Narrow 700c tyres?

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  • I have a 1990's steel frame with ultra close clearance on the rear triangle......vertical dropouts so no adjustment, question is what is the narrowest 700c tyre available that won't rub on the seat tube? at present it has 700/20c but even they're too close by about 1mm.....

  • What wheels are you using?

  • am using Campag Scirocco's

  • pic please.

  • the current 700/20c tyre tends to throw up grit on dirty roads and scuff the back of the seat tube

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    • CB 3.JPG
  • ....this will give an idea!

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    • CB 10 - Copy.jpg
  • Yikes. Possible it's supposed to take 650b?

  • I did try by borrowing a pair of 650A's but there's then the problem of the brake drop plus the front wheel clearance is normal at 700c

  • Ah yes. Long drop brakes possible with 650s? Less than 20mm tyres won't be fun

  • Do you know the original maker? That's rebadged as a Claud right?

  • Needs one of these

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    • 2c5d5e0c3b7d28833d4417a5a3b61b3d3eea96a8.JPG
  • It's a gen-u-wine Claud, one of the last of their handbuilt steel frames

  • Are those the sciroccos with the 17mm internal rim? Your tyres would come up smaller with some old style 15mm internal

  • I'll get the mallet to it!!

  • Mind you even with that the biggest tyres I can get in there are 25mm.

  • Ah, worth checking out, thanks for the heads up!

  • Nice. 18mm tubs imported from Japan then.

  • That’s insanely small clearance. 650A?

  • When I tried an old pair of 650 triathlon wheels the bike just looked really odd with the aesthetic perspective, plus the brakes would have had to have a bracket made of sorts to lower them....the bike clears (just!) on a 700/20c tyre but it fouls against the seat tube when road shite gets thrown up in inclement weather

  • Can you add some kind of a spacer in the dropout for the axle to sit on?


  • As the clearance issue is at the seat tube the 'height' of the tyre is the factor not the width, so would actually some wider rims (19mm internal) stretch the tyre profile wider but shorter if that makes sense?

  • there's a thought! I'll check tomorrow with the width of the Scirocco's that are on it

  • Have you considered taking a file to the fork ends in order to move the wheel slightly further back?

    Tyres less than 23mm were never really much of a thing - I wonder if this frame is just a miscalculation by the builder. Such things have been known!

    A possible solution might be to change the rear drop outs to track ends with a derailleur hanger brazed on. This would make it possible to move the wheel further back. 'Unfortunately' the frame doesn't need a respray, but it would be easy to match that colour (it's just silver with a touch of black) - touch in as necessary and it will be barely noticeable.

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Narrow 700c tyres?

Posted by Avatar for saxby's @saxby's