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mike gaines
02-25-2007, 11:17 PM
Hi Guys,have decided to replace my wheel rims and tyres with modern rims. What will the handling consequences be of replacing my current 205/15/70 rims and tyres with 225/19/40 rims and tyres.The first # is the width of the tyre , the second is the size of the rim and the third is the tyre profile. I am told by the tyre shop that the new tyre will have the same rolling circumference as the existing tyre. I am concerned about the effects of the lower profile tyre on cornering,tracking and suspension. I have checked that the proposed new set up fits in the wheel arches and there is no snagging on brakes etc. The offset on the new rims is 20.

blackhawk
02-26-2007, 12:32 AM
quote:Originally posted by mike gaines

Hi Guys,have decided to replace my wheel rims and tyres with modern rims. What will the handling consequences be of replacing my current 205/15/70 rims and tyres with 225/19/40 rims and tyres.The first # is the width of the tyre , the second is the size of the rim and the third is the tyre profile. I am told by the tyre shop that the new tyre will have the same rolling circumference as the existing tyre. I am concerned about the effects of the lower profile tyre on cornering,tracking and suspension. I have checked that the proposed new set up fits in the wheel arches and there is no snagging on brakes etc. The offset on the new rims is 20.
Mike - In general, lower profile tyres provide quicker steering response and a harsher ride. Both are due to there being less sidewall to flex. I think you will enjoy the increased steering response but you may find the ride too harsh. I haven't tried a change as radical as you propose, so I will let others who have tried it provide the specifics. Dale

StudeRich
02-26-2007, 03:11 AM
Well handling should improve, that offset sounds scarry! 20 inches, should be about 2 3/4 to 3!!
You have to understand that you are not just going up a size or two, but changing ALL of the aspect ratios from the stock wheels/tires which will affect the alignment settings and handling-some good, some maybe not so. You are basically EXPERIMENTING with technology 55 years beyond that of the Automobile! While in my own opinion the look will be 2007 Honda and not only not appropriate for a 1950's? car but flat ugly. Maybe it will look more like a 1852 Studebaker Wagon :D:D Grin! But hey it's your car man! I can't tell you what to do, based on my recollection of what it SHOULD look like.

StudeRich
Studebakers Northwest
Ferndale, WA

sbca96
02-26-2007, 04:02 AM
Wow .. this is becoming more and more common. I didnt go quite as
large as your are proposing. Karl did with his Avanti though. I used
17 inch rims, 8 inches wide with a 5.02 back spacing. The 13" Cobra
brake setup I developed, puts the rotor between the hub and wheel so
its used as a spacer cutting the back spacing down to 4.75. You can
use up to a 4.5 inch backspacing with stock setup. As mentioned the
lower the tire profile, the harsher the ride. Thou when you go wider
too, it can smooth it out some. My tires dont "feel" small potholes
since the tire is too wide to "fall" into them. I didnt notice the
ride becoming too harsh with the 17's. I am running a 245/45 tire.

Not sure what model Stude you have.

http://hometown.aol.com/sbca96/images/Avantinewimages/Cobra_brake_breakin/cobra_brake_testdrive007a_thumb.jpg

Maybe Karl can chime in here on the ride with his Avanti :

http://hometown.aol.com/sbca96/images/karls_avanti/100_2069_00a.jpg

Tom

'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

bams50
02-26-2007, 06:42 AM
quote:Originally posted by StudeRich

, that offset sounds scarry! 20 inches, should be about 2 3/4 to 3!!


Mike's from South Africa, so I'm guessing he means 20 millimeters... but I could be wrong.

I seriously doubt he meant 20 inches...

Robert K. Andrews Owner- IoMT (Island of Misfit Toys!)
Parish, central NY 13131
http://www.cardomain.com/ride/2358680/1

N8N
02-26-2007, 08:20 AM
yeah, 20mm would be about 25/32" which is pretty close to the offset of the stock wheels which should be fine. I'd be more concerned that the stock Stude geometry probably isn't just so perfect for best handling, which a compliant sidewall will mask a little bit but a low profile tire will really show up.

nate



--
55 Commander Starlight
http://members.cox.net/njnagel

John Kirchhoff
02-26-2007, 08:30 AM
The new tires will be about 1/4 inch shorter than the present ones. As far as messing up the steering geometry, the present wheels are nearly 2 inches shorter and 1.5 inches wider than the orginal. So, the steering geometry has already been altered and if it goes, turns and stops ok now, it should do the same as long as nothing rubs.

Karl
02-27-2007, 03:40 AM
Hi Mike I am running 225/35/20 on the front and 255/35/20 on the rear.My wheels are 8.5" wide. Handling is day and night for the better. Ride is no worse, but my car has HD suspension.
http://i117.photobucket.com/albums/o50/twnchgr/CruiseninPlamSpringsringataAvantiow.jpg

63 Twin Supercharged Avanti
64 Avanti R3w/NOS
88LSC Avanti 350 Supercharged w/NOS

mike gaines
03-04-2007, 02:44 AM
Thanks for all the comments and the deed is now done.I have kept all my original rims tyres , hubcaps etc so I can go original at any time.As a precaution ,I reset alignment and have spent the first day driving the car......ITS GREAT!!! Much better steering response , much straighter steering tracking , and even more whistles and cheers from other motorists.

sbca96
03-04-2007, 04:09 AM
I have also experienced all three of those since going to the 17 inch
Cobra wheels, and most definately that last one![8D];)

Tom


quote:Originally posted by mike gaines
Much better steering response , much straighter steering tracking , and even more whistles and cheers from other motorists.

N8N
03-04-2007, 07:21 AM
pics?

nate

--
55 Commander Starlight
http://members.cox.net/njnagel