Fahrenheit531 

I've got a set of Compass Chinook Pass tires, extra light, black/black. They're listed 700x28, but they're not even close. Caliper puts them at 25.02mm. Also noticed the center tread is different from the other Compass tires I'm running: both the Bon Jon Pass and Stampede Pass have simple lines parallel to direction of rotation, while these have a tiny diamond pattern instead.

Looking for someone also running Chinook Pass to compare these observations to what they've got before I start pursuing refunds and such. Any assist is appreciated.

Tread detail:
Stampede Pass


Chinook Pass

HTupolev

Not sure on the width, but the tread pattern is expected. Look on the Rene Herse website: the Cayuse Pass and Chinook Pass have the diamonds instead of the centerline ribs of the wider tires.

Spoonrobot 

GIS shows that's the normal pattern for the Chinook Pass. Otherwise IME Compass won't do anything about your (potentially perceived) lack of width. They'll tell you to measure at max PSI and leave it at that. The casing used for Compass tires appears to be less consistent than Panaracer's OEM models and I've noticed of the few dozen tires I've had over the years they vary in width/height from different production runs moreso than other manufacturers.

Fahrenheit531 

Yeah, "perceived" is what got me reaching for the caliper, as they looked to be the same size as the Continental GP Classics (700x25) they were meant to replace. Fancy digital machine says my eyeballs are correct. Interesting take on Compass' consistency, though. I've found them to be of excellent quality in all areas, including being within a mm of listed size.

I guess I'll hold out a little longer and see if anyone else chimes in; maybe we can get another caliper on another set of alleged 28s.

shelbyfv

The tire width will likely vary with the rim width. Compass probably measures them on current rims. If you are using them on narrow retro rims, that could account for the difference.

ThermionicScott 

Are the tires brand-new? Compass/RH will tell you that they might start narrow, then grow closer to the nominal size over time. (My not-Compass-but-might-as-well-be Pacenti Pari-Motos have actually outgrown their nominal 38mm size and tire manufacturers would rather have tires that are slightly undersized, than to have angry customers when their tires should fit but don't.)

They claim "(The tread of our narrower tires is not wide enough for ribs, so small dots are used instead.)" but I don't really buy that.

Koyote

OP, you have no cause for a warranty claim. It's a different tire, so why would you expect it to have the same tread as different models? And as others have noted, tire width depends on rims and psi. I don't think I have ever measured a tire, on any of my wheels, and found it to be the width that was stamped on the sidewall.

Fahrenheit531 

Yeah, brand new straight out of the packaging. I just took them out today sort of hoping they'd "soften up and expand a bit" with some miles. We'll see how it plays out over time; I'm skeptical but hey, stranger things have happened. Just sort of a bummer to shell out Compass/Rene Herse money and end up where I started.

aclinjury

ugh, I would NOT want any tire that expands to its advertised width. Good tires should only expand very very minimally.

ThermionicScott 

I'd give them a bit more time, then, especially if you are using pressures appropriate for a 28mm tire. My Compass/RH Naches Pass tires started out around 41-42mm, but are now up to 43mm after a thousand miles or so. That's close enough to the 44mm nominal size for me. A larger person needing higher pressures might get them to the nominal size faster...

I would disagree that tire growth over time is any way an indicator of poor quality. Cheap thick low-tpi tires might stay the same size from birth until death, but we're talking about something lightweight and flexible here.

Hiro11

As others have said, advertised tire width is almost always different from actual tire width, at least partially due to rim width. I've found that most tires are narrower than advertised, a notable exception being Continental who generally runs true to size. I run Rene Herse Snoqualmie Pass tires on one bike, they're suppoed to be 44s but are more like 42s on the 23mm rims I'm using. Your experience seems to match my experience. Rene Herse/ Compass tires are awesome, don't worry about it and ride 'em.

canklecat

Ditto, the rim factor. But even that doesn't mean actual measured tire width will match nominal specs. Continental SpeedRides are nominally 700x42 but almost every owner agrees the tires measure closer to 700x38. I've used 'em on 622x19 and 622x14 rims, and they're still closer to 700x38 than the nominal 42 width.

And some tires do seem to expand a bit. A few months ago I got a set of Conti's handmade Grand Prix Classic skinwalls, nominally 700x25. When I first mounted them on a set of 1980s Wolber Alpine rims the tires just cleared the chainstays of my 1993 Trek 5900 (then Trek's flagship carbon fiber toy), which predated the current trend toward wider tires for road racing. In the early '90s they'd have installed 700x18 to 700x23 at widest. I rode that set of tires on that wheelset for about 500 miles, before switching wheelsets to a narrower semi-aero wheelset with 700x23 tires.

Now, a couple of months later, I decided to try the Wolber wheelset with the Conti GP Classics again. Same wheelset. Same tires. Same bike. But the tires appear to have expanded just enough while sitting around inflated and unused that it barely clears the chainstays. If I redish the wheel it'll fit, just barely, but there's zero room for error. Not worth the risk, so I'll use that wheelset and the GP Classics on my '89 Ironman with more generous clearance.

That's the first set of tires I've had that actually expanded significantly. I'm assuming the ulta-thin skinwall is a factor -- held against a bright light the skinwalls are translucent. And perhaps being handcrafted they're more susceptible to minor but measurable variations from lot to lot and tire to tire.

kingston 

I still like the wide RH tires, but in 28c there are now lots of other tires that are at least as good and much less expensive.

CliffordK

The photos on the web look like the OP's tires:

https://www.harriscyclery.net/produc...tires-4935.htm


For road racing tires, I've seen smooth, longitudinal grooves, and the tiny bumps. I'm not sure it really makes much difference.

A light pattern like that will wear down fairly rapidly in the middle of the tire.

ThermionicScott 

Yep, here's their updated photo with the new logoing:

Miele Man

I've often read that road racing bicylce tires do NOT need any tread pattern at all. However according to those articles most people don't feel safe on a treadless tire but that's the perception of the person not an actual fact. One fear of bicyclists regarding treadless aka slick tires is that they'll hydroplane when going through water. apparently hydroplaning on a road bicycle tire is a physical impossibility due to the fact that the narrow tires of a road bicycle will simply push the water aside and make contact with the pavement. At least that's what the articles said. I wish I still had those articles.

Cheers

CliffordK

I don't know. I really liked the traction with my (32/35mm) Michelin Protek Cross Max tires, although I had the perception of them being slow rolling. I even hit slush with them a few times and they just ate it up. My Gator Hardshells might have dropped me like a rock on the same surface.

I thought the 25mm Schwalbe Marathon Plus tires did pretty well too.

I can't tell if it is a tread issue, or a rubber compound issue. Those heavy tires have thick rubber, but also wear fast, presumably due to soft grippy rubber.

Spoonrobot 

I read some of the same articles:

https://www.sheldonbrown.com/brandt/slicks.html

https://www.sheldonbrown.com/tires.html#hydroplaning

Now there's a counterpoint:

https://janheine.wordpress.com/2018/...r-on-the-road/

I don't particularly care about tread for my road bike tires but I have noticed a significant deterioration in wet road grip once the tread pattern wears off. For both Compass and Panaracer's GravelKing slicks. Unfortunately this happens within the first third of the tire's life, so I try to just ride within the same bounds regardless.

FWIW it is possible to simulate hydroplaning on a bicycle by riding demi- and balloon slicks on very thin mud. The bike floats on the surface layer and traction is lost at both the front and the rear. Steering has no effect and pedaling produces nothing but wheel spin. Interesting and very exciting if one is not aware of the issue.

Miele Man

Ah but those demi and balloon slicks are NOT narrow road bike tires. LOL

I remember reading about Pete Pensayres riding slick tires (iirc Avocet ones) up a hill riding on the fog line in the rain and NOT being able to make the tires lose traction. I had the same experience riding a road bike on a street with hard packed snow when my tires were folding 19mm Micehelin slicks. I could NOT get the rear tire to slip even when starting from a dead stop. I was amazed at how grippy those tires were even in the rain. Once on the way to work I was going around a corner and had the bicycle leaned over a fair bit when I then hit some wet leaves. It was lightly raining at the time. The entire bicycle slid sideways still upright, the wheels rolled off the leaves and the tires immediately regained the grip on the road. Again it was an amazing thing. When the bike first started sliding I was positive it was going to go down. I LOVED those Michelin slicks and would consider getting them if they were still available and in 25mm size.

Cheers

ThermionicScott 

My impression is that Jobst Brandt's arguments about poorer grip and rolling resistance with "tread" were against the bigger knobs seen on MTB tires and the chunky block tread on some road tires, not the file treads that we're discussing here.

Some quotes:
"I have ridden nothing but Slick or effectively slick tires since the days when only tubulars were available in high pressure tires."
"When Avocet decided to enter the tire market I convinced them to make a smooth tread tire, a slick, because that is essentially what we rode in the days of tubulars, the tread of those tires being about 1/2mm deep when new."

The tubulars he preferred looked like this, of course:



So while he was happiest when Avocet made him completely slick tires, I feel like his arguments in favor of "slicks" apply to our tires with very fine tread patterns, too.

Fahrenheit531 

Thanks to everyone who chimed in on this, and the comment that follows isn't meant to discourage further conversation:

One of my favorite things about BikeForums is how somebody can ask "hey, can someone else with these tires measure theirs and see if we match up?" and in no time at all we're on to rim variability, slicks vs tread, and muddy hydroplane simulations.

Still looking for a comparative measurement, but in the meantime I'm reading every word.

shelbyfv

Yep, threads tend to take on a life of their own. A good thing in this case, as your concern about the tread pattern was addressed as well as a probable reason the tires in your particular application don't match the advertised width. Saved you the embarrassment of "pursuing refunds."

Fahrenheit531 

Well I got my response from Rene Herse customer service and in what can only be considered a stunning upset, the "tire will stretch to size over time" people got it right. (looking at you, @ThermionicScott) Apparently they will take 2-3 weeks to do so.

Continuing, he did note that rim width will impact the final observed size but to a much lesser degree than what I'm seeing now.

So there we have it, right from the source. I'll be putting the caliper on them again in a couple of weeks. You know, for science.

Spoonrobot 

I'd be curious to see how much larger they get. I've not had a Panaracer (Compass, Grand Bois, OEM) tire grow more than 0.5mm since I started riding and measuring them in 2015, probably because of the lower pressures I run.

Bill in VA

I had the tan Compass (not RH labeled) Chinook Pass (standards) tires on Alexrims A23 rims and they have the file pattern tread and started at 27.5mm. A year later, when I removed them and put them on a new set of wheels with Velocity Dyad rims (1mm wider) they were at 28mm. I inflate the tires to 95+ on my Silca Pista floor pump until they have minimal deflection or softness by thumb pressure.

The Dyad wheels now have Stampede Pass (tans) 32mm (standards) at the rated 32mm after a season of riding. I have found them to be accurate in width and I am a heavy rider with them inflated higher. Interestingly, I found the Stampede Pass 32mm tires has a longer roll down coasting distance than the lighter, narrower 28mm tires.

This size change is quite a difference from my prior Continental GP4000SII in 28mm that actually measured 30mm, on the Alexrim A23 wheels. They started at about 28.5 and grew to 30.5.

I found that the Clement Seta tubulars with the ribbed tread (circa mid-1970s) to be the best tires I ever had UNTIL I tried the Compass Chinook Pass and 28mm Conti GP4000SII.tires. Both ride closer to tubulars than I thought would be possible.