700c fork on 27 inch frame

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700c fork on 27 inch frame

Postby Dale E Grind » Fri Jul 11, 2008 1:13 pm

I've thought about it - in my head, and cant see any reason why it cant be done. Sure, I understand that there could be some geometry changes. But it wouldn't be unrideable would it?

I'm just trying to recycle some old bits and pieces that's why ask. I have a few old 27 inch steel frames of no particular value hanging around and 700c wheels are easy to come by.

The only reason I want to do it is to build up a pub bike. SS/Fixie.... whatever.... just as long as nobody wants to steal it. It's all about being sustainable - Sustainable, Lowcost, Urban Transport (S.L.U.T.)

Anybody care to tell me why it cant be done?
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by BNA » Fri Jul 11, 2008 1:26 pm

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Postby rustychisel » Fri Jul 11, 2008 1:26 pm

no reason at all... inch fork steerer in old frame, sweet as apples. No real issues with differing headsets (hiddenset, A-head, integrated etc), and the ability to use front brake caliper which needn't be unfeasibly long. If you're really unlucky the bike might appear to slope forward very slightly, but my guess is you wouldn't even notice it.
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Postby Dale E Grind » Fri Jul 11, 2008 1:35 pm

rustychisel wrote:no reason at all... inch fork steerer in old frame, sweet as apples. No real issues with differing headsets (hiddenset, A-head, integrated etc), and the ability to use front brake caliper which needn't be unfeasibly long. If you're really unlucky the bike might appear to slope forward very slightly, but my guess is you wouldn't even notice it.
Yeah - that's what I thought. And the front brakes is one reason to go 700c with the old steel frames. I've got a 105 claiper hanging around somewhere which should do nicely.
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Postby gsxrboy » Fri Jul 11, 2008 1:51 pm

Just remember... once you have had a few beers down at the local, your cheap s.l.u.t might end up looking like a high end carbon road warrior in your rose coloured beer goggled eyes.
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Postby Dale E Grind » Fri Jul 11, 2008 3:07 pm

gsxrboy wrote:Just remember... once you have had a few beers down at the local, your cheap s.l.u.t might end up looking like a high end carbon road warrior in your rose coloured beer goggled eyes.
It wouldn't be the first time :roll: :wink:
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Postby kukamunga » Fri Jul 11, 2008 4:20 pm

Just checked some of my collection of 27" & 700C bikes. Fork axle to crown heights vary between 360mm to 415mm. Be careful not to vary this too much from the original unless you want to vary your head angle and handling characteristics
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Postby mikesbytes » Fri Jul 11, 2008 4:41 pm

It might be easier to find some brakes with a bit more reach for the 700c wheel which is 4mm smaller than the 27"
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Postby Dale E Grind » Fri Jul 11, 2008 5:10 pm

Thanks guys - I'll throw fork under and she how it goes.

That's a wide variation in measurements though.
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Postby VIC Mech » Wed Jul 23, 2008 9:16 am

If you really cant sort the forks out just keep the originals and make up some drop bolts for the brakes. The ones ive just made for my Carlton drop the brake caliper about 8mm so plenty of scope to use whatever 700c wheel you have in traditional 27" forks.

Cheers m'dear, JJ
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Postby Mulger bill » Wed Jul 23, 2008 12:57 pm

Tell us more about these drop bolts please VIC Mech. Photos too if I'm not asking too much. :)

OTOH, would finding 27" rims and lacing in new hubs let me use modern short reach brakes on me old girl?

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Postby 531db » Wed Jul 23, 2008 1:18 pm

Mulger bill wrote:Tell us more about these drop bolts please VIC Mech. Photos too if I'm not asking too much. :)

OTOH, would finding 27" rims and lacing in new hubs let me use modern short reach brakes on me old girl?

Shaun


Then the challenge is availability of decent 27" tyres. They are increasingly hard and expensive to find.
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Postby Mulger bill » Wed Jul 23, 2008 1:26 pm

Bugger, thanks 531. Time to rethink.

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Postby kukamunga » Thu Jul 24, 2008 2:15 pm

Mulger bill wrote:Tell us more about these drop bolts please VIC Mech. Photos too if I'm not asking too much. :)

drop-bolt explanation
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Postby Mulger bill » Thu Jul 24, 2008 11:40 pm

Thanks Kuka, don't think I'm up for a reflector bracket jobbie tho'

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Postby kukamunga » Fri Jul 25, 2008 8:32 am

Sheldon's drop bolt example looks pretty flimsy. If you had a lathe :wink:, I could think of a much better design :roll:
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Postby VIC Mech » Fri Jul 25, 2008 2:05 pm

hi sorry I didnt get back to you sooner.

The drop bolts I designed to use on my Campag calipers are fairly simple blocks of stainless steel with studs pressed into them. Flimsy they aint!! I deliberately designed them to be actual replacements for the original "in line" bolts with slots for the springs and everything. Polished they look great and will allow me the wider tyre choice that 700c wheels have rather than 27" these days.

having said that quality 27" tyres are still available from Continental but for how long is anyones guess! The drop bolts shown on Sheldonssite are pretty similar to mine only mineare shinier lol! I gave myself an 8mm drop between centres. If you can get some stock stainless bar and are any good with a file and a drill you dont need any special techniques but the holes and studs have to be an interference fit. The easiest way is to freeze the studs and press them into the block. you can go as technical as you want with reamers etc but thats not entirely necessary. believe me the studs in mine arent coming out again in a hurry.

Have fun.

Cheers m'dear, JJ
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