MG Sports Cars

I started setting mine up this evening in prep for putting the fender flares on.

I wasn't sure how Ted's IFS is designed to be set up, but I guessed the lower control arms should be parallel to the ground so that's how I did it (I have a call into Ted to verify). Assuming that's right, I get about 14.25" from center of spindle to bottom of chrome strip which is about average for CB ride height based on the MG Experience survey. I then set the back so the car sits level.

With the car set up that way, I have 6.75" to the bottom of the frame rails. If I recall Tom Lay came up with something like 5 1/2" when he asked folks recently. Seems like a big variance... is my car sitting at RB height or is Tom's car sitting an inch lower than most CB cars?

Another measurement surprise was with the bottom of the frame rail level to the ground (also checked that the bottom of the flange below the rockers is level to the ground), I get 14.25" from bottom of chrome strip to center of the hub in the front, but only 13.25 out back. Does that make any sense?

Did you figure in your tire size Rob? That almost always will make a difference. Then when you say you set the car up so it sits level, what part were you referencing? I suspect the variances you are seeing have to do with non-parallel body lines as much as anything else. In the end it's probably best to set it up so that you like the appearance and the ride. Nothing else really matters that much.

Jim

I had googled around looking for original specs - what I saw on a UK mg site mentioned 5" ground clearance for CB cars and 6" for RB cars. I remember it was tight getting a floor jack under the rails with the stock wheels/tires on. But looking at a lot of conversion pics, it seems some folks are tending to be closer to 7" maybe more. In thinking about exhaust, I'm a little concerned I'm on the low side (but I like the look) - esp. with 17" wheels - but overall diameter is still close to stock - I'm at 24.6 in the rear and 24.5 in front. Some of the specs are showing even lower - wondering if that's exhaust, not frame rails.
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Edited 1 time(s). Last edit at 09/21/2008 11:46PM by t.lay.

my tires are 225/50/15 rear & 205/55/15 front -- each 23.85" diameter +/- a couple hundredths so tire size isn't affecting the measurement.

measured three ways...
+ bottom of the frame rails to the ground -- consistent 6.75" from where they flatten out after coming down from the engine bay to about the middle of the car where they end at a cross brace.

+ bottom of the flange that runs from back of front wheel well to front of rear wheel well along the rocker -- again, consistent (don't recall the number this morning)

+ bottom of chrome strip to center of hub -- front 14.25"/rear 13.25"

I think you're right about stepping back & looking at the stance. It's in the garage right now so it's hard to get a look at it. Will have to roll it out on the driveway one evening this week if I can get a chance.

Rob,
Most vehicles are designed with a positive rake (rear set higher than the front) to allow for load additions (driver/passenger/fuel/luggage, etc) which almost always add additional weight on the rear axle.
My conversion is set so that the rear (ground to chrome strip) is about 1" higher than the front in the unloaded state to allow for this.
If you currently have a negative rake, you might want to check the clearance to your rear axle bump stop to see if you're satisfied with that.
I can check my hub to chrome strip dimensions later today and report.

Rob,
Curiosity got the better of me, so I just had a measuring spree under the car keeping in mind that I removed my 1" lowering blocks from the rear suspension prior to the trip to The Glen a few weeks back. As you know, I run the same 23.8" tire diameter as you. Personally, I'd still like the front up a little higher than it is.......so here goes!
Front crossmember to ground......4-1/2"
Rear susp bumpstop to pad......2-3/4"
Front hub to chrome strip......13-3/4"
Rear hub to chrome strip......15-1/2
Front of chassis rail to ground........7-1/4"
Rear of chassis rail to ground........8-1/4"
I have the 2 degree castor reduction wedges in the front suspension which will affect some dimensional comparisons to yours.
I'm not suggesting that the numbers above are correct - they are just meant to give some comparitive feedback. A lot of this ride height exercise comes down to personal preference as to what "looks right".
Just as a PS - with 2 passengers and the car fully laden with tenting gear, there were a few rough spots on roads heading to The Glen where the rear suspension bottomed out - so is 2-3/4" bump stop gap enough?

Excellent info Graham. Thanks.

I defintely agree I want some positive rake. I must have an error in the measurements from my car though because I can't explain how/why the chassis rail to ground would be the same front to rear & yet the chrome strip to hub mesurement came out smaller in the back? It was late; maybe I was more tired than I thought. With luck I'll get a chance to check it tonight or tomorrow.

I did talk with Ted & he says it's normal for his IFS to have the lower control arms angled up as they go from the upright to the crossmember so i'm sitting a little low in the front -- maybe 3/4". I think my next step will be roll the car out on the driveway where I can step back & look at it & adjust accordingly.

Thanks for the bump stop gap info; that will definitely come in handy!