Tyre Pressure for MTB trails

QueenMTBee

I haven't had to adjust my tyres since I bought my full suss but something felt a bit "off" on my last ride and the tyres look a bit squishier than they did before. What pressure should my tyres be at for trails (both natural and the likes of Ticknock)? I have access to a very fancy bike pump (triathlete housemate).

Lemming

QueenMTBee wrote: »

I haven't had to adjust my tyres since I bought my full suss but something felt a bit "off" on my last ride and the tyres look a bit squishier than they did before. What pressure should my tyres be at for trails (both natural and the likes of Ticknock)? I have access to a very fancy bike pump (triathlete housemate).

It depends really. There's a lot of personal preference (within reason) on tyre psi taking into account everything from rider weight to how wide your rims and/or tyres are, how strong your tyre side walls are, tubes vs. tubeless for rim seating, etc. Not to mention how comfortable you are with your setup and what sort of riding/riding-style you're expecting of yourself & your bike.

I would hazard an estimate anywhere in the 20-30 psi range give or take. I've seen comments in various media about running 21-24 psi but again take that with a pinch of salt as your mileage may vary.

QueenMTBee

Lemming wrote: »

It depends really. There's a lot of personal preference (within reason) on tyre psi taking into account everything from rider weight to how wide your rims and/or tyres are, how strong your tyre side walls are, tubes vs. tubeless for rim seating, etc. Not to mention how comfortable you are with your setup and what sort of riding/riding-style you're expecting of yourself & your bike.

I would hazard an estimate anywhere in the 20-30 psi range give or take. I've seen comments in various media about running 21-24 psi but again take that with a pinch of salt as your mileage may vary.

Thanks. I'll see what pressure they are at now and maybe put a little air in and see how it rides.

They are 27.5, 2.25, tubes at the moment but tubeless compatible. Also has "29C" and "tire section width 54mm" on them.

C3PO

QueenMTBee wrote: »

Thanks. I'll see what pressure they are at now and maybe put a little air in and see how it rides.

They are 27.5, 2.25, tubes at the moment but tubeless compatible. Also has "29C" and "tire section width 54mm" on them.

Because you have tubes in them you will need to run them a bit harder to avoid "pinch flats" - depending on your weight, I would inflate them to about 28-30psi. See how that feels and go from there!

QueenMTBee

So I pumped them up to just under 30psi and took it out for a spin in the local woods. I think they are too hard now as it was very bouncy and bumpy and I didn't feel like I was in control when going over tree roots. I'm around 58kg. I think I'll let a little air out and try it again.

Mr. Grieves

It should be proportional to your weight, and a bit higher if you're using tubes.

I would put 20 psi in the front and 23 psi in the back as a starting point and see how you get on. It's very difficult to pinch puncture a front tyre so you should be safe bringing that one lower.

C3PO

QueenMTBee wrote: »

So I pumped them up to just under 30psi and took it out for a spin in the local woods. I think they are too hard now as it was very bouncy and bumpy and I didn't feel like I was in control when going over tree roots. I'm around 58kg. I think I'll let a little air out and try it again.

Yep - that's the correct approach! Most people will try and run as low pressures as they can get away with for grip and comfort. I use 23-24 psi in 2.25 29er tyres at 81kgs but I run them tubeless so don't have to worry about pinch flats!
Probably the best upgrade you can do to an MTB is to convert to tubeless - makes a huge difference!

QueenMTBee

C3PO wrote: »

Probably the best upgrade you can do to an MTB is to convert to tubeless - makes a huge difference!

Stupid question but how do I do that? I can't just take out the tubes and put air straight in the tire?! (I know I'm going to read this in a year and be scarlet that I asked this!!!)

C3PO

QueenMTBee wrote: »

Stupid question but how do I do that? I can't just take out the tubes and put air straight in the tire?! (I know I'm going to read this in a year and be scarlet that I asked this!!!)

Fair question ... we all started at some stage!

It all depends on your current set up. At best you need to take out the tubes, insert tubeless valves into the wheels, put tyre sealant in and inflate. But more likely you will need to do a conversion on the wheelset and the tyres may not be suitable. I would suggest visiting your LBS and asking them to have a look. Where in Dublin are you based?

QueenMTBee

C3PO wrote: »

It all depends on your current set up. I would suggest visiting your LBS and asking them to have a look. Where in Dublin are you based?

I'm getting my dropper fitted this weekend so will ask the guy to take a look at my tyres. Damn the shopping list just keeps getting longer!

QueenMTBee

C3PO wrote: »

But more likely you will need to do a conversion on the wheelset

My wheels are tubeless compatible already.

C3PO

QueenMTBee wrote: »

I'm getting my dropper fitted this weekend so will ask the guy to take a look at my tyres. Damn the shopping list just keeps getting longer!

It will get worse ... much worse!!

QueenMTBee wrote: »

My wheels are tubeless compatible already.

Probably still need to have tubeless rim tape fitted.

Mr. Grieves

QueenMTBee wrote: »

My wheels are tubeless compatible already.

If you are lucky, you won't need rim tape. Take off the tyre and if the rim is solid with no tape and you can't see holes for the spokes, then no tape is needed.

Otherwise you'll need to buy and fit tubeless rim tape.

You'll need valves- you can buy them or cut them off an old tube.

You'll need sealant.

You'll need a means to inflate the tyre very quickly so that it will 'pop' onto the rim. A CO2 canister works, or a compressor (at a petrol station), or a special tubeless pump like an Airshot. In some cases a regular pump is enough. CO2 canister is my prefernece, they're cheap, although you should deflate the tyre and pump up with normal air once the tyre is seated on the rim becuase CO2 is bad for the sealant.

So it's a bit of hassle you may prefer a shop to deal with, but it's worth it for the low pressures you can run!

LagunaSeca

Tubeless conversion is a great upgrade.

Haven't had a puncture in 15 months since I did it and ride quality/damping is so much better.

Good tips above for set up and inflation. My method is to pump like a mad thing using a track pump and if that fails to seat the tyre bead spin down to the local garage and use the compressor. You'll need one of these to use the garage compressor with a presta valve....

http://www.chainreactioncycles.com/ie/en/stans-no-tubes-presta-schrader-valve-adapter/rp-prod38828

Last tip is to remove the presta valve core before inflating which will let a bigger volume of air quicker into the tyre.

Used to run around 28psi with tubes and now run 21 front / 23 rear.

nordicb

You may also try latex tubes, performance wise they are somewhere in between normal butyl tubes and tubeless, at a fraction of a price of tubeless.

muckwarrior

Another tip to get the tyre to seat is to inflate it with a tube first. Then take out the tube while ensuring that that one side of the tyre stays seated on the rim. I find if one side of the tyre is fully seated then the other seats handily enough, whereas if you're trying to get both to seat at once then air just escapes too fast for it to inflate.

saccades

nordicb wrote: »

You may also try latex tubes, performance wise they are somewhere in between normal butyl tubes and tubeless, at a fraction of a price of tubeless.

I really wouldn't and they really aren't - they don't hold air as well butyl and you are missing out on the benefits of tubeless, lower pressure giving massive amounts of grip, low rolling resistance with no pinch flats.

And no sealant for regular punctures either.

QueenMTBee

Thanks everyone for the advice - however, it turns out I am already tubeless!!! I've reduced the tyre pressure considerably and it rides a lot better now. I've now 18psi at the front and 22psi at the back.