How much does the wheel size affect the performance in the Atom?

[capblaster]

I have 2 questions regarding the wheels. The Atom 3 comes standard with 15' Wheels. Does the 16" and 17" wheel offer any difference in performance? What size wheel do you think looks best on the Atom?
Thanks for your input.
Cap

[dp35]

Opinions WILL vary.  But IMO, for looks - a larger, wider, and taller rear wheel looks best on an Atom.  The reason for this is that the car's rear frame/body isn't super low like the front or like an open wheel or prototype race car.  Short and/or narrow rear wheels look somewhat out of place on an Atom to me.

I don't think 17" wheels have been offerred by the factory for a while.  For performance, the shorter rears might allow the suspension to perform better.  More importantly, a wider rear wheel will help, becuase it'll allow wider rubber.  This might not be true if you use street tires such as A048's or 888's, because they won't get hot enough.  But if you use an appropriate tire for track use of this car, which (IMO) would be a street legal semi-slick like a Hoosier A6, or a full race slick like the Dunlop Radical tires, then wider is MUCH better.  That last part is more than just an opinion.

[capblaster]

QUOTE I don't think 17" wheels have been offerred by the factory for a while.  For performance, the shorter rears might allow the suspension to perform better.  More importantly, a wider rear wheel will help, becuase it'll allow wider rubber.  This might not be true if you use street tires such as A048's or 888's, because they won't get hot enough.  But if you use an appropriate tire for track use of this car, which (IMO) would be a street legal semi-slick like a Hoosier A6, or a full race slick like the Dunlop Radical tires, then wider is MUCH better.  That last part is more than just an opinion.


Thanks for the feedback. Currently TMI is offering the 16" and 17" wheel upgrade. The 17" is (17" X 9") rear. I have noticed that some use 16" front and 17" rear. What's the reason?

[silver]

if tire replacement costs matter and availability of tires you should research how much the 17's / 16's cost versus 16's/ 15's  I have no idea what the results are otherwise I'd just tell you the answer......if tires aren't that important then no worries

for what it's worth I'm in need of my 4th set of rears and my car has 6500 miles, and I've only done 2 track days..........so tires don't last too long.

[fishkiller]

I've got a set of 15x9's on order.
15's offer a larger selection of compounds.
15's are a bit cheaper than 16's or 17's.
I plan on rotating them front to back to even out the wear.

Plus I  don't want to end up like Silver, no rears 

On another note, taller tires have a larger contact patch, tire for tire.

[capblaster]

[quote="silver"]
for what it's worth I'm in need of my 4th set of rears and my car has 6500 miles, and I've only done 2 track days..........so tires don't last too long.

What tire have you been using? Mark Swain recommended the A048 since I would primarily do street driving.
Thanks Cap

[silver]

always a048's medium compound for me, some use the toyo r888, and some use some cheaper street tires for either transport or whatnot so they don't use useless miles on their good tires, but of course that means you'd need 2 sets of wheels

[dp35]

[quote="capblaster"]
Currently TMI is offering the 16" and 17" wheel upgrade. The 17" is (17" X 9") rear. I have noticed that some use 16" front and 17" rear. What's the reason?[/quote]

I was not aware of the TMI 17" x 9" option.  I like that.  My car has 17" x 8.5" rears, 15" x 7" fronts, and I'm running Hoosier A6 275/40/17's in the rear and 205/50/15's in front.  (I only have fenders in the front)

I don't know why anyone would use 16" front wheels on an Atom, other than their own personal preference in terms of appearance.  I haven't tested it, but I doubt there's any performance advantage, because traction at the back wheels is the Atom's weakness.

With 9" rear wheels, 275's would fit nicely, and you could also try 295's, 315's, or even 335's!  Although I'm not sure if 335's would fit on 9" wide wheels.  I'm considering 295's for my next set of rears.  Hoosier makes the A6 for 17" wheels ranging from 275 to 335 with virtually the same overall diameter, therefore requiring no ride height adjustments.  When increasing tire diameter, its important to adjust your ride height & other alignment settings, if you're after max performance.  The most important thing is the rear toe adjustment.  If you accidentally get toe out in the rear, you'll have a car that's only good for drifting & scaring its driver. 

I don't consider cost when determining which tires to use.  Compared to any other track car, the Atom is dirt cheap on tires, because it uses relatively small tires that wear slowly.  Four sets of rear tires in 6,500 miles indicates either lots of tire spinning entertainment, or a really bad alignment.  That is not normal. 

IMO Atoms should not be driven on tracks with A048, R888 or similar tires, because the car can't get them hot enough to work correctly.  The Hoosier A6 works much better, and is also street legal (barely and only good for dry weather, just like the Atom).  With Hoosier A6's, the car can perform the way its meant to, and is much easier & more fun to drive.  The performance improvement from A048 to Hoosier A6 is night & day, easily several seconds per lap faster.  There's also other tires similar to the A6, such as the Hankook, that I've heard good things about but haven't ever tried.

I think 2 sets of wheels is a great idea & would be the ideal setup for the typical street/track Atom.  One would have A048's or R888's for the street, and the other would have track tires that are appropriate for the car.  I only have one set of wheels, and my criteria was always to keep the car & tires street legal.  Based on that, I like the Hoosiers, but I don't drive on the street very much.

[Terry Kennedy]

Four sets of rear tires in 6,500 miles indicates either lots of tire spinning entertainment, or a really bad alignment.  That is not normal.

True. I got 7500 miles on my factory A048's (medium front, medium-hard rear). There wasn't a lot of tread left on the back when I got home, though.

only good for dry weather, just like the Atom

I think 2 sets of wheels is a great idea & would be the ideal setup for the typical street/track Atom.  One would have A048's or R888's for the street, and the other would have track tires that are appropriate for the car.

I have a a 15/16 set with A048's and another 15/16 set with ES100's (no longer made in the factory Atom sizes). I also have a pretty good collection of new, unmounted A048's in both medium and medium-hard, so if I get caught somewhere with an unrepairable tire, I can have one overnighted from home in the event Tire Rack is out of them. Since I drive the Atom to events, it would be difficult to bring spares with me.

[silver]

[quote="dp35"]
Four sets of rear tires in 6,500 miles indicates either lots of tire spinning entertainment, or a really bad alignment.  That is not normal. 
[/quote]

DP35, I think you're right, I don't do any spinning of tires and my alignment thankfully has always been awesome!  I think I'm needing my 3rd set of tires on the rear which means I've used almost 2 full sets.....and now that I'm thinking about it, I have had a nail in my front tire and my back tire, that were not repairable so instead of replace the single tire, I retired the good tires early so I would have decent spares and that means I really replaced them early.


So I stand corrected, I have replaced my fronts and rears 1 time but my rears are really low so I'm close to replacing them again and when I do i'll be on my 3rd set of rears.

[Lane]

[quote="dp35"]
IMO Atoms should not be driven on tracks with A048, R888 or similar tires, because the car can't get them hot enough to work correctly.  The Hoosier A6 works much better, and is also street legal (barely and only good for dry weather, just like the Atom).  With Hoosier A6's, the car can perform the way its meant to, and is much easier & more fun to drive.  The performance improvement from A048 to Hoosier A6 is night & day, easily several seconds per lap faster.[/quote]

Alright, a related question -

When the tires are not warmed up or hot as they would be after the first few laps on a road course, do the A6s still have more stick than A048/888s?  Or do they need to be heated up to surpass them?  I'd love to have more grip without the tires needing to be hot, for street driving, short-course autocross, and so on.  But I have not moved beyond R888s due to the concern about the tires not heating up enough to be in the temp zone they were designed for.  And that's made worse by the fact that the car is so lightweight.

[Monza]

dp35 : i run both 205x15 and 225x16 R888 Front to test, the only differences are :
. it's become very directive (difficult on average roads, even when decreasing Toe Out to zero or toe in, but good on tracks)
. more important, the braking performance becomes incredible with big front !
But they are more difficult to Heat, so for hot days only.

[capblaster]

[quote="Monza"]
dp35 : i run both 205x15 and 225x16 R888 Front to test, the only differences are :
. it's become very directive (difficult on average roads, even when decreasing Toe Out to zero or toe in, but good on tracks)
. more important, the braking performance becomes incredible with big front !
But they are more difficult to Heat, so for hot days only.
[/quote]

Are you saying that with  16" on the front it is difficult for average roads, but has better braking 

[Heywood-Yablowme]

Wheel size has no affect on performance. Tire selection is critical,though.

[Monza]

Capblaster : Yes, but it's not because of 16' wheels, it's because it's 225 width tyres R888 on them. My 15, 16x8 and 17x9 are Dymags. Tyres are always R888, i don't drive with slicks.
Best choice is certainly 15'x8 Front (205 to 225) and 15'x9 (245 to very big ) Rear because it seems that you have good tyres for it in USA, but we don't here in Europe  .