kevmk81

I dunno what's goin' on. Have a 700c rim, tried to put new Gatorskin 700c x 25 tires on the bike (Nishiki Olympic). Tire's rubbing on the brake bridge/thing that the brake attaches to on the bike (seen in pic). Is the rim not really a 700c? Rim says "avaya 7000". I could have sworn the inside of the rim said 700c. Tire itself fits on the rim. Has a low spot though where the bead doesn't seem to meet up with the edge of the braking surface. Doesn't rub too bad, just a little 'nic'.

kevmk81

I find it hard to believe a 700 x 25 tire won't fit. Would a 700 x 21 be better?

Myosmith

What kind of bike is it? That's a darn tight clearance when a 700 x 25 rubs. Are these these the original rims for the bike? What size tire was on it before?

kevmk81

It's a Nishiki Olympic. I think it's an '88. I don't know if it's the original rims, bought it from someone. He may have replaced teh rims. It's a freewheel setup. The rims were tireless when I bought it. Bought it for 40 btw... probably got screwed.

DX-MAN

Betting money you don't have a 700c FRAME; likely a 27".

kevmk81

I wouldn't doubt it's the wrong sized rims. How can I measure the frame to get which rim size is the correct size?

Bill Kapaun

A 27x1" tire would be SLIGHTLY bigger than a 700x25c.
Most 27" tired bikes used a larger tire then 27x1".

27" rim = 630 MM
700c rim - 622 MM

1" = 25.4 MM
25MM = 25MM

Is the rear axle seated fully in the drop outs?

bikeman715

27 " is bigger there fore it will not fit . you might want to try a 650c wheel and tire if you can find one .

ScottNotBombs

If your doing a 700c conversion from 27", you should have a huge gap and need long reach brake calipers or to file your calipers down to move the brake pads further down. If you fit a 700c tire on the rim, it's 700c. My guess is that your bike doesn't take 27" or 700c wheels.
Maybe it's 26" or 650?
What size is on the front? Is the fork original?

LarDasse74

If the 700c tire fit on the wheel then the rim is 700c.

It is very very odd that you have so little clearance.

HillRider

There are 25 mm tires and there are 25 mm tires and some are a lot bigger than others despite the sidewall markings. I've seen tires marked 700-25 that were smaller than 700-23's and others that were as large as 700-28's. If you have a true or oversize 700-25 on a frame built around 700-23 or even 700-20 tires, that may explain the mis-fit.

LarDasse74

There aren't too many bikes 'designed around' 20mm tires. Modern road bikes tend to have extremely tight clearance - certainly tighter than any Nishiki Olympic from the 80s - and you'd have to search pretty hard to find a 25mm tire that would not fit on most. 28mm tires are a different story.

That is almost definitely a frame designed around 650c or b wheels. Perhaps the previous owner swapped to 700c and used 20mm tires.

kevmk81

Yeah, that's what I'm betting, that he swapped to 700c. You think Vittoria Rubino Pro 3 clicher folding tires would fit? It's such a close fit as it is... and yeah, it's as far in the dropout as possible... couldn't get any further back!

kevmk81

Same 700x25 tire on the front. Original tire. The front has plenty of clearance.

LarDasse74

If the rubino tires are labelled as a 23mm tire then I bet they would fit. You don't need much more room.

kevmk81

I actually found a 700x20 set... those have gotta fit!

dave35

650C tires and ultra-skinny tires (down to 19 mm) were popular on triathlon-inspired road bikes in the late '80s or so. However, pictures of other Olympics (I used the Google) from the mid-'80s show 700C tires with moderate brake clearance. I couldn't find anything about 650B Olympics from that era (although that's still the best explanation we have).

One very unlikely possibility is that the bike was built around 700C wheels and the previous owner replaced them with 27" wheels, and you had the arm strength to wrestle the slightly too small tires onto the old rims. (The difficulty of getting the tires on is what makes this almost impossible.)

How's the clearance between the front tire and the front brake/fork crown, and between the rear tire and the chainstays? Any chance you could post a few more pictures?

EDIT: Sounds like you do have plenty of room at the front. This all sounds weird!

AEO

those are probably "Araya 7000" rims, not avaya.

As far as I can tell, 7000 probably means 700c, not 27"

kevmk81

Just tried an old pair of 700x23's. They clear it. Oh well... guess it's just a tight fit.

hueyhoolihan

my latest bike purchase, i am sure, will not permit a 25mm tire. 23mm is tight already.

i'm not too surprised that an decent '88 road bike doesn't have clearance for a 25mm tire. i think it was the zenith of OE skinny tires. IIRC one could stroll down the row of new bikes at the LBS and group them pricewise by the width of the tires.

and as someone already mentioned, maybe you can just mount the rear axle in those short horizontal dropouts a little toward the opening to give you a bit more room and get that 25mm tire in there.

HillRider

If the bike was intended for 650c wheels, the brake reach would have to be a lot longer than for 700c wheels as the radial difference is 25.5 mm. So if any common reach (either long or short) brakes line up with the current 700c wheels, that almost certain what it was made for.

The probability of it being intended for 650b wheels is remote. That size was obsolete for many decades and only made it's niche reappearance a few years ago. No major maker I know of builds for this size and certainly didn't when this bike was made.

LarDasse74

I found this 1987 Nishiki catalogue scan and (almost at the bottom where the details specs for each bike are) you can see the original tire size on the 'Olympic 12' was 700X25C...

I originally figured the bike originally had 650 c wheels, which used to be semi-common on small framed road bikes. But the swap to 700C would put the braking surface 25.5mm higher, which means that if it now works with 39-47mm (standard 'short reach' brakes), it would have had to have used brakes that could reach 65mm or more - which are not commonly spec'ed on many bikes. So that seems unlikely.

ThermionicScott 

The "C" on those Araya labels looks an awful lot like another "0". Any chance you got a 700x28 tire by accident? Continentals are known for being a little too small, not too big.

- Scott

FastJake

+1

My 1989 Trek 1500 came stock with 20mm tires. The '89 catalog states that the 5000 came with 18mm tires! Now the 'standard' has settled on a slightly more reasonable 23mm size.

I'm not surprised a 1988 road bike would not fit 25mm tires. IIRC the Gatorskins run true to their size, so maybe they are a little fatter than other tires labeled 25mm that really aren't. It's not the brakes, it's not the rim, it's the design of the frame.

ultraman6970

If a 700C cant fin in there you have 3 options.

1 the frame is for 650C wheels or 26.
2 the rear brake bridge was modified but doesnt looks like it was, no idea if what u have there is a nishiki anyways.
3 You did not mention anything about the fork so i will assume the fork works fine.

Between the 3 my fav is number 1.

Sure a 700x23 will fit. The rims are 700C or you would not have been able to put the tires on the rim.

My theory, you have a 650 frame in there, the fork might not be the original either.