|   Review: Python Airlight/Fire XC Pro/Klimax Lite | xc-baby
May 29, 2002 5:29 AM | | Well,
Went out on ride #3 on my sweet little sub 21 pound FLY 9357.
I have gotten it down to 20.2 pounds with a few parts substitutions.
The FLY 9357 comes stock from Motobecane with Kenda Klimax Lite tires.
I have tried a Klimax Lite rear/XC Pro front, Python Front/Klimax rear, Python front and rear.
The Klimax Lites have an incredibly thin casing and low profile tread.
I used them in the rear but substituted a Fire XC Pro on the front for my first ride. The Klimax lites kept up with the XC Pros on corners. Dry, sandy and leafcovered hard pack were all handled very well. I never felt that the Klimax Lites couldn't track the same line as the XC Pros. On hard pack and pavement, the Klimax lites had very little rolling resistance. Even with the high pressures I usually run (40-45 psi) I never felt like the Klimax lites were too hard. The only place the Klimax Lites let me and my Motobecane down were in deep sand and loose climbs where I used to tractor through and up with an XC Pro in the rear. The Kendas would do OK for a few feet but the tread would soon pack up and cause major traction loss.
On this third ride, I went with Python Airlights front and rear.
On the short paved section before the trail, I felt really high rolling resistance and had to stop and pump up the rear tire. I was using about 35 psi and I think I had to pump it up to 40 psi. My old 2.1 XC Pros had less rolling resistance at the same pressure.
On the trail, the Python was not as secure as the XC Pro was in the front. It had a lower cornering threshold and would tend to wash and break sooner and more suddenly than the XC Pro did. The rear did not track as well as an XC Pro OR Klimax Lite. It tended to slide a bit on leafy sections a bit more than either tire. The Pythons did MUCH better on loose deep sandy pockets and climbs than the Klimax's. They allowed me to clean sections that the Klimax in the rear did not.
I might go to 1.8 XC Pros front and rear - has anyone tried this?
How does it compare to the 2.1's?
I really wish Panaracer would take the XC Pro tread design and come up with a 2.0 tire with the casing that Kenda uses on the Klimax. |
| Use lower pressure on the trails... | shiggy
May 29, 2002 9:31 AM | | ...and the Pythons will track better. I run 32f/34r with great results (170 lbs). I full knob tire does corner better on the front but I have had no complaints with the Python in dry conditions. |
| Python Rolling Resistance is poor at lower pressures... | xc-baby
May 29, 2002 6:23 PM | | I am strongly considering going back to Fire XC Pros front and rear- maybe use a 1.8 in the back or the Klimax if it is not too sandy and loose.
Anyone want to buy my Python Airlight 2.0's?
Two near new (one ride) $20 each plus shipping.
I have one that is patched from a small 1/2 inch cut in the sidewall - $10 plus shipping. |
| There is no way that a Fire XC Pro's rolling resistance is less | AZ-X
May 30, 2002 2:27 AM | | than the Python, Bontrager SuperX or any other tire with those sort of low-profile, small knobs. Even at various pressures. The Fire pro wasn't made for low rolling resistence, it was made for grip at a reasonable weight. I'm not sure where you were riding, but that has definitely not been my experience. I've been using Pythons for about 2 years now and I used the Fire Pros when they first came out and ditched them for the reason that they didn't roll fast enough and that the knobs gave too quickly in gravel and sand. The Fires are much better suited for softer terrain with roots and some rocks than hardpack conditions.
Any tire will increase its rolling resistance if you lower the pressure... |
| I do not think so | shiggy©®
May 30, 2002 7:18 AM | | I find the Python to be a very fast tire at 32-35psi.
High pressure on rough surfaces increases rolling resistance. The casing can not follow the contour of the surface as well. A hard tire bounces on the rough stuff and slows down. A softer tire conforms to the surface and keeps moving forward. |
| That is also true to an extent... | AZ-X
May 30, 2002 7:58 AM | | I was thinking more about him riding on pavement where lower pressure usually does mean more resistence... |
| Agreed, to a point. My response is to his about... | shiggy
May 30, 2002 9:46 AM | | ...my post on (is that too confusing?) using lower pressure on the trails for better tracking. One of the reason tires track and corner better at "lower" pressures is that they are not wildly bouncing off of things. When a tire hits an object or bump it tends to slow down and move backwards. If the pressure is high, the entire wheel moves back. If the tire is able to deform and conform to the bump the wheel can continue moving forward more easily (i.e. lower rolling resistance.) This is also how suspension works.
It happens to a small extent on pavement with road slicks. Very high pressures can have more rolling resistance than moderately high pressures. The max pressure listed on the side of the tire does not mean that it is most efficient at that pressure. The road surface and rider weight also factor in to the equation. |
| Understood. That resistance is felt more at low pressures... | AZ-X
May 30, 2002 10:04 AM | | when you are using wider tires. Same reason your gas mileage for your car or motorcycle will suffer if your tire pressure is too low. On a basically smooth surface, the wider the tire is, the more likely that the surface area increase caused by low pressure will overcome any tracking or suspension benefit gained by being able to absorb imperfections in the surface. So you need to take the terrain or surface into account also.
I think we've both discussed this before so I know you already know this--just clarifying the point for people who are new to the discussion... There may be some exceptions to this from factors such as tire compound and shape aslo... |
| Fire XC Pro's Lower Rolling Resistance... | xc-baby
May 30, 2002 5:47 PM | | I run my Fire XC Pros at 40-45 psi.
The trails are mainly hardpacked sandy and leaf littered turns with some deeper sandy sections and loose sandy climbs.
I have probably gotten used to running the XCPros at high pressure and have adapted to the extra rebound.
I'll take one more ride on these Pythons but I don't expect any different from them. Actually, my experience with them was so disappointing I don't know if I can give them another chance... |
| If your trail is leafy, the Pythons aren't the tire for you... | AZ-X
May 30, 2002 6:09 PM | | That is not what they were made for. Forest type riding over leafy trails is better with larger, blocky knobs. Otherwise, you'll be slipping and sliding all over the place. Explorer Pros or your Fire XCs would probably serve you better in those conditions. |
| Don't forget surface area! | pedalinbob
May 31, 2002 5:29 AM | | lower pressures tend to allow the tire to deform more, which places more surface area on the trail. this contact patch is what will likely give good traction (on hardpack, anyway).
this is especially true with semi slick tires like the python, etc.
semi slicks have short/low/stiff/closely spaced knobs which place a lot of rubber on the trail.
a tire with big knobs may not have more surface area (on hardpack) because only the knobs are contacting the trail, which may be a pretty small contact patch. a knobbier tire will have more contact patch if the trail is soft enough to allow the tread to punch through the upper layer, therefore allowing the knobs AND the casing to contact the trail.
as far as speed goes, it is my belief that lower pressures are actually faster on the trail, due to less bouncing (which Shiggy stated above), and greater grip.
conclusion: lower the pressure, use a wider/higher volume tire (except in mud), and you will go faster.
Bob |
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