Hello. I just put some different wheels on my gs300. I bought them used with tires. The tire size is 2xx-30-20 all the way around. Is a 30 series tire up front bad to have? I notice a lot more bumps now after I had 18's with 40 tires. What size should I be running? I plan on dropping it with DF210's soon.

 

you should be fine. your gonna feel i lil difference from a 35 series tire.

 

most people run a 35 series tires on 20's unless they are really low and need the additional tire clearance. u will feel it. just remember to watch the tire pressure on those rubberbands

 

It's not bad, but you'll be a bit more prone to wheel/tire damage. Not to mention you'll feel it a hell of a lot more. I'm riding on 18's now with 245/40 tires and they feel so much better from the 245/35 I had. I could only imagine that a 245/30 or 235/30 would feel worse. Personally, I wouldn't run 2xx/30 up front unless it was only a weekend car that I drive locally so I'm familiar with the roads/highways.

Here's the sidewall height from each of the tires.

245/40 = 98mm

245/35 = 85.75mm

245/30 = 73.5mm

So basically, you went from 98 to 73.5 which is why you feel a tremendous difference. That is 25mm (A bit over an inch) of sidewall less from your old tires.

Some guys here are running top-notch suspension so they don't feel the difference. Aside from feeling the bumps/dips, I would run 245/35 or 235/35 just to help protect my wheels a bit better.

 

I agree, 30 up front isn't ideal. But since they're already on, might as well use them up and then swap for some 35's when its time. Just be sure to keep an eye on the tire pressure to help prevent any wheel damage.

 

On a 20" wheel, a 30 series is actually ideal: it's the
"correct" fitment for the GS, technically. A 245/30-20 is
about as close as you can get to the OE tire circumference.
A 255/30-20 is just a smidge taller.

Unless you drive on the pocked surface of the moon, moving
to a 35 series really doesn't help protect the wheels that much.
And inflating the tires to 40+ psi just makes the car ride like
a dump truck.

I've been rolling on my 255/30-20 + 305/25-20 combination for over
a year now and have zero issues. Previously, I had 255/35-20 and
285/30-20, and I have to say with a high-end, quality 30 & 25
series tire I really can't tell the difference in ride quality (I run
Yokohama Advan Sport, smooth, quiet... love these tires).

Also, running the shorter tires will keep the final drive ratio closer
to stock, making the car a little quicker light-to-light; I could actually
feel the improvement in quickness with my current set-up (the 35 + 30
series set-up is 1" taller than OE). Not to mention the shorter tires have
less chance of rubbing the front fender liners when the wheels are turned.

And the car looks cooler with the shorter tires when it's dumped (lowered).

 

socal, what psi do you have your tires set at?

 

max psi on most 30 series is usually around what? 50 psi? I'd definately run 40 psi...