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New to carbon rims: Tire pressure?

1766 Views 8 Replies 6 Participants Last post by  Tjomball, 
Prognosticator
My new bike came with Astral carbon rims. Sounds like they have a pretty good reputation. I have always ridden aluminum rims and run my tires at between 18 and 23 PSI depending on where I am riding. As you can tell by those pressures, I am not a gravity defier. Never had a problem with aluminum rims at that pressure.

It might also make a difference that I went from 100MM to 120MM in the rear.

Do I need to run my tires at a higher pressure to avoid damaging the carbon rims?

Thanks!
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127.0.0.1
Q: Does Astral recommend a maximum tire inflation pressure?

A:The size and tire pressure are related and are dependent on the inner width of the rims. Check you wheel for a sticker indicating the rim size. The format is similar to '622 x 25TC'. Correlate the 2nd number to the tire width and pressure in the chart below. In this example, a 25TC wheel could use a tire as narrow as 40mm at 35-60 psi (tubeless) or as wide as 67mm (2.65") at 20-35psi (tubeless).

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Prognosticator
I didn't realize that rim manufacturers had recommendations. Based on my rims (30TSS) and tire width (2.25), it looks like 25 PSI is as low as they recommend. That's kind of a bummer.

How closely do folks adhere to these recommendations?
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Jayem
Do you occasionally bang your rims on rocks and hard things?
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Prognosticator
Jayem said:
Do you occasionally bang your rims on rocks and hard things?
Click to expand...
Not really. The trails here are rough but sadly I don't think I am fast enough to do that.
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127.0.0.1
the rules are: don't explode rim from high pressure, charts tell you this


the low end is, don't bash the rim on rocks and whatnot, charts can't tell you this,
it depends on you to make adjustments
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M
I'd start by running the same pressure as your other rims. If you feel that you're hitting the rim then up the pressure. I would think the same hit that would deform an alloy rim would also damage a carbon rim at the same tire pressure.
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hammersorethumb
Danny MacAskill test Carbon Rims

I wouldn't worry about it.

Also this: Silca Tire Pressure Calculator
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Tjomball
I have a set of carbon wheels on the way. And I will absolutely be running inserts with that wheelset.
In my case,Vittoria Airliners.
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