FrontEngineDragsters.Org Forum

Technical => Roo Man's Room => Topic started by: wideopen231 on March 22, 2017, 05:54:43 PM

Title: ground clearance
Post by: wideopen231 on March 22, 2017, 05:54:43 PM
Wondering how much ground clearance others have in their FED?Looking at some pics on sit of others cars it looks like most have quite a bit more . I'm at 3.5" at nose and 3 at motor plate.Legal yes.Wiil I have issue with any bounce causing rubbing problem  is another story.
Title: Re: ground clearance
Post by: dreracecar on March 22, 2017, 07:45:50 PM
You are fine with those numbers
Title: Re: ground clearance
Post by: nostalgic371 on March 22, 2017, 08:52:54 PM
Ok - a dumb question, just how low is considered too low, anyway?
Title: Re: ground clearance
Post by: rooman on March 23, 2017, 04:25:20 AM
Ok - a dumb question, just how low is considered too low, anyway?

When it wears holes in the lower frame rails  :)

Roo
Title: Re: ground clearance
Post by: wideopen231 on March 23, 2017, 07:10:07 AM
That's funny Roo Man.Well unless its your car with wholes in i.
Title: Re: ground clearance
Post by: dreracecar on March 23, 2017, 08:50:23 AM
If you mount Ti skids to the frame, you will give the fans a show when you click it ;D
Title: Re: ground clearance
Post by: nostalgic371 on March 23, 2017, 08:52:47 AM
Ok - a dumb question, just how low is considered too low, anyway?

When it wears holes in the lower frame rails  :)

Roo
Ok - a dumb question, just how low is considered too low, anyway?

When it wears holes in the lower frame rails  :)

Roo
Stocking up on skid plates.   ::)
Title: Re: ground clearance
Post by: wideopen231 on March 23, 2017, 11:09:10 AM
Well I am a show man. Wait maybe that's show off, well which ever .I have fun.
Title: Re: ground clearance
Post by: PSweeney on March 27, 2017, 02:18:24 AM
build in sufficient ground clearance so a drop tire size doesn't materially affect the ground clearance.   Not so much an issue on a funny car but diggers can run anywhere from 30in to 33.5in tire. 
Title: Re: ground clearance
Post by: rooman on March 27, 2017, 05:11:59 AM
build in sufficient ground clearance so a drop tire size doesn't materially affect the ground clearance.   Not so much an issue on a funny car but diggers can run anywhere from 30in to 33.5in tire.

Actually the spread can be anything from 28" to 36" depending on how much motor you are trying to hook up. And if you are making that big of a change you either guessed very wrong to start with or made a radical change to the overall powerplant package. If anything, you should build for the smallest tire that you might run and live with the subsequent change in motor angle etc if you go larger. Depending on the wheelbase and  how far out the motor is in your 30 to 33.5 example the ground clearance will vary by more than an inch at the mid plate.

Roo
Title: Re: ground clearance
Post by: wideopen231 on March 27, 2017, 08:44:14 PM
Mine has 32" tires and doubt I will ever go below that.If anything I will go up in tire size and hopefully no time soon since these are new slicks.
Title: Re: ground clearance
Post by: PSweeney on March 28, 2017, 03:57:10 AM
build in sufficient ground clearance so a drop tire size doesn't materially affect the ground clearance.   Not so much an issue on a funny car but diggers can run anywhere from 30in to 33.5in tire.

Actually the spread can be anything from 28" to 36" depending on how much motor you are trying to hook up. And if you are making that big of a change you either guessed very wrong to start with or made a radical change to the overall powerplant package. If anything, you should build for the smallest tire that you might run and live with the subsequent change in motor angle etc if you go larger. Depending on the wheelbase and  how far out the motor is in your 30 to 33.5 example the ground clearance will vary by more than an inch at the mid plate.

Roo

Your right Roo, I built mine to run a 33.5in tyre and I don't like it, too much sidewall for a 138in car. If I were building again I'd mock up based on 30-31in tyre.
Title: Re: ground clearance
Post by: dreracecar on March 28, 2017, 09:38:47 AM
Altered chassis dont flex and respond better to a bigger tire, dragsters work better with a smaller tire
Title: Re: ground clearance
Post by: PSweeney on June 08, 2017, 03:39:47 AM
Just bringing this one up again.  I've currently got 3.5" at the motor plate and 2.5" at the lowest point (which are actually rub blocks 3/4" off the frame rail).   I'm going from a 33" tire down to 31", so that's 1" reduction in rolling radius.   Tires are MT ET's , do you have any idea of the likely ground clearance on the 31's ?
Title: Re: ground clearance
Post by: rooman on June 08, 2017, 05:54:10 AM
It depends on where the blocks are relative to the tire contact patch. If they are in the middle of the wheelbase you would lose 1/2"--further back would be more and forward would be less--you are basically rotating the car around the front spindle with different rear tire diameters.

Roo
Title: Re: ground clearance
Post by: PSweeney on June 09, 2017, 01:08:57 AM
cheers Roo, kind of hard to visualise at the chasssi kick up from the front of the motor which is where the blocks are.  I've ordered tires so will see how it goes.