scale

I took advantage of the deal at performance bike this past holiday. They had gators on sale and my old 23s were extremely worn and old. I opted for 25c this round figuring i might get a bit less RR and maybe a bit more comfort. They both measure about 23c. The 25s are not where near 25. I am kind of bummed. Maybe they will loosen up after a few rides but i doubt it.

THis is my second (rain) bike which i use in bad weather so it doesnt see as much use as my others but it still gets about 1000mi per year.

My main bike has 25c gators and they measure at 25c. I put the digitial caliper to both bikes. The rim width is exactly the same on both bikes as well.

I dont get it. I guess i thought i was getting 25c like my other 25c gators. Perhaps i should have opted for 28. Too late now. They are worlds better than teh old set i had so i cant complain too much but if i wanted 23c gators i could have gotten them used locally for about $10 a piece. It seems nobody wants 23c tires anymore

I know a lot of ppl dont like gatorskins but they have treated me well. I will never race so i dont need the fastest tires in the world and when i am out riding id rather not patch flats or at least minimize the risk of flats....especially in the rain/wet/snow per this bike.

Doctor Morbius

23c tires is last week's fashion.

I've been wearing the same size Levi jeans for several years now. However, when I buy them I have to try them on first as they don't all fit the same. Should they? Yes. And they used to but not any more. The only reason I can think of is ... China. Manufacturing moved to China and now it seems fit varies from one pair to the other given the same size.

McBTC

That's a big variation but maybe not unusual for Conti:

atwl77

Did you measure the internal width?

scale

Interesting. I am wondering if they are mislabeled. Either way....i hope they stretch a bit.

BlazingPedals

Yep. Sometimes I wear a size 10 shoe, sometimes an 11. Right now I wear the metric equivalent of a size 12 in my cycling shoes. I think it depends on if the shoe was made in China, Vietnam, or Bangladesh. Before Nike started the avalanche of outsourcing, I was always a perfect 10D.

fietsbob

So you measured?

Retro Grouch 

Try measuring from the bead around the tread to the opposite bead.

WNCGoater

Similar experience with Continentals. I ordered 32's for a touring bike and the tire actually measures 29. Not sure WHERE they take the measurements but it was always my understanding that the size indicated the width. In looking in to it a bit, is seems Continentals measuring smaller than indicated is a common occurrence, and complaint. I haven't seen any other brands that mimic this.

McBTC

The latest info is that wider (not taller) tires have a lower rolling resistance than skinny tires. Given that, I wouldn't mind going with wider 28s to replace OEM 25s but my frame doesn't accommodate a taller tire. 23 and 25 Gators were the tires I enjoyed for years – even on tours – but, that was then and they are old school with their low TPI, extra layer of rubber and the toughest (and likely most inflexible) sidewall around (which may have been to offer better resistance to snake-bite blowouts when underinflated). If they stand taller rather than of wider, Gator 28s probably wouldn't work for me now unless they really are miss-marked.

cyclintom

The actual width of the tires is dependent somewhat on not the outside rim width but the inside rim width which can be rather dramatically different. It is likely that over time the tires will loosen up a bit and go to your expected width.

I started a thread on flat resistant tires and, with all of the noise pushed off, it appeared that Gatorskins is still the king of flat resistant tires. I have tried five different company offerings and I'm still convinced that Gatorskins are the best.

McBTC

Okay, okay, not touring, not a racer (i.e., not wearing a $500 pair of white, Sidi Wire Speedplay shoes), so– be happy with 25s… got it:

No 28s because, if I ever did tour again it'd be with a credit card not front and rear panniers...

Iride01 

I had a question recently about some Continental Ultra Sports that I used to ride on. I sent an email to Continental Support and they answered that same day. I was very impressed with speed and information they were willing to provide.

If you've measured correctly, then I suspect the issue gets back to quality control and possibly they contract some manufacturing that is not directly under their authority.

John_V 

Foldable or wire bead? There is a slight difference in the width of the bead that can cause the difference.

rickyk76

As someone who works in quality control in the rubber manufacturing industry, I’m going to assume it’s not a quality issue. Bike tires don’t require extreme precision in their application and the 2-3mm difference isn’t that bad when thinking about the molds and manufacturing process used to make tires. I’m also going to assume that the consumer market wouldn’t pay for tires at what it would actually cost to make the mold and process be more precise. The products I work with require tolerances of 0.005”-0.010” and cost easily in the 6 figures just for the mold, let alone the time and resources to develop a stable molding process that will repeatedly produce precise products. When I buy bike tires I assume that there’s going to be a tolerance on those tires of at least 2-3mm, just because that’s how it works.

SethAZ 

I think the divisions are artificial at best, and detrimental at worst. I'm now riding on 32mm tires and loving them to death, on regular road rides. I think they are subjectively far nicer than even the 28mm tires I was riding on before. I don't believe you give up anything at all other than a little weight going from 25mm to 28mm, and the 28mm are far more comfortable, whether touring or not. And with judicious choice of tire you don't even really give up much weight. My Compass 32mm tires (the extralight version) actually weigh less than a Continental GP4000II 28mm, and are nicer to ride on as well.

Besides, calling 28mm a "touring" tire is ridiculous, because if you ask many of the touring and rando guys, they're riding much wider than that, even into the 40s. I'd be shocked if almost any rider other than perhaps certain racers wouldn't be happier on 28s than 25s or 23s. So 28s are stuck in this no-man's land where they still fight for respect among "recreational road cyclists" but aren't really the serious choice of the long-distance crowd either. Too bad, because they're awesome for the "recreational road cyclist."

Iride01 

Since they sell these things generally in 2 mm increments, I'd think 1 mm would be a reasonable expectation of tolerance. Maybe not.

When they are on the same size rims, I can tell the difference between the 23 mm and 25 mm tires I put on my bike visually. I will say that the same size tires on different size rims will both look and measure differently.

Whether it is or isn't a quality control issue, it's still a good idea for the OP to contact Continental. If they are as forthcoming with information to the OP as they were with my questions I posed to them then the OP will know a lot more than will be gained from us guessing and opinionating here.

rickyk76

Check this out that shows it’s not uncommon for tolerances to be +/- 4mm

Technical FAQ: Why are labeled tire sizes inconsistent? | VeloNews.com

Iride01 

Well you need to read the article closer and all the way to the end. Lennard said the +/- 4 mm was something he learned from the industry over 20 years ago.

In the manufacturer responses that Lennard received about the issue,Continental said they look for -0/+2 which is close enough to the 2-3 mm you said in your first post to make you correct.

As well Vittoria, which is my tire choice at the moment said +/- 1 mm on the width which also boils down to an absolute 2 mm which still goes with your post.

The response from Challenge seems to indicate that Lennard's +/- 4 mm is old stuff for modern bike tire manufacture.

So I'm happy that we can meet near the middle at 2 mm.

WNCGoater

They are awesome! I tried out some 28mm Conti Grand Prix 4000 from 25 Conti Ultra Sports and Oh My! Yes BIG difference in ride comfort and no noticeable difference in speed. Just LOVED the feel. However, my road bike wouldn't handle the size, just wasn't clearance in the rear.
Oh, it cleared. I mean, if you shined a bright light you could see light between the frame and tire.
But any road dirt or grit picked up would grind against the frame, or the slightest out of true on the wheel had me constantly adjusting spoke tension because of rubbing about every third or forth ride. I could imagine the carbon being slowly ground away. Anyway, I took them off after about 500 miles and went back to the 25's.

Sigh.

Anyone want some used 28mm Continental Grand Prix's for cheap?

It did inspire me to buy a steel touring bike and I'm riding my new Marin with 32's on up to 40's at reduced pressure.
My butt loves me.