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Motorcycle Safety & Driveability/correct tire pressure of motorcycle


good day!i have a bike with 135cc and the original size of tire before is 90/80/17 front and 100/90/17 rear but now ive change it to 100/70/17 front and 120/70/17 many psi do i have to load in my tire sir..kindly help me please sir?thanks

First of all, you should never change the size of a tyre profile without checking with the bike maker first that it is safe to do so. The narrower profile may slip from the rim and a larger profile can cause a flatter profile making cornering unstable.
The tyre pressures should be the same but you MUST   check with the bike manufacturer that it is safe to change to the size you have chosen.

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Andrew Booth


Motorcycle safety in the UK and providing links to safety organisations in the UK. I can also advise on road safety issues and some areas of road safety law in the UK although I can only offer guidelines, there is no substitute for a qualified legal advisor. Please do NOT ask me questions of a mechanical nature as I will be unable to answer. I am not a mechanic, I am a road safety advisor.


I was a Gold Star Riding instructor in the eighties until a serious accident nearly cost me my life. I have been active in road safety for over ten years in the UK and have had success in having road safety measures implemented in various areas, mainly around our local schools. I have ridden motorcycles of all sorts (from GT750 waterbus to CB250 dream) since the late 70's and prefer four stroke road bikes, my favourite was my old CB750F. two strokes are too noisy, off-road bikes are impractical in this part of the UK. I now ride a 23year old Suzuki GSX600 (Teapot)

NABD. (National Association for Bikers with a Disability - Patrons; Suzy Perry, Billy Connolly) Ridesafe Backsafe M.A.G. NEBOSH

Local and regional newspapers.

RoSPA/Gold star rider. C&G in Commercial; and Domestic Electrical Installation.

Awards and Honors
Gold Star Riding certificate. (Now part of RoSPA)

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Wigan MBC Ridesafe Backsafe Brake

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