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MTB Specific: What Tyre Pressures


Theo18

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I'm 68kg, running tubes with 29er Racing Ralphs 2.25, front 1.7 and back 1.9

 

Ride all kinds of stuff, from road to magalies monster to hakahana trails on same pressures.

Edited by Kraggie
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I recently bought a new floor standing pump. With my old pump my pressures were usually 1.5 bar front and 1.8 rear (I weigh +- 85kg), but with the new pump to get to the same "feel" in the tyres, it's now 1.2 and 1.5 respectively. So this is a bit frustrating, because now which one is the "correct" pressure? :blink: But anyhoooo, I go with the ol' "thumbing the tires technique" in any event, so don't really care what the pump's dial says. :D

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  • 1 month later...

I've just pumped my tyres up to about 1.8 front and rear (tubeless) and they are super hard... Racing Ralph 2.1 EVO. Can't think they should be this hard? I weigh 86kg 

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I've just pumped my tyres up to about 1.8 front and rear (tubeless) and they are super hard... Racing Ralph 2.1 EVO. Can't think they should be this hard? I weigh 86kg

 

Take advice from the post above yours. Not all guages were created equally. If you sit on your bike with your rear tyre on a square edge, it needs to deform quite a bit. Probably about 1/3rd of the height of the tyre.

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  • 5 months later...

Morning everyone need some advice on tyre recommended pressure for my new Maxxis Cross mark tubeless 29er. I weigh 65 kg. Will have to see which pressures work for me but any suggestions are welcome. Cycle safely

Edited by Bloukrans
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  • 2 weeks later...

My sons and I have been doing a study of MTB tire pressure for his school project with lots of different trials - tar, dirt road, bumpy technical stuff. Collecting lots of data with different bikes and tire pressures. Interesting all tire pressures result in very similar times for timed runs in the trials, within the error margin of the tests which is about 5 %. The main thing that differs is the handling and grip. On tar the MTB tires have better handling and grip with higher pressures (2.5 to 3 bar). Off road is it is the reverse, less pressure has better handling, grip and braking until the tire feels squishy, which is a subjective thing. We experienced tire and rim damage when pressures were too low in the tests (1 bar).

 

So my opinion is that an off roader should ride with the lowest pressure that does not allow damage to your rim or tire in the style that you ride. For me this is 1.5 bar, front and back on tubeless (70 kgs). For tires with tubes, the tube is more easily damaged than the tire, so tubes I would ride at 2 bar at least for my weight. Maybe even more.

 

If you are running such low pressures, make sure you check your tire before each ride and finger tighten the valve as tight as you can. 1.5 bar could easily end up as 1 bar, if this valve is a little leaky because of sealant being stuck in the valve. This would ruin your ride for sure with a burped tire or rim damage.

Edited by martinpe
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  • 1 month later...

I run my front 1.5 and back 1.7 and weigh 84kgs.

This is on 29er Arch Ex rims, with tubeless Specialised purgatory's

Edited by Chubba
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I run my front 1.5 and back 1.7 and weight 84kgs.

This is on 29er Arch Ex rims, with tubeless Specialised purgatory's

I was also wondering about pressures since I went to tubeless. Currently 1.9 and 83kg (also 29er).

How do you find 1.5? I understood that you should not go too low else the tubeless tyre may unseat? Also a bit worried about klapping my rim when hopping up pavements on my week round the burbs rides. You ever had an issue with this?

 

If I go softer, can I corner on the single tracks faster? I understand grip gets a bit better. How is rolling resistance affected of going softer?

Edited by DominionZA
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No issues with the pressures I run and I have a lot more grip now, especially on tight single track corners. Also much better on loose sand/gravel single track at speed.

 

The rolling resistance is a little compromised, as the wheel is softer, but I have 2.3 inch trail tires on specifically for grip on the trail, so doesn't factor really.

 

I suggest you play around with the pressures all tires handle differently, but a lower pressure is better, in my opinion.

Edited by Chubba
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Interesting comments. I am running tubes at the moment and the front is on 1.2 bar and back on 1.5

I weigh 105kg :eek:  and the pressure seems fine though I do prefer a slightly harder tyre, 

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Interesting comments. I am running tubes at the moment and the front is on 1.2 bar and back on 1.5

I weigh 105kg :eek: and the pressure seems fine though I do prefer a slightly harder tyre,

Holy crap. I am so used to tubes that 1.2 just seems extreme. My mate keeps telling me to lower the pressure, and based on what you guys are saying - I should.

 

One thing... When you ride Road on your MTB, do you up the pressure again? Or leave it low?

During the week I go for quick spins around the suburbs, and weekends hit the trails. So wondering if i should alter the pressure based on road or trail riding.

 

Edit: Just realised you said tubes at that pressure. Make that a double holy crap.

Question still stands for tubeless guys though please. Adjust or not when riding road vs trails?

Edited by DominionZA
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Interesting comments. I am running tubes at the moment and the front is on 1.2 bar and back on 1.5

I weigh 105kg :eek: and the pressure seems fine though I do prefer a slightly harder tyre,

Surprisingly low for 105 kg...I suspect a dodgy gauge. You should be getting snakebites with tubes at those pressures.
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Naa just strong sidewalls in tyres. I should be running the front aroun 1.5 and the rear around 1.8. I dont ride my MTB on tar if I can help it. Also if the terrain is harder then I will increase the pressure abit.

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Front 1.2 Bar - Rocket Ron 29 x 2.2

Rear 1.4 Bar  - IKON's 29 x 2.2 ( perhaps the tire with the most Volume compared to any other tire in its Class) 

 

Weight 75kg.

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