Crewman 6 speed manual. Anyone put big diameter tyres/wheels on?

[rudi]

Sorry for the repost. I originally put this in the VZ Commodore section but didn't get any replies so I thought try here.

Hi all
I haven't given completely up on getting a Crewman yet because of the apparent bad fuel economy.
I drive highway a lot but also go up bush gravel road/tracks (not 4x4) just rough gravel roads.

I see the gear ratios appear to put the 6th gear slightly shorter (I think means more RPM) at cruise highway speed than a Commodore Wagon. 1st gear is very short, so again I assume this means 1st gear has very quick high revs and not much top speed? The below specs is all I could find. I assume they are correct.

Manual Auto


1st 4.48 3.06

2nd 2.58 1.63

3rd 1.63 1.00

4th 1.19 0.70

5th 1.00

6th 0.75

Reverse 3.96 2.29

Final drive ratio
3.46:1 V6 3.08:1 V8 3.07:1

Had a thought about putting bigger rolling diameter tyres/wheels on to also get some lift. Plus having that as a thought, It made me wonder if this would help improve fuel consumption on the highway. by reducing the RPM at 100/110 kmh and allowing 1st gear to be more useful, like a normal 1st gear in most cars. Id no doubt have to use 5th gear more and use the 6th gear primarily for dead flat roads to prevent the engine from labouring.
I did this in an old (don't laugh) 2.0 litre Camira manual. It worked a treat getting a bit extra clearance and I didn't notice any difference in fuel consumption. But it was a cheap car to run anyway.
Though I do think if I did this in a Auto then the Crewman would perform very sluggish and use a lot more fuel. So hence the thought of manual 6 speed. More gears to play with.
ps I don't carry much extra weight. I carry long skis/kayaks on the roof but they weigh bugger all.

Is there much room under the guards to fit larger diameter wheels/tyres in there?
Or has anyone put a Standard Commodore (3.08) diff into a Crewman to improve economy?

Anyone done this? Thoughts?

 

[Trayner]

interested in this too , my one tonner sucks on fuel

 

[figjam]

This is only in regard to bigger diameter wheels/tyres.
You are restricted on the front by the spring seat on the strut, and the clearance within the wheel cavity when the wheels are being turned lock to lock, ignoring whether the tyre will hit the inner guard or not.
My tyres are standard 225/55x17 on my X6. I could probably fit 225/60x17, but was advised by a couple of tyre retailers not to, due to possible clearance problems with suspension movement during normal driving.
An enquiry to a ‘reputable’ suspension outlet about fitting longer struts with more vertical height to the spring seats met with “Sorry mate, no such animal”.

 

[rudi]

Thanks Figjam
I think your right. I went into a tyre shop and they said to watch out for that too. He said go and have a feel of a Standard Crewman and feel how much room is possibly available.
So I will when I find one.
One can only hope. Till Reality takes all hope away .