Hi
We all know the recommended tyre pressures are 42psi front and rear.
What is the legal/liability situation if a specialist bike tuning/set-up company recommends the tyre pressures should be 36psi front and 42psi rear - it would be in writing from the company and they say it would beneficial to the handling of the bike???
I am thinking if the Vehicle Inspectorate/Police or in the worse case scenario an accident investigation team found the tyre pressures are not in accordance with the bike manufacturers or tyre manufacturers recommendations? Tyre wear would be a different issue but that's not the question.
Thoughts/comments or I am asking a question that isn't likely to arise or worth pondering about ??
Kind regards
Steven
I'm sure someone will be able to answer your question, but when i had my 1st set of PR2's fitted by a very reputable bike tyre shop they initally inflated them to 36F and 42R.
They were surprised when I asked them to put the front to 42.
I subsequently asked Kawsaki UK about pressures for these tyres on the GTR and their reply was on the lines off "we've not tested those tyres so cant reccomend a pressure"
P
Difficult question in one respect becasue there probably isnt a right or wrong answer, but on the other hand if it feels right with the lower pressures then run it at that. You'll know relatively quickly if its better or worse than 42+42.
I find that the bike isnt as reactive when cornering at the lower pressures but that could just be my style of riding.
From a Police point of view the AIU ( Accident Investigation Unit ) or now days called the ( Collision and Forensic Investigation Team ) will simply measure tyre pressures at any serious injury / fatal RTA as a matter of course. They will then check to see what is recommended for that bike / tyre mix, and if the tyre itself needs examining they will do it and then send it off to the makers for their expert opinion. That will constitute the case for the prosecution, so to speak. If the tyre is in good nick etc it would be for you to prove that it was NOT under/over inflated at the time of the accident if that was a contributory cause.
It would be MOST unlikely that you would get stopped and have your tyres checked as a matter of course on a day to day basis ... ie.. in all my years on Traffic I never did that !
In my honest opinion you are asking for trouble if you ran tyres at a pressure much different to that which is recommended .... all I would say is that your tuning / tyre company would get slaughtered at Crown Court ( if they had the balls to attend in the first place ! ) A letter, " In writing from a Company " would be worth jack shit ..... The entire world knows about tyre pressures and wear and stability which all leads to safety ... if you knowingly change that pressure, and have an accident in which tyres and pressures are a primary cause then you deserve what you get ... and that will either be cold porridge in D Wing or a life of being pushed about in a chair.
Hope that is plain enough ;D ;D ( it is of course only my personal opinion !!! )
What Rusty said, ;D yeah, that's what I meant.
My tyre pressure went down to 250 KPa, (app 36 psi) in the front and it definitely isn't an improvement.
To the contrary the front felt twitchy and unstable around corners.
Apparently the only advantage was that according to the computer I got more miles out of a litre of fuel and the difference between the speed my GPS showed and the speedo changed. :P
I am now back to 280-290 KPa (as it was when I got the bike) and it is nice and stable again.
DON'T DO IT!!!!
Many thanks LR.
I wasn't intending to run the tyres at those pressures because I didn't feel at all comfortable with the idea and that has confirmed what I thought would be the case if should ever have the severe misfortune to be subjected to another accident - one in a lifetime is one too many. I have seen Collision and Forensic Investigation officers in action, through work, and I know how thorough they can be.
Many thanks
Steve
A few years ago it was decided by the Japanese motorcycle industry to adopt a 'safe' set of tyre pressures for most of the bikes available on the market. 36psi front, 42 psi rear.
Using these presures gave a good level of stability and tyre life at normal road use, and also took away the time consuming job of testing new bikes and tyres at different pressures.
But some specialist bikes, like the GTR were tested because they fell out of the norm, the GTR being as heavy as the Space Shuttle and producing the same amount of thrust, also certain Bikes have had tyres designed round them, and so they have a different set of pressures to cope with the stresses on the tyre.
also you may find that some manufactures have done independent testing on their tyres with different bikes, so its worth checking the web sites to see if it differs.
For thems that have a sports bike as well, it can be well worth having a play with the pressures, 'specialy on hot days, my Tuono is crap with the rear at 42 psi but is fookin awsome at 38, but the trade off is heavy tyre wear.
Tis all about how the tyre deforms under load..... I used to work for Michelin motorcycle tech department before they moved from Watford so i can talk fer hours about tyres ...
Mogs
The tyre fitter I use also set the front PR3 to 36PSI which I didn't know until I went out on them for the first time, set it to 42 when I got home.
If you look in the owners handbook for the GTR it states to use ONLY the OE tyres on the bike which may throw a spanner in the works if you have an accident where tyres may be at fault.
PR3's do come up on Michelin's website as recommend for the GTR though.
LR, what pressures r u runnin ur PR3's at ?
I run my PR3's at 42 front and rear.
Quote from: Lonewolf on September 03, 2011, 06:13:41 PM
I run my PR3's at 42 front and rear.
Thanks for that LW.
42 Front and rear ... and all is well.
Bloody Hell that's some topic....Ill get me coat now...!
I have only had my GTR since March, but already have found unlike other bikes I have had, that the bike is really sensitive to tyre pressures. I have toured Germany Denmark, Ireland and France so far since I have had it, and really feel for me the bike is best at 42 Front and 45 Rear. I have gone through the original tyres with the bike, and unfortunately had a puncture on the replacement after only a few hundred miles, so on my third rear (Due to having to throw the punctured tyre away) and all differing makes. Now on Metzlar front and rear and the bike is really responsive at 42/45.
On the bike there is a plate showing recommended tyre pressures, and the above I think is about spot on.
Different tyres respond to different pressure ranges. Obviously severely over or under inflated tyres are just asking for trouble. Mine tend to be in the 42 psi range