Hi everyone,

What are the current tire recommendations for C4s? This is a weekend driver vehicle.

Thanks!
Reuben

 

I put Riken Raptor on my 96 sawblades. One size smaller.

 

Rueben,

I've been pretty happy with the Nitto NT555's. They have a decent ride for cruising. Cannot speak to recommended tires for other uses like autocross, etc

 

I love the Continentals
https://www.tirerack.com/tires/tires...6&autoModClar=
https://www.tirerack.com/tires/tires...6&autoModClar=

Smooth, Quiet and good in wet and dry

 

Are your fronts 17x9.5 with 275/40/17 tires front and rear (Z07), or the base 17x8.5 with 255/45/17 front and 285/40/17 rear? If the latter, you may consider stepping down from your stock tire sizes to 245 and 275, as puterami suggested. That gives you a lot more choices.

For a weekend driver (no competition and no winter driving), I suggest the Riken Raptor as a good budget option or the Continental ExtremeContact Sport 02 for the best wet/dry (but not snow) tire you can get that still isn't priced out of sight. The Nittos are horrible tires using 30-year-old designs with low quality, but priced like a mid-tier tire. Way overpriced for what you get. The Rikens are better in quality and performance and still way cheaper.

 

Thanks all, right now, I have the tire sizes below:

• front: 255/40/zr17
• rear: 285/40/zr17

So, I'm guessing I have the base 17x8.5 that you listed?

It looks like there are a few options at tirerack if I change to:

• front: 255/40/zr17
• rear: 275/40/zr17

I'm thinking I will go with the Continental ExtremeContact Sport 02.

 

Yep. That was standard fitment starting in 94.

If you opted for those sizes, you'd have significantly shorter front tires than rear. They would fit, but they'd look a little odd. I recommend either 245/45/17 and 275/40/17 OR 255/45/17 and 285/40/17 to keep tire diameters equal. Luckily, the Conti is available in either of those sizes, and you've decided to go with that tire (which is a great choice). If you go with the larger combo (255 and 285), you'll get a little cushier ride quality at the expense of slightly slower steering response. If your car rides pretty high (like all later base C4s - Chevy raised the ride height to make up for the softer springs), the taller tire diameter of this combo will fill the wheel wells a little more to hide the added ride height. The smaller combo (245/275) gives you a little sharper steering response at the expense of a bit of ride quality and a little more wheel well gap. Take your pick.

 

A 255/40ZR17 tire has a dynamic rolling radius of 830 revs/mile, a 275/40ZR17 tire has a dynamic rolling radius of 810 revs/mile and a 285/40ZR17 has a dynamic rolling radius of 800 revs/mile.

This is a 3.75% difference for the current combination and a 2.5% difference for the proposed combination. The ABS (and TCS) systems will need to compensate for the difference in velocity for each wheel which can take some time. This can result in either less sensitive control or more sensitive control than intended before correction can be applied. If you can tolerate this its up to you. I don't know if the stagger is visually apparent, but this might be a factor if you like the look of staggered tires.

A square tire setup of either 255/40R17 or 255/45R17 will work with both wheel sizes and as a bonus you can pretend that you have an 84 Z51 car. This would also provide another tuning variable depending upon which axle you choose to run the wider wheel/stretched tire. I would probably put the 9.5" wheels on the front to move the bias towards oversteer.

 

The current stock tire fitment is 255/45/17 front and 285/40/17 rear. They are the same diameter, and there is no difference in rolling radius.

I'm pretty sure they don't do any learning/compensating over time. They just have whatever calibrations they have. This is true even on current GM cars. The most like result is the possibility of increased likelihood of encountering "ice mode" ("hard brake pedal"), which is no fun: it can lead to ****-your-pants mode! That's a good reason not to go with a shorter front tire, although I note that many people throw C5 wheel/tire sets on their C4s without any obvious ABS confusion. I am sure that going with larger diameter up front than rear encourages ice mode, and going with a smaller front diameter is probably less risky.

Although one could fit either height of 255 tire both front and rear, the dicey issue with it is that you're going to get different steering response on the pinched set (8.5") than the stretched set (9.5"). This isn't really the same as steady-state grip, so you aren't really balancing handling like that. With the narrow wheels still up front, it would at least be safe. With the wider wheels up front, as you suggest, you'd get some pretty bad handling characteristics and I would never recommend that. Furthermore, you don't want to sacrifice rear-axle grip on a RWD car. There's really no need for any of this weirdness when the tire the OP wants comes in either of two proper size combos for his current wheels.

If the OP wants to pretend he has a Z07/Z51 car, the thing to do would be to buy two more "rear" wheels for his car. He'd then have a square set of 17x9.5 et56 sawblade wheels and he could fit 275/40/17 tires front and rear. This is what Chevy in all his performance handling packages from 88-96. Those wheels tend to be fairly cheap, so this is a viable option.

 

Thanks everyone for all the information and it is very helpful! Until I started investigating, I had no idea about the lack of options for these wheels.

I like the suggestion to get two wider sawblades for the front, so I'll stay on the lookout for a matching pair in the for-sale section.

For now, I'll go with the Continental ExtremeContact Sport 02, in the sizes listed below:

• front: 255/45/zr17
• rear: 285/40/zr17

Reuben

 

Hey folks,

Just a quick follow-up post after the installation. These tires look and ride great.

 

Also, I checked the QBO codes and confirmed all the recommendations provided previously for sizes.

• QB6-aluminum wheels 17 x 8.5" front, 17 x 9.5" rear
• WY5-PERFORMANCE PACKAGE, EXTENDED MOBILITY TIRES (EMT)
• XFR-FRONT TIRE P255/45 ZR17, EMT
• YFS-EMT REAR TIRE P285/40 ZR17

Thanks again.