• Advertisement

No Down Travel

For all suspension modifications

No Down Travel

Postby DragonMU » Sun May 01, 2011 11:10 pm

Hi All,

This is my first post but have spent quite a bit of time getting info here so thanks already.

I have a 1991 2.8td mu pretty much standard at the moment.

I installed efs lifted rear springs and rancho rs5000 shocks in the rear today. All went well but when I jacked the front to crank the torsion bars to match the rear I found that I had run out of down travel (i.e. The wheels were in the air) after only jacking the front about 2.5 inches.

Is this normal? I know the Mu doesn't have great front travel but I thought you could get away with a two inch lift just by cranking the torsion bars without the need for further mods?

I was thinking to get better downward travel in the front and allow the torsion bars to be wound 2 inches I might do the following:
Ball joint flip;
1/4 inch Ball joint spacers; and
Shave bump stops in half.

Does this sound ok?

I know similar questions have been asked but I just thought it was strange that I can't seem to get away with winding the bars a couple of inches as others have done.

Cheers for help guys.

Andy
DragonMU
Isuzu Baby
 
Posts: 7
Joined: Mon Feb 22, 2010 11:16 pm
Age: 23
Country: Australia
City: Brisbane
Vehicle: 1991 MU
2.8TD Manual

Re: No Down Travel

Postby Captcol » Mon May 02, 2011 4:48 am

I did a really long reply but got logged out and lost it, here it is in brief.

From contact with the truck you only jacked 2.5" and your wheels were off the ground, which part of the truck were you jacking off?

Your shocks may be limiting down travel, whats the ground to top of the wheel arch measurement?

The ball joint flip is to solve an issue with castor on lifted torsion bars and AFAIK doesn't affect down travel

My truck is lifted 2" approx and doesn't get near the bump stops, I will leave the bottom ones alone to stop severe angles on CV's

Never heard of ball joint spacers and don't see how they can help in this instance.
Captcol
Isuzu Guru
 
Posts: 724
Joined: Tue Mar 02, 2010 6:57 pm
Location: Whakatane, New Zealand
Age: 36
Country: NZ
City: Whakatane
Vehicle: New to me 1996 Isuzu wizard with issues!

Re: No Down Travel

Postby pig75 » Mon May 02, 2011 7:17 am

A ball joint flip will give you more down travel but it will put more load on the cv joints
92 MU, 91 MU ute, 90 MU, 96 Wizard, 14 MUX,2019 Dmax LSU
Australia's loudest MU
MY SITE MY YouTube SPL 152.3dB
If beef is in beef mince, What is in pet mince?
User avatar
pig75
Site Admin
 
Posts: 1522
Joined: Sat May 09, 2009 7:38 am
Location: Proston
Age: 50
Country: Australia
City: QLD
Vehicle: 90MU, 91MU ute & 92MU, 96 Wizard, 2014 MUX LST 2019 Dmax LSU

Re: No Down Travel

Postby DragonMU » Mon May 02, 2011 11:29 am

I jacked it from the middle of the axel so both sides dropped their full length. Could this mean the torsion bars were already wound up? It is sitting much higher in the back than the front with the new rear springs.
DragonMU
Isuzu Baby
 
Posts: 7
Joined: Mon Feb 22, 2010 11:16 pm
Age: 23
Country: Australia
City: Brisbane
Vehicle: 1991 MU
2.8TD Manual

Re: No Down Travel

Postby Captcol » Mon May 02, 2011 6:45 pm

reading that link elsewhere about the steering dampner me and my 33's might be interested
Captcol
Isuzu Guru
 
Posts: 724
Joined: Tue Mar 02, 2010 6:57 pm
Location: Whakatane, New Zealand
Age: 36
Country: NZ
City: Whakatane
Vehicle: New to me 1996 Isuzu wizard with issues!

Re: No Down Travel

Postby turnturn » Mon May 02, 2011 7:56 pm

At the end of the day you will only get as much wheel travel as the bumpstops will permit.
Not so much an issue for you but I think you can be failed a WOF (Warrant of Fitness) in New Zealand if they notice you have trimmed your bumpstops.
In my opinion you should only raise (wind up torsion bars) to the point that you are still getting full compression on individual wheels. Any further and you are reducing articulation. Unless you are consistantly running out of ground clearance then articulation is more important.
When I first got one of my Mu's it was wound up so high that I improved it's score on my home made RTI ramp by lowering the front suspension.
I also think that the first things people should do for their Mu's before mucking around with the factory suspension is to fit good tyres, good shocks and all the traction aids you can afford (LSD, Air locker etc).
User avatar
turnturn
Global Moderator
 
Posts: 950
Joined: Wed May 13, 2009 4:26 pm
Age: 57
Country: New Zealand
City: Dunedin
Vehicle: 1992 Isuzu Mu 2.8 Manual (UCS55)
Snorkle, Intercooled
1993 Isuzu Mu 2.8 Manual (UCS55)
Spare Parts/Donor
1994 Isuzu Mu 3.1 Manual (UCS69)
Snorkle, Intercooled
1996 Isuzu Mu 3.1 Manual (UCS69)
Completely Standard

Re: No Down Travel

Postby geeves » Fri May 06, 2011 2:49 pm

You can fit low profile bump stops which overcomes the cut bump stop issue. A ball joint flip does help travel as will spacers. Do remember that extra down travel increases angle of the cv joints which will cause extra strain.
Beyond this you have to think about diff drops which is major engineering.
50mm is really the limit without this.
What is the measurement from the centre of the hub to the top of the guard at rest
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8993
Joined: Sun May 10, 2009 1:36 pm
Location: Rangiora
Age: 63
Country: NZ
City: Rangiora
Vehicle: 94 bighorn 4jg2
2013 Subaru XV


Return to Suspension

Who is online

Users browsing this forum: No registered users and 0 guests