odometer and speedo sensor location on GP GXP?
07-04-2011, 05:37 PM
#1
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odometer and speedo sensor location on GP GXP? I'm using some free time today to shop for tires (even though I don't need them right now) for my GXP.
Question: Does the odometer count the revolutions of the FRONT tires or the REAR tires? Same question for speedometer sensor...?
Why? I was thinking of going with 255/45 on the front, and 235/50 on the rear instead of 255/45 on the front, and 225/50 on the rear. I don't want to make my speedometer and odometer slightly inaccurate by having slightly taller or shorter tires than the Bridgestone Potenza RE050A tires these cars came with stock. If the sensors are on the rear wheels, I may not want to upsize them.
Question: Does the odometer count the revolutions of the FRONT tires or the REAR tires? Same question for speedometer sensor...?
Why? I was thinking of going with 255/45 on the front, and 235/50 on the rear instead of 255/45 on the front, and 225/50 on the rear. I don't want to make my speedometer and odometer slightly inaccurate by having slightly taller or shorter tires than the Bridgestone Potenza RE050A tires these cars came with stock. If the sensors are on the rear wheels, I may not want to upsize them.
07-04-2011, 06:13 PM
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i would assume front wheels, because if i floor it in the snow/ice and spin itll say im going like 90 when im going 15. however each wheel has a "speed sensor" , i had them replaced at the dealer at one point.
07-04-2011, 06:40 PM
#3
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Good point gxp-miller! If anybody else has info, or opinion, let me know. Still interested in my above questions, but here's a bit of tire research I've done...
From some research, the tires for our GXPs are technically discontinued, but Bridgestone continues to make some RE050As at different speed ratings. If the RPM (revolutions per mile, not minute) is similar, then the speedo and odometer should remain relatively accurate.
OEM RE050A:
255/45, 99W, ??? RPM
225/50, 94W, ??? RPM
close to OEM RE050A tires w/ diff specs:
255/45, 99Y, 772 RPM
OR
255/45, 99Y, 766 RPM (no idea what the diff is b/t them)
225/50, 95W, 774 RPM
So it's important to try to find tires that are between 766 and 774 RPM to help ensure the speedo and odo are accurate.
I've been looking at Bridgestone Turanza tires with Serenity technology (what Mercedes, BMW, etc. use) b/c they have an extremely high comfort rating, extremely high wear rating, and they are quiet. I don't drive particularly sporty and never race, so my goal is to compensate for the roughness of the Bilstein suspension with tires that are more forgiving than the sporty type.
Can either go...
255/45, 769 RPM
235/50, 763 RPM
Or I could get 4 matching tires at an in-between size
245/45, 780 RPM
I'm not sure if those tires are directional and can be rotated or not, but it's a possibility.
From some research, the tires for our GXPs are technically discontinued, but Bridgestone continues to make some RE050As at different speed ratings. If the RPM (revolutions per mile, not minute) is similar, then the speedo and odometer should remain relatively accurate.
OEM RE050A:
255/45, 99W, ??? RPM
225/50, 94W, ??? RPM
close to OEM RE050A tires w/ diff specs:
255/45, 99Y, 772 RPM
OR
255/45, 99Y, 766 RPM (no idea what the diff is b/t them)
225/50, 95W, 774 RPM
So it's important to try to find tires that are between 766 and 774 RPM to help ensure the speedo and odo are accurate.
I've been looking at Bridgestone Turanza tires with Serenity technology (what Mercedes, BMW, etc. use) b/c they have an extremely high comfort rating, extremely high wear rating, and they are quiet. I don't drive particularly sporty and never race, so my goal is to compensate for the roughness of the Bilstein suspension with tires that are more forgiving than the sporty type.
Can either go...
255/45, 769 RPM
235/50, 763 RPM
Or I could get 4 matching tires at an in-between size
245/45, 780 RPM
I'm not sure if those tires are directional and can be rotated or not, but it's a possibility.
Last edited by Brangeta; 07-04-2011 at 06:46 PM.
07-04-2011, 08:31 PM
#5
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I forgot to hit "post reply" on my last post. Oh well.
Long story short, it is over $400 cheaper to get a full set of 255/45 and 225/50 OEM size tires that are Kumho brand than the Turanza ones. A full set of tires for about $620 (the price of 2 OEM front tires practically) so the Kumho grand touring tires are going to fit my purposes exactly. Made to last long, be comfortable, and be quiet compared to the OEM tires that are made to have good grip, extremely hard sidewall, etc. The Turanzas would have been over $1200 and I'd have to do 255/45 and 235/50!
The Kumho tires are the only ones on tirerack in the grand touring section for the GXP. Why I didn't think of just looking at grand touring tires ONLY in the first place... I don't know... DOH!
Long story short, it is over $400 cheaper to get a full set of 255/45 and 225/50 OEM size tires that are Kumho brand than the Turanza ones. A full set of tires for about $620 (the price of 2 OEM front tires practically) so the Kumho grand touring tires are going to fit my purposes exactly. Made to last long, be comfortable, and be quiet compared to the OEM tires that are made to have good grip, extremely hard sidewall, etc. The Turanzas would have been over $1200 and I'd have to do 255/45 and 235/50!
The Kumho tires are the only ones on tirerack in the grand touring section for the GXP. Why I didn't think of just looking at grand touring tires ONLY in the first place... I don't know... DOH!
