Adjusting Tire Pressure

[ebjr]

So I have already done some extensive reading using the search function. Most of what I read seems to support what I was told on my last ride earlier this week…high tire pressure (mid 50’s) is likely contributing to my excessive sliding on turns and cornering. It was actually recommended that I drop down to mid 30s on both front and back and perhaps adjust down from there. My friend with a FS set up was riding on 25 for the front and 28psi for the rear.
So this seems to make sense but I do have a bit of an odd concern/question. I also ride paved trails near my house a few times a week. When I ride these trails I would need to bump my pressure back up to the high 50s as I am looking for more speed to get some good miles in during the week…when I hit the trails, I’d lower the pressure back down. This leads to my concern, is there a such thing as perhaps stretching and decompressing the tube too much with these increases and decreases in tire pressure?
Perhaps this is a nonsense question that will cause some eyes to roll at the newbie nature…but I would certainly appreciate the insight of some MTB’ing veterans.

[CP1]

"ebjr" wrote

So I have already done some extensive reading using the search function. Most of what I read seems to support what I was told on my last ride earlier this week…high tire pressure (mid 50’s) is likely contributing to my excessive sliding on turns and cornering. It was actually recommended that I drop down to mid 30s on both front and back and perhaps adjust down from there. My friend with a FS set up was riding on 25 for the front and 28psi for the rear.
So this seems to make sense but I do have a bit of an odd concern/question. I also ride paved trails near my house a few times a week. When I ride these trails I would need to bump my pressure back up to the high 50s as I am looking for more speed to get some good miles in during the week…when I hit the trails, I’d lower the pressure back down. This leads to my concern, is there a such thing as perhaps stretching and decompressing the tube too much with these increases and decreases in tire pressure?
Perhaps this is a nonsense question that will cause some eyes to roll at the newbie nature…but I would certainly appreciate the insight of some MTB’ing veterans.

Hey ‘ebjr’

Yes, higher tire pressure does tend to lead to tire slide on dirt trails and very hard riding in softer soil as well. The best pressure to run at for trail is between 28 to 35psi, but for hard pack, running between 32 to 42 tops works great for FL trail riding. I trail and urban shred, so i usually run a constant psi between 38 to 42 psi, though my wire bead tires can handle down to 20 to 25 psi, but this is not recommended for any tire though. Too little air pressure with the wrong tires will bring on pinch flats, if not excessive pinch flats. That is soooo damned annoying… 😆

On pavement, a higher pressure is always recommended by far, so topping it off between 45 to 55 psi is a great pressure range, and depending on your tire, maybe even up to 65 psi.

Hope this helps bro! Hope ya have fun at Carter this weekend. Going to be shredding our local trail….hahaha

[ebjr]

Thanks man. I am going to try the lower pressure next time out. Pinch flats are a concern but so is another sliding incident that leaves me on my back again! How common are pinch flats and is that caused more by going below a certain threshold?

BTW, Carter is now in jeopardy. I made the mistake of asking my wife to join assuming the grandparents had no plans. not so lucky as they are out of town this weekend. so now since she can’t go, apparently I can’t either as I already rode too many times this week without her. not sure if that is a fair stance on her part but i’m gonna let it slide for now and likely stay close to home. If I don’t hit it this weekend I will definitely try it sometime next week.

[CP1]

What tire are you running on your bike? What size as well? That would give me a better ideal. Generally you really want to stay withing the realm of the PSI recommended on the tire itself. My 2.4 Ardents will go as low as 25psi by the tire standards, but can go as low as 20 psi if so needed (but I do not like that at all) because of my thicker tubes.

Pinch flat is when the tire pressure is usually lower than normal and the tube gets pinched on the rim, causing a snake hole bite, causing a flat (hole in the tube). Can be very annoying.

I seldom ever get them, as I run heavy duty DH tires and thicker tubes.

"ebjr" wrote

BTW, Carter is now in jeopardy. I made the mistake of asking my wife to join assuming the grandparents had no plans. not so lucky as they are out of town this weekend. so now since she can’t go, apparently I can’t either as I already rode too many times this week without her. not sure if that is a fair stance on her part but i’m gonna let it slide for now and likely stay close to home. If I don’t hit it this weekend I will definitely try it sometime next week.

BUMMER!!! I understand, but my wife is happy when she gets rid of me per say… 😆 She rides with us on the trails and urban, but she is a real passive rider, and does not do the things we do.. 😆

[ebjr]

They are the stock tires that came with the bike…Maxxis Sphinx. 26 x 2.1 in front and 26 x 1.95 on the rear.
The Psi listed on the tires is 35-65psi.

[CP1]

"ebjr" wrote

They are the stock tires that came with the bike…Maxxis Sphinx. 26 x 2.1 in front and 26 x 1.95 on the rear.
The Psi listed on the tires is 35-65psi.

drop them to 35 to 38psi and try that, as that should help you out with the tire sliding. I would recommend carry a hand pump and tube patches as well. Comes in pretty handy… 😉

[Greg Heil ✓ supporter]

"ebjr" wrote

This leads to my concern, is there a such thing as perhaps stretching and decompressing the tube too much with these increases and decreases in tire pressure?

This shouldn’t be an issue… don’t worry about it.

Also, finding the sweet spot between traction and pinch flats can take a little time, but once you do, you’re golden!

[blundar]

There are a few variations to the tire pressure thing:

The first 4 were already mentioned…
1. Pavement and hard packed limestone fire roads, Raise your tire pressure.
2. Singletrack trails and softer soil, Lower your tire pressure.
3. Getting pinch flats, Raise your tire pressure.
4. Too much sliding on dirt trails, Lower your tire pressure

Add these to the tire pressure equation:
5. If you are a heavy fellow, Raise your tire pressure.
6. If you have high volume tires (2.3" up to 2.5" or higher), Lower your tire pressure.
7. If you have tubeless tires, Lower your tire pressure.

I always carry these with me on every ride: frame pump, pressure gauge, tire patch kit, tire levers, and an extra tube.

Like mtbgreg1 said:

"mtbgreg1" wrote

…finding the sweet spot between traction and pinch flats can take a little time, but once you do, you’re golden!

[ebjr]

Thanks everyone for your input. I rode a bit Christmas day and lowere the pressure from 60psi down to 38. Definitely notice a big difference. My wife did as well. Looking to ride again tomorrow and may drop it down a bit more…maybe, It felt pretty good at 38. I think learning to take corners and turns better helped as well. I was using my handlebars way too much.

[BRuybalid]

Read this blog about cornering skills…
http://www.bikecarson.com/2009/10/23/tu … ter-rider/

I would experiment with tires as well. Some tires grab the trail much better than others. Ask around to see what others are using on the trails you ride most and try to find a set that works for you. Keeping in mind that wider tires work great in soft conditions, aggressive side knobs corner better, some tires are great on the front but you might need something different on the back, and dual compound tires are a must for all around performance.

[CP1]

Here is another video to definitely watch for cornering techniques…

http://www.pinkbike.com/video/265915/

[ebjr]

Great article and link. I have been practicing turning my knee out and putting pressure on my outside foot. Not sure ive been turning my upper body as well. Will be heading out to Carter tomorrow and will give this a try. Thanks again.

[CP1]

"ebjr" wrote

Great article and link. I have been practicing turning my knee out and putting pressure on my outside foot. Not sure ive been turning my upper body as well. Will be heading out to Carter tomorrow and will give this a try. Thanks again.

You can really practice this anywhere bro, even on your street or even paved trails. Just remember that you are kinda of throwing your bike into the turn per say. This is what it will feel like when you execute this move. Swing those knees into the direction of your turn and your back side outwards from your turn and somewhat lean into you bars in the direction of the turn. It is a simple and absolutely fun execution, but it will take a few times and runs to get it to perfection per say. When you are riding down your street at speed or slowly, execute this move and do a complete switchback with out turning off the road. Other words doing a complete u-turn on a single lane street. It can easily be done with this hip turn. I just taught my son how to execute this move almost flawlessly on street and dirt, and he has been shredding big features since he was 6 years old (14 now). Yes, he is a slow grass hopper per say… 😆 😆 😆

[Tragedy1965]

I use 45-50 lbs. all the time and haven’t had any problems yet, but I happen to like a firm ride (for both my bike and my car) no matter the surface I’m riding.

[blundar]

"Tragedy1965" wrote

I use 45-50 lbs. all the time and haven’t had any problems yet, but I happen to like a firm ride (for both my bike and my car) no matter the surface I’m riding.

That is a good pressure if you are riding pavement or packed limestone trails. For off road use, you will loose a lot of grip with that kind of pressure.

[Author]

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