[Malta Mick]

Hi. I have a VN750 and would appreciate any advice for correct tyre pressures.
Front is 100/90 - 19
Rear is 140/90 - 15

I guess that these may not be the standard sizes but look forward to your replies.

Mick

 

[rick]

factory pressures should be on a sticker on the bike. Look on the inside of the side covers for it, possibly under the seat if not there. On my 800, its on the backside of the left cover I believe.

 

[Malta Mick]

thanks for reply, but we're talking about a 1989 bike that's had modifications - no stickers anywhere. Hence the request for advice.

 

[rick]

Found this info that shows the rear tire 150/90/15 as stock, the front looks right. Not sure what the pressures it shows mean, 0.14PSI front 0.14-0.15PSI rear?

http://www.mbike.com/kawasaki/vn750/1989

Just found this also that shows 34 front, 36 rear for the 84-86 models. yours should be about the same.

http://www.drivegreen.com/Motorcycle_Tire_Pressure_kawasaki.htm

 

[JS60]

Here is your key to tire pressures.
If you are using the same brand size and model tire as what came on the bike from the factory, ... then use the OEM recommendations.
If you are using aftermarket tires, ... then use the inflation recommendations printed on the sidewall of the tire.
This will give you the best performance and longest tread life out of that particular tire.
Good Luck, and keep the shiny side up.

 

[PatC]

Should be on the tire.

 

[Malta Mick]

tyre only shows maximum recommended pressure - 40 psi

think i'm going to go front 28 & rear 32

unless anyone has better suggestion.

thanks to all

 

[Wild Bill]

Here is your key to tire pressures.
If you are using the same brand size and model tire as what came on the bike from the factory, ... then use the OEM recommendations.
If you are using aftermarket tires, ... then use the inflation recommendations printed on the sidewall of the tire.
This will give you the best performance and longest tread life out of that particular tire.
Good Luck, and keep the shiny side up.

Not according to Michelin.

NB: The maximum pressure indicated on the tire is never to be considered for road use. This is the pressure corresponding to the tire’s load index.

http://motorcycle.michelinman.com/advice/faq/about-tire-pressures

 

[JS60]

Wild Bill does have a point. Running right at the Max in not a good idea. I should have included that 10% under that is about right, but it slipped my mind. My apologies.
I got this directly off the Michelin site he recommended;
"Too much pressure and the contact patch shrinks, the grip is reduced and you can expect a harsh ride. ... Low air pressure causes the contact patch to increase causing unsafe handling, an unstable sidewall and damage to the tire casing. Riding on tires with improper inflation, especially under-inflated, is dangerous and a serious safety issue."
I found with Avon Venom tires, that if you ran at the Kawasaki factory recommendations, they would squirm, flex, slip, and the tread would cup. However, at about 10% under the Max on the sidewall they felt like the bike was glued to the road. the ride wasn't as cushy, but not harsh. and even after slight cupping I was able to get over 10K from the rear and 14K out of the front. (exceptional mileage for an Avon Venom)
If your tire says 40 on the side, I would start at about 36. if it feels soft & squirms, go up a pound or two. if it feels harsh, go down a pound or two.
1 psi goes a long way in a bike tire!
I currently am running Michelin Commander II's and the sidewalls say 44 for the rear, and 42 for the front. ..... I'm running 39 and 36 respectively and they seem to be doing very well. The grip is excellent, and the tread-wear is phenomenal, and the ride is firm but not harsh.
(I am hoping to get better than 20K out of these Michelins)
Hope this helped a little
J.

 

[Malta Mick]

thanks J. But isn't 36 psi a bit high for motorbike tyres ?? That's taking your 10% off 40 max. recommended

 

[JS60]

"Too much pressure and the contact patch shrinks, the grip is reduced and you can expect a harsh ride. ... Low air pressure causes the contact patch to increase causing unsafe handling, an unstable sidewall and damage to the tire casing. Riding on tires with improper inflation, especially under-inflated, is dangerous and a serious safety issue."

It all depends on the tire construction. And the people that made the tire, should have the best idea of what that particular tire requires.
Use that 10% as a starting point to get yourself into the ballpark.
Then you use the feel of the ride to fine tune it.
And remember that 1 pound can go a long way in a small tire like what's on a bike.
If the ride feels to harsh, let a pound out, and ride it again. Repeat until the ride no longer feels harsh.
But if it feels soft & squirmy in the corners, go up a pound, and try it again.
eventually you will get it dialed in.

As for 36psi sounding a bit high, remember that a lot of the newer tires are designed to run at higher pressures than the exact same tire made a decade ago.

over-inflated a little is much safer and more forgiving than the same tire under-inflated

 

[PatC]

In the heat of summer, I run mine at 32 front and 36 rear. But I have the fat Classic tires.