Using tires to increase ride height and cushion ride
 

So, my stock suspension is pretty much trashed. I am looking at doing coilovers and replacing bushings. I have 2 sets of wheels for the car, 16s and 17s. Thinking of putting some tall all seasons on the 16s to counteract the ride height decrease of coilovers and to give some cushioning for potholes, and then sticking real performance tires onto the 17s and letting it ride low when I go to autocross.

Thoughts?

Tall tires won't help with the resulting reduced suspension travel from slammed coil overs.

You'll need to be careful with the fit of tall tires as well when you lower the body. Continental ExtremeContact DWS has one of the most forgiving sidewalls.

You'll also hinder acceleration and MPG with a larger diameter.

all good points.....

It's a tough predicament.. The MINI is my (somewhat) daily driver, practical car, but I've already modded the hell out of the powertrain and would l like to have some running gear that will allow the car to really perform to its potential in AX.

Unfortunately, I also drive over the absolute worst streets in America (NYC after the polar vortex plowing). There are potholes big enough to swallow my car, and even after they've been patched, it's still a warzone out here.

If the roads were a bit more modern around here, I'd look at a really nice set of coilovers like KWs and just put some Michelin Super Sports on and call it a day (this is the setup on my Cayman that only goes out of town or on the track).

You need to check the rules for the class you want to run. I'd bet just power train mods put you in a class where you are seriously outclassed no matter what suspension you put on...

MPG may not suffer--it may even improve! In general, running the engine at lower RPM gives you better mileage. So a taller tire does, in many instances, result in better freeway MPG.

Note that your speedometer and odometer readings will be off.

Or your speedometer might be fixed. Mine runs 3mph slow on stock tires.

your results may vary as i have a cms all4

i went from stock size 225/45R18 to 225/50R18 (25.9 inch OD to 26.9 inch OD) and my speedo went from reading 1.9mph higher than actual to reading spot on, per my aviation gps and a stopwatch.

for winters, i went to 205/70R16s (27.3 inch OD) and the speedo reads .6mph lower than actual again per gps and stopwatch

using the winters over the OEM, i picked up about .7 inch ground clearance, handy for snow running

225/45R18 on left, 205/70R16 on right

https://lh3.googleusercontent.com/xy...w260-h194-p-no

https://lh5.googleusercontent.com/_O...w136-h181-p-no

scott

No it's the other way around, as you go taller it requires more engine power to turn a taller tire. It's easier for the engine to spin a smaller diameter tire up to a certain point, it's not like a 13" inch tire will give you better MPG. My 2 cents

You are both right, smaller diam is quicker and easier to get moving, but once moving at speed, the additional rotating mass will roll easier if you are at a moderate speed (50-70mph).

I saw this on my old truck. 32" tires vs 35" tires was the same mpg or a hair better if I kept it under 80 mph. In town it was a little more sluggish and I saw a bit of drop in MPG. I added a programmer and got about 30hp or so and it was back to normal in town and a shade better on the highway.

Right, there's more to the "taller tire" effect than additional weight. Increasing tire diameter is essentially the same as going to a taller gear ratio in your final drive. Yes, the engine turns slower once you're up to speed, but getting up to speed is more work because of the higher ratio. So if you do mainly highway miles, you'll see an increase in MPG. Conversely, if you mainly drive around town, you'll see a decrease.

Just my tuppence,

Spridget

If you want better performance but still want some comfort or want to battle poor road conditions, I'd recommend skipping the coilovers and do a strut spring combo. Any coilover is going to hit pot holes super hard. Plus the chance of strut tower mushrooming will greatly increase unless you have some sort of strut defender.

I too would like to go to coilovers, however with the frost heaves around here during winter, there is no way I could run this car as a DD with coilovers. I would die. My neck would break and I would die.

i thought this was just me!! i dont drive in the mini very often but when i do im like holy cow the car feels like its going slow.. i thought it would seem faster since it's lower, but it's always had this eerie sensation of going slow. i assumed aftre a while that the speedo is off or soemthing. people don't really speed where i'm located but when i go "60" in the mini it seems like everyone is zooming by

Very common, most are 2-3mph off, so it's not you. A 'safety' feature I suppose.
Regarding MPG, it's best in top gear at low rpm. Taller tires may or may not help depending on factors like gearing, weight, etc. No 2 cars will be the same.

There is one coilover (Öhlins) that will give you racetrack performance with street comfort because there dual valved, but it will cost you $3500.

yea for sure - i think with the mini it must just be a little more significant/noticeable.

agree here. i've got ohlins on the evo, and they ride amazingly despite the higher rates. one thing though - they've all gone on sale recently/oddly - sale like, $1k off. annoyed me, as mine are only a year old.

If I could afford the Öhlins coilovers only then would I consider 18" inch wheels! I see that there dipping below $2500, amazing!

just FYI about the mpg discussion - if you measure mpg with ur odometer, which most people do, you're not going to get any higher readings with whatever tire u get, because the car doesnt "know" what's on the wheel. so while you will be traveling further per revolution, the odometer will think its going less than it actually is, and thus your mpg READING will be the same, and thus your mpg if you're inputting it by what the odometer reads