Re: Tech. Wheels and Tires
Answer to. "will these tires fit my SyTy."
YES, They will fit. Now. Will they look good and function properly? That is the real question you should be asking.
What makes a wheel set function properly you ask. Can you go around a turn without your wheels rubbing the inside of your frame or cladding? Can you go over a bump and not bottom your truck out and brake your cladding? If you answered YES to both questions, your wheels function properly as far as fitment goes. Any other function isues like tracking, bouncing, shuttering, over steer, under steer, toe in, toe out, ect should be covered in the suspenshion section of the forum. Please note that whenever you change tires and wheels it is a good idea to have all your suspenshion bushing checked and to have a front end alighnment done. M2C
What makes a set of wheels look bad on a Syclone or Typhoon? There is only one answer. Your wheels will look bad if they don't line up to the cladding like the stock wheels do. M2C
Because SyTy's have two different offsets, front and rear. I will start with the front. In my opinion. The fitment of a stock wheel looks best. A stock front wheel is 8" wide with a 41mm offset. This gives you a 5.614 back space and a 2.385 front space. The front space is what gives your SyTy the best look. The smaller the offset, the more your wheels will stick out past the cladding. If you use a larger offset, you can compensate with a spacer or adapter to get the correct front space. The front space is the distance from the mounting surface to the outside of the stock wheel. To figure the proper wheels for your SyTy. I have come up with this formula.
W/2=A-2.386=Bx25.4=
W= Width of the wheel
A= Centerline of the wheel
2.386= The factory front space.
B= the offset in inch
X25.4= the offset in mm
To make things easier. I already did the math. Note: The offset is to stock location. Most wheel companies will not have this exact offset. You will have to compensate the difference with a spacer or adapter.
FRONT WHEELS
(After checking several different SyTy's. I noticed that the front stock wheels sit out about 1/4" further than the rears. So. For a little better look. I would add 5mm to 10mm to the front offset. This will inset the front wheel and the tires/wheels will line up better with the cladding. You can always add a shim to bring the wheel out.
7.0" wheel 28.3mm offset (backspace close to 5")
7.5" wheel 34.6mm offset (backspace close to 5-1/2")
8" wheel 41mm offset (backspace close to 6")
8.5" wheel 47mm offset (backspace close to 6-1/2")
9" wheel 53mm offset (backspace close to 7")
9.5" wheel 60mm offset (backspace close to 7-1/2") RUBS A little WHEN TURNING
10" wheel 66.3mm offset. (backspace close to 8") RUBS a lot WHEN TURNING.
Most SyTy's usually run up to a 9.5" wheel in the front because of turning issues. 9.5" do rub.
Did you get it? Good. Lets talk about the rear wheels now.
The stock rear wheels are 8" wide with a 13mm offset and a 3.489 front space. Here is the formula.
W/2=A-3.489=Bx25.4=
a
REAR WHELLS
7.0" wheel 0mm offset (backspace close to 3-7/8)
7.5" wheel 6.6mm offset (backspace close to 4-3/8)
8" wheel 13mm offset (backspace close to 4-7/8)
8.5" wheel 19mm offset (backspace close to 5-3/8)
9" wheel 25.6mm offset (backspace close to 5-7/8)
9.5 wheel 32mm offset (backspace close to 6-3/8)
10" wheel 38mm offset (backspace close to 6-7/8)
10.5" wheel 45mm offset (backspace close to 7-3/8)
11" wheel 51mm offset (backspace close to 7-7/8)
11.5" wheel 57.4mm offset (backspace close to 8-3/8)
12" wheel 63.78mm offset (backspace close to 8-7/8)
Note: 11.5" & 12" wheels with tires have little to no back space clearance to the frame. Might need spacers for clearance.
Because of tire to cladding clearance. I do not recommend a wheel larger than 18" front and rear. But, you can do what you want.
Now TIRES
If you are using the same size diameter and width wheel, front and back. Use the same size tire. It is easier. But if you want a staggered set you will need to do the math and make sure that the staggered set has the same rotations per mile. (Usually a 1 Rev per mile difference between tires is acceptable. But keep in mind that 5 revolutions per minute at the V-clutch will not result in the clutch initiating lock up, with subseqvent damage. That is at the T-case. NOT the tires. That is also per minute. ) (Thanks DaveP) See added info for more about t-case.
THE SAME Revs per mile is best.
What does this mean? It means that even though your rims are different sizes. Your tires must have the same outside diameter. Failure to do so WILL result in mechanical failure.
I have come up with several staggered tires that are an exact match to each other.
Also: Keep in mind a stock SyTy tire has 786 Revolutions per mile. Any variance from this will affect your speedometer and you will have to have your drac re-programed. The closer you can get to this number, The better off you are. There are only 3 sets that are close. But I put them all down anyway.
Each tire manufacturer has its own recommended rim size for its tires and specified Revolutions per mile. So when looking for Tires and rims for your SyTy, Please keep this in mind. The below revolutions per mile is to show you what tires are close to 0% mismatch in RPM and should not be used as gospel. Please check tire manufacture for your application
The tire sizes below are from current available tires from.
http://www.tirerack.com/tires/sizes/...sp?diameter=17
1) Front 245/55-17 Rear 295/50-16 Revolutions per mile = 730,
2) Front 245/50-16 Rear 275/40-16 Revolutions per mile = 786,
3) Front 255/50-16 Rear 255/45-17 Revolutions per mile = 775
4) Front 245/45-17 Rear 315/35-17 Revolutions per mile = 785 (using tire size comparison chart)
http://www.miata.net/cgi-bin/tirescgi
-- Front 245/45-17 Rear 315/35-17 Revolutions per mile = 808 (Sumitomo) (Thanks DaveP)
http://www.tirerack.com/tires/tires....=yes&tab=Specs
-- Front 245/45-17 Revolutions per mile = 808 (Kumho) ( Thanks DaveP)
http://www.tirerack.com/tires/tires....=yes&tab=Specs
5) Front 275/40-17 Rear 315/35-17 Revolutions per mile = 808 (Sumitomo)(Thanks DaveP)
http://www.tirerack.com/tires/tires....=yes&tab=Specs
-- Front 275/40-17 Rear 315/35-17 Revolutions per mile = 809 (Kumho)(Thanks DaveP)
http://www.tirerack.com/tires/tires....=yes&tab=Specs
-- Front 275/40-17 Revolutions per mile = 811 Rear 315/35-17 Revolutions per mile = N/A (Goodyear Eagle F1) (Thanks DaveP)
http://www.tirerack.com/tires/tires....=yes&tab=Specs
6) Front 235/45-17 Rear 265/40-17 Revolutions per mile = 796
7) Front 245/35-18 Rear 285/30-18 Revolutions per mile = 815
8) Front 245/45-18 Rear 275/40-18 Revolutions per mile = 756
9) Front 245/55-17 Rear 245/50-18 Revolutions per mile = 730
10) Front 255/40-17 Rear 255/35-18 Revolutions per mile = 806
11) Front 255/45-17 Rear 255/40-18 Revolutions per mile = 775
12) Front 255/50-17 Rear 255/45-18 Revolutions per mile = 746
13) Front 245/40-18 Rear 285/30-19 Revolutions per mile = 784
14) Front 245/45-18 Rear 325/30-19 Revolutions per mile = 756
15) Front 255/35-18 Rear 255/30-19 Revolutions per mile = 806
16) Front 255/40-18 Rear 255/35-19 Revolutions per mile = 775
17) Front 255/45-18 Rear 255/40-19 Revolutions per mile = 746
18) Front 255/35-19 Rear 255/30-20 Revolutions per mile = 775
19) Front 255/40-19 Rear 255/35-20 Revolutions per mile = 746
20) Front 245/35-20 Rear 285/30-20 Revolutions per mile = 754
Each tire manufacturer has its own recommended rim size for its tires and specified Revolutions per mile (rev/mile). So when looking for Tires and rims for your SyTy, Please keep this in mind. The above revolutions per mile is to show you what tires are close to 0% mismatch in revolutions per mile and should not be used as gospel. Please check tire manufacture for your application
Added info.
Tire Revs per mile/ T-case, V-clutch info. by DaveP
Recent discussion on this topic revealed that FIVE revolutions per minute at the V-clutch will not result in the clutch initiating lock-up, with subsequent damage. But that's at the T-case, NOT the tires, and that's per minute so there's a vehicle speed involved.
First multiply both tires' revs per mile by 3.42 axle ratio, as that is the rotation at the V-clutch.
786 X 3.42 = 2688.12
788 X 3.42 = 2694.96
Difference = 6.84 revs per mile. (Note that that is 3.42 times greater than the tires by themselves).
To get the road speed at 5 RPM at the V-clutch:
360 / 6.84 = 52.631 MPH is the maximum speed allowable before the 5 RPM limit at the V-clutch is exceeded, and it initiates lock up.
Or another way to visualize this: At 70 MPH the difference is 478 Revs per hour at the V-clutch. 7.98 per minute, or one complete procession every 7.5 seconds. Seems like that would create a lot of heat in a device where the spec for a properly operating clutch is 60 seconds to rotate one revolution with 40 ft lbs applied. To rotate it one rev in 8 seconds would require 300 ft lbs of torque. I don't care how "OK" or "minor", or "no issues" 2 revs per mile at the tires seems to you guys. A sustained input to the clutch of 300 ft lbs will tear shit up.
If you never drive it at all, or around the block a couple times a year, or only drive it at 45 MPH, you'll be fine. Take a 1,000 mile trip in it at Interstate speeds, and you'll burn the V-clutch up.
WHEEL SPACERS
a 1/4 inch spacer on the front only gives you about 3 threads to tighten down on per lugnut. If you go with any spacers wider than 1/8" in the front. I would suggest getting longer lugbolts.
ADAPTERS.
On a stock SyTy. After several different fitments of wheels on stock trucks. If you can find a direct fit offset for the front, The rear spacer would be 1-1/4 thick. Otherwise you have to play with the gap. The Rear lug bolts are a little over 1" long. Because of the thickness of a lugnut the thinnest adapter you can ues is 3/4. A 3/4 adapter would require cutting the lug bolts down. A 1" adapter is fairly close to the stock length of an original lug bolt. You might have to grind a little bit off of the tip of the lug bolts so that the bolts will sit flush with the mounting surface of the adapter. Some wheels are recessed on the back side. So you will not have to cut anything. I dont like cutting the lug bolts because it makes it easier to go back stock.
I hope that you can find this post useful.
Helpful information
Tire size to rim calculator
http://www.tyresizecalculator.com/ty...dth-calculator
Calculating Tire dim.
http://www.tirerack.com/tires/tirete...e.jsp?techid=7
Staggered Tire Calculator
http://www.miata.net/garage/tirecalc.html
Forum Tech
http://www.syty.net/forums/showthread.php?t=14353
