What offset is better for a Gemini

Technical Disscusion Forum will be used for in depth threads that are moved here by a mod/admin member.... everyone is welcome to add their input, but only on topic replys
Dyllan1
Chatterbox
Posts: 61
Joined: Wed Aug 05, 2009 11:35 pm
Location: Brisbane

Post by Dyllan1 »

Yeah thanks for the help
Im not that up with all the offset stuff but I understand it now
I'll cheack the offsets and all that and let you's know how things go
Germinator
Long Term Member
Posts: 5903
Joined: Sun Jul 09, 2006 6:13 pm
Location: Albury/Wodonga
Contact:

Post by Germinator »

If you're unsure, ask us before you buy, you can't change a bad offset!


I have SL/X alloy rims on my TE diesel, pretty sure they are et35 but I'll go double check and measure the clearance between the rim edge and the shock at ride height and at fully jacked up height. That will give us a basis to calculate all other rims for correct clearance. It won't mean it's the be all end all for some rims that are close fits, those will still need hands on final checks.
.

I do not give permission for anyone to reproduce content from my posts.
Reposting any of my forum posts (or substantial parts thereof) breaches the copyright act.
leviathan937
Regular
Posts: 246
Joined: Mon Feb 25, 2008 7:10 pm
Location: Shepparton VIC

Post by leviathan937 »

When the car is full lifted, how much of an angle does the shocker lean on? It will obviously be more shallow than at ride height, but would the angle be great enough to take that into account for sizing as well?
If it ain't broke, then it DOESNT HAVE ENOUGH FEATURES YET!!!
Germinator
Long Term Member
Posts: 5903
Joined: Sun Jul 09, 2006 6:13 pm
Location: Albury/Wodonga
Contact:

Post by Germinator »

The angle difference between operating height and fully jacked up makes little difference to the clearance distance. You'll find it reasonably common for FWD offset rims to touch at fully jacked position but clear at normal operating height.

You really need to check it both at normal operating height and at fully off the ground. After all you can't tighten wheel nuts while it's pressing the wheel against the shock absorber! If it hits and someone jacks up the car from under the body, not from under the lower control arm, you risk damage to the shock absorber, they are NOT designed for tyres pressing against them sideways! That bends shafts. :oops:
.

I do not give permission for anyone to reproduce content from my posts.
Reposting any of my forum posts (or substantial parts thereof) breaches the copyright act.
troyrotor
Long Term Member
Posts: 1016
Joined: Thu Feb 14, 2008 9:03 am
Location: gold coast RIP MANWELL we will always remember you

Post by troyrotor »

i fully measured everything i could before buying my wheels. they dont hit the shock at all when up and my shocks are inflatable so they are quite a bit wider than standard shock absorbers and i still have around 10-20mm space.

the offset may suit fwd but i dont think you can call them fwd wheels.
they fit my car perfectly and its clearly not fwd
MY BUILD viewtopic.php?t=36388 OF THIS s@*tter BELOW
Image
Germinator
Long Term Member
Posts: 5903
Joined: Sun Jul 09, 2006 6:13 pm
Location: Albury/Wodonga
Contact:

Post by Germinator »

Inflatable? Do you mean rear air pump up shocks? That's not such an issue at the back, it's the front shock that hits on FWD wheel rims.

Are you saying that your 18"x7.5 et40mm wheels don't touch the front shocks at all, not even when jacked up? Are you using wheel spacers with standard Gemini disc brakes or are the front brakes changed from Gemini standards?
.

I do not give permission for anyone to reproduce content from my posts.
Reposting any of my forum posts (or substantial parts thereof) breaches the copyright act.
leviathan937
Regular
Posts: 246
Joined: Mon Feb 25, 2008 7:10 pm
Location: Shepparton VIC

Post by leviathan937 »

Germinator wrote:The angle difference between operating height and fully jacked up makes little difference to the clearance distance. You'll find it reasonably common for FWD offset rims to touch at fully jacked position but clear at normal operating height.
Can clear in one position and foul at the other.. thats a big enough difference for me.
Last edited by leviathan937 on Sun Jul 18, 2010 6:25 pm, edited 1 time in total.
If it ain't broke, then it DOESNT HAVE ENOUGH FEATURES YET!!!
troyrotor
Long Term Member
Posts: 1016
Joined: Thu Feb 14, 2008 9:03 am
Location: gold coast RIP MANWELL we will always remember you

Post by troyrotor »

18x7.5 +40 offset.

i have the shocks front and back my hose also run on the wheel side and dont touch.
as far as i know i have stock brakes. no spacers they fit well. i think it may be easier to fit 18s rather than 17s cause of the height buys you more distance from the shock
MY BUILD viewtopic.php?t=36388 OF THIS s@*tter BELOW
Image
Brazzo_tg
New Member
Posts: 20
Joined: Sun Jul 27, 2008 8:31 pm
Location: Griffith

Post by Brazzo_tg »

hey mate my gemi runs 19inch savanahs in 8inch wide & personally i wish i didnt get them if u want it to sit nicely & not look like a monster truck then go maybe 18'z. In saying that. the car had 18's on it & had lipped guards all round & was dumped on super lows with coils cut out of them (I didnt do this). To do this with 19's basically shorten the diff.

With 19's for you to achieve full lock turns u must lift the height of the car so the guard clearly doesnt touch the lip & u will have to modify the inner rear of the front wheel arch/ firewall to get this result.
From experience saying that 18's should be the biggest wheels to fit to a gemini without having to go out of ur way to make them fit proplerly
I Like Biscuits and I like cheese, I keep them in the poket of my favourite jeans...
su59em
Regular
Posts: 711
Joined: Mon Mar 26, 2007 5:39 pm
Location: Sydney

Post by su59em »

even with 18's in my experience are huge cos of the very very minor (bout 5mm) clearance you have between the tyre and the inner guard/drivers footwell on full lock, in some cases ive had the tyre rub the sway bar on 18's ... 17's would be the absolute largest wheel id ever put on a gem
Dyllan1
Chatterbox
Posts: 61
Joined: Wed Aug 05, 2009 11:35 pm
Location: Brisbane

Post by Dyllan1 »

Well got my 19s and fitted them yesterday and not a problem only thing is the front at full lock and I mean full lock hit the inside wall only the slightest. So I'm pretty happy and the back sit fine with no spacers nothink
troyrotor
Long Term Member
Posts: 1016
Joined: Thu Feb 14, 2008 9:03 am
Location: gold coast RIP MANWELL we will always remember you

Post by troyrotor »

my 18s are the exact same diametre as my 13s just an inch wider so they take up practically the same space
MY BUILD viewtopic.php?t=36388 OF THIS s@*tter BELOW
Image
User avatar
redzone (coxy)
Long Term Member
Posts: 1659
Joined: Sat Jun 10, 2006 3:22 am
Location: sunshine coast

Post by redzone (coxy) »

troyrotor wrote:my 18s are the exact same diametre as my 13s just an inch wider so they take up practically the same space
yes but the inside of the rim where it is likely to hit the shock at full droop is in a different spot on the 18's due to their diameter..
GARAGE REDZONE sunshine coast ph 07 54433507

1975 TX coupe 4ZD1 efi turbo 10.787 @ 123/128
1977 TC Fashion Pack sedan draw through turbo
1984 TG PF60E dohc Group A racecar
1984 TG Panelvan
2006 Crewman SS 6.0
troyrotor
Long Term Member
Posts: 1016
Joined: Thu Feb 14, 2008 9:03 am
Location: gold coast RIP MANWELL we will always remember you

Post by troyrotor »

yer thats true, well mine dont hit anyway so im happy
MY BUILD viewtopic.php?t=36388 OF THIS s@*tter BELOW
Image
Beano
New Member
Posts: 36
Joined: Wed Jul 27, 2005 6:29 pm
Contact:

Post by Beano »

Another thing to consider is that when comparing say 13's and 18's with the exact same rim width, offset, and overall rolling diameter, the tyres on the 18's will have a sqare shoulder being low profile, while the 13's will be more rounded. This means that the edges of the tyres on the 18's will be closer to things (front guard lip and rear panel/footwell panel inside guard) and the lower profile tyres will be more likely to rub against things.
www.turbogemini.com

Big Brake kits, EFI & Turbo kits & Weber carbys.
Post Reply