Upsizing Tyre Aspect Ratio

[bupalooga]

I've got 19" 50th anniversary turbo rims that I love so much that I've bought a second set. (matching trailer) However my issue has been load rated tyres.

In the factory 245/35/19 I can only get a 93rating (650kg). Local Bob Jane guy said they upped the Aspect ratio and fitted 245/40/19, 98(750) to a GS ute a while ago and haven't had any clearance issues so far. Speedo is 3.8% off. Also thinking possibly 255/40/19, 100(800kg), 5% off.

Specifications for the One Tonner say max rear axle load is 1700kg so if I got to 1600kg worth of tyre rating that's enough for me.

I also what the bigger numbers so I can register my trailer with a higher Load capacity.

So whos done this before and had experience?

How does upsizing affect acceleration, drag times, launching, handeling, cruising revs etc? Considering the same brand/pattern tyres.

Also how would I find out the weight rating of the rim itself? The local parts department potatoes aren't that helpful, they couldn't even find my wheels on their system & said they must be an aftermarket option.

http://www.tyresizecalculator.com/tyre-wheel-calculators/tire-size-calculator-tire-dimensions

http://www.bobjane.com.au/info/load-index-speed-symbol/

[gaz097]

The rim would be stamped on the inside if its a quality rim. You will still get defect for being under the load rating

As for driving it will be geared up slightly. Not a massive problem for most people. Look at all the staggered 20" rim guys running 275/30 rears and 245/30 fronts. Which are already massive compared to the stock 235/45/17 wheels.

[Panda Eyes]

you will find most run a larger profile on the front if the rim is narrower. b series dont play well with different rolling diameters front and rear- will cause abs problems.

Edited 27/10/15 07:41 AM by Panda Eyes

[bupalooga]

  On 27/10/2015 at 6:55 AM, gaz097 said:

The rim would be stamped on the inside if its a quality rim. You will still get defect for being under the load rating

As for driving it will be geared up slightly. Not a massive problem for most people. Look at all the staggered 20" rim guys running 275/30 rears and 245/30 fronts. Which are already massive compared to the stock 235/45/17 wheels.

It's a genuine 50th anniversary Ford 19"X8" rim. There's random codes stamped in the back but couldn't figure out if any of them meant anything.

It's a turbo FG so only rated for 500kg payload, I often carry more than that though Which is why I'm chasing better Tyre ratings.

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[bupalooga]

  On 27/10/2015 at 7:39 AM, Panda Eyes said:

you will find most run a larger profile on the front if the rim is narrower. b series dont play well with different rolling diameters front and rear- will cause abs problems.

Mine are same widths front to back. Alloy wheels can't be widened can they?

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