Tire pressure, drilled rims, and gauges

MadFurai · 2012-07-31, 02:09 PM

I recently replaced my Nimbus 24 Muni with a KH 26. The Nimbus had a 24x3 duro leopard and the KH26 has a 24x2.6 duro razorback.

I've only had the 26 for a month or so, but it has been really hard for me to find a tire pressure for technical single track that works well. On my Nimbus 24, I would basically adjust the pressure by feel, squeezing the tire to see how much it would give. I haven't been able to do this with the 26 and I'm wondering if it's the tire size or the rim. I've also tried going by a gauge, but 15 psi one day doesn't always feel like 15 psi on another day. It could be heat and humidity changes or it could be a bad gauge.

I'm wondering if others find it hard to get a reliable/consistent pressure in their tires on the KH drilled rims. At this point, I am considering going to a 26x3 tire to soak up the roots better. I also plan on buying a better tire pressure gauge, does anyone have any suggestions? Thanks.

davidp · 2012-07-31, 02:22 PM

A squeeze test can give an idea of air pressure but a better test is to hop on something like a root (or, if you're in the garage, a rake handle). You want the tire to have enough give to deform but not hit the rim.

I have both drilled and undrilled rims and in terms of riding feel it makes no difference. What does matter is rim width and the tire being used.

Nurse Ben · 2012-07-31, 03:02 PM

Auto parts store, buy a good quality "stick" gauge.

16-18psi should be good for your weight on that tire, maybe as low as 14psi, just so long as you're not getting rim shots.

Tires lose pressure from day to day, so I check my pressure before every ride.

A fatter tire is probably what you're looking for in terms of returning to that fat feel, though in time you'll find that you can roll over obstacles with a skinny tire, but you need to use a different technique.

I roll over logs up to 12" in diameter without hopping, on a 29 x 2.4, and it's all in the technique. I can do similar roll overs on my 36er, same technique, just ride up and over the obstacle like you would on a bicycle.

A good way to practice is to do repeats on a log that is perpendicular to the trail, ride at the log without a running start, so start from a standstill no more than ten feet rom the log, and try and rise up and ride over the log.

You'll know you're doing it right if you don't feel the wheel "hit" the log. Start small and work your way up. No Hopping!

MadFurai · 2012-07-31, 03:41 PM

I do check the pressure every time before I ride. Some days when I get it right, the ride is noticeably better. I'm just finding it hard to get it right all the time. It just seems the 24x3 had a larger pressure range for the "sweet spot." In the 26x2.6, a 0.5 pound pressure change can be the difference between a really hard ride and a really soft ride. I was just wondering if it could be because of the drilled rim.

It's possible that better riding technique might change all of this in the long run, but my progress has plateaued for the moment.

Nurse Ben · 2012-07-31, 03:53 PM

Stop using the digital pressure gauge, at low pressures they are notoriously wrong.

Maybe a change in your riding choices?

How about some faster riding on XC stuff, where you can complete a ride with few UPDs, make it competition with yourself that you can win.

I have different rides I do depending on mood and mojo, sometimes I can slam out a tech ride and feel great, other times something a little milder is better for my psyche.

Saurday I did a big double track ride on the 36er which left me flat, so when I went for a tech ride on Sunday it was a little rough so I cut it short, took a day off, so tonight I'm going to ride some more double track on the 36er.

Success feeds the ego like nothing else can

MilanMUni · 2012-08-01, 02:33 PM

Hi Nurse Ben,

can you describe this technique:

"I roll over logs up to 12" in diameter without hopping, on a 29 x 2.4, and it's all in the technique. I can do similar roll overs on my 36er, same technique, just ride up and over the obstacle like you would on a bicycle.

A good way to practice is to do repeats on a log that is perpendicular to the trail, ride at the log without a running start, so start from a standstill no more than ten feet rom the log, and try and rise up and ride over the log.

You'll know you're doing it right if you don't feel the wheel "hit" the log. Start small and work your way up. No Hopping!"

or you have a video with this technique?

It´s very interesting! How can I lighten the wheel when I´m rolling through higher obstacles without hopping? I use less pressure in tire or hoping...

jbtilley · 2012-08-01, 03:20 PM

^

Recently I've been slowly coming around to that technique. I tried it several times on our ride yesterday and with repetition I've learned a bit more, still have work to do though.

The first thing that helped me was lowering my seat, giving it somewhere to go once I hit the log. Now I'm only up to 8" logs myself but I've found:

1) Approaching too fast doesn't work. The uni hits the log, stays behind, and I keep going.

2) Approaching too slow doesn't work. I'll hit the log, stall, and not have the raw leg strength to get over.

So a medium speed worked. Enough to get the tire up on the log and use normal pedal strength to carry me the rest of the way over. Now to try and write something I can't really explain... when I hit a log I bend my knees and lift up on the seat at the same time. That's where having the seat low helps - gives the seat someplace to go. I think the thing that has helped me in all my seat lowerings is that it doesn't matter as much what position the pedals are in at initial impact, meaning if they are positioned vertically I can still bend my knee on the leg that's lowest.

Maybe I'm doing it wrong though. I'll feel the "hit" but it's usually not a hard hit. Enough of one to remind me I'm trying to roll a unicycle over a log. Now I'd love to learn how to do a rolling hop where you're already up on the log before that initial impact occurs. Always something to work on.

I've still got quite a bit of learning to do to hop the same logs I can roll. When road riding I can hop up curbs/stairs a bit but when it comes to muni I usually have 2L of water on my back and am too tired to muster any hop over 1".

/threadjack

blueharmony · 2012-08-01, 05:14 PM

Quote:

Originally Posted by MilanMUni

You'll know you're doing it right if you don't feel the wheel "hit" the log. Start small and work your way up. No Hopping!"

or you have a video with this technique?
:

A video would be very helpful, when you say "no hopping" I am confused. There must be some kind of "elevation technique" during the ride up to the log, otherwise a 12" log would simply stop you during a direct hit.

Do you mean that you take pressure off the tire by "jumping slightly" during the ride, thus enabling the tire to roll over the log?

uniShark · 2012-08-01, 07:02 PM

I use Ben's technique on logs successfully quite frequently. . .

. . . but only on "logs" up to about 3".

knoxuni · 2012-08-01, 07:31 PM

practice practice practice.

Nurse Ben · 2012-08-01, 08:08 PM

No videos, sorry, I guess I could try and make one now that I have a Go Pro

There is some lifting, but I'm not hopping or prejumping.

It's no different from what you do on a bicycle, rising up with the bike lightens it, so then you can climb up and over the log. I'm not going fast when I do this, it is a low speed maneuver, otherwise you'll have too much forward momentum and you'll run into the log.

You are probably already doing this with smaller obstacles, so just up the ante and go bigger and bigger. A larger wheel helps, but it can be done on any wheel size.

I think JBTilley describes it well. It's not a hop, more like a climb up and over starting with a lightening of the uni. When I think of this move, I can see it better in skiing/boarding, where you absorb a bump and ski on like it wasn't there...

uniShark · 2012-08-03, 04:00 PM

George Peck video of the technique, see @ 2:20:

http://www.youtube.com/watch?v=30vVEaO2Qqw

Peck makes it look so simple - he doesn't even use a handle! I don't feel like I have any more excuses, particularly given how much better my equipment is, and that I'm on a bigger wheel! Curb practice tonight. . .

Thanks to jbtilley for finding it!

knoxuni · 2012-08-03, 04:15 PM

that is super cool. ima try that tonight!

Nurse Ben · 2012-08-05, 12:36 AM

Hey Unishark, I watched Peck's video posted in another thread, saw him climbing up that big curb and thought that it was a good example of what I was trying to convey in words

Notice he does it without hands, so there really isn't any significant pulling up or hopping, you just "rise up with the unicycle" and roll the obstacle.

Yeah, he was amazing in his time and his riding is still pretty contemporary, and look at that tire, talk about skinny. Seriously, you can't really blame the equipment when what we have now is so much better than what he rode.

The fattest tire I've ridden since this past March is a 2.4", took a cue from KH and some of the other long time riders, seems to be working well so far

knoxuni · 2012-08-05, 12:40 AM

@NB you should ride a OLD 26in muni :P

2012-07-31, 02:09 PM	#1
MadFurai Skateboarder to Marine to Unicycler Join Date: Aug 2011 Location: Central Virginia Age: 42 Posts: 536	Tire pressure, drilled rims, and gauges I recently replaced my Nimbus 24 Muni with a KH 26. The Nimbus had a 24x3 duro leopard and the KH26 has a 24x2.6 duro razorback. I've only had the 26 for a month or so, but it has been really hard for me to find a tire pressure for technical single track that works well. On my Nimbus 24, I would basically adjust the pressure by feel, squeezing the tire to see how much it would give. I haven't been able to do this with the 26 and I'm wondering if it's the tire size or the rim. I've also tried going by a gauge, but 15 psi one day doesn't always feel like 15 psi on another day. It could be heat and humidity changes or it could be a bad gauge. I'm wondering if others find it hard to get a reliable/consistent pressure in their tires on the KH drilled rims. At this point, I am considering going to a 26x3 tire to soak up the roots better. I also plan on buying a better tire pressure gauge, does anyone have any suggestions? Thanks. __________________ MadFurai's YouTube channel

2012-07-31, 03:02 PM	#3
Nurse Ben XC Muni Join Date: Jul 2008 Location: Southeast USA Age: 47 Posts: 3,967	Auto parts store, buy a good quality "stick" gauge. 16-18psi should be good for your weight on that tire, maybe as low as 14psi, just so long as you're not getting rim shots. Tires lose pressure from day to day, so I check my pressure before every ride. A fatter tire is probably what you're looking for in terms of returning to that fat feel, though in time you'll find that you can roll over obstacles with a skinny tire, but you need to use a different technique. I roll over logs up to 12" in diameter without hopping, on a 29 x 2.4, and it's all in the technique. I can do similar roll overs on my 36er, same technique, just ride up and over the obstacle like you would on a bicycle. A good way to practice is to do repeats on a log that is perpendicular to the trail, ride at the log without a running start, so start from a standstill no more than ten feet rom the log, and try and rise up and ride over the log. You'll know you're doing it right if you don't feel the wheel "hit" the log. Start small and work your way up. No Hopping! __________________ I dream of hamsters and elderberries Last edited by Nurse Ben; 2012-07-31 at 03:04 PM.

2012-07-31, 03:41 PM	#4
MadFurai Skateboarder to Marine to Unicycler Join Date: Aug 2011 Location: Central Virginia Age: 42 Posts: 536	I do check the pressure every time before I ride. Some days when I get it right, the ride is noticeably better. I'm just finding it hard to get it right all the time. It just seems the 24x3 had a larger pressure range for the "sweet spot." In the 26x2.6, a 0.5 pound pressure change can be the difference between a really hard ride and a really soft ride. I was just wondering if it could be because of the drilled rim. It's possible that better riding technique might change all of this in the long run, but my progress has plateaued for the moment. __________________ MadFurai's YouTube channel

2012-07-31, 03:53 PM	#5
Nurse Ben XC Muni Join Date: Jul 2008 Location: Southeast USA Age: 47 Posts: 3,967	Stop using the digital pressure gauge, at low pressures they are notoriously wrong. Maybe a change in your riding choices? How about some faster riding on XC stuff, where you can complete a ride with few UPDs, make it competition with yourself that you can win. I have different rides I do depending on mood and mojo, sometimes I can slam out a tech ride and feel great, other times something a little milder is better for my psyche. Saurday I did a big double track ride on the 36er which left me flat, so when I went for a tech ride on Sunday it was a little rough so I cut it short, took a day off, so tonight I'm going to ride some more double track on the 36er. Success feeds the ego like nothing else can __________________ I dream of hamsters and elderberries Last edited by Nurse Ben; 2012-07-31 at 03:56 PM.

2012-08-01, 07:02 PM	#9
uniShark muni commuter Join Date: Aug 2009 Location: Missoula, MT, USA Age: 41 Posts: 1,362	I use Ben's technique on logs successfully quite frequently. . . . . . but only on "logs" up to about 3". __________________ My 29er is my little wheel. Roll it, baby! pLs forgve anu typist imak win positing forum my fone.

2012-07-31, 02:22 PM	#2
davidp Registered User Join Date: Jun 2009 Location: Chelmsford, MA Age: 33 Posts: 705	A squeeze test can give an idea of air pressure but a better test is to hop on something like a root (or, if you're in the garage, a rake handle). You want the tire to have enough give to deform but not hit the rim. I have both drilled and undrilled rims and in terms of riding feel it makes no difference. What does matter is rim width and the tire being used.

2012-08-01, 02:33 PM	#6
MilanMUni Registered User Join Date: Jul 2011 Posts: 67	Hi Nurse Ben, can you describe this technique: "I roll over logs up to 12" in diameter without hopping, on a 29 x 2.4, and it's all in the technique. I can do similar roll overs on my 36er, same technique, just ride up and over the obstacle like you would on a bicycle. A good way to practice is to do repeats on a log that is perpendicular to the trail, ride at the log without a running start, so start from a standstill no more than ten feet rom the log, and try and rise up and ride over the log. You'll know you're doing it right if you don't feel the wheel "hit" the log. Start small and work your way up. No Hopping!" or you have a video with this technique? It´s very interesting! How can I lighten the wheel when I´m rolling through higher obstacles without hopping? I use less pressure in tire or hoping...

2012-08-01, 03:20 PM	#7
jbtilley Muni Foot Join Date: Jul 2011 Location: North Carolina Posts: 556	^ Recently I've been slowly coming around to that technique. I tried it several times on our ride yesterday and with repetition I've learned a bit more, still have work to do though. The first thing that helped me was lowering my seat, giving it somewhere to go once I hit the log. Now I'm only up to 8" logs myself but I've found: 1) Approaching too fast doesn't work. The uni hits the log, stays behind, and I keep going. 2) Approaching too slow doesn't work. I'll hit the log, stall, and not have the raw leg strength to get over. So a medium speed worked. Enough to get the tire up on the log and use normal pedal strength to carry me the rest of the way over. Now to try and write something I can't really explain... when I hit a log I bend my knees and lift up on the seat at the same time. That's where having the seat low helps - gives the seat someplace to go. I think the thing that has helped me in all my seat lowerings is that it doesn't matter as much what position the pedals are in at initial impact, meaning if they are positioned vertically I can still bend my knee on the leg that's lowest. Maybe I'm doing it wrong though. I'll feel the "hit" but it's usually not a hard hit. Enough of one to remind me I'm trying to roll a unicycle over a log. Now I'd love to learn how to do a rolling hop where you're already up on the log before that initial impact occurs. Always something to work on. I've still got quite a bit of learning to do to hop the same logs I can roll. When road riding I can hop up curbs/stairs a bit but when it comes to muni I usually have 2L of water on my back and am too tired to muster any hop over 1". /threadjack

2012-08-01, 07:31 PM	#10
knoxuni wes style!! Join Date: Jun 2010 Location: central ohio Age: 18 Posts: 4,695	practice practice practice. __________________ Be a dumbass experience dumbass consequences its full circle of dumbass And then, do it again. That makes it an infinite loop!

2012-08-01, 08:08 PM	#11
Nurse Ben XC Muni Join Date: Jul 2008 Location: Southeast USA Age: 47 Posts: 3,967	No videos, sorry, I guess I could try and make one now that I have a Go Pro There is some lifting, but I'm not hopping or prejumping. It's no different from what you do on a bicycle, rising up with the bike lightens it, so then you can climb up and over the log. I'm not going fast when I do this, it is a low speed maneuver, otherwise you'll have too much forward momentum and you'll run into the log. You are probably already doing this with smaller obstacles, so just up the ante and go bigger and bigger. A larger wheel helps, but it can be done on any wheel size. I think JBTilley describes it well. It's not a hop, more like a climb up and over starting with a lightening of the uni. When I think of this move, I can see it better in skiing/boarding, where you absorb a bump and ski on like it wasn't there... __________________ I dream of hamsters and elderberries Last edited by Nurse Ben; 2012-08-01 at 08:15 PM.

2012-08-03, 04:15 PM	#13
knoxuni wes style!! Join Date: Jun 2010 Location: central ohio Age: 18 Posts: 4,695	that is super cool. ima try that tonight! __________________ Be a dumbass experience dumbass consequences its full circle of dumbass And then, do it again. That makes it an infinite loop!

2012-08-05, 12:36 AM	#14
Nurse Ben XC Muni Join Date: Jul 2008 Location: Southeast USA Age: 47 Posts: 3,967	Hey Unishark, I watched Peck's video posted in another thread, saw him climbing up that big curb and thought that it was a good example of what I was trying to convey in words Notice he does it without hands, so there really isn't any significant pulling up or hopping, you just "rise up with the unicycle" and roll the obstacle. Yeah, he was amazing in his time and his riding is still pretty contemporary, and look at that tire, talk about skinny. Seriously, you can't really blame the equipment when what we have now is so much better than what he rode. The fattest tire I've ridden since this past March is a 2.4", took a cue from KH and some of the other long time riders, seems to be working well so far __________________ I dream of hamsters and elderberries Last edited by Nurse Ben; 2012-08-05 at 12:40 AM.

2012-08-05, 12:40 AM	#15
knoxuni wes style!! Join Date: Jun 2010 Location: central ohio Age: 18 Posts: 4,695	@NB you should ride a OLD 26in muni :P __________________ Be a dumbass experience dumbass consequences its full circle of dumbass And then, do it again. That makes it an infinite loop!

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