Holds hands up and admits to an error

Message

Aladinsaneuk · #1 Post by **Aladinsaneuk** » Sat Jun 09, 2007 12:39 pm

(copied from my post on another forum - hammonds is a local place to us that has a ride in ride out tyre fitting service, that also does chain checks etc)

Went over to see the chaps at hammonds today, and had the tyres checked, wheels balanced and chain checked

First off - even though I had no vibration, the wheels were slightly out of balance - nothing major, but did need doing for peace of mind

Second - my chain was spot on - but, as Kev said, he had checked a bike yesterday that was wrong - the marks needed were 3 1/4 and 3 1/2 notches (Not the 3 1/2 on both sides!) - if left alone it would have shortened the life of the chain a fair amount

Finally - you live an learn. My aprilia manual has the tyre pressures listed in bar - 2.5 and 2.9 respectively. My own pressure gauge is in pounds so, i went on line and found a nice conversion utility that gave me what I thought was correct - 32 and 36 pound.

WRONG

it appears that there is a difference between USA/Canada pound per square inch and the UK measurement - I should have actually had something like 36 and 42. (Kev showed me some tyres that actually had the pressure guide on the side of them - and in big letters it said USA/Canada only

something maybe for us all to learn

Needless to say the bike felt a lot better - and I take back my niggle about conti tyres taking a while to warm up - now they are spot on from the off :)

Fausto · #2 Post by **Fausto** » Sat Jun 09, 2007 5:57 pm

Pete - my manual says Front = 2.4 bar and rear = 2.5 bar for solo riding.
Are you setting up for passenger carrying??

I have converted that to 34 and 36 or near. This was based on my pump guage which gives both calibrations.

Aladinsaneuk · #3 Post by **Aladinsaneuk** » Sat Jun 09, 2007 9:34 pm

the manual does say what you have paul - but the official paperwork from bridgestone shows that their tyres should be at 36 and 42. Now I am on conti's but i thought it worth a try to see what happened so went with equivalent - all i can say is that wether or not I was wrong in my conversions, or made an error elsewhere, or the tires need a bit more in.... they sure are better handling now

D-Rider · #4 Post by **D-Rider** » Sat Jun 09, 2007 10:47 pm

Pirelli recommend 2.5 bar front and 2.9 bar rear for Diablos and Diablo Stradas on the Falco.
That's what I run and it feels pretty good (it's quite noticeable when the pressure drops off a little).

Pirelli

.... and here's a PSI / bar conversion table

Pressure Conversion

36psi / 42psi is about right.

Aladinsaneuk · #5 Post by **Aladinsaneuk** » Sun Jun 10, 2007 7:20 am

cheers andy

maybe that is one reason why the stock metzlers got such a bad review!

what tyres are you on paul - and perhaps try a little harder pressure? I never really complained about the handling, but i always said the conti's were average till warm - now I reckon that once they were at temperature, they were at the right pressure!

lazarus · #6 Post by **lazarus** » Mon Jun 25, 2007 6:54 pm

I think the info you have been given is wrong - there is no practical difference between US and UK psi figures. A bar is one atmosphere of pressure (ie 1000mb) and is equal to 14.5 lbs/sq in. So 2.5 is 36.25psi and 2.9 is 42 psi. both here and in the US.

paddyz1 · #7 Post by **paddyz1** » Mon Jun 25, 2007 10:11 pm

I use a digital tyre pressure guage. It measures in psi, bar and kpa. They are well worth the money.

Aladinsaneuk · #8 Post by **Aladinsaneuk** » Mon Jun 25, 2007 10:16 pm

nod Lazarus - am sorry if it was not explained properly

I went by what the official aprilia owners manual said for the stock tyres

at the same time, it was brought to my attention that there is a difference between desired/intended pressures in the USA and europe

having done all that, there is a major thing - the official manual differs markedly from what the tyre manufacturers say they should have their tyres run at - and the difference is marked

hope that clarifies it a bit

IN SIMPLE TERMS - CHECK THE TYRE MANUFACTURERS GUIDELINES FOR TYRE PRESSURES PER BIKE