Road Tires: Width vs Speed Penalties?

Try a conti cyclo-cross tirefrom bike tires direct or universalcycles

On 2017-12-14 07:14, jbeattie wrote:
On Wednesday, December 13, 2017 at 8:24:56 PM UTC-8, Tim McNamara
wrote:
On Mon, 11 Dec 2017 11:54:52 -0500, (PeteCresswell)
wrote:

snip

For me, the relevant Compass slick widths are 35, 38, and 44 with
two case options: Regular and Lightweight. I'm thinking that
anything below 35 would defeat my purpose, which is a tire that:

snip

I have a pair of Compass 26 x 1.8s that I bought for my birthday,
which was the only way I could justify such extravagant tire
prices. I'm sorry but nearly $90 for a g*****n bike tire is just
too damn much money. Compass is by no means the most expensive
tire on the market, indeed they seem to be in the middle of the
spectrum these days. My baseline comparison on that bike is
Panaracer Pasela 27 x 1.75, which were about $25 each.

I will also say up front that I am delberately skeptical about
Jan's various tests and claims. My tastes in bikes are somewhat
similar to his- with the primary exception of not liking very low
trail bikes- and I am suspicious of confirmation bias on my part as
a result.

Conclusions:

1. If you run at Jan Heine's recommended pressures and weigh 230
lbs ike me, handling will be unstable. The tire starts to collapse
as you lean it into corners. I run 50 psi in the front and about
55 ps in the back and that solved that problem. The threshold of
this phenomenon is pretty sharp.

2. Jan makes various claims about the tires. The ones that I can
say are true my experience are (a) the tires are very, very quiet
on the road; (b) rolling resistance seems a bit lower but I find
this only noticeable at low speeds and while climbing, where it
really does seem noticeable. At least the feel of the tires is
different. The quietness is my favorite feature, actually- the
Pasela tread gives a little buzzing noise. They are a pleasant
tire to ride and I would say I enjoy the bike a more than I did
with the Paselas.

3. The claims I can't confirm are (a) that the tires are faster
than my Paselas- my average speeds over my usual routes are within
.1-.2 mph of each other. Nothing else on the bike is different
other than the tires- even the same inner tubes were used; (b)
tread longevity as I only have about 400-500 miles on them so far.

4. The tires (I bought the extralights) are noticeably lighter
than the Panaracers. I don't have a suitable scale to weigh them.
This is not apples to apples as the Compass tires have folding
beads and the Paselas do not. But the tread is obviously thinner
and the casing feels thinner. There are testamonials of getting
5000 or more miles on a set of these tires- if that works out for
me, probably about 5 years of riding on that bike, I will withdraw
my complaint about price and buy another set.

5. The tire casings seem more consistent than the Paselas- the
Compass tires don't have a wobble or distortion at the joint
whereas every Pasela I have ever used does. They fit well to the
rims; mounting on Sun CR18s was about par for the course with
folding beads. I have old school fabric rim strips on those rims
and that makes mounting just a smidge more difficult. I have not
had any flats and have not tried to remove them yet.

I found the Paselas were prone to sidewall damage. I also had a
problems mounting Gatorskins on a CR18s because of the shallow rim
well, so choosing a tire that fits that rim is important.

I'm still amazed at the $90 on price tag. What about all the
Schwalbe tires?

My complaints about tires typically involve tires that are sluggish.
I've rarely felt like a well made 25/28mm tire was beating me to
death on the road, although I've had some larger hard-case tires that
rode like wagon wheels.


Do you know any 25mm that ride like wagon wheels? If that makes them
more sturdy and maybe longer lasting I want wagon wheels.


... Tire dimensions are no guaranty of comfort.
I've got some 35mm studs that ride like tank tracks. I'm riding 32mm
tires on my commuter for better footing in the rain, which has gone
away for the last few weeks (bad news for snow at the resorts).
They're fine, but nothing special in terms of comfort. They really
feel no different than my 28mm Gatorskins except they're heavier and
a little more sluggish.


The knobby tires on my MTB (currently trying Geax Saguaro) ride like a
tank. On the road and MUP they are so loud that people hear me coming.
They sound like an approaching light rail train.

--
Regards, Joerg

http://www.analogconsultants.com/

On Thu, 14 Dec 2017 07:14:50 -0800 (PST), jbeattie
wrote:

I found the Paselas were prone to sidewall damage. I also had a
problems mounting Gatorskins on a CR18s because of the shallow rim
well, so choosing a tire that fits that rim is important.

I have had several Paselas fail due to casing separation where the ends
of the carcass overlap (also every Ritchey Tom Slick I ever used had a
casing failure). Most of them have just worn out. I've neved
specifically had sidewall damage with the Paselas. Generally I run
tires at the maximum rated pressure, unlike Jan Heine. I've just too
heavy for lower pressures at 230 lbs. The Compass tires are rated to 75
PSI, though, and I find 50-55 works very well so they are the exception
so far. I think lower pressures increase the risk of sidewall damage.

I'm still amazed at the $90 on price tag. What about all the Schwalbe
tires?

Bike component makers have figured out that we will pay stupid amounts
of money for products that wear out and have to be replaced relatively
often- $200 chains, $150 cassettes, $100 tires, etc. Repeat customers
are where the cash is...

My complaints about tires typically involve tires that are sluggish.

The Compass tires feel less sluggish than the Paselas, althouogh as
noted that is most noticeable at slow speeds and climbing. When rolling
along on flat ground, wind drag overwhelms the signal from the tires
pretty quickly. At the same pressures I would say the two sets of tires
are similar in comfort.

All that being said, I know a couple of people who have switched to
Compass tires and sing their praises loudly and enthusiastically. I am
reasonably satisfied with them but am a bit more muted about it.

On Thu, 14 Dec 2017 11:48:24 -0500, (PeteCresswell) wrote:

Am now looking for something in a 35mm for the front that will cut
down on the face plants compared to a slick when, for instance,
negotiating a wet grass-covered slope.

Vibram.

but don't say
anything about width-vs-speed penalties.

Compass generally claims that width itself doesn't cause significant differences in net performance.

I can't remember which issue it was (43 maybe?), but one of the editions of Bicycle Quarterly included testing on the apron of Marymoor Velodrome where the entire range of Compass tire widths performed identically, within the precision of their measurement methodology.

The diff in cruising speed between 40's and 28's looks like 1-1.5 mph.

Fully-rigid bike.

Does this sound reasonable?

I haven't done a rigorous study attempting to only change tire width on the same bike. But when I run Rat Trap Pass ELs (53mm) on my gravel bike, on flat ground, I can't distinguish a cruising performance difference between it and my skinny-tired road bikes (assuming they're also equipped with high-performance tires).
This confuses my riding buddies to no end; there have been group rides when I've ridden my Emonda where people asked me if I was having a bad day, because my pulls weren't hurting them any more than when I previously rode my huge-tired bike.

What I *do* notice having a big effect on paved performance is the style of tire. There was a small period of time last year when I had ThickSlicks (which have a coarser casing and a bunch of puncture protection) rather than Rat Trap Pass ELs on the gravel bike, and it was seemingly around 1mph slower. Knobby MTB tires tend to have an even bigger hit.

Road bike slicks last 1100-2500mi depending on type and brand. If the
sidewalls hold out that long which isn't always the case.

My current rear Compass Rat Trap Pass Extralight has about 2,000 miles on it, and based on the wear indicators, has over half its life left. The sidewalls are doing fine.

1. If you run at Jan Heine's recommended pressures and weigh 230 lbs
ike me, handling will be unstable. The tire starts to collapse as you
lean it into corners. I run 50 psi in the front and about 55 ps in the
back and that solved that problem. The threshold of this phenomenon is
pretty sharp.

Are you sure that you're running his recommended pressures? I thought he's posted before that he runs higher pressures on pavement-only rides than gravel due to this phenomenon, and he definitely recommends experimenting with wide tires because of how sensitive their behavior is with tire pressure changes.

For what it's worth, when I ride good roads, I ride my Rat Trap Pass ELs (measure 2.1") at 40r/35f, and I weigh 170lbs. Considering your added weight and the reduced width of your tires, I'm not surprised you'd like running your rear at 55PSI for pavement, especially given that you've got narrower rims than I do (CR18 has 18mm internal width, my rims have 24mm internal width).
I often ride 30PSI or lower on gravel rides, where foldover is less of an issue because the riding surface breaks away when you corner hard. When I have them set up like that, they definitely feel squirmy in paved cornering.

2. Jan makes various claims about the tires. The ones that I can say
are true my experience are (a) the tires are very, very quiet on the
road

I'm not familiar with that particular claim, but I'd actually strongly disagree with it. My Rat Trap Pass ELs absolutely roar on good roads. Road hum is a pretty common thing with supple road tire setups.

On Thursday, December 14, 2017 at 3:14:56 PM UTC, jbeattie wrote:

What about all the Schwalbe tires?

You have to choose your Schwalbe right, too. Horses for courses. Schwalbe's Marathon Plus beat the hell out of my back, in return for exceptional freedom from flats and huge mileages. The American workalike (and pretty much lookalike -- to me it looked like they were made in the same mold) is the Bontrager Elite Hardcase, which I also have and would describe as ditto.

Compare to my fave Big Apples with the soft sidewall: same puncture proofing or better, huge comfort, sticks to the road like **** to a baby's blanket, very, very modest rolling resistance, a genuine high-speed tire if you have the legs and the lungs for it on the flat, or the brass balls on the downhill, and really exceptional longevity -- all for a tyre that isn't expensive at all. I consider it a huge allrounder, but note that we get no snow here and I don't ride when the roads are frozen.

My complaints about tires typically involve tires that are sluggish. I've rarely felt like a well made 25/28mm tire was beating me to death on the road, although I've had some larger hard-case tires that rode like wagon wheels. Tire dimensions are no guaranty of comfort. I've got some 35mm studs that ride like tank tracks. I'm riding 32mm tires on my commuter for better footing in the rain, which has gone away for the last few weeks (bad news for snow at the resorts). They're fine, but nothing special in terms of comfort. They really feel no different than my 28mm Gatorskins except they're heavier and a little more sluggish.

It's not the dimensions by themselves that make the difference. If you want comfort, you gotta take the soft sidewall, and knobbles are a no-no too. I don't understand why bicyclists insist on treaded tyres at all: all the nasties you complain of find their root in stiff sidewalls and treads, the chunkier the nastier.

You ever hear that little British sports cars from Lotus had exceptional handling (handling being the recovery potential when you exceed the car's roadholding capability or your own driving capability)? They were crap little cars that fell apart at the end of the assembly line, with chassis none too stiff, but they handled exceptionally well, and for little English sports cars they even rode almost acceptably. (Muzi probably, despite knowing better, still dreams of finding a cherry Elan or Elite that a little old lady drove only to church on Sundays, and only when the weather was fine.) What gave the Lotus both its comfort (in its class) and its exceptional handling (in any class) was that, contrary to type and expectation, Colin Chapman didn't give his cars the short springs and firm dampers of other little English sports cars, and even German autobahn bullies, but long springs with long travel between the stops, firmly damped. Thus, as my late chum LJK Setright once joked, Chapman turned the necessity of McPherson struts (included because they were cheap from the Ford and Vauxhall/Opel -- European baby Chevies --parts bins, despite being generally frowned on in the sporting community as inferior to properly arranged short and long A arms) into the chief characteristics of his road cars, next to their intolerable unreliability, of course.

There's nothing that damps as smoothly as air, and the more of it the better in bicycle tyres. But it doesn't help if you're such a fashion victim that you then wreck the fatter tyre's main advantages by insisting on a chunky tread and stiff sidewalls.

Andre Jute
As usual, Jobst got it right first time

On Fri, 15 Dec 2017 16:07:29 -0800 (PST), HaloTupolev
wrote:
but don't say anything about width-vs-speed penalties.

Compass generally claims that width itself doesn't cause significant
differences in net performance.

I can't remember which issue it was (43 maybe?), but one of the
editions of Bicycle Quarterly included testing on the apron of
Marymoor Velodrome where the entire range of Compass tire widths
performed identically, within the precision of their measurement
methodology.

I haven't read that one, but their earlier ones involved roll-down
testing and (from one of the photos in the article) timing with a
wris****ch. I put little credence into that article because if the
likelihood of noise in the data.

They later did some interesting testing using a power meter, which
struck me as a better way to assess performance.

That said, I think that Compass is correct in that given identical
construction (casing, tread thickness, rubber compound) the effects of
width as a variable would be small. The more traditional drum tests
suggested (e.g. the ones done for Avocet). For as long as I can
remember, most wider tires also feature heavier casings and much thicker
rubber- wide high performance tires were rare. Compass has pushed in
that direction quite aggressively and good for them.

Compass's assertion that inflation pressure has little impact on
performance is out of keeping with that testing, although when
real-world road textures/roughness are included there may be relatively
little adverse impact from lower pressures. Jim Papadopoulos wrote
about that in this forum many years ago under the rubric of suspension
losses, and his thinking had a direct impact on Compass's tire design
philosophy.

My bike with 26 x 1.8 Compass tires seems as fast as my bikes with 700 x
25 or 700 x 28 Paselas. At least based on average speeds on my cycle
computer and similar subjective effort. That is of course far from a
scientific approach!

On Fri, 15 Dec 2017 16:37:04 -0800 (PST), HaloTupolev
wrote:
1. If you run at Jan Heine's recommended pressures and weigh 230 lbs
ike me, handling will be unstable. The tire starts to collapse as
you lean it into corners. I run 50 psi in the front and about 55 ps
in the back and that solved that problem. The threshold of this
phenomenon is pretty sharp.

Are you sure that you're running his recommended pressures? I thought
he's posted before that he runs higher pressures on pavement-only
rides than gravel due to this phenomenon, and he definitely recommends
experimenting with wide tires because of how sensitive their behavior
is with tire pressure changes.

Well, as noted the slope for revealing the effect is sharp- just a few
PSI makes a huge difference. I expect to run higher pressures than Jan
writes about because I am probably 60+ pounds heavier than he is. I am
still fine tuning my inflation pressures with those tires, having only
400-500 miles on them.

For what it's worth, when I ride good roads, I ride my Rat Trap Pass
ELs (measure 2.1") at 40r/35f, and I weigh 170lbs. Considering your
added weight and the reduced width of your tires, I'm not surprised
you'd like running your rear at 55PSI for pavement, especially given
that you've got narrower rims than I do (CR18 has 18mm internal width,
my rims have 24mm internal width). I often ride 30PSI or lower on
gravel rides, where foldover is less of an issue because the riding
surface breaks away when you corner hard. When I have them set up like
that, they definitely feel squirmy in paved cornering.

"Squirmy" is a good descriptor of the phenomenon. The oversteer
characteristic that he attributed to tread pattern is, in my experience,
solely due to underinflation.

2. Jan makes various claims about the tires. The ones that I can
say are true my experience are (a) the tires are very, very quiet on
the road

I'm not familiar with that particular claim, but I'd actually strongly
disagree with it. My Rat Trap Pass ELs absolutely roar on good roads.
Road hum is a pretty common thing with supple road tire setups.

Compared to my Paselas the 1.8s are very very quiet. But yes, there is
a beach-ball-noise effect with wide tires. It's even more pronounced
IME wth latex tubes.