8" Rim on 2500M?

[Dragnet]

Would anybody know if a 15x8" rear rim would fit on a 2500M? If so what offset, backspacing would be necessary?

Thanks.

[davidy]

I used to have 15x7 front and 15x9 rears on a Taimar. You will have no problem, given the right offset on the rear, but you are really going to struggle on front as either the wheel will be proud of the front arches, or it will hit the wishbones when turning (unless you increase the size of the stop, then you'll have the turning circle of the Ark Royal) or both!!

davidy

[19560]

Agree with D. You could try -15mm ET all round and fit steering stops.

[Dragnet]

Thanks.

The front rims I am looking at are 15x7 with a 4 1/2" backspacing. The rear rims are 15x8 with a 3 5/16" backspacing.

From what I have been told the rear rims backspacing should not be too much and they should fit there. My concern is if the rim and/or tire will rub on the fender lip once mounted. I believe the rim will sit about an inch and a half further out then stock. Any ideas if this is too much in the rear?

Would I need a spacer up front to mount the front rim? I guess another way of saying this would be how much backspacing will fit in the front?

Your respnses are much appreciated as this is all new to me.

Thanks.

[davidy]

My wheels had zero offset, ended up with nothing on the rear and a 19mm spacer on the front.

The best thing to do is try them and see, TVRs of that age all differ from mould variations, where the body bolts are, to how how it is actually positioned on the chassis.

I would also make sure your rear springs are in good condition, otherwise the rear wheels almost certainly will hit the arches.

FYI I ran 205/55 on the front and 225/50 on the rear.

Hope that helps

davidy

[19560]

Dragnet said:

The front rims I am looking at are 15x7 with a 4 1/2" backspacing.

What is back spacing? Is it inner rim to mounting surface? If so then that is far too much and the wheels sound like a non-starter. You need less than 3.5"; I would have said 3 or 3.25, davidy was sucessfully running 2.75".

[Dragnet]

I figured the fronts would be far too much offset. That is why I mentioned the 1 inch spacer up front to get back to about 3 1/2" backspacing. I believe the stock rims have a 3" backspacing being that they are 6" wide with 0 offset. I have seen many people with 7" wide rims and 0 offset which should translate to 3 1/2" backspacing. Given that I imagine about the most backspacing you could get away with would be 3 1/2". The rear rims should fit but may touch the fender being that wide. Is there a lot of strain added to you front end if you space your wheels out an inch or so?

Thanks.

[heightswitch]

A Zero ET will equate to a 41/2 inch backspacing on an 8" Rim. Not sure about an M, but a Std Vixen etc will cause fouling on the rear pins at bottom of upright. I am Building a Griff racer which has a piggy back arrangement on the rear wishbones to allow the coil over to sit on top of the wishbone, this has the effect of moving the bottom shock mount inboard and upwards allowing more positive offset to be used.

You neet to work out clearance from hub to inner arch and outer arch. Have a look at Compomotives website which explains what you need to measure and how to work out offset measurements.

Don't listen to hearsay, all cars differ and even some of the same cars differ, you need to measure the individual vehicle and check.

Neil.

[19560]

heightswitch said:

A Zero ET will equate to a 41/2 inch backspacing on an 8" Rim.

Sounds like I have misunderstood the term backspacing then. I thought that an eight inch rim with a zero offset would give a 4 inch backspacing. (BTW isn't the standard ET -3/32"?)

heightswitch said:

Don't listen to hearsay, all cars differ and even some of the same cars differ, you need to measure the individual vehicle and check.

Yes, but the wishbone problem should be a common factor.

[Nick_f]

The 8" refers to the distance between the inner and outer rims as measured on the inside, not the overall width of the wheel.

And differenet wheel manufacturers use different thicknesses and profiles of rim.

[heightswitch]

have a look at this rather nifty site. All will become clear..

www.rsracing.com/tech-wheel.html

Neil.