UKC

My sister asked me to check her tyre pressure (Suzuki Celerio 17) the door plate says 36-39psi rear and 41 front.

This seems unusually high even for small wheels. I'm used to cars being in the 28-34psi range, what's your thoughts?

In reply to The Potato:30- 35 is what I read.  Odd the door plate says more.  What about the manual?

In reply to The Potato:

They can go higher.  The rears on my Defender (OK, not quite a car, but still) can go up to 65 with a heavy load.  I've had cars that were 40 all round.

If it's on the door plate it will be correct.

This:

http://www.tyre-pressures.com/bycar/manu_suzuki/62130/63712

reckons 39 front 36 rear which is about what the plate says by the way (1/2 will barely make any difference, most gauges aren't that precise anyway).

In reply to The Potato:

Google says 39 front and 36 rear unloaded and 41 front and rear loaded. 

I'd go with the plate.  Its seems normal enough to me.  

In reply to The Potato:

That does seem very high. I have a Suzuki Ignis which is similar size and mine are only 33psi front and rear.

Thanks everyone glad it's not just me then 

I'll set it to what the plate says and see how the wear pattern develops

In reply to The Potato:

Who on earth names a car “Celerio”?

Pressures seems perfectly normal for a city runabout on small wheels.

In reply to The Potato:

You have to be a bit of a twit not to go with the manufacturer's recommendations!

In reply to John Stainforth:

Although I'd always say go with the plate recommendations.. 

.... my considered experience, is that it just doesn't matter very much - there's a fairly big margin. 

    Higher pressures give better handling with higher speeds and higher loads. Lower pressures may improve stopping distances.

Its all a balance between costs and benefits and 5psi won't make very much difference. The difference between budget and expensive tires is likely to be far higher. The difference between driving carefully and pushing it will be FAR higher. 

In reply to The Potato:

Think of a similar amount of air being needed to support a certain weight so a smaller wheel-tyre combo needs a higher pressure in the smaller volume. 

In reply to Jim Fraser:

Probably 3 or 4 psi would be enough to hold the car up. The pressure influences the lateral and longitudinal stiffness of the tyre and thus the handling particularly in extremis, low profile tyres normally run lower pressure as they are by design more stable. Cheap little cars (especially fwd)  normally need suprisingly high pressure due to the miserable suspension geometry.

In reply to wintertree:

Wouldn't it be suggesting speed or nippiness, or does it make you think about vegetables? Not half such a stupid name as Cee'd. What the hell is that apostrophe about?

In reply to wintertree:

From a Latin root meaning "swiftness"; it gives us "accelerate".

Classic example of a brand name not working in certain languages though! 

In reply to McHeath:

I live and learn!

In reply to Rog Wilco:

Not just vegetables but weak and watery vegetable soup.  

In reply to wintertree:

Soup is all celery is good for. But celeriac is quite nice as a roasted veg and in stews.

In reply to The Potato:

Perhaps the general increase in recommended tyre pressures is about reducing rolling resistance and thus improving fuel economy?

In reply to wintertree:

Due to being one of a pair issued with a box of compo rations "10 man - one day" unlike the more fortunate occupants of the ten man tents who had a change of recipe more often I got to know the tinned powdered celery soup very very very well on a school camp near Otterburn  in 1973 ...

In reply to Rog Wilko:

It was going to be Ceeed and someone said "no, looks weird" and the solution was the apostrophe! True!

In reply to Tony Jones:

The general increase in tire/tyre pressure was a result of the Firestone and Ford tire scandal in the USA about 20 years ago. There were several hundred fatalities and many hundreds of injuries in Ford Explorers fitted with Bridgestone/Firestone tires. 20 million tires had to be recalled and Bridgestone/Firestone nearly went out of business. Both Ford and Firestone were to blame. Ford had been recommending too low a tire pressure and the failing tires were second-rate. There was also a tendency for drivers to drive on under-inflated tires, which aggravated the problem. As a result of this recommended tire pressures were increased everywhere.

In reply to The Potato:

Nice to see we're still using PSI, none of that foreign (bar) muck.