When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Have had many inquiries about the roof rack I assembled to carry tires to the track and decided to post a set of instructions I was producing for a friend. Uses the Porsche roof transport system and Rhino Rack aluminium alloy trays which makes for both a very light and very solid platform.
It does look very nice. My only reservation is a roof rack load capacity of 165lb only. 4 typical track tires in 18" like 245/305 would weight more than 200-220lb along + 46lb for carrier itself. I know Porsche built some safety margins but if anything goes wrong on a road... it is illegal. I guess it is all personal. Don't get me wrong, I am not trying to criticize your great set up just playing engineering inside of me.
I built a 5lb wooden platform for 2 rear tires only and carry other fronts inside. Not sure what to do if I install a cage.
------------------
05' C2S 997
Wheels and tires are 195lb (245/310X18) and I'll check the rack, but it appears much lighter than listed.
Porsche appears to have capped the roof load biased on the allocation to passengers, fuel load, luggage etc. I have used the setup on two separate cars over two years with many long trips to the track with all and there has been no sign of wear, deformation, stress etc.
As an aside, I leave the mounting blocks fastened to the roof to minimize wear on the screw holes into the roof. The screw holes for mounting the Porsche rack to the mounting blocks are replaceable.
In any case, for those looking for a better option than a trailer this has worked for me.
Very nice solution and one I am planning to do myself.
The last piece of the puzzle is how you secured the wheels to the rack. Can you provide the specific product?
I think they just use ratcheting tie-down straps, in a cross-formation secured to the eye-bolts. You can get them anywhere. In thinking about it myself, finding straps that are relatively short, and that have a long-enough tether on the ratchet side (although I guess that depends on whether the wheels are carried face up or face down).
I have the rack for my Cayman S, and have ordered the AT tray and fit kit. I believe the dimensions listed in the instructions above will not be right for a cayman. For example, the rear cross-bar is about 5" shorter than the front, so at the very least the access holes will change location. When I figure all that out I can post here for a 987.2 . It might be a bit because the AT1512 is backordered by a couple weeks.
I wonder if the DMV would allow the center cap tie down.
First thing ... find out your local state and provincial load laws.
Most loads must be secured with certified strap. I know motor cycles and snowmobiles.....
Don't know about a spare tire on the roof?
Tire in the car? Tie that down too. In an accident a 40lbs tire in the head? Would make a mess of your full leather interior?
That why they call the accidents, and not onpurposes.
I have to agree. A loose wheel at speed can be lethal. Best to use tie-downs to the eye-bolts that connect through to the roof rack itself.
I completed my installation on a 987.2 Cayman. The dimensions in the diagram above are a bit different for the CS roof rack. The center lines for the holes are still 15.5" from the front and rear. The four 5/16" holes for the bolts are in the same place as well - 14.5" in from the sides.
But on the CS the front rack cross-bar is wider than for the 911 and the rear is narrower, so your access holes for the allen wrench will be in different places.
Double check this yourself, of course, but I put the holes 1/2" wider then the ends of the aluminum cross-bars. For the front, that's 37-3/4" between the holes, or 18-7/8" off the center line. For the rear I have 34-1/4" between the holes and 17-1/8" off center. I drilled a 1/8" pilot hole and used a thin wire to make sure I had correct access to the bolt below. I used a 1/4" access hole, and take note of the angle the long allen key will be going and it helps marginally to angle the drill a bit to match.
The Rhino-rack AT tray in question has 5 planks. (compared to the 4 in the illustration above) so the holes come out in very convenient places - they don't interfere with the structural rib down the center of each plank.
Oh, and since the bolts and eye's connect through the planks and not the intended side brackets, that raises a question. There are metal reinforcing places that are used when bolting the side bracket to the roof rack. I think you could leave them off, but I felt like they could help, so I found some short bolts and washers and just bolted them in. It will make more sense when you are looking at the parts.
Loaded up the rack. For my CR 19" wheels with RE71R 35 profile tires it was a very very tight fit. I had to reduce the pressure to about 10 lbs. Once loaded up though, very solid. A couple more pics. Also, I followed a link here initially and didn't notice that this is in the 997 forum. Oops!
What happens if your car breaks down at the track? Anyone who tracks their car knows the probabilities increase as track useage increases.
This is always a possibility. But, up until recently, I've never had the room or ability to own a 20 foot trailer. So I've always driven to and from the track. On a stock car, there isn't too much to go wrong, and if something does go wrong, track people are nice, you can probably catch a ride pretty close to home, uber the rest of the way and rent a trailer to come pick up the car...
07-31-2015, 02:28 PM
Roof Rack Track Tire Carrier
