Wheel sizes

[Fred W.]

Hi all

After looking at heaps of pictures of cars in various stages of build I think I have got my mind set on rear wheel size of 17 diameter and a tyre width of 315. I'm trying to get a definitive answer as to what width the wheel needs to take this size tyre. I know its a bit of a broad question so if someone can elaborate on wheel sizes and tyre sizes widths and aspect ratios for 17 and 16 inch diameter wheels go ahead. Thanks!

 

[EGLITOM]

Hi

Check this excel file

TOM

 

[Phil]

Fred;
I am using a 15 X 14 wheel in the rear with Avons. Backspacing is 4 7/8", and I am showing approx 75" across the top of tread side to side. The tires have a 13" width across the tread which is close to what you spec'd. The tread is narrower than the actual sidewall. My body work shows 77 1/2" inside to inside so I have approx 1" clearance on each side from the tread, and a little less from sidewall. I am running a track of 56" with pin drive adapters 3/8" thick so my actual track is 56 3/4". Tire diam shows about 26 1/2" with the car in all fours and although the Avons are not marked as such the aspect ratio would come in somewhere around 48, or close to a 50 series tire.
I guess a lot would depend on the bodywork you have, wheel offsets, track etc.
I know that you mentioned that you would like to run 17" wheels so I suspect that you would need an aspect ratio of 35 or 40 to maintain correct chassis height.
I hope some of this info helps.
Here is a photo of my rear setup
Cheers
Phil

 

[Bob Putnam]

Tire rack specs for an Ecsta 315/35-17 tire: 10.5"-12.5" wide

 

[Charlie M]

Phil,

What are you using for tires, wheels, and track width in front? Are you using a Bill Hough MkI body?

Thanks,
Charlie

 

[Phil]

Charlie:
Track width in front is 56", wheels are 15 X 10 with a backspacing of 4 7/8", the bodywork I have was from a GTD, but the rear deck is an original piece, which I am having copied. All the bodywork is stuff I had accumulated.
Here are some photos of the front setup.
Cheers
Phil

 

[Charlie M]

Thanks Phil. How did your front setup work out with the wheel position relative to the body? The tires fit in the fenderwells OK? I was planning a 57" front track width with 8" wide wheels. If your setup works well I could go to a 58" track width and have the same width as yours to the outside of the tires. I'm trying to spread the front suspension out as far as I can to get more room in the footwells.

Charlie

 

[Phil]

Charlie:
I can tell you that the front tires are closer than the rear to the bodywork. I will take a measurement of the front bodywork today and post it later. The front was a bit of a challenge as the adapters would have put me beyond the bodywork so it was necessary to fab an adapter/hub which brought me back to 56" track to fit the 10" wheels. I would guess it all depends on your backspacing and width of your body. My front tread fits within the bodywork but its close. If I remember there were some posts previously on the forum about front track being too wide with adapters, and the availability of different backspacing dimensions was limited, which is a problem you may encounter. Here is a photo of my front setup, I will post the dimensions of the bodywork tonight which is probably close to what you would have.
Cheers
Phil

 

[Phil]

Charlie:
Front bodywork is 69" to outside with a 1/2" lip to inside. so I have 68" inside. Tires measure 68" full width, and 66 1/2" across tread. As I said it is close.
Depending on your backspacing with an 8" wheel you should be able to go to a 58" front track as long as it is 4" or more, and it would be approx the same dim. I am getting, but that would be your max wheel with that setup. It may allow you to expand the footwell area a bit.
Cheers
Phil

 

[Howard Jones]

The tires on the rear in this picture are 315X35X17 on wheels that measure 10.75" wide between the wheels lips.

I would recommend 11.5 inches in width for a 315X35X17 tire. Have a look at Tire Rack - Your performance experts for tires and wheels for tire specs and a lot of information on tire/wheel sizes, tire width, height, and section width

 

[Fred W.]

Thanks guys for the help. I kind of figured that 11.5 or 12 inch would be the go for 315x35x17 . Now I just need to find out whats available. I was hoping to be able to buy BRM's at this size but I have bought hubs with five studs and am not sure where this leaves me for choice.

 

[Dimi Terleckyj]

Hi Fred

These are 345 Pirelli on 12 inch rims.

You would not want to put smaller tyres on a rim 12 inches wide.

As it is with these there is very little bag in the walls.

Dimi

 

[Fred W.]

OK. Really this why Ive put up the post. Those are bigger than I have in mind and they are on 12 inch rims. Its a personal taste aesthetics thing that I'm looking for. Ive seen the 315x35x17 on other cars and think they are just right. But I haven't been able to find out what width is best to use with this tyre and whats out there for purchase. Bearing in mind I'm using five nuts and not a single spinner.

 

[Randy V]

Not to hi-jack your thread as it's somewhat in the same vein..

I'm curious what the widest tire that anyone has put on their 15" by 10" wide rims would be...
I know what the recommendation would be and that oft times that is a bit shy of the real world..

I'd really like to consider going Gulf-Wide on he rear of my forty - but don't want to pay for the widening of the rims nor the price of wear and tear on the rear bearings.

 

[EGLITOM]

Randy

check ray maserangs rcr built he has put real big tires on 10 "

TOM

 

[Charlie M]

Phil,

My body is the same width as yours so those dimensions help a lot, thanks. I spoke to Bob Lacey at Vintage Wheels. He told me that the standard backspace on their 17 x 8 BRM style wheel is 4.5" and he can remachine them to get 5" if I need it.

Fred,
Vintage Wheels has BRM-style wheels and adapters for 5-lug hubs (both Ford and Chev. bolt circle).

Charlie

 

[Randy V]

Randy

check ray maserangs rcr built he has put real big tires on 10 "

TOM

Thanks Tom - I found his Build Thread and have sent him an email inquiring on size of tires and if he has the longer rear control arms.

BTW - Ray's build thread is here:

http://www.gt40s.com/forum/gt40-build-logs/22221-customers-car.html

 

[Mike Drew]

I'm curious what the widest tire that anyone has put on their 15" by 10" wide rims would be...
I know what the recommendation would be and that oft times that is a bit shy of the real world..

15-inch tire sizes are limited, but several manufacturers make a 295/50-15 which fits perfectly on a 15x10 wheel. Most are pretty crappy hot-rod tires, but a few makers (Toyo, Maxxis for starters) make high-performance SUV tires in that size, which do an excellent job. Matching or near-matching front tires in appropriate sizes are also available.

I'm working on somebody's Pantera right now equipped with the Toyos, and I am amazed at how far superior they are to the BFGs on my own car. I wonder if he'd noticed if I swapped? :laugh:

 

[Bram Boekestein]

Mike, which Toyo's are you talking about? I can only find 17" and up in those width's.

regards,

bram

 

[Julian]

Mike,

The Toyo's were short lived; although finally a 'V' rated 15" tire that everyone rates highly came on the market, they have sadly now been discontinued. Thus the Toyo ST's in 295/50/15 are already nigh impossible to find by all accounts from both GT40 and Pantera owners. The BFG's are in a different league and those SHOULD be discontinued in my opinion!

Latest tire discussions center on going for the Avon CR66Z tires as supplied by Roger Jraus (Racing Tires - Hand-Grooved Tires - Wheels | Castro Valley, CA) or I heard a Michelin XWX tire is now available through Coker.