Tyres, Tpi And Tubeless | MTB Workshop & Tech | Mountain Bike | Forums - BikeRadar

pedlad · **Posted** Thu Nov 5, 2009 8:02 pm

I'm keen on replacing my slippy bonty tubeless tyres with Panarace Fire XC pro's which I liked on the old bike but does anyone know why would the UST version of the panarace fire xc pro would be shipped with a far lower tpi than the aramid tubed version (66 Vs 126) ?

After inital confusion on http://www.bikeradar.com/forums/viewtopic.php?t=12646957&highlight=

the panaracer site confirms that this is the case.

Can anyone tell me what are the pros/cons of lower tpi ?

Also they seem heavy compared to the non-ust ones. Would I be better looking at other tubeless tyres for all round use (nevegals had good write ups but they seem toi be discontinued)

nicklouse · **Posted** Thu Nov 5, 2009 8:08 pm

UST are heavier than tubes tyres as they have two jobs to do. Keep the air in and work providing grip.

tubed can have thinner walls as they dont need to hold air.

TPI the lower the number the bigger and stronger the threads.

"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools

SheldonBrown

pedlad · **Posted** Thu Nov 5, 2009 8:15 pm

cheers for the quick answer to my particularly geeky question!

So if tpi is not a consideration (it's lower to provide a stronger tyre to do the two jobs as you describe, can I expect the tread on the ust ones to operate as well as I remember the aramid XC pro ones doing?

Also will UST be as squidgy for uphill traction as the bonty ones - read somewhere UST was stiffer than other tubelss types?

cheers for you help

nicklouse · **Posted** Thu Nov 5, 2009 8:18 pm

well you can run UST at a lower pressure so yes they could be squidgy if you run them that low.

"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools

SheldonBrown

pedlad · **Posted** Thu Nov 5, 2009 9:02 pm

ok not really been running the bonty xc tyres at particularly low pressure but they seem to just squidge and grip going up rocky gravelly ascents...i'm new to both tubeless and full sus so hard to tell which is responsible for extra traction over my merlin HT with tubed Fire XC pro's.

The Bontt XC's just scare me over rocks though - no grip at all and lots of the trails round here have rocky corners...so if I can keep the uphill traction and gain some grip on the fast corners I'd be happy to spend the £70 on the Panarace Fire XC USTs

Doesn't sound like anyone is shouting NO - get these instead..........

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