TRF Forums

Hi All
I have just rebuilt a 1997 army xr250r
so its road legal with road legal / off road tires fitted
the service book says 15psi front and back can this be right????
where as all my others bikes have been at least in there 20's /30's
why so low???????????????
I will use this on the road as well

Thanks in advance
Si

nothing wrong with 15psi, depends what your riding on, do go down to 12psi for muddy stuff

Sounds like an off-tarmac (only) tyre pressure to me. The 20s / 30s (psi, F/R) would be on-tarmac pressures.

15psi will feel pretty vague on tarmac, and will start to overheat the tyres due to excessive flexing of the tyre if you start ride at a reasonable whack (i.e 'decent road speed') with the tyres set to an off-tarmac pressure - to the point that you will almost see them wear down as you ride! (although the lower pressure will serve you well on the softer stuff by giving the wheels a nice, wide footprint from the resultant chubby contact area).

I don't stop and alter tyre pressures for tarmac and green lanes, just leave it at the same all day, and have never had any issues, but it is why rim locks are required

You'll get lots of different opinions on this subject, i'm not saying mine is correct but it suits me.

I ride a Yamaha TTR250 and average 6000 miles per year.

My mileage is probably 60% - 40% in favour of road use, but all this is done on various makes of road legal knoblies which I never run above 15psi back and front. My journey to one ride meeting point includes a 20 minute motorway stretch, when I ride up to 60mph quite comfortably, and sometimes a bit more.

Recently three mates and myself did a 3 day trail riding trip of at least 400 miles, 2 TTRs, XR250 & XR400, there were several types of road legal knoblies between us, all running 15psi and not a tyre isssue for any of us, we do all use rim locks [security bolts] whatever, and heavy duty tubes.

The choice is yours.

Get out and enjoy

2 Yams

What i do's is, have my front and rear at road pressures (22f, 27r i fink) until i get to my first lane, then let them down to 15ish psi and leave them like that until i get home even though i'm doing mixed road/lanes

I ride with 12 in the rear, 15 front.
I've stayed at these pressures on all my trail bikes from a TTR250 to my current WR450.
I do use rim locks.
How heavy are you? I'm 11 stone but my 16 stone mate has a bit more in his tyres

I use 10-12 psi rear & a tiny bit more in the front + rim locks on the Serow & don't change pressures. I run the KTM on 12-14 psi rear (bit more in front) & don't change pressures. I ride 15 miles to work mostly around 60 mph, but sometimes a blast of overtaking to above 70. The rear (mitas CO2) is still going strong after 3000 miles. Handles well, for a knobbly now it's worn down a bit, too. Not saying it's right for all, but it works for me.

Hi All Thanks for the comments
The main thing is not knowing
My tenere 750 runs at 25 front and 29 rear but it is double the weight
as long as there not going to fall off the rim!
Sounds like running low will wear out on the road quick
but what about running to high what will that do????????????
apart from a spine nobblie ride.

You will get less grip if you run the tyres too hard. For the cost of Mitas CO2 or Army Specials you may as well run soft & get the grip. You'll get more wear, but it's better than possibly falling off.