Wide, fat, heavy and slow on the hills!

[PATRICK MOORE]

I just pushed the Fargo 19 rolling-hilly miles around Rio Rancho, NM
with the SnoCat/Big Apple wheelset at about 30/35 -- much higher and
the bumps start feeling as if I'm riding 23s at 120 (that is a slight
exaggeration, but seriously, I've found that the fatter the tire, the
harsher the ride if you overinflate); this after having let the
heavyweight wheelset sit for weeks while I rode the Rhyno Lites with
the new 330 gram, 35 mm Kojaks. I must say that the combination of 800
gram rims with 800 gram tires (both rim and tire are the "Lite"
versions) and 200 gram tubes makes a, ahem, difference -- a 3 1/2 lb
difference between the two wheelsets, I estimate. This wheelset is
wonderful on sandy terrain and it rolls very well on the flats, both
on pavement and on choppy but firmish dirt, but as soon as you
encounter an incline, man do you feel that weight! I emphasize: the
Big Apples roll very, very will for such a wide carcass with a
protective belt -- I push along on the flats on firm surfaces in a
46/20 for a 67" cruising gear, compared to 70 to 75 for a road bike
with nice tires. But again, tilt upward, and wham, gravity intervenes.
(Btw, Newton posited "gravity" as a placeholder for his theory; a mere
name to signify that one body moved toward another in proportion to
their respective masses; but he said quite explicitly that he had no
idea what cause, if anything, was behind this word and, further, he
says explicitly in the Principia that "action at a distance" -- ie,
physical action without actual contact of bodies -- was, quite
literally, unthinkable.) Whatever "gravity" may or may not be, those
BA and SnoCats sure feel like cold molasses on uphills.

Long windup. Those of you who ride 60 mm Big Apples or similar tires:
how do you find them on hills? What pressures do you use on pavement,
and what is your weight? -- of course, that decides how firm the tire
has to be. Would I be better off with lighter and narrower rims (wish
I hadn't sold those Salsa P35s!) at the expense of less sidewall
support?

The new 42 Noodles felt noticeably more "natural" than the 46s they
replaced. More generally, the Fargo is set up very nicely: it feels
very "natural" even though the bar is some 4 to 5 cm higher than on
the benchmark Rivs. On pavement I spend most of my time in the hooks,
for with the bars this high, even the hoods seem rather "tippy" unless
I bend my elbows, a natural inclination.

The BB7s are powerful but lack the nice, smooth and easily modulated
control that good cantis have -- by good cantis I mean either old
Shimano wide profiles or those IRCs that Riv sells. And you have to
keep bending the g-d disks back into plane, at least if, as I do, you
very frequently carry the wheels off-bike in the back of your car. I'd
prefer a bit more weight and thickness for disks that didn't bend out
of plane so easily. OTOH, with riding in sandy soil and swapping
between 44 and 27 mm wide rims, the disk system makes up for its
defects, at least for my taste.

--
Patrick Moore
Albuquerque, NM
For professional resumes, contact
Patrick Moore, ACRW
http://resumespecialties.com/index.html

[charlie]

Hmmm, It's all kind of relative to ones weight and the load carried.
I'm riding the 700x47 Schwalbes now at around 60 psi probably only 50
psi today and I currently weigh 257. When I get to hills I gear
down....flats find me in the 44x18 or 44x16.....not sure what that is
right now. Not sure of my speed either. I took my speedo off a couple
years ago. I do use a wrist watch and I seem to get where I want to in
about the same amount of time. In the spring and summer I run 700x40
Supremes and they feel a little faster on the hills. I find I can use
a cog higher gear with them. My Simple One sports lighter rims and T-
Serve 700x35's and its definitely easier to pedal up hills until I run
out of "gearing" (51" and 66") I sure do feel (my) added weight when I
approach hills but I don't worry about wheel weight that much. I end
up breaking lightweight rims and popping skinny tires plus my bike
takes a beating if I ride them too much. For me there is a certain
confidence that I get when using parts that are a little overbuilt. Go
wide with pride !
Oh yea ! I always wanted a bike with disc brakes living in rainy
Washington State but I haven't thought of the drawbacks now that you
mention bent discs.

[tdusky]

Use this tire pressure calculator for good results:

http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

Tom Dusky

Huntington Woods, MI

[Smitty]

Hi Patrick,

I ride 60mm Schwalbe Fat Franks on my Big Dummy. Rims are 28mm wide Mavic... I forget the model name/number and don't know the weight. I inflate to 35 rear and 30 front. I've played with lower pressures without incident but have a paranoia of the tire rolling sideways off the rim. I've never noticed significant uphill drag from the wheels but I generally have at least 40 pounds of kids/cargo on the back... often significantly more. So its hard to determine what exactly is slowing me down on the hills. I assume the drag caused by 80 pounds of children plus a week of groceries dwarfs any slowing effect of heavy wheels. On the occasion that I ride the bike "empty", which is not very often, it feels really light... even though it weighs 65 pounds.  

I have BB7s on there too. I'm always impressed with the stopping power of the disks. I find modulation increases with weight... a lot of variability when there's 400 pounds of bike+rider+cargo. Plus they work just as well in the rain, which is a huge bonus in the rainy Northwest.  

Not sure if any of this is helpful, but it's my experience with similar fat tires and brakes. Even if they're on a completely different type of bike. 

--Smitty  

[Ryan Ray]

Looks like I'm about right for using that calculator. I'll have to read the work it's based on now..

- Ryan

[PATRICK MOORE]

Thanks, Tom -- and thanks everyone for the comments. Too bad this
calculator only goes up to 37 mm tires; also, seems high: 116 or so
for a 175 lb rider on 23s compared to the 90/10 or 65/70 for 35s that
I personally like, tho' I don't aim for a 15% drop.

Hope to get out on this sunny, forecast-mid-60s day for some dirt 'n'
pavement on the 60s.

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[Philip Williamson]

This one here allows you to input your own widths into a Google Doc.
http://www.biketinker.com/tire-pressure-calculator/

Agile is smart to make theirs a web form (says the guy who cleans up
broken formulas).

Philip

Philip Williamson
www.biketinker.com

[Philip Williamson]

It looks like the numbers are congruent with the Agile tool and the
"BikeTinker" chart at 25mm + 200lbs, but diverge at 37mm + 300lbs.
I have it on good authority that the responses are not linear:
http://www.biketinker.com/2010/bike-resources/optimal-tire-pressure-for-bicycles/

Philip


On Mar 12, 2:18 pm, Philip Williamson <philip.william...@gmail.com>
wrote:
> This one here allows you to input your own widths into a Google Doc.http://www.biketinker.com/tire-pressure-calculator/

[PATRICK MOORE]

Thanks for this -- tried the spreadsheet and I'm close enough not to
worry (the difference between f and r seems too large, but I'm pretty
satisfied with my "educated thumb" guess for the Kojaks onroad and the
BAs off.

I was going to ride dirt today on the BAs but a foolish accident on
Sat night left me with a sprained joint or torn ligament on the middle
finder knuckle of my right hand (leaving that hand suitable only for
"traffic signaling") so I decided to play safe and stay on pavement.
Accordingly, I switched to the Kojak wheelset and did much the same
route -- a bit extended -- as with the BAs on Sat. What a world of
difference! Beautiful day, ~65F, breezy S wind. 22.4 miles in the
46X18 (~70") except for a couple of longer hills. What wonderful tires
those 35 mm Kojaks are: they make the same, porky Fargo feel almost
like a racing bike!

Oddly, the annoying finger injury -- hard to type! -- makes very
little difference on the bike except that it's harder to operate the
right brake lever fro the hood. Won't be able to ride my Rivs for a
while as they each have the single brake operated by the right lever.

[Bruce Herbitter]

I input my data.  Bike # 2 (a Riv Road w/Maxy Fastys) looks suspect. Rear pressure of 5 psi and front of 1?


bike 1    bike 2         bike 3    bike 4   
38          33.4            36              37     Tire Dia
193        193             193             193   total weight
60%       60              60%            55%  wt rear
40%      40%            40%           40%    wt frt
115.8     20.04          115.8          115.8  
77         13               77               77     
50          5                55               52    rear pressure
31          1                 34               33   frt pressure
               

[Philip Williamson]

Thanks, Bruce. And that's why Agile is smart to have a web form!
Google docs doesn't allow protecting individual cells or rows.
I deleted that column. When I get time, I'll rebuild it. So for now,
you can look at 3 bikes and a randonneur... I guess seven columns
would be the ideal sheet, since that's the ideal number of bikes... or
a form where you can add as many "bikes" as you want. Maybe I'll talk
to my developer friends and see if I can trade them something to build
that out.

Thanks again,
Philip

Philip Williamson
www.biketinker.com

[Bruce Herbitter]

Phillip,  great work to get the form up in the first place. I admit i am gun shy about such low front pressure.  I usually tun 65 rear and 60 front, but i will have yo be brave and try your figures!

Sent from my Kindle Fire

---

From: Philip Williamson <philip.w...@gmail.com>
Sent: Tue Mar 13 11:08:19 CDT 2012
To: RBW Owners Bunch <rbw-owne...@googlegroups.com>
Subject: [RBW] Re: Wide, fat, heavy and slow on the hills!

[Mojo]

I too am not ready to follow the very low front tire pressures. For one thing here in windy, hilly Colorado I get out of the saddle regularly for power surges thus weighting the front tire more than the 40% estimate while seated. I do not want a squishy squirmy front tire when I am trying to power my way up a hill. So I go 10psi below the rear tire and call it good. 

 

On Tuesday, March 13, 2012 3:23:12 PM UTC-6, Fullylugged wrote:

Phillip,  great work to get the form up in the first place. I admit i am gun shy about such low front pressure.  I usually tun 65 rear and 60 front, but i will have yo be brave and try your figures!

Sent from my Kindle Fire

---

From: Philip Williamson <philip.w...@gmail.com>
Sent: Tue Mar 13 11:08:19 CDT 2012

To: RBW Owners Bunch <rbw-owners-bunch@googlegroups.com>

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