19bonestock88's 2004 Saturn "Ion Green Line" build...

[mpg_numbers_guy]

Originally Posted by 19bonestock88

It’s same bolt pattern but I don’t know the center bore... I have a set of factory Saturn alloy wheels, but they’re 16x6.5”

Weigh them out maybe, and if the alloys are lighter than the steelies you can get a taller, narrower tire with less sidewall and less weight.

Originally Posted by 19bonestock88

Realistically I’m not in a big hurry to do alloy wheels, as about any upgrade will be expensive and the ROI isn’t that great... due to my considering ROI when planning mods, most of them have paid for themselves almost immediately

True, if you don't have another set of wheels to sell to cover the cost, I agree ROI will be a while.

Mine cost ~$310 roughly including tires and balancing, and with a ~5% improvement in city driving, that's over 80,000 miles to break even if it weren't for selling my OEM set for nearly $400.

[19bonestock88]

I done some research on the wheel sizing thing... if I bought a 16x7” RPF1 wheel at around 12# and ran a 225/50 tire, I should be around the same weight as my current setup, but the widertire theoretixally having lower RRc and way more lateral grip... the Redline only specced a 215 section tire, and with a suspension setup not unlike mine, cornered like a dream...

[California98Civic]

I am not sure wider is better. Larger yes. But larger can also be bigger diameter without the biggest possible width. Bigger diameter with narrow width is what BMW is doing with its EV. And you would gain aero benefits and gearing benefits from narrower but taller. Just a thought. Consider this discussion (the link is to a comment of mine in the middle of the discussion): https://ecomodder.com/forum/showthre...tml#post564182

And this graph from that thread. I think it shows that for FE purposes, the picture can be more complicated.

[19bonestock88]

Following the theme of staying skinny but gaining diameter, the ideal would be a 195/65-16 (25.9” diameter) but those are almost all commercial tires(8+ply), but a decent compromise would be a 205-60-16 which is 25.7” tall... I started thinking of rubber to gain lateral grip and lost sight of FE, lol

Really is like to go even taller to gain a gearing advantage but I haven’t got the room for anything over MAYBE 26” before I’d have to clearance the strut...

[mpg_numbers_guy]

Originally Posted by California98Civic

Is this implying that tires with 165mm width have more RR than tires with 215mm width???

[19bonestock88]

It would appear so, but that chart doesn’t show rolling diameter, which we all know affects FE...

[California98Civic]

Originally Posted by 19bonestock88

It would appear so, but that chart doesn’t show rolling diameter, which we all know affects FE...

And it is not accounting for the aero penalty of a 225 width versus a 165 or 175. Too, it is not strictly the case in the chart that wider is always the better. There are exceptions due to variation arising from tire design, I was told.

[mpg_numbers_guy]

Originally Posted by 19bonestock88

It would appear so, but that chart doesn’t show rolling diameter, which we all know affects FE...

Makes no sense...less rubber on the road = less resistance, if tread pattern and depth is the same.

[19bonestock88]

Well a larger diameter tire experiences less angular deflection as you drive over bumps, makes them seem smaller... it’s partly why crossovers and trucks ride better over rough roads than a small car does...

[19bonestock88]

So, I had the FE5 control arms installed on my car the other day, and gave the old arms to the mechanic... the new arms are a little lighter than the old ones, due to being aluminum vs steel for the old ones, so the car lost a little unsprung weight, but most of the reason for this mod is to get a stiffer control arm. In theory it should flex less under load and I should be able to stuff it harder into corners and launch it off the line harder, with less wheelhop and more control... also, the bushings on my old control arms were pretty wasted and it sounded horrible going over bumps, and I was gettting about 7500mi to a pair of new front tires... measured alignment afterward with a tape and the front tires are toed out about 1/4” but I’ll get it corrected soon enough...