Ridgeback 605 Competition ?1989: Seatpost diameter?

LuckyLuke

Retro Newbie
Hi, I’m building up the above model Ridgeback. Would anyone know the seatpost diameter? It’s Tange Prestige tubing. Have tried Googling but no luck.

It came with a 26.0mm post that slides down the seat tube once the quick release is undone, suggesting it’s undersized I think.

I found a frame database on here, no Ridgebacks specifically, but most of the Tange Prestige frames used 27.0mm posts. Does that sound about right.

Cheers in advance for any help,

Luke
 
Love a Ridgeback.
Is it the fillet brazed 605? - that has to be one of my favorites from the Freewheel Catalogue of the same year. Any pics/ build thread?
My 1990 704XT that is also Tange Prestige takes a 26.6mm seat post.
Can't confirm that's the same for yours. Can you measure with a set of digital calipers? - I got mine from Aldi....one of the best £9 I've spent. Use it loads.

Sorry can't help more. Good luck.

Cheers
boy"O"boy
 
Last edited:
Hi boy”O”boy,

Ah that’s great intel, thanks very much! Think I’ll look for a cheap 26.4mm post and try it out. Funnily enough I’ve got a set of digital callipers, but when I dug them out the battery was dead. Always the way.

Yes, I think it’s the fillet brazed one.

I’ll try and attach a couple of pics. It’s a work in progress, needs cables and the lights and Dynamo wiring doing.

(Apologies to the purists but I’m butchering it into a gravel bike.)

Cheers,

Luke
 

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Hi boy”O”boy,

Ah that’s great intel, thanks very much! Think I’ll look for a cheap 26.4mm post and try it out. Funnily enough I’ve got a set of digital callipers, but when I dug them out the battery was dead. Always the way.

Yes, I think it’s the fillet brazed one.

I’ll try and attach a couple of pics. It’s a work in progress, needs cables and the lights and Dynamo wiring doing.

(Apologies to the purists but I’m butchering it into a gravel bike.)

Cheers,

Luke
Have you considered shims to get your 26.0 seatpost to the right size? I got some from ebay to get the correct size for one of my Dynatech Endeavor builds. If it's only a small amount...what about a bit from and aluminum can? My aluminum "O" still runs the 'shield' from a Guinness can to stop the slip. It's a ideal template!

Love the 605. Proper rarity! - the only other one I've seen is also in a huge frame size.

Cheers
boy"O"boy
 
Hi boy”O”boy,
Cheers for the tips. I’ve already dived in and ordered a 26.4 post from SJS.
Will post back to confirm whether or not it worked.

Yes, really looking forward to finishing her off, maiden voyage probably next weekend ish.
It sounds like you’re happy with your 704, hopefully mine will hit the spot too.

Cheers

Luke
 
Always liked these. Had the 89 604 non fillet, now sold. Should ride very nicely. Cant remember the seatpost diameter alas. Enjoy 🙂
 
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