Author Topic: tyre pressure  (Read 6078 times)

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lms6201

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tyre pressure
« on: June 07, 2008, 06:01:53 am »
 something i,ve always just guessed my way around , but would anyone have a good base formula for  things like fr/rear  hard surface /soft ? any thoughts appreciated , like does more pressure stick the tread in deeper when it,s wet/soft or is it better to let the tyre spread over

Offline caps 999

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Re: tyre pressure
« Reply #1 on: June 07, 2008, 08:20:06 am »
13 front 13 rear and ajust from yjere if neccessary
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Offline Stewart Allen

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Re: tyre pressure
« Reply #2 on: June 07, 2008, 09:09:55 am »
I just make sure I blame incorrect pressure too hard or too soft when I fall off, sounds a whole lot better than I can't ride any good.
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Offline Freakshow

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Re: tyre pressure
« Reply #3 on: June 28, 2008, 08:16:51 pm »
I think 10-18 is a good mark for anything specially on loamy or soft stuff, any less and you need to check you rear has a good tube lock, and totally unscrew your valve retainers. 

IF its hard packed or you want to brake traction on corners you can keep uping as far as you like on the rear up into the 20 somthings, although i would keep the front under 20 unless you only had only long corners to run.

Also JUmps if they are ski jumps you might want to keep pressure in them both so you dont pinch a tube, you can always ride slower but if you got a flat you aint riding no where.
« Last Edit: July 04, 2008, 02:41:04 pm by Freakshow »
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Offline DJRacing

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Re: tyre pressure
« Reply #4 on: June 28, 2008, 08:30:48 pm »
I think it can change with different tyres and dirt conditions.
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Rosco400

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Re: tyre pressure
« Reply #5 on: June 28, 2008, 08:33:28 pm »
13-13 dry 11-11 mud, mind you I do occasionaly rip valves out of tubes ::)

Offline vandy010

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Re: tyre pressure
« Reply #6 on: June 28, 2008, 09:35:28 pm »
i used 13 13 for years and found the grip ideal and predictable but after a few flats, and i hate flats, i now run 15 15.
big change hey...
"flat bickie"

Offline Nathan S

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Re: tyre pressure
« Reply #7 on: June 28, 2008, 09:40:36 pm »
Wet = less pressure.
Rocky/hard = higher pressure.

The compromises aren't hard to work out:
Less pressure means less stability, increased chance of ripping out valves (Rossco will be delighted when I inform him of the new-fangled invention called a 'rim-lock'...;D ), more traction on soft/uneven surfaces, better clearing of the tread in mud, greater chance of a pinch-flat.

For racing, I start with around 13~14psi F&R and then adjust to suit. I never go below 10psi, and never above 18psi...
Trail-riding, I tend to add a bit more pressure because I feel that the small-but-definite reduction in traction is worth the extra puncture resistance.
I usually run more pressure on the short travel bikes for much the same reason. Maybe I should spend some money on suspension...


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Offline Freakshow

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Re: tyre pressure
« Reply #8 on: June 28, 2008, 09:40:54 pm »
So vandy you need to change your tag to " Flat bikie "
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Offline vandy010

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Re: tyre pressure
« Reply #9 on: June 28, 2008, 09:56:37 pm »
i'll pay that one freaky!
 :D
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Offline holeshot buddy

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Re: tyre pressure
« Reply #10 on: June 28, 2008, 10:28:19 pm »
heres my input been racing mx off and on
for 30 years
always ran 13 psi nearly everywhere
10 psi in the mud
never had flats  using standard tubes
in the bush 15 psi or less if using hd tubes ;D ;D
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Offline Graeme M

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Re: tyre pressure
« Reply #11 on: June 28, 2008, 10:36:45 pm »
By and large I run 12-14. Sometimes if it's wet I'll drop the rear to maybe 11-12, but that's about the only time I change it. Can't say I've ever noticed the difference between 12-15, it's really only when I get up above 15 or below 12 that anything becomes noticeable. Maybe I'm just not sensitive enough, but I reckon anything around 12-14 will work just fine.

Doc

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Re: tyre pressure
« Reply #12 on: June 29, 2008, 06:13:52 am »
I normally whack in 20lb front and rear before I leave and then when I get to the track and see what it's like I bleed out the excess pressure. Same as Graeme, I 'normally' run about 12lb. Have been known to run down to 7lb on the rear but that was with a low profile 6 ply tyre. Pieces of old inner tube slipped through under the tube and out each side onto the beads will do away with the need for those pesky pain in the arse rim locks or 'sun rim' type rim screws. Never had a tyre creep using this method and the 400 is a good test as it destroys tyres if you feel that way inclined. The guy who told me to try it was an ol' speedway sidecar racer (Vincent 1000) and he'd run next to no pressure on the biggest muther tyre you'd seen in all your born natural and all without any rim creep whatsoever.
« Last Edit: June 29, 2008, 07:57:14 am by Doc »

090

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Re: tyre pressure
« Reply #13 on: June 29, 2008, 08:26:50 am »
I was told the tyres these days need a bit more pressure to work properly so i run 16 psi. I dont like the tyre flexing on the rim either. If its muddy i take my ball and go home!Oh except if its cd5... or 6  ;D

mainline

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Re: tyre pressure
« Reply #14 on: July 01, 2008, 06:46:21 pm »
on a related note, what do you guys use for rim tape? is normal duct tape/wide electrical tape ok?