RE001 review

[Nark]

FWIW. 205/45R16 tyre weights:

Bridgestone RE001: 9.5kg
Hankook R-S2: 9.0kg
Federal 595RS: 8.9kg

[drifter]

Same size 16\" T1R is 8.6kg

But the RS2 is the best performance tyre out of that list

[TieNN89]

Same size 16" T1R is 8.6kg

Is that Toyo Proxes T1R?

I just made a post up for tyre weights

http://www.mx5cartalk.com/viewtopic.php?p=411595

[TieNN89]

What psi is everyone using the re001 on? 195/50 R15

[marcusus]

I'm running 34psi, but I think it's too much. I was getting pretty average (and when I say average, I mean below average) fuel economy with the Adrenalins, so I think when I put them back on the car I'll drop them to maybe 30 and work my way back up til I find the sweet spot for economy.

[rjastra2]

I'm running 34psi, but I think it's too much. I was getting pretty average (and when I say average, I mean below average) fuel economy with the Adrenalins, so I think when I put them back on the car I'll drop them to maybe 30 and work my way back up til I find the sweet spot for economy.

Why would reducing tyre pressure improve fuel economy?

[marcusus]

Why would reducing tyre pressure improve fuel economy?

Because it depends on the make/model of the tyre. Correct me if I'm wrong, but I'd say each make/model of tyre would have its own pressure sweet spot for maximum fuel economy.

If you had your current tyres up to 40 psi, do you think your economy would be worse or better? What if it was down at 20 psi?

[bigdog]

More pressure = smaller contact patch = less friction = better fuel economy. Obviously you will eventually reach a point where 'she canna take any more cap'n' and the whole thing will explode, but the but until then the theory applies, as does the converse - less pressure = worse fuel economy. Interestingly there is a 'sweet spot' as you call it, but this relates to braking and cornering particularly, not economy. The sweet spot for braking is generally where the maximum contact patch is available - as this means the tyre is able to maintain grip and apply the force generated by the brakes most efficiently. For cornering its a whole lot more complicated and beyond my meager skills to explain here - there are some great text books on the subject though

[marcusus]

More pressure = smaller contact patch = less friction = better fuel economy. Obviously you will eventually reach a point where 'she canna take any more cap'n' and the whole thing will explode, but the but until then the theory applies, as does the converse - less pressure = worse fuel economy.

I would hazard a guess and say that economy would peak at some amount of pressure then drop off a la bell curve style. I very much doubt that it will plateu once it's reached any pressures greater than a certain amount, which seems to be what you're implying here.

[bigdog]

It would peak when the contact patch (friction) is at its smallest, and no doubt that would occur some time before the tyre explodes - the side walls would start to bulge for example. When entering an economy run (popular events in the 70's) it was common practice to inflate the tyres to 45 or 50 psi to enhance fuel economy. More pressure may have helped, but the risk of blowing the tyre out on bumps/potholes etc became greater. I doubt there would be a drop off effect, as it purely relates to friction - and friction would simply plateau, not decrease. But hey, I'm no physicist, and short of setting up a controlled experiment I doubt we will ever know...

[marcusus]

It would peak when the contact patch (friction) is at its smallest, and no doubt that would occur some time before the tyre explodes - the side walls would start to bulge for example. When entering an economy run (popular events in the 70's) it was common practice to inflate the tyres to 45 or 50 psi to enhance fuel economy. More pressure may have helped, but the risk of blowing the tyre out on bumps/potholes etc became greater. I doubt there would be a drop off effect, as it purely relates to friction - and friction would simply plateau, not decrease. But hey, I'm no physicist, and short of setting up a controlled experiment I doubt we will ever know...

I don't dispute that as you increase tyre pressure you reduce your contact patch. However, there surely would be a point where the lack of adhesion would create a negative effect since less of the power being generated by the engine is actually getting to the road via the tyres? Less contact = less grip = more radial changes with less lateral change?

As for a controlled experiment, the best I've done is played with my tyre pressures a month at a time with no change in driving style (as best as you can do anyway). I should really analyse the data properly and see whether I can find a correlation between higher pressure and better economy, but I seem to recall that having the pressure higher than a certain point made it worse.

[Alex]

but once you go so far with the pressures you will have trouble with even tyre wear

[rjastra2]

Why would reducing tyre pressure improve fuel economy?

Because it depends on the make/model of the tyre. Correct me if I'm wrong, but I'd say each make/model of tyre would have its own pressure sweet spot for maximum fuel economy.

If you had your current tyres up to 40 psi, do you think your economy would be worse or better? What if it was down at 20 psi?

The PoGo runs 38/35. I can guarantee the economy would get worse under that pressure.
I would expect the economy would improve if I raised the pressures to 40psi and above.

It was the reason the VE commodore got an unexpected raise in recommended tyre pressures prior to release. To get a reduction in the placarded fuel economy figures.

[Hot Rodders]

I'm running 34psi, but I think it's too much. I was getting pretty average (and when I say average, I mean below average) fuel economy with the Adrenalins, so I think when I put them back on the car I'll drop them to maybe 30 and work my way back up til I find the sweet spot for economy.

32 PSI works for me. Good economy and grip in both wet and dry. Wear on tyres is even.

[manga_blue]

I've tried mine from 26 up to 38 psi. 28 all round was best for grip, ride and noise and equal to anything higher for turn-in. I'd say these tyres really like to run soft.