Cold pilot power pressures

Northern RR · 04-14-2005, 11:01 PM

I have spent the night reading up on what pressures to run in my new pilot powers(

) I have seen anywere from 29 to 34PSI for the front and 31-36PSI for the rear...I just wanted to make sure that these are taken when the tire is COLD and also I wanted to find out how the tires wear at the lower pressures for street riding? Any help is greatly appreciated...Northern RR

Kidder · 04-15-2005, 12:02 AM

I run 36, 40 on my 04 Gixxer Thou.

Northern RR · 04-15-2005, 8:06 AM

Do you have any traction issues running those pressures

? how are they wearing?

I have been finding that when running around 36-38 in the rear that it likes to break traction a lot(probabbly just the roads around here

)

Newfie TLR · 04-15-2005, 8:43 AM

Rob, I'm not sure of the rear, but I know in the front, less than max rated pressure will cause a bad case of cupping. I've found once it starts, the tire will always have it and will usually get worse. Now, you must note that I've never run on Michelins so I'm only guessing those will act the same as Bridgestones and Dunlops.

I run 42-42 almost all the time unless I go to the track. If you go for a "spirited" ride in the twisties, you may want to drop pressures, but then bring them up again. You know the roads down here, any ride is 99.9% on the center of the tire so we never get a chance to break the tire free.

ccwilli3 · 04-15-2005, 9:56 AM

I'd contact a michelin tire rep or race tire distributor, but I'd doubt that 36/42 would be what they'd recommend.

Newfie TLR · 04-15-2005, 10:57 AM

Quote:

Originally Posted by ccwilli3

I'd contact a michelin tire rep or race tire distributor, but I'd doubt that 36/42 would be what they'd recommend.

If that's what's on the sidewall, I'll bet they will, under normal street riding, that is.

motojedi · 04-15-2005, 11:51 AM

I just ran mine for the first time on the track last sunday. I started with 30psi front and rear and had a 4 lb. gain in the front and 5 lbs. in the rear after the first session. I find this to be perfect. The tires felt fantastic. I'll probably add about 4 to 6 lbs. for the street. (34-36f/34-36r) The 30 psi starting point (cold) was reccommended by the tire-guy with Sportbike Track Time.

Northern RR · 04-15-2005, 1:06 PM

sounds good, that is pretty close to what I am running now, I guess I just need the roads to clean up so that I can really have a good uidea of how well they stick

CBR929RE · 04-15-2005, 10:13 PM

Quote:

Originally Posted by Newfie TLR

If that's what's on the sidewall, I'll bet they will, under normal street riding, that is.

doesn't the sidewall just give the MAX psi for the tire

FuTAnT · 04-16-2005, 12:20 AM

Quote:

Originally Posted by Newfie TLR

Rob, I'm not sure of the rear, but I know in the front, less than max rated pressure will cause a bad case of cupping. I've found once it starts, the tire will always have it and will usually get worse. Now, you must note that I've never run on Michelins so I'm only guessing those will act the same as Bridgestones and Dunlops.

Bzzzt, the Michelins love lower pressures, and don't cup like the Bridges and Dunslops.

I run 32f, 36r and find them brilliant. Wear rate is also fantastic. I just leave them at this and scratch away! They really do work well at lower pressures than other tyres.

Scratch · 04-16-2005, 12:22 AM

Quote:

Originally Posted by FuTAnT

<snip> I just leave them at this and scratch away!

You rang?

I find 32f 33r to be optimal for the street w/ power's. But that's just my opinion.

Newfie TLR · 04-16-2005, 12:35 AM

Quote:

Originally Posted by CBR929RE

doesn't the sidewall just give the MAX psi for the tire

Yes, just the MAX. That's all I've ever seen anyway.

MrFurious · 04-17-2005, 5:45 AM

I will concur of the approximate pressures of 33F - 34R

abtech · 04-17-2005, 8:32 AM

Okay, just had to check in on this one:

Picking an "ideal" pressure for track riding is like trying to pick a single "ideal" gear ratio for 4 different/dissimilar tracks. It just ain't gonna happen.

First of all, the starting pressure is relative and is used as a baseline to attain a 20% growth in pressure once the tires come up to full running temperature. Although the ideal "running temperature" can vary from brand to brand and compound to compound, it is usually between 170 and 185 degrees fahrenheit. This correlates to a standard increase (from stone cold to full hot) in pressure of approximately 20%.

In other words, regardless of your original cold pressure, once the tire is hot it should now be: original PSI + 20% of original PSI (30 pounds cold should be 36 pounds hot).

The actual percentage can be fine tuned, but this is a generally accepted guideline and the reason some manufacturers recommend a higher than "popular" cold starting pressure, as lower cold pressure will cause overgrowth and the tire will run much hotter than the compound/carcass was designed for.

This procedure of measuring pressure growth will take all of the variables into account including bike/rider combined weight, pace, ambient and surface temperatures as well as tire compound.

NB: As mentioned in another thread long ago and far away, the growth percentage for street riding (all else being equal) is around 10 percent.