I've built up an old Kirk frame as an 'interesting' commuter for winter to keep my steel single speed nice. Commute is only 3 miles so performance isn't high on the agenda.
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Took it round the garden and I thought I'd left something loose, checked it over and couldn't find anything out of place. It felt like the front wasn't connected, I found that I could move the seat tube laterally just by holding the bars and leaning on it. How did this ever make it to market? It must have been fascinating being a Bike journo back when stuff like this was coming out.
Check out this clip of the frame flex.
I haven't cut the grass between the slabs as it's at the wildlife end of the garden and it's full of froglets and newtlets before the commentators chip in...
are you sure that's not just the camera moving!?!?
bike still look cool regardless of flex! we all know looks come first
Dave Mann was winning races on those things 😯
fascinating being a Bike journo back when stuff like this was coming ou
yeah it must be real interesting to make [s]shit up just because an advertiser wants you to say their product is great[/s] accurate observations regards a product and have them in print for others to base their purchasing decisions
Welcome to the world of old skool bikes...
Must be great riding it on off camber corners.
I still ride a 90's Zaskar, it's still a brilliant frame, I guess the double diamond was already perfected and this was all a bit more at the experimental end. Did no-one at Dawes ride one and think, hang on, this can't be right...
It's not the camera, I can actually get it to flex more but I was being careful to keep the phone steady. Pretty sure I could snap it without a great deal of effort.
Be interesting to read the original mag ride reports, and see if the same [s]liars[/s] staff are still spouting rubbish.
I remember these back in the day, they redefined flex.
Good luck riding it as a single speed, any climbs on your commute? 😯
That Kirk Revolution frame was made of magnesium from my recollection. Magnesium frames - what a Revolution that wasn't!
I'm pretty sure they all broke. 😯
This explains why.
They're worth a few quid over on Retrobike.
I thought they were supposed to be very rigid (and strong)! 😀
They're worthless, hence the purchase. I do have a small hill on the ride to work. I have a horrible feeling it's going to be unrideable and this will have been a total waste of time and money.
I read that they were flexible but I didn't really expect this.
all of those Kirk frames 'went floppy' within a few months of ownership, sold through Halfords if I remember correctly?
cost the manufacturer and retailer a huge amount in warranty claims, they soon disappeared after that..
I thought they were supposed to be very rigid (and strong)!
That 4x4 was totally unnecessary!
I remember watching that Tomorrows World!!!
We have a pretty large collection of retro bikes in the SF office, one of which is a rather natty purple Kirk Revolution.
As such I can confirm they are flexier than a flexy thing that's been left in the sun to get flexy.
And to think I actually lusted after one in the early 90's !!!
I'd be tempted to launch it on top of a bonfire come November the 5th and see how bright it burns!
IIRC they were pretty heavy and pretty dead feeling to ride.
mine was pinched before I could break it. I know the bolt on dropouts cracked on mine, replaced under warranty. Dunno about flex, first "proper" mtb I guess (after a hi ten steel mtbso) I know I can get a few of my bikes to flex like that while stood still and leaning on it, doesnt really become apparent while riding tho.I'm pretty sure they all broke.
is it a large? Polished LX parallax hubs with shiny shiny campag rims, Altus A10 sti, dart front tyre zmax rear?a rather natty purple Kirk Revolution
I can still vividly recall the shock I had when cornering in a car park test on one of those. A mate's raleigh banana replica had significantly less flex.
It's akin to the sensation of sliding on gravel yet not falling off...
I lusted after one of these to - glad that i went the Dyna Tech route instead 🙂
yeah, but no chainsuck.
A mate of mine had a road version and actually did pretty well on it considering. It was still going a handful of years ago....he had given it to his dad who used it as a commute. Looked horrible IMO.
My brother used to have one of these. I only rode it a couple of hundred yards, but the feeling of the frame being connected to the bars by bungee ropes left me a little less than impressed.
I had one of those for a while - yes, it managed to be both flexy and dead-feeling at the same time. But I bought it NOS for £200, sold it on eBay for £400 😉
I think the whole thing was a marketing exercise for Sandvik, to show off their magnesium injection casting technology.
no youre all wrong, the flex was designed to be in the frame to provide trail bump absorbing qualities, its actually early full sus without a shock.
...joke.
the only bikes with decent frame flex are those actually designed to flex. My ibis BowTi has allegedly five inches of travel in the ti frame and no pivots. Still going strong. Still a good ride.
look on the bright side if the seatpost ever gets stuck removing it with caustic soda will be so easy
the only bikes with decent frame flex are those actually designed to flex
Yup - the Castellano designs are lovely, with flexy chainstay plates. There's a lot of logic in that - bearings aren't really designed for small cyclic loading, so if you can use a flexible link instead it saves maintenance. Some companies have also made bikes with flexible carbon plates instead of bearings or bushings.
its probably the weight of that saddle causing the frame to flex so much?
I just watched your video on headphones at work...and jumped at the very end with the loud noise. My boss gave me funny looks! 🙄
I'm assuming the handlebar clocked something?
A mate had one. Not long after he bought it, he painted it hammerite black so that "no-one would nick it".
That Kirk Revolution frame was made of magnesium from my recollection. Magnesium frames - what a Revolution that wasn't!
(dusts off bikegeek memories) They were actually made by Norsk Hydro, who manufacture magnesium components for the hydro-electric industry, as a demonstration of their prowess in complex castings.
no youre all wrong, the flex was designed to be in the frame to provide trail bump absorbing qualities, its actually early full sus without a shock.
did it bring the trails alive? 😀
http://www.kirk-bicycles.co.uk/Kirk-History.htm
Lifetime warranty
This would have been a good bonfire.....
They were actually made by Norsk Hydro
Yup, not Sandvik as I misremembered.
Yup - the Castellano designs are lovely, with flexy chainstay plates. There's a lot of logic in that - bearings aren't really designed for small cyclic loading, so if you can use a flexible link instead it saves maintenance. Some companies have also made bikes with flexible carbon plates instead of bearings or bushings.
F1 sometimes use titanium or carbon 'flexures' instead of rose joints in wishbones where there is low angular movement, simply clamp in place.
http://www.kirk-bicycles.co.uk/Kirk-Foreword.htm
"Then, in 2005 I received an email from Frank Kirk himself, asking if I still had the bike and whether I would consider selling it. That took me by surprise, but a meeting was arranged and both the MTB and Racer were sold to a good home."
Trying to remove the evidence?
I found a review. Journo said: "If only it had bigger wheels."
Did I hear that Tomorrow's World video correctly?
Do pro riders really replace their frames several times per year, due to the constant flexing distorting the frame for good?
Or is it, as I suspect, that upgraded frames have been made, they've suffered crash damage, or they simply have access to lots of frames, for when they get a teeny weeny scratch on their bike?
WOW I like this. Thanks OP 😀
I suspect it will be going in the bin, I'll give it a week but it feels totally unsafe and I don't think I'll enjoy riding it.
Balls.