Back To The Future For The Kirk Precision

Discuss light weight issues concerning road bikes & parts.

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hockinsk
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by hockinsk

A typically British engineering failure, but few frames in 1986 turned heads like Kirk Precisions managed to, or at least that's how I remember it anyway! Even today, this £80 heavyweight still gets plenty of attention up against £5K pieces of carbon fiber perfection sitting next to it. If you were into road bikes in 1986-1988 you might remember the frenzy this frame created at the cycle shows. Some of that magic still seems to rub off on people despite its reputation for failure! Put it up against any 1986 frame of the day and you have to agree its design is timeless and ageless. Not bad for a frame inspired by a Ford Sierra bumper in Dagenham!

This frame I got hold of very used and have modified it a fair bit to bring it into the future. Those in the know will notice the hump on the down tube with the bonded gear lever bosses has been removed and STI/Ergo stops riveted on in their place. The blanked mudguard bosses only there so they could be drilled for the Touring model have also been sliced off. Not so noticeable is the removal of the pronounced bulges on the non-drive-side rear triangle that allowed a frame pump to be fitted (co2 for me now). The rear dropout inserts have also been machined down, with 2mm taken off each side to move the spacing from 126mm up to 130mm for 10 speed and modern hubs. The frame although re-painted by me in 2K, will eventually be sandblasted and UV powder coated once I’m happy the modifications are all ok. I've already done nearly 300 miles on it since the weekend so far. Nothing has snapped, un-bonded itself or gone floppy despite everyone warning me all these things would happen within a few miles and I would kill myself when the frame explodes into magnesium dust at the first pot hole . What do they know : )

Believe it or not, the ride is great. The geometry is pretty much as my Look 595. T/Tube is identical with just a slightly longer wheel base and half degree of head tube than the 595. It really doesn't ride as bad as everyone makes out they do/did/will. Sure it's a bit heavy and slightly dead out the saddle like any 20 year old frame can be, but you really would be surprised at how little difference there is in the ride compared to my 595. I am still supprised at just how good it rides and still can’t figure it out because the frame design and manufacture is about as far removed from a 595 as you can get? No doubt the modern forks have improved the handling greatly compared to the bendy OEM Vitus alloy that came with the frame originally and were notoriously wobbly on fast roads.

Only things remaining to do is I need to machine an alloy derailleur hanger that will fit on the outside to replace the current plastic one that hits the chain on smallest sprocket due to how it wraps around both sides of the dropout.

Anyway, just thought some might be interested in something completely different and from a different technical era. So far it's the best £80 I’ve ever spent on anything to do with a bicycle. Comments welcome.

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by Weenie


KB
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by KB

Love what you've done with this bike. The only change for me would be to go the extra mile and have the forks white as well. But a small quibble on a great looking project.

And would imagine this has given you more pleasure than any other project or build you've done.
Last edited by KB on Wed Nov 12, 2008 2:49 pm, edited 1 time in total.

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BikeTech
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by BikeTech

Congratulations on that sweet build; classy and tasteful. Your preparation notes are going to come in handy if I ever find an elusive Kirk Precision frameset in the smaller size. I believe only two sizes were made.

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hockinsk
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by hockinsk

Yep, I agree, the forks will be white eventually. My biggest fear at the moment is the frame might fail and i'm left with a pair of white EC90's that might be difficult to sell on in a 1" version. Once I hit 1000 miles on it, the frame will be stripped and powdercoated and the forks will get a matching 2K paint. I'm possibly going to link the red of the discobrakes.com pads and fizik saddle stripe with some red hudz and possibly red Look Sprints, but it needs some quality paint first!

I'm pretty sure the road model only ever came is this size BikeTech. I haven't ever seen any in a smaller size. Basically there was one mold and they made a batch of 100 or so at a time.

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BikeTech
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by BikeTech

hockinsk wrote:I'm pretty sure the road model only ever came is this size BikeTech. I haven't ever seen any in a smaller size. Basically there was one mold and they made a batch of 100 or so at a time.


That would explain why my search has been so elusive. Thanks for the information, it'll save a year or two of my life for other pursuits :lol:

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J-Nice
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by J-Nice

Is the frame aluminum?

The jet black color of the rims is very nice!!! Who makes them?

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de zwarten
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by de zwarten

magnesium.

H+SON?

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mrowkoob
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by mrowkoob

Congratulations what a cool bike!
What is the weight of the frame?
The unbearable wallet lightness of being a weightweenie

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Danton
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by Danton

They were made from pure magnesium, no? Can you imagine crashing it, a scratch on the paint, some friction and soon it is not the white paint that is glowing white. :wink:

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hockinsk
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by hockinsk

They are not made of pure magnesium as this isn't strong enough or corrosion resitant. They are made of a magnesium casting alloy called AZ91D I believe. Basically the same as your cars gearbox and possibly your engine components and alloy wheels. Many F1 components are also magnesium alloy. It certainly doesn't burn like you remember in Chemistry class. This is just a myth and part of why the Kirk idea didn't catch on.

Mg: BAL
Al: 8.5-9.5
Zn: 0.45-0.9
Mn: 0.17-0.4
Be: 0.003MAX.
Si: 0.05MAX.
Cu: 0.015MAX.
Fe: 0.004MAX.
Ni: 0.001MAX.

Essentially you can treat these frames just like alluminium frames. i.e. you can use a grinder on them (how I removed the shifter hump), use a blow torch on it etc. Heck you can even weld it if you really want to.

Alan Sherman
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by Alan Sherman

Super-cool! A great update on the original. I nearly bought one around 1992 - weren't they still available then? Also it would have ben with early Ultegra STIs then too i think.

I remember them being raced in the kelloggs town centre series to some good results. They were (alledgedly) prone to cracking which is why I didn't buy one in the end. I wonder where the moulds went?

NS
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by NS

Christ I wanted one of those when I was 15!
Didn't they have a pro team in the Kellogs era?

Have to take issue with the typically British engineering failure though, if there was one thing we at least used to be good at it is engineering.

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Redddraggon
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by Redddraggon

hockinsk wrote:Essentially you can treat these frames just like alluminium frames. i.e. you can use a grinder on them (how I removed the shifter hump), use a blow torch on it etc. Heck you can even weld it if you really want to.


Magnesium alloys aren't as easy to process as you make out. I've got a couple of friends who've worked in the magnesium industry, and the risk of fire is still pretty great - one them burnt down the workshop causing a few grand worth of damage a few months ago.

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hockinsk
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by hockinsk

Yep there was a British pro team sponsored and they also supplied the TVM Team in the Tour de France in 87/88 maybe? Phil Anderson and a Danish guy I forget the name of, mainly rode them in bright yellow.

By engineering failure, I really meant it failed to make a profit, not that the engineering was a failure. They did have a reputation for breaking though, but more on the later ATB version when norways Norsk Hydro took over development.

by Weenie


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hockinsk
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by hockinsk

Redddraggon wrote:
hockinsk wrote:Essentially you can treat these frames just like alluminium frames. i.e. you can use a grinder on them (how I removed the shifter hump), use a blow torch on it etc. Heck you can even weld it if you really want to.


Magnesium alloys aren't as easy to process as you make out. I've got a couple of friends who've worked in the magnesium industry, and the risk of fire is still pretty great - one them burnt down the workshop causing a few grand worth of damage a few months ago.


It's only when the magnesium is in small particles/forms it gets dangerous. The Kirk Factory almost burnt down after all the sanding dust generated from the robots finishing the frames caught a spark and ignited. In large solid formats like bicycle frames, gear boxes, alloy wheels and engine blocks etc it is almost impossible to ignite even with a naked flame. I've tried it on the bits i've cut off the frame and they didn't even burn when I got my blow torch on them.
Last edited by hockinsk on Wed Nov 12, 2008 4:47 pm, edited 1 time in total.

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