205/50/15 >>> GTU transmission >>> GTUs speedo gear = accurate speedo?
11-18-07, 08:34 PM
#1
Eats, Sleeps, Dreams Rotary
Thread Starter
205/50/15 >>> GTU transmission >>> GTUs speedo gear = accurate speedo?
The difference between 205/60/15 and 205/50/15 (the only size close in high-performance tires) is like 7%, and the difference between the GTU (standard NA) and the GTUs is about 5...
Will using a GTUs' speedo gear get you within a 2% change (and within OEM specs)?
Will using a GTUs' speedo gear get you within a 2% change (and within OEM specs)?
11-18-07, 10:28 PM
#5
Eats, Sleeps, Dreams Rotary
Thread Starter
You apparently don't know WTF you're talking about
Go try to find a set of Falken Azenis or any other ultra high perormance tire in that size.
You're lucky if they even have 205/50/15, a far more common size, to begin with.
Go try to find a set of Falken Azenis or any other ultra high perormance tire in that size.
You're lucky if they even have 205/50/15, a far more common size, to begin with.
11-18-07, 10:29 PM
#6
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11-18-07, 10:41 PM
#7
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11-19-07, 02:02 AM
#11
your na would have a fun time getting up there anyways... and the link for the set of falken azenis in the 205/50/15 size like you asked is here. http://www.edgeracing.com/tire/1532/ - posted again.
11-19-07, 12:38 PM
#12
Eats, Sleeps, Dreams Rotary
Thread Starter
No crap it's 1.5 MPH at 100 MPH.
But NO ONE makes any tires I want in 215/50/15.
And NO CRAP the Azenis comes in 205/50/15. That's what I was planning on getting anyway. I was simply saying that we're lucky they even make them in that size, and not JUST in 16s and 17s.
My question was about whether using a GTUs speedometer drive gear will correct for the 7% difference, which is 5 MPH at 70, which isn't within OEM accuracy specs.
OR, would it go in the opposite direction and make it 5% worse.
Also, for the record whenever I pass a radar gun display on the highway, it shows me that I'm going pretty darn close to what my speedometer is telling me. If you guys think it's all that inaccurate, perhaps you need to check your tire pressure...
(all mechanical speedos are inaccurate at over 100 though, I'm talking about normal speeds)
But NO ONE makes any tires I want in 215/50/15.
And NO CRAP the Azenis comes in 205/50/15. That's what I was planning on getting anyway. I was simply saying that we're lucky they even make them in that size, and not JUST in 16s and 17s.
My question was about whether using a GTUs speedometer drive gear will correct for the 7% difference, which is 5 MPH at 70, which isn't within OEM accuracy specs.
OR, would it go in the opposite direction and make it 5% worse.
Also, for the record whenever I pass a radar gun display on the highway, it shows me that I'm going pretty darn close to what my speedometer is telling me. If you guys think it's all that inaccurate, perhaps you need to check your tire pressure...
(all mechanical speedos are inaccurate at over 100 though, I'm talking about normal speeds)
11-19-07, 01:04 PM
#13
you are not making sense... at all... and a 1.5% difference is 1.5mph @ 100mph.
your na would have a fun time getting up there anyways... and the link for the set of falken azenis in the 205/50/15 size like you asked is here. http://www.edgeracing.com/tire/1532/ - posted again.
your na would have a fun time getting up there anyways... and the link for the set of falken azenis in the 205/50/15 size like you asked is here. http://www.edgeracing.com/tire/1532/ - posted again.
um NA's have no trouble blowing past a 100 mph?
BTW 205/50/15's also stack nice and neatly behind the seats, making a tire trailer unecessary
11-19-07, 04:37 PM
#15
It will make it more accurate.
The GTUs speedo gear compromises for the 4.3 GTUs diff.
Say that now you have a 4.1 NA diff, with a smaller rear tire. That, in effect, spins your axles faster, just like having a higher final drive. Gear ratio is gear ratio at the end of the day.
Why are mechanical speedos inaccurate over 100? Isn't the amount of tire rolling on the ground the same per mph at 20 as it is at 100?
The GTUs speedo gear compromises for the 4.3 GTUs diff.
Say that now you have a 4.1 NA diff, with a smaller rear tire. That, in effect, spins your axles faster, just like having a higher final drive. Gear ratio is gear ratio at the end of the day.
Why are mechanical speedos inaccurate over 100? Isn't the amount of tire rolling on the ground the same per mph at 20 as it is at 100?
Last edited by Roen; 11-19-07 at 05:01 PM.
11-19-07, 05:20 PM
#16
Lives on the Forum
The speedo is inaccurate at any speed, it just gets worse (in # of mph) as you get faster because it'll be a % out. Check the FSM, there's a pretty loose tolerance there.
11-19-07, 06:55 PM
#17
Eats, Sleeps, Dreams Rotary
Thread Starter
It will make it more accurate.
The GTUs speedo gear compromises for the 4.3 GTUs diff.
Say that now you have a 4.1 NA diff, with a smaller rear tire. That, in effect, spins your axles faster, just like having a higher final drive. Gear ratio is gear ratio at the end of the day.
Why are mechanical speedos inaccurate over 100? Isn't the amount of tire rolling on the ground the same per mph at 20 as it is at 100?
The GTUs speedo gear compromises for the 4.3 GTUs diff.
Say that now you have a 4.1 NA diff, with a smaller rear tire. That, in effect, spins your axles faster, just like having a higher final drive. Gear ratio is gear ratio at the end of the day.
Why are mechanical speedos inaccurate over 100? Isn't the amount of tire rolling on the ground the same per mph at 20 as it is at 100?
I know that, I was just asking to make sure.
11-19-07, 07:37 PM
#18
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No crap it's 1.5 MPH at 100 MPH.
But NO ONE makes any tires I want in 215/50/15.
And NO CRAP the Azenis comes in 205/50/15. That's what I was planning on getting anyway. I was simply saying that we're lucky they even make them in that size, and not JUST in 16s and 17s.
My question was about whether using a GTUs speedometer drive gear will correct for the 7% difference, which is 5 MPH at 70, which isn't within OEM accuracy specs.
OR, would it go in the opposite direction and make it 5% worse.
Also, for the record whenever I pass a radar gun display on the highway, it shows me that I'm going pretty darn close to what my speedometer is telling me. If you guys think it's all that inaccurate, perhaps you need to check your tire pressure...
(all mechanical speedos are inaccurate at over 100 though, I'm talking about normal speeds)
But NO ONE makes any tires I want in 215/50/15.
And NO CRAP the Azenis comes in 205/50/15. That's what I was planning on getting anyway. I was simply saying that we're lucky they even make them in that size, and not JUST in 16s and 17s.
My question was about whether using a GTUs speedometer drive gear will correct for the 7% difference, which is 5 MPH at 70, which isn't within OEM accuracy specs.
OR, would it go in the opposite direction and make it 5% worse.
Also, for the record whenever I pass a radar gun display on the highway, it shows me that I'm going pretty darn close to what my speedometer is telling me. If you guys think it's all that inaccurate, perhaps you need to check your tire pressure...
(all mechanical speedos are inaccurate at over 100 though, I'm talking about normal speeds)
well i know these are not racing tires but they are f'n awsome tires none the less! i had them on my 87 gxl when i first bought it and was dumbfounded at how well they stuck to the road, rain, dry, snow, ice, what ever it was these tires just stuck to the road!
http://www.tirerack.com/tires/tires....eed_rating=(Y)
11-19-07, 09:02 PM
#20
200, it's either the Azenis or the Ecsta MX.
The 180 Advan Neova isn't really worth the money, but it's the best street tire.
The 180 Potenza RE-01R isn't a bad tire in terms of longevity. I've had one year from May to December of normal street use before I switched to snow tires. From March of the next year, I've used them for street use, and from April to now I've used them for street, autox and track use. They've finally let go.
I've seen that the Azenis and the MX are far inferior to the Potenza and the Advan in inclement weather racing, as well as track use. On the track, they seem to get greasier faster as their best laps are typically early on. In a wet weather autocross, the Azenis and the MX's finished much lower than the other two that I've mentioned.
The 180 Advan Neova isn't really worth the money, but it's the best street tire.
The 180 Potenza RE-01R isn't a bad tire in terms of longevity. I've had one year from May to December of normal street use before I switched to snow tires. From March of the next year, I've used them for street use, and from April to now I've used them for street, autox and track use. They've finally let go.
I've seen that the Azenis and the MX are far inferior to the Potenza and the Advan in inclement weather racing, as well as track use. On the track, they seem to get greasier faster as their best laps are typically early on. In a wet weather autocross, the Azenis and the MX's finished much lower than the other two that I've mentioned.
11-19-07, 09:21 PM
#21
Eats, Sleeps, Dreams Rotary
Thread Starter
Except that Falken and Kumho's cost half as much as Bridgestones, and WAY less than Advans...
You can deal with the greasiness by spraying water on the Azenis to keep them from overheating.
You can deal with the greasiness by spraying water on the Azenis to keep them from overheating.
11-19-07, 09:28 PM
#22
You'd be surprised how fast they get greasy again....they really start to let go once they let go. There's a reason why the Bridgestones are kicking so much *** in Street Touring.
Anyway, the Potenza's in 195/50/15 are just about the same price as the Azenis in 205/50/15. They seem to be just as wide, if not wider and shorter. Seems like a win for me.
Anyway, the Potenza's in 195/50/15 are just about the same price as the Azenis in 205/50/15. They seem to be just as wide, if not wider and shorter. Seems like a win for me.
Last edited by Roen; 11-19-07 at 09:33 PM.
11-19-07, 09:36 PM
#23
Lives on the Forum
Maybe it's not an issue of winning, but more an issue of just getting some good street tires. MX's don't suffer the overheating issues that the Azenis do, but they're slightly slower.
11-20-07, 08:33 AM
#25
Eats, Sleeps, Dreams Rotary
Thread Starter
...you can get Ziex in the stock size... That's what my car came with before I got set of BFG G-Force sports, which are excellent for the price, but they didn't wear evenly (probably due to air pressure) since there is much more tread left on the sides than in the middle.
Hence why I need new tires...
If I had a huge wad of cash I'd just buy some new wheels so I could get a better size of tire...
Hence why I need new tires...
If I had a huge wad of cash I'd just buy some new wheels so I could get a better size of tire...