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-   -   Would 23 lb wheels (Miro) offset the advantages of upgrading to grippier tires? (https://www.ft86club.com/forums/showthread.php?t=99269)

Talus1 01-02-2016 07:03 PM

Quote:

Originally Posted by Meanderchap (Post 2496585)
Thanks! What do you mean by "smaller impact on steering feel?" +45 would retain the lightness of the stock steering feel?

Steering feel is complex and I'm no expert, but... Going from the low grip OEM 215 section tires to higher grip, wider tires is going to increase steering effort but not necessarily the feel. You'll notice the increased effort especially at parking lot speeds.

Moving the center of the contact patch outward by 13mm vs 3mm (stock is +48) will have its own effect, but it won't be large. There is precious little info on the Web about the effects of increasing scrub radius, independent of other geometry changes (caster, camber), but what little there is seems to indicate that the effects are minimal until you get to big positive or negative numbers. Back in the bad old days, RWD cars ran very large positive scrub radii (3-4") and had lots of kickback at the steering wheel. FWD cars started the move to negative scrub radii. In fact, VW ran ads in the 70s about how negative scrub radius (I think they called it "steering roll radius") on the Golf/Rabbit made them more stable under braking and acceleration on split surfaces (one wheel on ice or gravel). They had less steering kick back over bumps, but I also thought they had less "feel" because of it.

I've never seen a published scrub radius for the Twins, but I suspect it is slightly negative (~-20mm???), like most modern strut suspended cars. The effect of making it slightly less negative with wheel offset is likely small in comparison to the effect of the much wider tires.

The engineer in me wishes I had the $$ to do a direct comparison - same tires, different wheel offsets. :bonk:

swarb 01-02-2016 09:50 PM

Quote:

Originally Posted by Meanderchap (Post 2496541)
Thanks for the info! I've just about settled on the RPF1s after browsing some member photo galleries. I would get 17x9 (for flatter face) + 35 offset with a 1 inch drop on Eibach proline springs. I also hear I should dial in some negative camber to diminish some of the poke with a +35 offset. For tires I'll get PSS 245/40/17. Does this sound like a good overall set-up?

Also, would I need to get camber bolts to dial in negative camber, and can anybody chime in on some good camber specs for the above set up? Thanks.

Camber bolts will get you 1.0-1.3 of additional camber. Stock is very close to 0. Rear will have about 1.5 or more with the springs. Ideally, for this car you want more camber in the front for handling purposes. So you need to max out the camber bolts or use two sets(some say it is potentially dangerous). .5 more camber in the front than rear is a good starting point.

SHIFTEVO 01-06-2016 05:57 PM

Having lighter wheels is definitely a plus espeically if you work on your car....gains are minimal but you can feel the slight difference behind the wheel and accelerating.

Cmorris8848 01-07-2016 09:28 PM

Quote:

Originally Posted by Meanderchap (Post 2496534)
I got 23 lb from calling the Miro customer support line listed on their website. For all I know, the guy I spoke with could've been mistaken.

Hey, my Miro 398's just came in today. 18x8.5 and I just weighed one. Right at 21.6 lbs, so that should come in lighter than the stock wheels and tires


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