Alloy wheels and allignment

[slam_dunk]

Hello everyone - my first post!!!

I have put some 16" alloys onto my T25. They are marked as 6.5" rims, although they are actually about 7.5" wide edge to edge (I guess that is because the measurement is where the inside of tyre contacts, as with the diameter measurement. Anyway, they have 215 60 R16 with LI of 99H - I have a couple of questions. First, do I need this degree of load index, or would say 91H do? The problem is that the front tyres rub on the arch when I have a passenger and go down a dip, so I want lower profile, but they don't seem to come with adequate LI. Also, I had the van lowered 60mm and the rear wheels seem to have about 5-10 deg camber, which they didn't have before. Any ideas on this. I know there is a slot to adjust camber slightly, but not enough for this. The design of the trailing arm should allow it only to travel up and down with different height springs, so I am suprised that it has bent the top of the tyre in towards the van. Would this be due to having wider wheels, therefore creating more leverage from outside of wheel. Strange though, as I know some folks have 9" wheels on rear. Any help is appreciated.

[sherlock]

Hi Slam-dunk and welcome, not sure that im the man to help you but if you fill in your profile there may be someone in your neck of the woods to help you out. Cheers & all the best. Sherlock

[Fox McIntyre]

Also, I had the van lowered 60mm and the rear wheels seem to have about 5-10 deg camber, which they didn't have before. Any ideas on this. I know there is a slot to adjust camber slightly, but not enough for this. The design of the trailing arm should allow it only to travel up and down with different height springs.

Trailing arm is on a 'hinge' As the suspention goes up, it is going to pivot the top of the wheels in around the pivot point, as it will on many other cars with trailing arm suspention. Although it is a design to help prevent negative camber you are still gonna get some from a 60MM drop!!

[slam_dunk]

Fox - the hinge effect you have shown is more like the front suspension. Looking at the design of the rear trailing arm suspension it suggests that it shouldn't matter what height of spring you have. The hinge pivots on the inside and outside mounting of the chassis (both in front of the wheel) and so the arc would roll the hub upwards and forwards around the axis of that hinge, keeping the camber straight (as would happen when you go over a bump anyway.) I will put stock wheels back on and see if/how they change things!

[yan]

Did you fit new shocks when you dropped your van? My van is down 60mm and has the same tyres but never catches. My rear wheels dont seem to have the negative camber yours has either but there is a little on the front.

[kyleewyleecoyote]

Maybe the offset of the wheel is the cause of the problem. Do you have lots of room on the front face but too little on the rear face?

[slam_dunk]

Yes - new avo shocks as well as springs. The ET is 32 - which is the front and rear face?

[kyleewyleecoyote]

I meant the front to be the face that you will normaly see. Is there plenty of clearance between it and the edge of the arch(the part you see).
ET for the T25 is between 35-45 (think), someone should confirm or correct this.
you may just need a wheel spacer to clear the arches (check that your studs/bolts will be long enough though). You can always try and mock something up to test this theory.

[slam_dunk]

The offset (ET) is the distance between the center of the wheel across it's width, and the inside surface edge where it mates to the wheel hub. The ET on the stock 14" x 5" steel rims was about 35mm, I think. For wheels that are 2" wider, the same ET would mean that 1" is gained both inside and out e.g. to get the new wider wheel to only stick out as far as the old one, I would need a larger ET distance (about 57). Anyway, with approx the same ET as the original wheels, My rims are about 1" further out, and 1" further in too. That's why I suspect it is lowered springs that has produced the -ve camber, just can't work out how!!

[Simon Baxter]

Lowering a van produces negative camber all 'round.

The rear trailing arm mounts aren't in line, so, lowering produces negative camber at the rear too..
However, adjusting the rear camber is a different matter! The bolts never undo, the bolts sieze into the bushes and there isn't enough adjustment on the elongated slots anyway to achieve factory settings, plus negative camber at the rear is no detrement to road holding, if anything it improves it and it also doesn't increase tyre wear.
I just leave the rear alone and not get involved with it, can of worms, not worth the hassle and you gain very little.

The front is a different matter.
When lowering always reset the camber and tracking at the front as lowering gives loads of negative camber and a million miles of toe out leading to scrubbing the insides of the tyres like you wouldn't believe.

ET, stay within factory figures which are ET30 to ET39. Go less than 30 and yo will get scrubbing to the insides of the tyres and heavy steering, you can't really go more than 40 with wider rims as they will catch the suspension anyway.
Width, 8" at the front is about as wide as you can go at ET30, you will probably be rolling the arches to avoid tyre-arch contact.
Rear, 9" is about as wide as you can go and still open the sliding door, at ET30.

Theres loads of threads on Brick-Yard.co.uk for this sort of stuff, worth having a read.

Simon.