Grand Bois Cypres tires, a review.

[Anne Paulson]

I got back yesterday from Sierra to the Sea, a 586 mile supported bike tour from Lake Tahoe to San Francisco.

I used the Grand Bois Cypres tires. I now want to report that they were splendid. We encountered some roads with terrible pavement, as I knew we would since this was my second year on the trip.  The tires are marked for 75-95 psi, so I initially tried 80 psi. After a day, I let out some air; around 60 psi ended up working well for me. 

Others would slow down on the bumpy downhills, but I just zoomed. My buddy with narrow tires was constantly crowing about how great his tires were. When I followed him on some bad stretches of pavement on the flats, I grew tired of his weaving around trying to find a good line, whereas I just rode straight with no trouble. 

 

No flats, no problems.

I still think that there ought to be a standard way to measure bike tire width, so we can compare tires from different vendors. But these tires (which still measure 30mm wide on my bike) performed admirably. 

--
-- Anne Paulson

It isn't a contest. Enjoy the ride.

[eflayer]

I think a lot of bike parts hype is mostly just hype. And I prefer the scientific to mere annecdotal evidence. I have no real science on MY Cerfs and my Cypre tires. I don't even have a very good imagination. But I swear these 2 sets of tires have made their corresponding bikes so much more fun to ride. I rode my Cerf shodded Curtlo coupled bike yesterday. 35 miles, 3500 feet, up down and and all around fast curves, crappy pavement. Love the tires a lot. Cerfs at approx 60 psi, me at 195 lbs.

[Don Compton]

Just curious, what size are your "Cerfs"? I have 700x28s on my Riv Roadeo and am very happy with them. But, I have been running 75lbs front and 85lbs rear. I am lighter and wonder if I could ride with a little less pressure.

[eflayer]

Don,

 

My Cerfs are 28 mm. I run 85 psi in Michelin Lithion 25 mm. Reduce the pressure, enjoy the ride.

On Sunday, June 22, 2014 10:21:47 AM UTC-7, Anne Paulson wrote:

[Don Compton]

Thanks for your reply. I am going give it a try.
My go fast bikes are my Independent Fabrication bikes and the Grand Bois won't fit. I ride 25's on them. Its fun to have bikes with different handling and ride characteristics. Enjoy your riding.

[Tim Gavin]

Don-

The GB Cerf Blue (or Compass Cayuse Pass) tires measure 26 mm wide, so you may be able to fit those on your IF's.  I put them on my Giordana, which won't fit 28 mm tires.

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[Don Compton]

Tim,
Thanks for your reply. I have a pair of 700x26 cerfs, but the Vredestien 25mm Grand Fondo Tricomps are about the same size and I have had great luck with them including a great ride. I think that the 28 Cerfs are quite a bit more compliant than the 26's. The 28s seem large for their size, while the 26s seem more like 25s. Anyway, thanks for your suggestion.

[Bruce Herbitter]

Ann

My own experience is the same as yours.  60 psi rear and 55 in front.  Faster downhill on coarse roads and surprisingly good to climb on.

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[Anton Tutter]

I have the extralight cypres tires on my JT, and they're wonderfully supple and fast. I ride with 55/60 psi f/r with 195 lb combined weight of rider, bike and luggage.

Anton

ridingthecatskills.com

[Dave Johnston]

Why are everybodies F& R tire pressures so close? Are you really that centered over the wheels? I recently started running 45/65 psi on Cypress based on a 40%/60% weight distribution and its been a revelation that my front was pumped to hard and my rear not enough. The lower pressure in the front has made my hands much more comfortable and the higher pressure in the rear hasn't been much noticeable in my tush.

-Dave

[Anne Paulson]

What about steep bumpy descents? Doesn't that throw your weight forward, so that you need about as much pressure in the front as the rear?

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[Deacon Patrick]

I keep my pressure equal front to rear (40 psi on the QB, 20-30 on the Hunqapillar). I suspect due to the rocks in my head that my weight distribution is more even. Grin.

With abandon,

Patrick

[Jim Bronson]

I run 65/75, because I weigh 265 and I get pinch flats if I run less than 60/70.  My main concern is smoothing out the chip seal and those pressures work fine for doing that.

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Keep the metal side up and the rubber side down!

[Jan Heine]

When you brake hard, you put 100% of your weight on the front wheel. With wide tires that run at relatively low pressures, that determines your tire pressure more than the load on the tire. I find that about 10% less pressure in the front than the rear works best for me on 42 mm Extralight tires...

Jan Heine
Editor
Bicycle Quarterly
www.bikequarterly.com

[Bill Lindsay]

Jan Heine loves doing endos.  Rumor has it one of the reasons he likes SPD pedals is that they are good for bunny hops.  I've heard he's bad at wheelies, though.  I'm going to go out on a limb and guess he can't do a table top.  

:-)

[Philip Williamson]

That's an interesting thought. Off road, straight through the bumps, I move back on the bike, maybe even for a net effect of less weight on the front. 

On road, I do weight the front, because I want to commit to the turns. 

I usually run a five pound difference in pressure between the front and back: 40/45 or 50/55 depending on how I feel. 37mm C-Lines. 

Philip

www.biketinker.com

[Matt Beebe]

exploring the nuances of supple-walled* 20 inch tires in a controlled environment

*not really

[Jan Heine]

Here is a photo of what happens when you brake hard, even if you move your weight back:

http://janheine.wordpress.com/2013/08/23/how-to-brake-on-a-bicycle/

Since the rear wheel isn't touching the ground, 100% of the weight rests on the front wheel. BTW, the rider did not go over the bars, this was simply a controlled stop with maximum brake power during our brake tests.

[Anton Tutter]

Do you ride with a front load?  My pressures are optimized for a few pounds directly over the front axle via the handlebar bag.  Also Anne's comment about descents is absolutely true-- whether in an aero tuck or feathering the brakes from the drops, with my butt weight lifted off the saddle, during fast descents the weight distribution definitely shifts frontward.

Anton

ridingthecatskills.com

[David Johnston]

I don't have a front load and I had considered going downhill and had
added 5psi to account for different on bike positions. On rough steep
I tend to use my MTB skills and push my weight far back.
I had never considered breaking forces. I think that should be
mentioned anytime the Berto Pressure drop charts are mentioned. Maybe
I'll bump up the front another 5psi, but I hate to give up that nice
cush. I think I used to run 60/60 on 32mm tires. (I only weigh 140lbs)

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[Philip Williamson]

I think that's over complicating things. It's just a guideline. If you end up with 25% tire drop instead of the ideal 15%, under hard braking on a rough downhill... Who cares? Your tires are now compressing more than the ideal theoretical amount to give you the lowest rolling resistance, but you are BRAKING. You are resisting your forward momentum already, on purpose.

If you roll a tire, or get a pinch flat, it's NOT because you slavishly followed the chart recommendations.

Philip
www.biketinker.com

[Jan Heine]

I totally agree. As our research has shown, tire pressure is much less important than most of us used to think. This is especially true with supple tires. When we tested a Vittoria CX, it no longer held its line in corners because the sidewalls collapsed before the rolling resistance goes up significantly. These 25 mm tires had roughly the same rolling resistance at 70 psi as at 130 psi, and everywhere in between.

So start with Berto's chart and then experiment. If you feel like you could let out some air to get a more cushy ride on bumpy roads, do so. If you feel the tire sidewalls starting to collapse under hard cornering, increase the pressure a bit. If your tires feel great, just ride them. That's all.

Jan Heine
Editor
Bicycle Quarterly
www.bikequarterly.com

[Don Compton]

Ed,
I took the Roadeo out for a ride at 65lbs,75lbs front/rear. SWEET! I hadn't been riding it for awhile. I am back.
Don

On Sunday, June 22, 2014 7:01:19 PM UTC-7, eflayer wrote:

[eflayer]

Don Compton,

 

Congrats. That's where I started and then went down a bit more from there.

 

Cool that you either really noticed a difference or you are being taken in by just changing a variable and have the ride be different. I think the tires are actually that good and THEY do make a difference.

On Sunday, June 22, 2014 10:21:47 AM UTC-7, Anne Paulson wrote:

[Tom Virgil]

Naive question.  Just how does one determine one's weight distribution?  I am picturing a dubious situation with two bathroom scales.

Thanks in advance,

Tom

On Sunday, June 22, 2014 10:21:47 AM UTC-7, Anne Paulson wrote:

[Tom Virgil]

Did some searching.  Oh dear, it's as bad as I thought...

It’s easy enough to do: put a bathroom scale under one wheel and a wood block the same thickness as the scale under the other wheel. First, weigh yourself standing on the scale while lifting the bike off of the ground. Then sit on the bike perched on the scale and block and hold yourself up by touching an elbow against the wall. Have somebody else read off the scale reading. As a double check, turn the bike around so that the wheel on the scale and the wheel on the block are reversed, and take the measurement again.
Read more at http://velonews.competitor.com/2012/06/bikes-and-tech/technical-faq/technical-faq-bike-fitting-and-setup_224895#rDZPCQ0if36dPF4Z.99

Now given that I do something like that, and come  up with, say, 45/55, f/r, what is the magic for f/r tire pressure differential.

Thanks,

Tom

[Philip Williamson]

I did that with every bike in the house, and found the Bicycle Quarterly weight distribution breakdowns for different styles of bike 100% correct.

______Rear / front
"Road bike" - 60/40
"Low trail" - 55/45
"3 Speed" - 65/35 - ? From memory.
"Tri Bike" - 45/55 - ? Not verified by me.

I use the Edison Gauss (and me) Android tire pressure app, so I no longer have to remember the ratios.
http://www.biketinker.com/2013/projects/pressure-app/

Philip
www.biketinker.com