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After some research , I've come-up with a wheel tire combination that will fit over the C5 brake calipers & fit in the spare tire well of the 4th generation F-body. A spare wheel from a 2004 Pontiac GTO will fit over the C5 calipers, but it will not fit in the spare tire well due to the 25" O.D. of the 145/70/17 Goodyear tire. I called every major tire manufacturer that I could think of (Goodyear/Dunlop, Michelin/Goodrich, Bridgestone/Firestone, Cooper, Toyo, Yokohama, Continental, Uniroyal, Pirelli, Falken & Sumitomo). The smallest 17" convenience spare tire I could find was a Bridgestone 125/70/17. This tire is the OEM spare for the Mazda RX8. I located and purchased an unused RX8 spare tire (no wheel) on ebay for $40 shipped. I purchased an unused 2004 GTO spare wheel/tire through www.car-part.com for $100 shipped. I mounted the RX8 spare tire on the GTO spare wheel and it fits in the spare wheel well snugly...........UNINFLATED. It will NOT fit when inflated. I considered using a block of wood & a maul to "open-up" the well a bit, but have decided against. Instead, I will use some type of inflator to inflate the tire when/if needed. Some 3rd gen f-bodies used canned tire inflators. I'm thinking of converting an empty propane cylinder to a compressed air tank. I'm also considering using a GM air-ride compressor as I don't like the crappy 12 volt portable compressors that are available. Any ideas on tire inflators will be appreciated. I do NOT want to use Fix-a-flat because I do not want to put the sealing goop inside of the wheel.
As a side benefit the GTO wheel / RX8 tire combo is 6 lbs lighter than the LS1 spare tire.
I hope this helps
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Last edited by 95Z28A4; Jan 24, 2022 at 11:14 AM.
Reason: Uploaded original photos. Hyperlinks were broken.
Any chance that you checked the fit in an LT1 car?
Thanks
Z28
No, I have not posted this on FRRAX
My 95 Z28 IS an LT1 car! I purchased an LS1 spare when I converted to LS1 front brakes ~ 4 years back. Now that I have C5 front brakes, the LS1 spare will not fit over the C5 calipers. I also tried a 17" C4 spare, but it also won't fit over the C5 calipers.
My 95 Z28 IS an LT1 car! I purchased an LS1 spare when I converted to LS1 front brakes ~ 4 years back. Now that I have C5 front brakes, the LS1 spare will not fit over the C5 calipers. I also tried a 17" C4 spare, but it also won't fit over the C5 calipers.
Sorry I missed that, saw LS1 and assumed.
Even better that it is an LT1 car.
Alot of C5 Bob Bishop brakets were sold on the FRRAX site, but they might not care if they were running on the track only.
Like I said great work and detailed photos. I asked this same question, what to do about the spare, but I just gave up on it figured on doing a double change if the front went flat. You have come up with a better solution.
After some research , I've come-up with a wheel tire combination that will fit over the C5 brake calipers & fit in the spare tire well of the 4th generation F-body. A spare wheel from a 2004 Pontiac GTO will fit over the C5 calipers, but it will not fit in the spare tire well due to the 25" O.D. of the 145/70/17 Goodyear tire. I called every major tire manufacturer that I could think of (Goodyear/Dunlop, Michelin/Goodrich, Bridgestone/Firestone, Cooper, Toyo, Yokohama, Continental, Uniroyal, Pirelli, Falken & Sumitomo). The smallest 17" convenience spare tire I could find was a Bridgestone 125/70/17. This tire is the OEM spare for the Mazda RX8. I located and purchased an unused RX8 spare tire (no wheel) on ebay for $40 shipped. I purchased an unused 2004 GTO spare wheel/tire through www.car-part.com for $100 shipped. I mounted the RX8 spare tire on the GTO spare wheel and it fits in the spare wheel well snugly...........UNINFLATED. It will NOT fit when inflated. I considered using a block of wood & a maul to "open-up" the well a bit, but have decided against. Instead, I will use some type of inflator to inflate the tire when/if needed. Some 3rd gen f-bodies used canned tire inflators. I'm thinking of converting an empty propane cylinder to a compressed air tank. I'm also considering using a GM air-ride compressor as I don't like the crappy 12 volt portable compressors that are available. Any ideas on tire inflators will be appreciated. I do NOT want to use Fix-a-flat because I do not want to put the sealing goop inside of the wheel. I've attached a few links that may be of interest.
As a side benefit the GTO wheel / RX8 tire combo is 6 lbs lighter than the LS1 spare tire.
I hope this helps.
I just realized what you could use to inflate the spare, CO2.
Small bottle holds a lot of CO2 at low pressures because it is a liquid.
Flashes to a gas when the pressure is released. This is what some mountain bikers carry instead of a pump. It is smaller and lighter. You just need a larger version. I bet a fire extenguiser company could set you up. Or a google search might turn up a ready made solution. I think paintball guns use co2 also.
I just realized what you could use to inflate the spare, CO2.................I think paintball guns use co2 also.
Z28
Thanks! Great minds think alike. I'm already all over the CO2 inflator. I have a 9 ounce CO2 paintball cylinder on my desk as I'm typing this. They are also available in in 12, 14 & 20 ounce cylinders. I'm going to have this 9 ounce cylinder filled tomorrow and attempt to inflate the tire. Also, I read your post on www.frrax.com . The LS1 spare tire size is 135/60/16 amd has a smaller O.D. than the RX8 spare.
OMG
I never once thought about the spare now that I've changed the brake
Thank you
Re: CO2, it will work, you just need the correct tank size.
Just last week, my friend was showing me what he was going to buy and install in his Land Cruiser for off-roading. Yes, C02 is very popular with off roaders for inflating tires for on road use after off-roading. He's in Moab this very minute, doubt he's driving (its dark) now.
OMG
Re: CO2, it will work, you just need the correct tank size.
Just last week, my friend was showing me what he was going to buy and install in his Land Cruiser for off-roading. Yes, C02 is very popular with off roaders for inflating tires for on road use after off-roading.
Ken B
Yes, CO2 will "work". I tried a borrowed 9 oz paintball marker cylinder and it inflated the tire to 58 psi. A 12 oz cylinder would definitely inflate the T125/70/17 RX8 tire to the required 60 psi and have a little lextra for error.
I'm concerned about leaving a cylinder of liquid CO2 in my car during the summer months when temps inside the car approach 130F. I'm going to try compressed air next. I can purchase a 47 cu in 3000 psi HPA paintball tank for about $65 shipped. Before I spend that much $$, I'm going to try filling a 20 oz CO2 tank with compressed air to 1500 psi. The CO2 tanks are rated for 1800 psi. I can purchase a 20 OZ tank for about $30 shipped.
I hope to try the 20 oz tank this weekend. I'll keep everyone updated.
just to let you know your right on the co2 int he summer.. i use to play alot of paintball and the co2 tanks have a burst disk in them so when they get that hot they just dump all the air out. ive had several summer days ruin a can of co2
Re: C5 Brake Conversion Spare Tire & Tire inflator Question
