. As it didn't have to have a stem/wedge inside it anymore. A much better system.

On another thought I was told by my local bike shop when I went to buy a headset that soon they are to go bigger than 1"1/8th. This will start happening in the next year or so. That will make things interesting again!  :LolLolLolLol:
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Dannywhac on January 04, 2012, 12:45 PM
Nooooooooo ;) It'll be like them early 2000's KHE's all over again (but minus the internal gyro) :

http://bmxmuseum.com/bikes/khe_/12544

 :D
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Discostu on January 04, 2012, 12:56 PM
Tin can size headtubes!!  :LolLolLolLol:
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 04, 2012, 03:08 PM
Holding out for the right forks hmmmm, I dont think that will ever happen. These are the forks im after.
(http://www.radbmx.co.uk/archive/albums/y213/monkeybat/mk11001-1.jpg)

And these are the 1" steering tube models.
(http://www.radbmx.co.uk/archive/albums/y213/monkeybat/copydmcforks.jpg)

Now do you see.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Dannywhac on January 04, 2012, 03:37 PM
So the late 97/98 forks? They will crop up fella - you could try a wanted over at the Museum, or keep scouring here/eBay - I've found forks that I didn't think I'd get after a couple of months.

Those 'copy' forks are 1" ahead by the looks (could just be the piccy) - not threaded and they've got mudguard tabs. You'll need a 1" ahead stem for em.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Discostu on January 04, 2012, 03:46 PM
To be honest I would still wait for the correct ones to pop up. And they will!!  You can put other ones on there for now. But I wouldn't fit those 1" ones. The more people that know you want a set of those forks the better it is. As rad users are normally good on pm'ing you if they come across something.  I have asked for stuff on here several times and come up trumps whether it's been an item of another member or pointed to a sale on another forum or eBay. Good luck with your search mate :daumenhoch:

I will keep an eye out! We could turn this into a competition. Who on rad can find them quickest!
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: ED209 on January 04, 2012, 04:06 PM
A good link there ed. but monkeybat wanted a conversion the other way round. Old school 1" forks fitting into a mid school 1"1/8th frame. I think it would be good to pick up all the info from both threads and put it under headset conversions. Then it can have a sticky on it. As it does pop up now and again. All the info on all the conversions in one thread.  :daumenhoch:

I thought it was opposite day so I was not helping ... not  :D
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: fugazi on January 04, 2012, 04:16 PM
If it helps those style of forks were also used on the Mongoose AKA for some time & also on the K2 DMC Pro  :daumenhoch:
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: theRuler on January 04, 2012, 05:25 PM
That white DMC is awesome.
Seat is a little high though.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 04, 2012, 09:58 PM
Yes that pic was at MK11 and there were two of them owned by the same guy.
He had my problem, had to search for bars and forks. I have got the bars coming and now the search is on for the forks.
But there are two types of 1 1/8 bend forks, one with bosses one without.

Cheers guys and thanks for all your  help.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 05, 2012, 09:07 PM
An update the forks turned up today and the 1 1/8 steering tube slides nicely over the top of the threaded 1" tube. To secure the tube over the 1" was thinking of drilling a series of holes dowm the 1 1/8 tube then welding to the undertube. Thus securing tubes together then fileing down any bad parts for a flush fit.
For the bosses it will have to be some welding on the chrome but will rub down to bare metal the shine then polish then clear laquer(poor mans chrome)   
Any other  ideas will be listened to.

Cheers Steve.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: TwoBobRob on January 06, 2012, 07:16 PM
None of that made any sense bud......

You have a loose 1 1/8th piece of tube, is that right? And you want to slide it over the original 1" steerer?





Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 06, 2012, 08:52 PM
Thats about it Rob, the 1 1/8 steering tube is off an old set of Mongoose forks and thats where Im getting the bosses from too. It fits snugley over the 1" steering tube and just wondered if anyone had good ideas of how to secure it nice and clean.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: john4130 on January 07, 2012, 07:37 AM
be easier just to make a shim to fit inside the headtube of the frame or try the bigger balls for the headset. sounds like a lot of work making 1" forks to 1 1/8".
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: ozone on January 07, 2012, 12:38 PM
be easier just to make a shim to fit inside the headtube of the frame or try the bigger balls for the headset. sounds like a lot of work making 1" forks to 1 1/8".

You can buy them - I don't get it either?   :crazy2:

http://www.sourcebmx.com/product/bmx-racing-products/bmx-racing-components/stems-headsets/headset-spacers/sinz-headset-reducer/2103.shtml
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 07, 2012, 01:43 PM
I dont want to do it that way and I dont do anything the easy way out. Most of us wouldnt build these "OLD SCHOOL BMXs" if that was the case. Restos, Decals, Paint job its a long road to getting a bike to look exactly how We think it should look. I was just thrownin out there if anyone had a better way of anchoring the 1 1/8 tube over the top of the 1" tube.
 Its a mid school bike and I need to keep it looking as close to the day when it rolled of the production line. The look-alike forks -1"copys are the only ones that come close.
So I need to be useing the original mid school stem and no  old school headset.

Cheers anyway and all the best  Steve.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: TwoBobRob on January 07, 2012, 04:48 PM
 :LolLolLolLol:

Fair enough you awkward old bastard!

Right.

To secure your new steerer tube/shim thing, weld it all the way around at the top then grind/sand down to achieve a good looking finish.

Slightly more tricky I suspect will be securing the bottom bearing race. Depending on how fussy you want to be, you could either weld a washer on to act as a shelf for the race to sit on, or you could weld the race permanently in place. Just be careful setting it out correctly.

Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Gary72 on January 12, 2012, 11:07 PM
How about Odyssey Director forks? You can get those with brake bosses.
Not excactly MId school, But kinda the look you after and a lot less fooking about.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: pickle on January 13, 2012, 09:02 AM
Sorry Gary, i don't think directors come with brake mounts.  They don't have a drilled hole either to fit an AD mount or caliper
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 13, 2012, 09:13 AM
This project is just about complete. I have cut off an old 1 1/8 steering tube off a old set of bent forks(mongoose). The tube had to be drilled out towards the bottom, It got thicker as it went down. Drilled two small holes so I could weld it to the original tube. Fits perfectly, so now all I have to do is weld the tube as I mentioned and fix the bosses plus cable guide. That is all happening tonight.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: ED209 on January 15, 2012, 04:01 AM
worth a bodger hack for £8!

http://www.ebay.co.uk/itm/BANKRUPT-20-WHEEL-1-RIGID-THREADED-BIKE-FORKS-CHROME-/170389129081?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item27abfbc779
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: monkeybat on January 16, 2012, 04:33 PM
A little bit more than a bodge job Ed but those forks came good.
Pics speak for themselves.
(http://www.radbmx.co.uk/archive/albums/y213/monkeybat/oldforks001.jpg)

Donor forks steering tube and ad bosses

(http://www.radbmx.co.uk/archive/albums/y213/monkeybat/oldforks006.jpg)

Ebay custom forks finnished

(http://www.radbmx.co.uk/archive/albums/y213/monkeybat/mk11001-1.jpg)

Real DMC forks

The moral is dont throw those old BMX parts away.
Title: Re: Anyone converted 1" forks to 1 1/8 steering tube ?
Post by: Gary72 on January 16, 2012, 06:43 PM
Top engineering :daumenhoch:
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