robertj298 

Took my Team Fuji out for a short ride today and noticed an intermittent
scraping sound coming from the front end. After inspecting it it seems with a wet
road my tire was picking up tiny prices of grit that were rubbing against the
bottom of the brake caliper .The tires are Serfas Seca 700X25 tires. The rear tire
seems to have plenty of clearance. Do I meed a smaller tire? Different tire?
Here's a photo.

cxwrench

It would seem obvious that you need a smaller tire if you want to keep riding in the wet. Or you could take the other obvious option...don't ride when it's wet.

blamester

That's pretty tight. On wet roads it will pick up grit and rub. Dry days it will likely be fine. But I would prefer a bit more clearance than that.
I have run them.that tight before but I was never happy with it and didn't do it for long.

robertj298 

LOL I would think a bike that comes equipt with 700X25 tires would ride ok with any 700X25 tire under any condition.
I guess thats not how it works with bicycles

cxwrench

That bike definitely did not come equipped with 25mm tires.

robertj298 

JohnDThompson 

Yes, a narrower tire would prevent that.

N.B. I notice that your caliper release lever is in the "open" position:



That's only supposed to be open to increase clearance when you need to remove the wheel. It looks like you used the barrel adjuster to take up the excess cable to compensate for this. Screw the barrel adjuster all the way down and then close the caliper release lever to bring the pads closer to the rim.

cxwrench

I don't care what it says on the spec sheet those OEM tires were not actually 25mm wide. It was very common to label a tire 25 or whatever when it was only 20-21mm wide and then claim you had the lightest '25'mm tire available. The front tire on that 35 year old bike is brand new, obviously not the OEM tire that came on it.

robertj298 

I had just loosened those to find out what was making the grinding noise thinking it may have been the brake pads hitting before I realized it was grit on top of the tire doing it

trailangel

Maybe check the true on the front wheel.. looks off center to me. Maybe you could get another mm of clearance

robertj298 

If that is the case, how are you supposed to know what size tire to put on a 36 year old bike that
doesn't have the original tires?

cxwrench

By doing what you're doing. Now you know that particular 25mm tire barely fits. Conti is most likely the same. I would probably stick w/ a 23mm tire, maybe a Conti or maybe the Specialized tires that are labled '23-25'mm. Cycling is a learning experience isn't it?

robertj298 

I guess I'm learning lol. Here I just assumed if a tire said it was 25 mm it would be 25mm. My next question would be is there any guarantee that a 23mm tire
won't have the same circumference as a 25mm wide tire?

cxwrench

Nope. The cycling industry is famous for it's lack of 'standards'. Old bikes like yours had very tight clearances because people refused to acknowledge physics until about 5 years ago and firmly believed that small tires at rock hard pressures were 'fast'. Now we know better and bikes have much more room for big tires.

Bill Kapaun

Read Sheldon. Pursue his other articles too-
https://sheldonbrown.com/tire-sizing.html

zacster

700x25 tires from 35 years ago are probably a lot different than what we have now. It really just comes down to what will fit. My bike barely fits 700x25 Conti 5000 in the rear but has plenty of room for 700x28 in front. Put a 23 on if you're concerned. it won't feel much different. And your wheel doesn't look centered either, so maybe that is part of the problem too.

Charliekeet

Another cure (if OP finds that running smaller tires doesn’t work out) might be running a different brake. Not all single-pivot side caliper brakes had the same profile and since the issue with the tire is height, not width per se...

Russ Roth

I just ran into one with a friend where he complained that he bought a 28mm tire for a more comfortable ride and it was worse then the tires he had one. Got out the calipers and despite being in a wider rim (sun rhino lite) the 28 measured 24mm wide and only 23mm tall. He'd actually been better off with the previous 25mm tire.
cxwrench nailed it, back when your bike was made narrow high pressure tires were the thing to run and sizes were even less accurate then today.

Iride01 

Tire width is usually the tire casing width. Or at least that is what I thought I read a long time ago. That doesn't include tread material which can be significantly different from one model to another.

You might find some 25mm tires that give you more clearance. Are you certain the noise wasn't the wheel out of true scraping the brake pads occasionally? And the brake blocks look badly lined up. So maybe one is hitting the tire.

Kapusta

I’d would be fine with that clearance. I mean, more would be nice, but with tires that small, I’d want to eek out every mm I could.

Bill Kapaun

You could put on a super wide rim.
You'd probably have to shave the brake pads.
Easier to swap in different 622mm rims/tires from other bikes if available. That could give you some baseline knowledge.

robertj298 

Nope it wasn't the wheel out of true .I actually lifted the front end and spun the wheel slowly to where the grit would stop the wheel

Mr. 66

Did try flipping the wheel around? That will tell you if the wheel has dish, and or if the fork needs alignment.

Kapusta

He is worried about clearance above the tire, not on the sides.

EDIT: Never mind, I see the logic in ruling that out.