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post #1 of (permalink) Old 09-07-2000, 04:18 AM
Weakenedmchnix
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Bigger tires/Speedo diffrence

Hey

So after I installed my lift kit with 33's and the SYE, I noticed that the Jeep ran a bit slow....DUH. This weekend on a trip to Chama, NM, I noticed I couldn't get the Jeep over 55Mph. When we got there, my friend who was following me told me that there were times that I was doing well over 60....70 even!!!
So I guess my question is how did the lift/SYE/Tires affect my speedo. Also, what can I do to correct it.


Thanks in advance.
Paulee

'94 YJ Pro-Comp Coil-over kit. 33's
....and a cranky T-case.
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post #2 of (permalink) Old 09-07-2000, 06:37 AM
**DONOTDELETE**
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Re: Bigger tires/Speedo diffrence

Try this site http://www.cherokeeconnection.com/www/pages/speedo.htm

post #3 of (permalink) Old 09-07-2000, 07:56 AM
DRM
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Re: Bigger tires/Speedo diffrence

Keep im mind that difference in the speedo reading will change depending on how fast you are going. If you are reading 40 mph you may be going 48 mph, but if you are reading 50 mph you may be going 61 mph for example...

I onlu mention this because some people check how far their speedo is off at one speed and assume it is the same at all speeds...

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post #4 of (permalink) Old 09-07-2000, 08:50 AM
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Re: Bigger tires/Speedo diffrence

The cherokee connection link is dead. Here's another one that has identical info.
http://www.off-road.com/jeep/cheroke...do/speedo.html and go here
http://www.ring-pinion.com/RPMCalculator.html

GeeAea

Figures don't lie ....... but liars sure do figure.
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post #5 of (permalink) Old 09-07-2000, 06:28 PM
CJ Bob
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Re: Bigger tires/Speedo diffrence

Try this site it worked for me when I went to 4.56 gears and 33" tires...http://www.off-road.com/~jcyim/speedo.html
New Mexico Jeeper too.....

<font color=red> 83 CJ7 4" Superlift, 1" Body Lift, 33" MT's, 4.56's, Superior One Piece Axles, Rear Detroit Locker, Warn X8000I, K&N, S.S Brake Lines, 258 C.I., 5 Speed, Dana 300, York Air, Arizona Driveline</font>


post #6 of (permalink) Old 09-07-2000, 07:09 PM
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Re: Bigger tires/Speedo diffrence

On my YJ running 34" tires and changing no gears or anything else...my speedo is about 10% off. I used a radar gun from a friend on the police force here. The odometer was off about that much (I drove around a closed race track that measured 1 mile)

Assuming the radar gun was right at 50 mph I was really going 55 and at 10 mph, 11 mph. 33" inch tires depending on the brand will vary somewhat.



Hank
88 YJ (sort of)
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post #7 of (permalink) Old 09-07-2000, 07:49 PM
Weakenedmchnix
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Re: Bigger tires/Speedo diffrence

Thanks you guys! Big help!


Paulee

'94 YJ Pro-Comp Coil-over kit. 33's
....and a cranky T-case.
post #8 of (permalink) Old 09-08-2000, 06:10 AM
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Re: Bigger tires/Speedo diffrence

Try this as well:http://www.ring-pinion.com/RPMCalculator.html and http://www.ring-pinion.com/Tech Libr...edometers.html

I have a little "correction chart" I put on a magnetic business card backing for the different sized tires I run. I made up the chart in Excel. It's kept next to the speedo as a reference. So I know if the speedo says I'm running 55mph, I'm really doing 72, and I'd better slow down.



JEEPN
'81 CJ-8 Scrambled!
GM151/SM465/NP205 twinstick/7" Lift/33" Swampers/REP 8000/RS9000's/Scout II D44's F&R w/4.10's & Lockrights
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