NSW Corvettes
Technical Tips => Brakes, Suspensions, Steering, Wheels & Tyres => Topic started by: Cameron 77C3 on October 23, 2006, 06:43:32 PM
-
Has anybody got published data on what the running diameter on a 245/60/15 tyre is. I have measured it but I would like to know the published figure.
Second question. What DIAMETER size wheel did C3's come out with, 15" or 16"?
CAM:grr
-
Originally posted by Cameron 77C3
Has anybody got published data on what the running diameter on a 245/60/15 tyre is. I have measured it but I would like to know the published figure.
Second question. What DIAMETER size wheel did C3's come out with, 15" or 16"?
CAM:grr
easy to work out,.you have a 15 inch rim,with a 245/60 tyre.... so side wall of tyre is 60% of width.
now if only i had a calculater to make it easy for me.
c3's i think came with 15's
-
So 60% of 245mm = 147mm and that = 5&3/4"
So I add 15" + 5 3/4" + 5 3/4" = 26&1/2"
So my tire on rim measure 26&1/2".
Many Thanks.
Chromie or smokem, whats that equation again for the speedo gear teeth number?
I'm at home and the equation is at the factory. DOOHH!!
-
Hi Cam;;-)45;-)
All C3's had 15" X 8" rims with the exception of 1968 which had 15" X 7" rims
Tyre size varied through the C3's from 210 X 60 X 15 up to 255 X 60 X 15
and I believe there were some that were 70 series.;-);-);-);-)
So cam why do you want to know
And nifty is correct with his tyre formula;42
-
Originally posted by nifty
Originally posted by Cameron 77C3
Has anybody got published data on what the running diameter on a 245/60/15 tyre is. I have measured it but I would like to know the published figure.
Second question. What DIAMETER size wheel did C3's come out with, 15" or 16"?
CAM:grr
easy to work out,.you have a 15 inch rim,with a 245/60 tyre.... so side wall of tyre is 60% of width.
now if only i had a calculater to make it easy for me.
c3's i think came with 15's
This isn't the published figure but from memory the maths to arrive at a figure goes like this:
245mm/100 = 2.45
2.45mm x 60 = 147mm
147mm x 2 = 294mm
294mm + wheel diameter = actual total wheel diameter.
I'm sure if I've overlooked something one of you guys will pull me up on it. ;42
-
hi cam the formula is
63360 X axle ratio
-----------------------[divided by]
3141.6 X tyre diameter in inches
the figure you get for that is then times by 8. This gives ya the number of teeth needed on the speedo driven gear.
Ok Cam;53
-
Various tyres even though have the same tyre sixe actually can be quite different in height;50
I found that out the hard way;48
when I set a Corvette up with Comp T/A and then fitted yokohama
Bloody different by almost 1"
;30
i WAS NOT HAPPY JANE:20
-
Good man Chromie. I'm just double checking the gear that I'm changing on the speedo cable. I have Yoko's on her and they measured with the tape measure 26"
Thanks squire. You're a legend;42
-
yOU ARE SOOOOOOO WELCOME CAM :24
sO YOU SHOUTIN THE DRINKS AT DARLING HARBOUR PERHAPS;mmm
-
Sounds fair, since you're buying lunch. :22
-
Done deal cam:spook
I'll tell my other half she is payin;mmm
-
Funny....I'm telling Michelle the same thing.;43
-
arhhhhhhhhh great minds think alike:}
Just hope neither of them read the forum;mmm
-
so obsessed you staying very quiet;40
-
Originally posted by Chromie
so obsessed you staying very quiet;40
We do in the tech threads. We keep the jokes to a minimum here.;27
-
Originally posted by Chromie
arhhhhhhhhh great minds think alike:}
Just hope neither of them read the forum;mmm
Don't worry Chromie, I'll bring a printed copy of this thread to Darling Harbour.
Looks like I'll get a free lunch (Chromie) AND drinks (Cam) on the 5th. ;41 ;42
-
hey chromie....i was once told if i jacked the rear wheels off the ground,and rotated them twice,and counted the number of turns the tail shaft turned,that i would have a fair idea of the gear ratio....
eg. tyres rotate twice,but tailshaft goes just over 4 turns... so probably a 4:11 ratio... anybody tried it? is it gospel?
-
Diff ratio can be measured by
1/ Put a white pen mark of the differential flange (where drive shaft from transmission attaches)
This white mark has to be both on the differential flange and the differential housing so you will know exactly when the pinion has done one full turn (it will be many turns but this will tell you exactly how many turns).
2/ Put a white mark on both rims and backing plates as you want to do only one exact full turn of both rear wheels at the same time.
While rotating the rear wheels count the number of times the drive shaft rotates
1 wheel rotation will end up with just over 3 rotations of the drive shaft is you have a 3.08 ratio
Hope this helps:24
MAKE SURE VEHICLE IS JACKED UP AND CAR STANDS ARE USED CORRECTLY
-
Rotate the tyre once, count the turns of the tailshaft. eg. just on 3 turns = 3.08/3.07 ratio
-
Yes but both rear wheels have to end up with the white marks lining up exactly on both rear wheels or it will not be exact:drink
-
TIRE HEIGHT CHART
13 INCH
TIRES
TIRE
HEIGHT
175 50 13 19.89
215 50 13 21.46
175 60 13 21.27
185 60 13 21.74
195 60 13 22.21
205 60 13 22.69
165 65 13 21.44
165 70 13 22.09
175 70 13 22.65
185 70 13 23.2
195 70 13 23.75
155 80 13 22.76
165 80 13 23.39
175 80 13 24.02
185 80 13 24.65
14 INCH
TIRES TIRE
HEIGHT
205 50 14 22.07
245 50 14 23.65
265 50 14 24.43
185 55 14 22.01
195 55 14 22.44
205 55 14 22.88
185 60 14 22.74
195 60 14 23.21
205 60 14 23.69
215 60 14 24.16
225 60 14 24.63
235 60 14 25.10
245 60 14 25.57
165 65 14 22.44
175 65 14 22.96
185 65 14 23.47
195 65 14 23.98
175 70 14 23.65
185 70 14 24.20
195 70 14 24.75
205 70 14 25.30
215 70 14 25.85
225 70 14 26.40
185 75 14 24.93
195 75 14 25.52
205 75 14 26.11
215 75 14 26.70
15 INCH
TIRES TIRE
HEIGHT
195 45 15 21.91
195 50 15 22.68
205 50 15 23.07
225 50 15 23.86
245 50 15 24.65
265 50 15 25.43
275 50 15 25.83
295 50 15 26.61
305 50 15 27.01
185 55 15 23.01
195 55 15 23.44
205 55 15 23.88
225 55 15 24.74
185 60 15 23.74
195 60 15 24.21
205 60 15 24.69
215 60 15 25.16
225 60 15 25.63
235 60 15 26.10
245 60 15 26.57
255 60 15 27.05
275 60 15 27.99
315 60 15 29.88
185 65 15 24.47
195 65 15 24.98
205 65 15 25.49
215 65 15 26.00
205 70 15 26.30
215 70 15 26.85
225 70 15 24.70
235 70 15 27.95
255 70 15 29.06
195 75 15 26.52
205 75 15 27.11
215 75 15 27.70
225 75 15 28.29
235 75 15 28.88
265 75 15 30.65
16 INCH
TIRES TIRE
HEIGHT
205 40 16 22.46
215 40 16 22.77
225 40 16 23.09
195 45 46 22.91
205 45 16 23.26
215 45 16 23.62
225 45 16 23.97
245 45 16 24.68
195 50 16 23.68
205 50 16 24.07
215 50 16 24.46
225 50 16 24.86
235 50 16 25.25
245 50 16 25.65
255 50 16 26.04
265 50 16 26.43
275 50 16 26.83
295 50 16 27.61
195 55 16 24.44
205 55 16 24.88
215 55 16 25.31
225 55 16 25.74
235 55 16 26.18
315 55 16 29.64
345 55 16 30.94
205 60 16 25.69
215 60 16 26.16
225 60 16 26.63
235 60 16 27.10
285 60 16 29.46
205 65 16 26.49
215 65 16 27.00
255 65 16 29.05
275 65 16 30.07
205 40 16 22.46
215 40 16 22.77
225 40 16 23.09
195 45 16 22.91
205 45 16 23.26
215 45 16 23.62
225 45 16 23.97
245 45 16 24.68
195 50 16 23.68
205 50 16 24.07
215 50 16 24.46
225 50 16 24.86
235 50 16 25.25
245 50 16 25.65
255 50 16 26.04
265 50 16 26.43
275 50 16 26.83
295 50 16 27.61
195 55 16 24.44
205 55 16 24.88
215 55 16 25.31
225 55 16 25.74
235 55 16 26.18
315 55 16 29.64
345 55 16 30.94
205 60 16 25.69
215 60 16 26.16
225 60 16 26.63
235 60 16 27.10
285 60 16 29.46
205 65 16 26.49
215 65 16 27.00
255 65 16 29.05
275 65 16 30.07
17 INCH
TIRES TIRE
HEIGHT
225 35 17 23.20
245 35 17 23.75
315 35 17 25.68
335 35 17 26.23
205 40 17 23.46
215 40 17 23.77
225 40 17 24.09
235 40 17 24.40
245 40 17 24.72
255 40 17 25.03
265 40 17 25.35
275 40 17 25.66
285 40 17 25.98
205 45 17 24.26
215 45 17 24.62
225 45 17 24.97
235 45 17 25.33
245 45 17 25.68
255 45 17 26.04
305 45 17 27.81
205 50 17 25.07
215 50 17 25.46
225 50 17 25.86
235 50 17 26.25
245 50 17 26.65
255 50 17 27.04
275 50 17 27.83
215 55 17 26.31
225 55 17 26.74
235 55 17 27.18
245 55 17 27.61
255 55 17 28.04
275 55 17 28.91
215 60 17 27.16
255 60 17 29.05
275 60 17 29.99
305 60 17 31.41
235 65 17 29.03
245 65 17 29.54
275 65 17 31.07
265 70 17 31.61
255 75 17 32.06
18 INCH
TIRES TIRE
HEIGHT
285 30 18 24.73
295 30 18 24.97
315 30 18 25.44
335 30 18 25.91
215 35 18 23.93
225 35 18 24.20
235 35 18 24.48
245 35 18 24.75
255 35 18 25.03
265 35 18 25.30
275 35 18 25.58
285 35 18 25.85
295 35 18 26.13
335 35 18 27.23
345 35 18 27.51
215 40 18 24.77
225 40 18 25.09
235 40 18 25.40
245 40 18 25.72
255 40 18 26.03
265 40 18 26.35
275 40 18 26.66
285 40 18 26.98
215 45 18 25.62
225 45 18 25.97
235 45 18 26.33
245 45 18 26.68
255 45 18 27.04
285 45 18 28.10
295 45 18 28.45
235 50 18 27.25
255 50 18 28.04
285 50 18 29.22
225 55 18 27.74
255 55 18 29.04
275 55 18 29.91
305 55 18 31.21
245 60 18 29.57
265 60 18 30.52
275 60 18 30.99
285 60 18 31.46
315 60 18 32.88
235 60 18 29.10
19 INCH
TIRES TIRE
HEIGHT
265 30 19 25.26
275 30 19 25.50
285 30 19 25.73
295 30 19 25.97
345 30 19 27.15
225 35 19 25.20
235 35 19 25.48
245 35 19 25.75
255 35 19 26.03
275 35 19 26.58
285 35 19 26.85
295 35 19 27.13
245 40 19 26.72
255 40 19 27.03
245 45 19 27.68
255 45 19 28.04
285 45 19 29.10
255 50 19 29.04
20 INCH
TIRES TIRE
HEIGHT
275 30 20 26.50
285 30 20 26.73
245 35 20 26.75
255 35 20 27.03
265 35 20 27.30
275 35 20 27.58
245 40 20 27.72
295 40 20 29.29
305 40 20 29.61
275 45 20 29.74
295 45 20 30.45
305 45 20 30.81
265 50 20 30.43
285 50 20 31.22
295 50 20 31.61
305 50 20 32.01
325 50 20 32.80
275 55 20 31.91
22 INCH
TIRES TIRE
HEIGHT
285 30 22 28.73
295 30 22 28.97
265 35 22 29.30
305 40 22 31.61
325 40 22 32.24
305 45 22 32.81
23 INCH
TIRES TIRE
HEIGHT
305 35 23 31.41
305 40 23 32.61
24 INCH
TIRES TIRE
HEIGHT
305 35 24 32.40
Back to sstire.com
-
Good one 69DR. Very handy.;46
-
Ok I changed the gear to a 19 tooth as per the calculations. Speed felt better but still didn't feel right. So Bill came over and a few of the other lads and we put the GPS in and checked it. Sure enough 10klm out. Had to have the speedo at 70 to be doing 60. It's got me beat.
I'm going up to a 20 tooth to see what happens. :b4
-
Originally posted by Cameron 77C3
Sure enough 10klm out. Had to have the speedo at 70 to be doing 60. It's got me beat.
That can be a good thing Cam,
Thats playing it safe. Then the Coppas cant book you for speeding...;53
M;36
-
Wanna bet;35
-
Well I went up to a 21 tooth gear and checked it with Bills GPS. Almost, but not quite right. Have ordered a 22 tooth gear [grey] from Chromie and will try that.
So I'll need ya GPS for another day or two Bill if that's OK?
-
Cam get someone to go in front of you with a "NEW" car
get them to reach 60klms and follow them in your Corvette
Simply get them to put their hazzard lights on for a few seconds when they reach the correct speed then quickly check your speedo
When all is done flash your lights so they know to return to the garage/workshop.;27
-
Did you use the wrong smileyAGAIN :b2 ;39
The GPS is pretty accurate but I will check it that way as well to be double sure.
Thanks;42
-
yep you guessed it cam I used the wrong smile again;mmm;30