275s and Sluggish Steering

[Danny2323]

I recently installed some 275/35/19 PSS on 19x9.5 ET45 wheels. They were installed at the same time as Bilstein PSS10, adj UCAs, cornerbalance, and alignment. FTG is 26" (+/- due to cornerbalance). We started with:
Camber: -2.3F / -1.8R
Toe: 0F / .05" total toe-in R
Caster: 4.5deg

After driving this setup, the steering was slow to return to center. I asked to max out caster to see if it could fix the issue. We ended up with the following:
Camber: -2.3F / -1.8R
Toe: .07deg total F / .12deg total R (I don't know why the second sheet switched from inches to degs)
Caster: 6deg

This helped, but it's still slow to return to center. It returns to about 1/8 turn from center, but won't return without me correcting it. It is more resistant to return if I throttle through the turn. Is this due to the 275s impacting the scrub radius? Is it because of the minimal toe? I was informed we couldn't get any more caster. Do you have any ideas what we can try, while still keeping the wide tires, or do I just need to live with it? Preferably, I'd like it to snap back to center.

Thanks in advance!

[theswoleguy]

No help here but man 275s are meaty

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[OnEaNgRyBuNnY]

I have rims of the same dimensions running the same size PSS. I noticed no difference between these and the stock peelers with stock tire setup of the type your describing, personally.


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[Danny2323]

I have rims of the same dimensions running the same size PSS. I noticed no difference between these and the stock peelers with stock tire setup of the type your describing, personally.


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Interesting. What are your alignment specs?

On sweeping turns under throttle, I can just let go of the wheel, and it will hold the line around the turn.

[OnEaNgRyBuNnY]

Interesting. What are your alignment specs?

On sweeping turns under throttle, I can just let go of the wheel, and it will hold the line around the turn.

I never got the exact stats but it just recently had an alignment so it's within the stock parameters.

I can certainly not release the wheel on any type of turn.

[dizzlesizzle]

should stick with 255 i think u went to big with 275 IMO

[MrFunk]

should stick with 255 i think u went to big with 275 IMO

275's especially on the front axle are too wide. You gain increased surface contact / traction, but give up steering response and agility.

[OnEaNgRyBuNnY]

275's especially on the front axle are too wide. You gain increased surface contact / traction, but give up steering response and agility.

I hear what you're all saying and where you are coming from but I have the same setup and zero issue, certainly not a decrease in agility, more grip and agility if anything.

Have any other suspension/chassis mods? I DO have the AK and H&R oe springs on stock shocks (which I'm swapping shortly for some shocks that are a better match) and it was aligned after the install.

Edit: my setup is 275/30 not 275/35 but for this issue I can't believe that would be material.

What year is your S4?

[Danny2323]

I hear what you're all saying and where you are coming from but I have the same setup and zero issue, certainly not a decrease in agility, more grip and agility if anything.

Have any other suspension/chassis mods? I DO have the AK and H&R oe springs on stock shocks (which I'm swapping shortly for some shocks that are a better match) and it was aligned after the install.

Yes - PSS10, H&R sways, AK, UR brace, and CR-15. The wheels/tires, coils, and alignment were all done at the same time (the braces and sways were already done). I wonder if something happened during the coilover installation that might have caused it. Don't get me wrong, the car handles incredibly well. The return-to-center is the only issue.

[Danny2323]

AngryBunny - my car is a 2014. The only difference between that I can think of is camber. I know you don't have your spec sheet, but if you're within OEM spec, you could be running a full degrees less neg camber than me. I wonder if my higher negative camber would be enough to broaden the SAI. I don't know how significant one more of neg degree of camber impacts SAI. Any alignment gurus know?

[Jay@JXB]

I haven't had any issues with my 275 setup. Steering is heavier at low speeds due to increased contact patch, but nothing like what you're describing. Changing tires alone shouldn't affect the ability to return to center. I have about 3° of camber and haven't played with anything else just yet. I go in for corner balancing and alignment in a couple weeks. Hopefully I don't end up with the same thing. Certainly is a strange issue you're having...


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[Jay@JXB]

I'll have my setup on for an Autocross Sunday I'll pay special attention to see if I have any of these symptoms in a lesser form.


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[eurotic]

I haven't had any issues with my 275 setup. Steering is heavier at low speeds due to increased contact patch, but nothing like what you're describing. Changing tires alone shouldn't affect the ability to return to center. I have about 3° of camber and haven't played with anything else just yet. I go in for corner balancing and alignment in a couple weeks. Hopefully I don't end up with the same thing. Certainly is a strange issue you're having...


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Can you provide the wheel specs and tire info of what you are running in that picture?

[theswoleguy]

Can you provide the wheel specs and tire info of what you are running in that picture?

This is also be curious to know if there was a noticeable increase in speed through a corner with more contact patch. IE you same old fun offramp clover leaf went from 65-70


Edit found this: http://www.audizine.com/forum/showth...1#post11455276
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[yjypm]

Does anyone know if I put 275s on my 20x9 rims will they look weird?

[Jay@JXB]

Does anyone know if I put 275s on my 20x9 rims will they look weird?

Depends on what tires you put on. Most cheapo tires will run narrow and look fine. If you get into a wider running performance tire they may get kind of bulgy.

[yjypm]

Depends on what tires you put on. Most cheapo tires will run narrow and look fine. If you get into a wider running performance tire they may get kind of bulgy.

Do you think it's beneficial for me to run 275 at the front and 255 at the rear to reduce understeer?

[Jay@JXB]

Do you think it's beneficial for me to run 275 at the front and 255 at the rear to reduce understeer?

No just get a stiffer rear sway bar. I have perfect balance at the limit with the Eurocode bars set stiff in back soft in front.

[yjypm]

No just get a stiffer rear sway bar. I have perfect balance at the limit with the Eurocode bars set stiff in back soft in front.

I have 034's rear sway bar right now and the car has significantly less understeer but I still want it more tail happy. I know I should have gone for an m3 but I go ski a lot so Quattro helps me a lot in the winter on the mountains.

[Jay@JXB]

Winds like you just need some more power and to turn the wheel harder ;)


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[yjypm]

Winds like you just need some more power and to turn the wheel harder ;)


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Lol indeed. But any disadvantages with staggered tire setup with wider front tires?

[theswoleguy]

Yes may induce more over steer
Wider rears would make the car under steer

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[bhvrdr]

Lol indeed. But any disadvantages with staggered tire setup with wider front tires?

I would change the alignment specs if you want more oversteer/less understeer. I would not reverse stagger. I've done it on a different car and handling can get downright unpredictable (ie, you can get oversteer when you dont want it). It can be a handful. IMO its better to do it with alignment so if you have gone too far you can easily correct it, you can still rotate wheels, and you can easily swap back to safer settings during the winter in your case.


You can also just try changing your driving technique. If you practice lift off oversteer or even brake induced oversteer by using weight transfter (like trail braking but stab the brakes as you turn in) you can get these cars to come loose in the rear no problem.

You can also add some spring in the rear but alignment is usually the cheapest solution.

Mike

[yjypm]

I would change the alignment specs if you want more oversteer/less understeer. I would not reverse stagger. I've done it on a different car and handling can get downright unpredictable (ie, you can get oversteer when you dont want it). It can be a handful. IMO its better to do it with alignment so if you have gone too far you can easily correct it, you can still rotate wheels, and you can easily swap back to safer settings during the winter in your case.


You can also just try changing your driving technique. If you practice lift off oversteer or even brake induced oversteer by using weight transfter (like trail braking but stab the brakes as you turn in) you can get these cars to come loose in the rear no problem.

You can also add some spring in the rear but alignment is usually the cheapest solution.

Mike

Thanks for your advice. I now need to do some research on this.

[Danny2323]

I haven't had any issues with my 275 setup. Steering is heavier at low speeds due to increased contact patch, but nothing like what you're describing. Changing tires alone shouldn't affect the ability to return to center. I have about 3° of camber and haven't played with anything else just yet. I go in for corner balancing and alignment in a couple weeks. Hopefully I don't end up with the same thing. Certainly is a strange issue you're having...

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Thanks for your reply. It handles amazing, but the center returnability is odd. I tried playing around with tire pressures (everything between 34-41psi). It didn't cause any improvement with the centering. I figured 6deg of caster would be able to overcome any tire scrub created by the wider tires. I think jbullin and angrybunny's experiences confirm it isn't a scrub issue. Maybe it's toe? I'm running barely any front toe - .07deg total front. If you guys are running in the stock range, then maybe that makes a difference?

[anerbe]

See if you can swap with another person to put back stock 255 sizes. Some larger sizes and even the type of tire can exhibit different on-center feeling (like slow response/return to center).

Best to try your previous tire configuration (same OE tire if that's what you had before) to test.

[Danny2323]

See if you can swap with another person to put back stock 255 sizes. Some larger sizes and even the type of tire can exhibit different on-center feeling (like slow response/return to center).

Best to try your previous tire configuration (same OE tire if that's what you had before) to test.

Oh duh! That's a great idea. I still need to pick them up from my shop, but I have my stock wheels and tires. I'll try them out this weekend. Thanks for the idea.

[anerbe]

Oh duh! That's a great idea. I still need to pick them up from my shop, but I have my stock wheels and tires. I'll try them out this weekend. Thanks for the idea.

good luck!