turbotuner20v

I have a Z51 car, but base rotors/caliper brackets from my road course days. Can I swap on the base rotors/brackets and bolt on a set of GTO spares w/o any spacers or grinding?

Also, just out of curiousity, will I notice a weight savings at each corner going down to base brakes all around?

I'm hoping I can swap out my 19x10 ZR1 replica wheels (~60lbs ea.) for a set of the 17" GTO spares w/ M&H bias plys on them (~27lbs ea.) for a significant weight savings up front.

FloydSummerOf68

I'm hoping you meant that the 19x10 ZR1 replica wheels are 60lbs WITH tires, lol.

Also, are you running 19x10s up front?

The GTO skinnies SUPPOSEDLY fit without a spacer up front on base brakes (and yes, you'll save some weight going to base brakes from Z51).

If you look a few posts down you'll also see the option that I'm going after with a Z51 setup which includes running the CTS 18" spares which don't weigh much more than the GTO spares.

turbotuner20v

haha, yea, with tires.. and yes, they are the front wheels. I have 19x12 (dr) or 20x12 (street) in the back.

I saw your post about the CTS spares and that will be the route I go probably if I cannot fit the GTO spares on w/o modification or spacers.

turbotuner20v

I guess I have to modify the GTO wheels either way right, to expand the hub hole from 69.5mm to 70.5mm?

FloydSummerOf68

Yes, that is correct.

HOXXOH

You can open up the hole with a hand drill and a sanding drum. Just go easy and fit to the hub often so you don't take off more than necessary.

8850 just put the wheel on and slowly tightened the lug nuts equally in the standard pattern. That essentially worked like a broach.

The base rotors vs. Z51 rotors save approximately 15 pounds total, depending on wear of each.

turbotuner20v

can anyone confirm if they fit over the base brakes for sure w/o having to add a spacer or grind any part of the car?

dsp300c

my gto spares fitting over non z51 base front brakes. no spacer was needed. all i had to do was grind very little out of the hub hole in the middle of wheel, not the car, so it would fit. took me a few minutes. all i had to modify. my videos in my sig also show me running them at the track.

HOXXOH

If you search, you'll find many examples like this and posts that confirm.

turbotuner20v

awesome, that's the exact confirmation I was going for. Ordering today

turbotuner20v

I found quite a bit about using them with spacers and different tire options and even using them as true spares, but nothing that really confirmed if they fit over base brakes w/o modification, thanks for the info

8850

Correct but I still had to use a sanding burr with my phenumatic grinder to remove a slight bit more or the wheel was too tight on the hub.

No spacers are needed with base brakes. Bolt circles are not the same but again tightening down evenly they do work. Probably best to use whobble nuts.

turbotuner20v

I guess my only other question would be do people mix bias ply front runners w/ radials in the rear? I'm running nitto nt05r's in back.

debating between these two:

M&H Bias Ply 26x4.5x17 - 11.5lbs - http://www.mandhtires.com/store.php?...on=show_detail

M&H Racemaster 185 /55R17 – 18.5lbs - http://www.mandhtires.com/store.php?...on=show_detail

HOXXOH

I'm running the M&H bias ply. It's all about the weight. It doesn't make sense to spend the money and not get the lighter tires. I've trapped 126 with no issues and thesubfloor has gone 140.

turbotuner20v

Cool, I'll be trapping 130mph... I wanted to go as light as possible, but didn't know if it would cause any handling quirks or instability mixing them up like that.

FloydSummerOf68

To me the difference would be if you're driving to the track on them or not.

If you drive them on the street AT ALL I'd run the radial fronts. If you swap all of your wheels at the track I'd run bias ply.

HOXXOH

Neither are very good for street use. And the bias less than radials.

turbotuner20v

hmm... I had thought about driving to and from the track w/ them to avoid having to swap there. Would it just be the lack of stability at highway speeds, or ? Hopefully they're relatively stable at speed since I'll be going pretty fast down the track.

FloydSummerOf68

The radials will simply handle better at any speed.

If you drive to/from the track get the radials and don't worry about the few pounds difference. The increase in driving ability will far outweigh that small difference and you'll still be saving a ton of weight from stock wheels and full size tires.

I drive 60 miles to and from the track. I'll be going with M&H radials on my skinnies.

You DO NOT want to be caught in a freak shower or find yourself going through standing water on the road with bias ply fronts.

No doubt about it, bias ply are the best for weight reduction, but I consider them a track-only tire. I've driven radial skinnies on the road quite a bit and that's scary enough if you get caught in a bit of weather

LS1LT1

100%

I have also found that the radials can last longer/wear better.