amp fork extension near finished[now with pics]

[dyna-ti]

Ok then,as i'm sure most of you are aware ,i've been looking to extend an alloy ahead steerer tube 12mm,
the steerer extended 27mm above the top of the h/set and most stems need a minimum of 40 mm
i decided to use an extension that slides down inside the steerer tube rather than 1 that clamps externally ,prob' was, the internal 1 was designed for a treaded steerer not an a-head and uses a quill to internally clamp,and if i used it i couldnt 'properly' preload the h/set
soulition was to do away with the quill and use an azonic head lock to preload them before tightening the stem bolts

Ive had to shave a bit off the extension so it would slide into the tube but not enough to affect to strength
the steerer tube has walls that are 3.27mm thick and an internal dia' of 22mm so normally thats all that you need strength wise when you clamp your stem on
the walls to the extension started at[new] at 5.45mm and the external dia' was 22.12
i shaved off 0.15mm off the walls of the extension dropping its external dia' to 21.97mm ,this allows it to slide unhindered into the steerer tube and with near zero play[0.03]and the epoxy will take this up
Please remember i've got 3/4 of the original steerer tube to clamp the stem on to

1 little prob' that has arisen but im sure ill solve it ,is the steere tube is now 70mm long which i think is a little on the long side,i cant put spacers underneath the stem as i need to use all the original length for clamping strength ,this leaves some 30mm sticking out the top of the stem
The bolt for the extension is recessed 26mm inside the extension of which i can maybe cut it down say 13mm or 14mm but im still going to have a bit of steerer tube sticking out
Any 1 know of some trick looking cover for this extra 17mm or so sticky out bit???
Heres some photos of work in progress
PIC 2- you can see the original steerer tube 'stub' --the 1"1/8" extension sleeve-- and the extension [the top of it that is sticking out i can prob' cut down flush with the 1"1/8 sleeve
Im thinking of spraying the whole bike the same colour as the forks [a kind of bronze colour] but I'll leave the Ti tubes unpainted
Bike will be set up single speed, with bonty saddle,post,bars and stem
the bonty ck wheels i got on ebay are in incredibly great condition,i got a good bargain there[sorry to rub it in ]

 

[dyna-ti]

come on ,some one tell me if this is all going to end in disaster

oh and does anybody else think the fork is too much for the dynatech, im not sure if it was suspension adjusted and the top tube seems awfy steep to me

 

[BG]

I understand your pain. Whenever I spot a nice fork for sale I'm always stymied by it having too short a steerer (or the wrong diameter - yes I own an old 'evolution' Fisher).

There is a company here is Australia that extends steerers (and repairs the unrepairable) called Gripsport - http://gripsport.com.au/main.php?part=p ... &prodID=42 - I've never had any dealings with them, but have only heard good things. Now I know they are a long way away from you but it may be worth flicking them an email - or looking for someone similar in the UK if they exist (surely a good framebuilder would be able to help)?

It seems they cut the existing steerer and put a slieve in the centre section which is different to the route you've taken, but may be worth considering if the way your heading doesn't work out.

 

[dyna-ti]

Thanks very much for the link BG [Beer Guzzler?]

Their steerer extension looks as it was described by an engineer that i may use to extend a 130mm steel threaded to 240mm;
though he suggested that the sleeve be the full needed length and diameter but with the lower section turned down to the internal diameter of the 'stunp' thats there
I like the pinning idea as well , i didnt think of that

 

[hairstream]

come on ,some one tell me if this is all going to end in disaster

In for a penny, in for a pound... Keep Going!

 

[BG]

No probs.

Hope it works out for you.

Unfortunately (and boringly) 'BG' is just my initials... though I like the idea of 'Beer Guzzler'!

 

[Dr S]

Would it not be easier to mail Brion at AMP and get a new steerer? They are only 20-25 dollars and do fast shipping. They are easy to fit with a vice without stripping the fork down. In fact I have a long 1 1/8 threadless steerer that I removed from my fork when I changed it to inch. PM me your address and its yours for a RetroBike Karma credit!
Si

 

[orange71]

you managed it with a vice?!! :shock: I tried but no chance. Perhaps you have a bigger vice! I had to get somebody with a hydraulic press in the end. Having said that, yes, Brion at AMP will get it out to you for $50 in total (inc postage) - well, he did for me anyway.

 

[Dr S]

Oh yes its a big big vice! A little heat from a blow torch helps too. A little Loctite on re-assembly and jobs a good un.
S

 

[dyna-ti]

I've emailed Amp tech 3 times now DR S and still no reply,i feel like phoning them to ask -if they know how to open email , :roll:
but that wont start things off on the right foot,and i dont know how much it'll cost to phone
Anyone have an e-address for them ,the e-addresses at their site dont seem to be workings for me :cry:

And i got the two custom wound springs from the maker today,i've fettled them to fit but now i need a huge vice to compress the springs so the lock ring clips can be fitted
Must admit i was a bit skeptical,i mean TWO custom wound springs for £20[thats about $40 US] what are they made from? 'mild steel'?
Proper high tensile wire used ,heavier gauge too ,i reckon the compression is about 430lbs each,the original being 400lbs and they [Amp] supply springs up to 450lbs
Now for some plasti-kote ,hmmm what colour should they be?, i have some April green,Forest green,Baby blue[maybe not] and Dark cherry[maybe]
A good job from that spring maker,I'll use him again

I'll post pics when it's all finished.