# air pressure for cx tubeless tyres



## lvhdds (Jan 9, 2014)

Hello guys,

during Christmas Holidays I´ll will assemble my new Gravel-/Crossbike. The wheels are build with NoTubes Grail rims and I bought the Schwalbe X-One Tubeless tires. I have a lot of experiences with the air pressure for mountain bike tyres (tubeless). Normally I run 19,5 psi/1,35 bar in the front and 22,5 psi / 1,55 bar in the rear tyre (@ 172 lbs/78 kg). 

What about the cx typres? I think about starting at 36 psi/2,5 bar for the front and 40,5 psi/2,8 bar for the rear tyre. Does anybody have some experiences or recommendations? Thanks. 

Greets,
Daniel


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## bikerector (Oct 31, 2012)

Those would be good pressures to start with. If you're planning to do more of a pavement or hardpack gravel setting, a little more wouldn't hurt. I prefer a harder tire for pavement as squishier tires leave a bit to be desired when pushing it through corners. I prefer something in the 45-65 psi range for a mix of road and gravel depending on how much is gravel and how rough that gravel is. The 65 end is if the gravel is pretty smooth with almost no loose gravel to push the tire around, very hardpack.

I weigh 220 so you can probably easily drop 5-10 psi from my numbers to adjust for weight to get a similar ride. This is also assuming you're on 32mm or 33mm tires. I was using maxxis mud wrestlers at 33mm. I'm looking forward to trying the new 32mm refuse tires this season for gravel rides. I've loved the 28mm on my road bike for mixed pavement/gravel rides and the 32m tubeless on the CX bike should be stellar for gravel races in my area as long as it stays dry.


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## lvhdds (Jan 9, 2014)

Thanks for the very detailed feedback.

For dry conditions I´ll definitely increase the air pressure. 65 psi seems to be a good recommendation. 

In my area during winter you have muddy conditions or frozen dirt.

Hopefully the bike also has a good performance on easy to ride mountain bike trails without steep downhills or rocky section. For these conditions I`ll start with my proposed setting.

Tire width shouldn´t be a problem on the Grail rim. Already the Schwalbe One 28mm road tires have got a measures width of 32mm. I would predict something around 35mm for the "33mm" X-One tires.


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## Stoneman (Mar 1, 2009)

I run American Classic 29 tubeless wheels with 21mm internal width. I weigh about 175 and have raced hard as low as 28psi front and 30psi rear with no problems using Specialized Terra 2Bliss and Maxxis Mud Wrester TR tires. Tubeless ready rims and tubeless ready tires and the key.


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## serious (May 2, 2006)

Another datapoint: I weight 150lbs and use 30-32F and 38R when riding XC trails and push it to 40F and 45R for gravel or road. I have the American Classic Hurricane with the Challenge Chicane tires, but I use tubes.


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## lvhdds (Jan 9, 2014)

Stoneman said:


> I run American Classic 29 tubeless wheels with 21mm internal width. I weigh about 175 and have raced hard as low as 28psi front and 30psi rear with no problems using Specialized Terra 2Bliss and Maxxis Mud Wrester TR tires. Tubeless ready rims and tubeless ready tires and the key.


Very interesting. You´re riding your bike nearly in the same weight range as me. Internal width for the Grail rims is 20,3mm. As soon as possible I´ll also test different pressure setups. There seems to be some opportunities for dropping it.


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## November Dave (Dec 7, 2011)

You should be able to go down to 24ish in the front and 26-27ish in the rear using Grails. We haven't tried the new Schwalbe tubeless cx tires, but good tubeless tire setups aren't very limited in terms of running low pressure. A bunch of info is here. You will probably feel too much squirm before you're at risk of burping. 

Conversely, 65psi is going to be about the upper advised limit for any tubeless cx tire, and also your rims. I'm not near a Grail at the moment but the pressure limits are on the sticker on the rim.


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## namaSSte (Jul 28, 2004)

Some great suggestions here already. I did manage to burp some Specialized Tracers (33c) when running them around 22psi on the front. I took a hard hit but I did burp it. FWIW, I weight 155. I typically race and ride trail around 28F/32R and bump that up about 5-7psi if mixing in gravel and road.


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## mudge (May 15, 2010)

In the not to distant past, I was closer to 200 than I'd like to admit, and I would run 60 f/65 r in my 28mm Hutchinson road tires. At 180, I run a few psi less now. In 38mm cx tires, 35 f/38-40 r.


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## Manning (Jul 8, 2010)

I run the cx race wheels at 32psi f, 38 rear. I still bottom the tire on roots frequently at this psi. 
The gravel wheels are at 35 f, 45 R. I rarely get rim strikes at these pressures on gravel, and we've got chunky gravel around here. 

I'm around 170-175 lbs.


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## lvhdds (Jan 9, 2014)

November Dave said:


> ...I'm not near a Grail at the moment but the pressure limits are on the sticker on the rim.


The limit is up to 100 psi for 28mm tires.


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## michaelcogburn.c (Nov 22, 2015)

I've never run a tubeless tyres based cycle. But planning to get one for the first time. What brand would be good for a beginner?


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## namaSSte (Jul 28, 2004)

boy that's a tough one to answer. really depends on intended use. My suggestion would be to start with an all arounder unless you know you'll only be riding on certain terrain and in certain conditions. tires like the Specialized Tracer, WTB Cross Boss, and Clement MXP would all be good starting points in my opinion. let us know what you'll be riding/want to ride and I'm sure others will have many suggestions.


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## lvhdds (Jan 9, 2014)

Manning said:


> I run the cx race wheels at 32psi f, 38 rear. I still bottom the tire on roots frequently at this psi.
> The gravel wheels are at 35 f, 45 R. I rarely get rim strikes at these pressures on gravel, and we've got chunky gravel around here.
> 
> I'm around 170-175 lbs.


Which rim/tire combinations do you ride for cx race and gravel? 

I only have a lot of experiences with mountain bike rim/tire combos. Internal rim width seems to be most important. Followed by tire side wall stiffness.

Hopefully the rim strikes did not damage your rims. The latest rims with hookless profiles are a great improvement for that issue. Much more stiffness and less damage (dents etc).


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## November Dave (Dec 7, 2011)

Yup, and 45 for 32s (I'm near several Grails now)


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## thisisthebeave (Aug 30, 2015)

High 20 psi front, mid 30 psi rear. Nano 40's and I'm ~235lbs.


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## 4Crawler (Jul 13, 2011)

thisisthebeave said:


> High 20 psi front, mid 30 psi rear. Nano 40's and I'm ~235lbs.


I run about that pressure in my 700x40 Schwalbe Marathon Mondial tires, tubeless on Stans ArchEX rims. I have a short stretch of golf-tennis ball sized gravel on a trail that I use to test pressures on. I'll hit that section of trail at a good speed and feel for the tires bottoming out. Once I dropped to 27psi in the rear, I started to feel the tires bottoming out.

I run the same pressure on pavement or at most 5psi higher if doing an all pavement ride.


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## Manning (Jul 8, 2010)

lvhdds said:


> Which rim/tire combinations do you ride for cx race and gravel?
> 
> I only have a lot of experiences with mountain bike rim/tire combos. Internal rim width seems to be most important. Followed by tire side wall stiffness.
> 
> Hopefully the rim strikes did not damage your rims. The latest rims with hookless profiles are a great improvement for that issue. Much more stiffness and less damage (dents etc).


CX race wheels are Kinlin TL 21 rims from bikehubstore. 21mm inside width. Tires are Clement PDX/MXP/LAS depending on conditions. On these rims there are almost 37mm wide. 

Gravel wheels are some Alex rim that's 17mm inside width. Front tire is a WTB Nano 40, rear is a WTB Cross boss.


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## chandne (Jan 22, 2004)

Good info here. I just bought a Crux with Axis 2.0 heavyish rim s but will try to test them up tubeless. Instead of traditional rim strips, I will use Fatty Strippers (I know...I know..) rim strips cut in half. They are rubber rims trips that should do better than traditional rim strips since they actually cover the bead as well. Instead of using the stock Trigger tires, I should get some tubeless-ready tires though. I'll start at 65ish psi (175 lbs) since I will mainly be riding on pavement for now. When on gravel roads, I'll try the recommended 35-45.


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## lvhdds (Jan 9, 2014)

I did the first tests with my new bike. During the first ride I nearly had dry conditions. Starting with 36 and 41 psi I didn´t feel comfortable. Missed front wheel feedback while cornering especially on normal roads. But also on gravel. In the rear I wasn´t satisfied with the loaded tyre shape. Looks a little bit "squeezed". Bottom outs seemed only to be a question of time. That´s why I increased the pressure up to 40 and 45 psi. In my point of view a better trade-off. 

After rainy 24h we had muddy conditions for the second ride. I still felt comfortable with the "high" pressure setup in the front. Maybe for the next time I´ll drop rear pressure a little bit. Hopefully I could gain improved traction. Because missing it caused two interruptions in uphill sections :nonod:


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## single1x1 (Mar 26, 2005)

I agree with Dave, I was ridding trails today on my SS cross bike setup tubeless with Specialized Terra tires on Belgium plus rims, and I was running about 24 front and 25-26 rear, I'm about 165# and it felt pretty good, though I did feel the rear rim on some roots, but good traction, for reference I used to run 28F 30-32 Rear on similar sized tires even on narrower rims with regular tubes, though I had to be careful not to pinch flat, the difference between the tubeless or with tube pressures are more supple ride, and better traction when ridding trails, or cross racing, also more confidence that you will avoid pinch flats. When ridding gravel roads on Belgium + or my newer November/Pacenti rim wheels I would run 35-45 PSI with a set of the Specialized Trigger 38 tires tubeless, maybe a little higher if I would ride more on the road then on gravel. With similar sized Continental semi slicks and tubes I would run 50-60 PSI for gravel ridding, and even if I was just doing a road ride on cross tires I wouldn't go higher than 65 PSI



November Dave said:


> You should be able to go down to 24ish in the front and 26-27ish in the rear using Grails. We haven't tried the new Schwalbe tubeless cx tires, but good tubeless tire setups aren't very limited in terms of running low pressure. A bunch of info is here. You will probably feel too much squirm before you're at risk of burping.
> 
> Conversely, 65psi is going to be about the upper advised limit for any tubeless cx tire, and also your rims. I'm not near a Grail at the moment but the pressure limits are on the sticker on the rim.


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