| View previous topic :: View next topic |
| Author |
Message |
KennyG
Member
Joined: 26 Apr 2009
|
 Posted: Sun Apr 26, 2009 4:22 pm Post subject: 4" rough country lift |
 |
|
| I just got back into the Jeep scene. I had a few in the early '90s but just got a 2005 unlimited. It came with a 4" rough country lift and 33's. Is this a descent quality lift as I know nothing about lifts? The selling point was it only had 25K for miles and was very clean. If I am correct, this is a TJ right? I won't be doing much for serious off-roading, but will need to do a little for hunting. |
|
| Back to top |
|
 |
KennyG
Member
Joined: 26 Apr 2009
|
| Posted: Sun Apr 26, 2009 6:47 pm Post subject: |
|
|
| OK, I figured some of this out by reading old posts. Next I'm going to see how accurate the speedo is with the lift and big tires. I can just compare the speedo to a gps. |
|
| Back to top |
|
|
Orangeamc13
Got Rev Limiter?
Joined: 20 Feb 2006
Location: East Springfield, Massachusetts - U.S.A.
|
| Posted: Mon Apr 27, 2009 6:57 am Post subject: |
|
|
Welcome!
Yes, your Jeep is a TJ. With only 25k, you must've gotten yourself a nice Jeep! Post up some pics.
_________________
 |
|
| Back to top |
|
|
bubbaedc
Member
Joined: 12 May 2008
Location: tucson, AZ
|
| Posted: Sat May 16, 2009 4:29 pm Post subject: |
|
|
several ppl in my local club have the rough country 4" lift including me, for the money it is an awesome lift, i have so much articulation now, i went from 30" tires to 32"s and the speedo is still the same, it shouldnt change that much until you re gear
_________________
'98 TJ
4" Rough Country S lift 1" daystar BL
dana 60/44 combo
39.5x16.50R16 pitbull rocker extremes
Homemade Bumpers and rock sliders
check us out at www.tucsonoffroad.net
 |
|
| Back to top |
|
|
ehirner
Moderator
Joined: 01 Jan 2004
Location: Eastern PA
|
| Posted: Sun May 17, 2009 2:23 pm Post subject: |
|
|
| bubbaedc wrote: | | several ppl in my local club have the rough country 4" lift including me, for the money it is an awesome lift, i have so much articulation now, i went from 30" tires to 32"s and the speedo is still the same, it shouldnt change that much until you re gear |
The speedo is not the same unless you've got really small 32s.
_________________
04 Unlimited |
|
| Back to top |
|
|
bubbaedc
Member
Joined: 12 May 2008
Location: tucson, AZ
|
| Posted: Mon May 18, 2009 10:50 am Post subject: |
|
|
every police speed thing on the side of the road ive driven by has been within 1MPH of what my dash speedo says...
_________________
'98 TJ
4" Rough Country S lift 1" daystar BL
dana 60/44 combo
39.5x16.50R16 pitbull rocker extremes
Homemade Bumpers and rock sliders
check us out at www.tucsonoffroad.net
|
|
| Back to top |
|
|
ehirner
Moderator
Joined: 01 Jan 2004
Location: Eastern PA
|
| Posted: Mon May 18, 2009 1:08 pm Post subject: |
|
|
| bubbaedc wrote: | | every police speed thing on the side of the road ive driven by has been within 1MPH of what my dash speedo says... |
Like I said, unless you've got small 32s, and they do exist more commonly than you'd think, there's no way it is the same as it was with 30" tires.
I'll do some math for you.
30x9.50 BFG ATs have an overall diameter of 29.5". 32x11.5 BFG ATs have an overall diameter of 31.7" per BFG's website. For each revolution of the 30s, you travel roughly 92". For each revolution of the 32s, you travel roughly 100". That's about a 9% increase and would mean your speedo would be off by 9%. For the sake of easier math, let's say 10%.
At 30, you'd really be going 33. At 50, real speed 55. At 65, real speed ~72. At 75, real speed ~83.
_________________
04 Unlimited
Last edited by ehirner on Mon May 18, 2009 3:49 pm; edited 1 time in total |
|
| Back to top |
|
|
kaos
Member
Joined: 10 Jan 2006
Location: Iceland
|
| Posted: Mon May 18, 2009 1:25 pm Post subject: |
|
|
Speedometers are usually calibrated from the factory to show 3-5 MPH higher than true speed, given original size tires. Thus, moderate increase in tire size would tend to make them more accurate, at least in a certain speed range. IME with both the XJ and The ZJ the manufacturing error was absolute, that is, with original size tires, the speedo showed about 5 km/h too high, whether I was driving at 30 or 90 km/h. (With some other manufacturers this error is proportional.) The error caused by the increase in tire size is always proportional.
Thus, with the speedo showing 5 kph too high, and with tires with 5% larger diameter than the originals, the speedo would end up spot on at 100 km/h, but still be reading too high at lower speeds, and too low at higher.
--
Regards,
Kári. |
|
| Back to top |
|
|
bubbaedc
Member
Joined: 12 May 2008
Location: tucson, AZ
|
| Posted: Wed May 20, 2009 6:30 am Post subject: |
|
|
ahh ok i understand now
_________________
'98 TJ
4" Rough Country S lift 1" daystar BL
dana 60/44 combo
39.5x16.50R16 pitbull rocker extremes
Homemade Bumpers and rock sliders
check us out at www.tucsonoffroad.net
|
|
| Back to top |
|
|
r6less
Member
Joined: 09 Jun 2006
Location: Tennessee
|
| Posted: Sun Nov 08, 2009 8:59 pm Post subject: |
|
|
| I believe the Unlimited Jeeps are LJs. |
|
| Back to top |
|
|
Orangeamc13
Got Rev Limiter?
Joined: 20 Feb 2006
Location: East Springfield, Massachusetts - U.S.A.
|
| Posted: Mon Nov 09, 2009 8:18 am Post subject: |
|
|
| r6less wrote: | | I believe the Unlimited Jeeps are LJs. |
Yes, you're right! I missed the Unlimited part. 
_________________
|
|
| Back to top |
|
|
|
Watched Topics
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
