C4 Autocross Wheelbearing Usage?

[MBDiagMan]

I am considering taking up autocross using my 88. I just saw a post in the C4 forum that indicated that wheel bearing pacsk might not last very long in autocross usage. If this is true, then keeping the car in wheel bearings may cost as much as keeping it in competition tires.

Can anyone tell me of your experiences under autocross use, with how long wheel bearing packs will last on:

A C4 with street tires?

A C4 with competitions tires?

Thanks very much for sharing your experience and have a great day,

 

[froggy47]

Under heavy autocross use and if you change them when you "should" and if you drive at 10/10ths I'd say 10 to 25 k miles.

Low end with sticky tires higher end with street tires. The guys that get 50 or 100k miles on a set of bearings are commuters and guys that go to wax shows.

That's several years of autox & track use.

Tires otoh can be 2 or more sets a year, again depends on how many events & how soft & how hard you drive, pressures etc.

Don't forget brake pads

So bottom line is you'll go thru a few sets of tires & pads to one set of bearings, that's my experience.

 

[jsinga]

The set of wheel bearings on my 87 have lifetime warranty from Pep Boys. Word has it make sure the bearings either are Timken or NDH, made in USA. The NDH is stamped on the bearing in small letters. These are OEM, the same as the high priced ones in Delco boxes.

JS

 

[froggy47]

JS has a good point there are good bearing & there are cheap ones. The cheap ones don't last in a competition environment.

I use oem.

OTOH We all know that lifetime warranty never means that they are actually going to last anybodies lifetime, you will still be replacing bearings. The seller is betting that you will sell the car/crash/lose receipt etc. b4 they wear out.

 

[MBDiagMan]

Thanks very much for the responses and please keep them coming.

I am going to run an Autocross on Sunday. I will do it on my street tires and just get the experience. If all things cooperate I will try to prepare this winter and be ready for a full schedule next year.

With a kid in college it's going to be tough to budget enough for tires, bearings and pads. I will try to poorboy my way through it and see what I can get by with.

I so far have gotten no ideas in another thread about a way to get the most bang for the buck on the tire front. My thinking is to find a set of 17" wheels and get by with the cheapest tires I can run.

Will thin, street tires be stickier than castaway competition tires that have heat cycled enough times to lose their adhesion?

Thanks again,

 

[froggy47]

My thinking is to find a set of 17" wheels and get by with the cheapest tires I can run.

Will thin, street tires be stickier than castaway competition tires that have heat cycled enough times to lose their adhesion?

Thanks again,

I ran last half of my first season (Jul - Dec 03) and first half of 2nd season (jan 04 to jun o4) on GY GSC (oem street tires) that were put on by previous owner. These are jokingly referred to by Vette autox guys as Flintstone Tires because they are so hard a compound.

Then I bought Victoracers (Kuhmo) about the time that Kumho 710's came out (Remember the recall on those?) So again I was on uncompetative tires as all the fast guys were on 710's. Those lasted 7/04 to 6/05.

Then I got 710's & never looked back

If you have to use the car for any commute daily driver miles you might think about a 2nd set of rims & get good at changing wheels. I do it in about 25 min now (Two low rise jacks & air gun)

Myself I have another vehicle so I end up leaving the race tires on mostly. I will drive to the gym or such on the race tires & it does no harm. If it rains though you are screwed. Ask me how I know.

I also drive to events on the 710's. It adds a heat cycle & wears them some but not a big deal.

If the tire budget has you worried try to run in a class that street tires are required. Cal Club in LA region has SK1 and Sk2 for big cars & smaller ones.

Check your local scca guys or whoever you are going to race with.

As for your original question, it depends which street tires & which race tires. I think usually the race tires will win out due to stiffer sidewalls & being mostly like a slick. But if you came across some used Michelin Pilot Sport Cup - or the GY ultra high perf. tires - those would probably be better than a really used up race tire.

For cheap tires that work ok try Sumitomo - I forget the model. Also Hankook if they have your size. The comp tire to have is the Kuhmo 710. Check Tire rack & Discount tire online.

 

[MBDiagMan]

I have the rare 16" wheels for my 88 standard suspension car, one year only and those are my street wheels. I know to not leave competition tires on the ground. If I take the plunge to competition tires they will come off the car and on the trailer before putting the car on the trailer and will then be put back on when back at the event.

I've never timed myself but I can't imagine that it takes me as long as 25 minutes to change four wheels, but I've been doing such things for many years and have the right equipment. I won't use an impact to put lugs on, but don't mind when taking them off. I can do it almost as fast with a Cross lug wrench. In fact maybe faster if I have to wait for air pressure.

Due to mods on the car, I am stuck with B street prepared class. My thinking is to put on ZR1 wheels and street tires. to compensate for the wider rear wheels I might have to go to a stiffer rear bar, but that's no big deal.

I can get an aftermarket set of ZR1 wheels for not too much as long as I can find out if they are any good. Then I'm thinking with this bigger rubber in a sticky street tire, I can run them for several years as my Autocross tires and won't have to change them before and after every event if I'm not going to drive the car on the street.

Thanks for your input.

Please keep the ideas, experience and comments coming.

Have a great day,

 

[froggy47]

My friend occasionally runs scca bsp with 17x11 rims all around & 315 rubber. Depending on the design of the course (National style course) those big meats up front work pretty good.

If it's a Miata or shifter kart type course maybe not so good.

(The air gun is just for speed, I do final tighten w/ torque wrench - of course)

 

[MBDiagMan]

froggy,

Do you happen to know what offset his 11 inch wheels on the front use, or could you find out? Are they the same as the rear ZR1 wheels.

I would really appreciate it if you could find out offsets for front and rear so that I know for sure there are no clearance problems.

I think 315 street tires might accomplish what I want. It would let me use street tires and increase grip without buying $1000 sets of tires all the time.

Thanks for the comments and help,

 

[froggy47]

I believe they are the 50mm offset (1996 Grand Sport style) as opposed to the zr1 offset which I think is 36mm.

I'll see if I can find out for sure next time I see him.

His car is a Grand Sport, that's why I figure they are the 50mm offset. I doubt he'd have gone and bought zr1 offset.

 

[MBDiagMan]

Well I learned yesterday that if I'm going to autocross I will most definitely have to do something with the tires. I slid around like I was on a wet track.

If I can fit 11" wheels at all four corners that will be my preferred approach. If I can find out for sure what offset 11" wheels will fit under the front that will be really helpful.

Thanks for the responses,

 

[MBDiagMan]

froggy,

I see that wheel offsets are the same for the 88 to 99 cars. At least that is what I'm deducing from reading some of the info by a wheel supplier that advertises on ebay (some authority, huh?)

From that source they call for 11" 50MM offset for the rear of my car but I don't know about the front.

I have found a possible deal on a used set of 11" wheels but they are 36MM offset.

It would be pretty bad to get wheels and tires, mount them up, balance them and put them on the car only to find that they don't fit.

Thanks for any help you can offer.

Have a great day,

 

[froggy47]

froggy,

I see that wheel offsets are the same for the 88 to 99 cars. At least that is what I'm deducing from reading some of the info by a wheel supplier that advertises on ebay (some authority, huh?)

I don't think so, the offsets are not even the same for a single model year depending on the model 1995 zr1 vs LT1 for example.

From that source they call for 11" 50MM offset for the rear of my car but I don't know about the front.

Front on my 1996 is 56mm for 1996 coupe Grand Sport.

I have found a possible deal on a used set of 11" wheels but they are 36MM offset.

That is the zr1 offset - required the "wide body" of the zr1's

It would be pretty bad to get wheels and tires, mount them up, balance them and put them on the car only to find that they don't fit.

Thanks for any help you can offer.

I will ask around on Sunday - there will be some Vette guys where I'm racing.

Many guys now are into c5's and us guys with c4's are having a bit harder time getting info.

Have a great day,

see above

I think the guys that run 11's all around use Grand Sport rears (50 mm offset). There could possibly be some tire rub situations with this set up at full lock or going thru some bumps at speed. You need to understand that a really good set up for autox is much less than ideal for street. Is this a trailer car or will you use 2 sets of wheels & switch?

Are there any guys in your region with a similar set up?

It may be a while till my buddy pulls his wheels & I don't know if he knows FOR SURE the offset. It is stamped on the insides of the rims. When I ordered my set the first thing I did was confirm the offsets, b4 I even mounted a slick.

 

[MBDiagMan]

froggy,

First of all thanks for the dialogue.

I do indeed understand that the autox setup will not be my street setup. I will trailer the car or trailer the tires. I live in the boonies of NorthEast Texas so I drive to Texarkana (100 miles or so) or Bedford (130 miles or so) to autox. That means it would not be a good idea to drive my race tires even if they were streetable.

I am still trying to find out for sure what is known to work. My biggest concern is the front because I think the rear is just an issue of how far the tires will stick out. The front OTOH would be a bad deal if they were unusable after going to the trouble and expense of gathering up wheels and tires only to find that there are serious clearance issues. If I can't turn all the way to the lock I can work around that as long as it will get close.

Thanks again for your attention,

 

[froggy47]

See what I can find out sunday.

You might cross post this to the racing forum. Somebody should already have this info.

 

[MBDiagMan]

Thanks froggy. I thought this was the racing forum. I will look further.

Have a great day,

 

[froggy47]

Thanks froggy. I thought this was the racing forum. I will look further.

Have a great day,

You are right. I hang out mostly in c4 technical & thought I was posting there, my bad.

Try Corvette Forum & Digital Vettes though, maybe some help there.

 

[*89x2*]

I am considering taking up autocross using my 88. I just saw a post in the C4 forum that indicated that wheel bearing pacsk might not last very long in autocross usage. If this is true, then keeping the car in wheel bearings may cost as much as keeping it in competition tires.

Can anyone tell me of your experiences under autocross use, with how long wheel bearing packs will last on:

A C4 with street tires?

A C4 with competitions tires?

Thanks very much for sharing your experience and have a great day,

Since you asked the question here, rather than some other forum, as some may suggest :eyerole

I can offer you the experiences I am aware of - some even being my own

The wheel bearings in the rear will more than likely take the most abuse - esp the passenger side rear from what I have seen - and replaced

Obviously with "race tires", the driveline will be punished a bit more however, most street tires are quite capable of trashing a stock wheel bearing quick enough.

My suggestion would be to replace them with a part from your local "Pep-Boys", as they have, or at least had, a lifetime warranty for the part so you would only be out the labor - which is generally under 2 hrs. (we did my last one in about an hour and change...)
I have had stock wheel bearings last very little so I do not think that brand has everything to do with how long it *might* last.

Good luck

 

[*89x2*]

I thought this was the racing forum. I will look further.

It is :cool Enjoy!

 

[froggy47]

froggy,

Do you happen to know what offset his 11 inch wheels on the front use, or could you find out? Are they the same as the rear ZR1 wheels.

I would really appreciate it if you could find out offsets for front and rear so that I know for sure there are no clearance problems.

I think 315 street tires might accomplish what I want. It would let me use street tires and increase grip without buying $1000 sets of tires all the time.

Thanks for the comments and help,

It's the Grand Sport 50mm offset (11 wide) that the guys run in BSP (autox).

This also apparently is a good track set up. I was at Willow Springs & several c4 Vettes had the same rims all around - they seem to like Victoracers rather than the 710's - I suspect it's to get more track miles not because of better performance.