Visit The Dirt Forum for More Information

Author Topic:   112" or shorter wheelbase?
scanner
Dirt Roller

Total posts: 16
posted September 29, 2005 11:34 AM  
We now have a 112" wheelbase DW-8 short 2-link, & run on a fairily fast, usually tacky 3/8 mile, clay track. Would a shorter wheelbase car corner better on this size of track? I heared that the longer wheelbase cars don't corner quite as good as the shorter ones do on smaller tracks. Is this true? Thanks.

[This message has been edited by scanner (edited September 29, 2005).]

[This message has been edited by scanner (edited September 29, 2005).]

mod95r2
Dirt Roller

Total posts: 12
posted September 29, 2005 01:05 PM  
I BELIEVE THE LONGER WHEEL BASE EASIER, MORE DRIVER FRIENDLY, BUT THE SHORTER IS EASIER TO GET TO TURN BUT TWITCHY MAYBE ALITTLE FASTER. JMO

Fastride 38
Dirt Maniac

Total posts: 125
posted September 29, 2005 01:59 PM  
A longer wheel base car is alot more forgiving. You could be alittle off and still be fast because it takes alittle longer to transfer weight. If you get a 108in wheel base car and you hit it right weekend and week out it will be more responsive and faster. I perfer a longer wheel base car they seem to be more constant.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted September 29, 2005 09:34 PM  
the longer wheelbase cars can get a little more rear percent than the shorter ones can, but its small.
The shoter car has a lower polar moment so its easier to turn, but this can also mean that it is harder to drive.
On short tracks short cars do great
On long tracks longer cars are more stable.
I like the short car all the time.

2nd2none
Dirt Forum Champ
Total posts: 755
posted September 30, 2005 12:54 AM  
the 110" car is about the best for the average weekend warrior. Its more forgiving on a constant basis. You will get more rear percent with a 112" car than a 108" car, but if the front geometry is correct you dont need that extra rear percent.

scanner
Dirt Roller

Total posts: 16
posted September 30, 2005 08:40 AM  
The reason I asked, is that we had nights when we were bad fast, & nights when the car just wouldn't turn. The last few nights, the car seem to have picked up a bad off throttle push, even when the track dried out. One night we got the drag link & the idler arm bent real bad, & the car didn't seem right after that without making some major changes. The last night, we had to swap front springs,(put the 650 on the RF, & the 700 on the LF), add stagger to the front, & add some LR bite to get it to turn. Still, it was tight entering off throttle. The kid had to run the bottom in the slime, & use the throttle to turn it entering. We finished second in the 25 lap A-feature, but we had to do alot of work on the car at the track to get it that good. Our problem must be in the front end. We've got till next season to figure it out as we are done racing this year. I was just curious about whether or not it might be the wheel base that was causing part of our problem.

jonboy
Dirt Full Roller

Total posts: 26
posted October 13, 2005 04:46 PM  
The lenght of the wheel base will not cause those problems, all things being equal.

Here are some things to look for....

(1) Bent shock (check rear shocks too)
Cycle them by hand and rotate them slowly. You're looking for a rough spot.

(2) Check for any binding in front end by jacking up the car, removing springs, take shocks loose and move the a frames by hand.

(3) Check the jack bolts to see if they've moved.

(2) Toe. Not enough toe out will do it. Inspect the spindle arms for bending. You could reset the toe to compensate, but it throws off the geometry to run a bent spindle.

(3) Bent lower ball joint (right front)

(4) Check the wheel base

(5) Put the car on the scales and compare to original scale sheet.

(6) Also bleed the brakes and check the right front brake caliper for binding. Remove rubber O rings so the caliper pins will be loose.

I would take my car through this process about once a month, whether it needed it or not, just to catch the little things. Sometimes its a combination of things that add up. Its a lot of redundant work, but there are enough things to go wrong without lack of preparation added to the mix.

Good Luck

scanner
Dirt Roller

Total posts: 16
posted October 15, 2005 09:34 AM  
jonboy,All of these things will be checked out during our off season. We always take the car apart, & inspect it from front to back before reassembling it. Thanks for the advice.

jonboy
Dirt Full Roller

Total posts: 26
posted October 16, 2005 12:01 PM  
I've run the long wheelbase on the 1/2 mile and its real stable and predictable. I ran 2offs on the front and you could drive it with one hand.

I think the long wheelbase may be just the ticket if you can carry a lot of momentum.

I agree with the other guys, the 108" will turn better on a tight track.

speedy79
Dirt Forum Racer

Total posts: 92
posted October 17, 2005 11:21 AM  
I had two 112" cars and they were very fast on bigger or tracks with longer corners, I struggled to make it turn on tighter cornered bullrings.

blong
Dirt Newbie

Total posts: 4
posted October 24, 2005 03:16 PM  
quote:
Originally posted by speedy79:
I had two 112" cars and they were very fast on bigger or tracks with longer corners, I struggled to make it turn on tighter cornered bullrings.

I have a crazy question. How do you make a 112" wheelbase car. If the motor and rearend are to be 72" from each other, did you have to move the motor back further in the chassis to lengthen the rear end out more? I run a GRT and found that you pretty much have to have a car made for 112" to make it work. Our wheelbase is 109.5. I run on a 1/2 mile and wondered what was invloved in doing this.


speedy79
Dirt Forum Racer

Total posts: 92
posted October 24, 2005 03:39 PM  
The 112" cars are built special, on mine the front stubs are built longer to put the motor where it needs to be and have the extended wheelbase.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted October 24, 2005 03:42 PM  
the distance doesnt have to be exactly 72" it just cant be any less than 72". So either you build the car as 112 and move the engine back, or you can lengthen your trailing arms 2" make and make a 112 out of a 110. etc.

JT54
Dirt Maniac

Total posts: 170
posted October 25, 2005 08:19 AM  
isn't the idea to get the weght of the engine back a couple more inches and keep the left rear as close to the drivers but as possible?....I would think the reason for 112 wheel base is more for trying to gain more rear percent than anything.

Fastride 38
Dirt Maniac

Total posts: 125
posted October 25, 2005 08:39 AM  
Yes and no on the rear percent. A longer wheel base car is also more stable in the corners. Yes it might take alittle longer to transfer weight but you can be alittle off and still handle. I like to think of it as a 4 link and a three link. A four link perfect is faster than a three link anyday of the week on any given surface. A good three link alittle off will beat a 4 link alittle off anyday of the week. Of course you throw the driver into the mix then it's a whole new ball game on which is better and when.

fr1
Dirt Forum Racer

Total posts: 93
posted October 25, 2005 08:58 AM  
Really you build the same car, but slide the front clip forward. You don't want to extend the rear radius rods. That will cost rear percentage and change all your geometry on shocks, springs, radius rods, ect.

Kromulous
Dirt Forum Champ
Total posts: 796
posted October 25, 2005 09:52 AM  
108" wheel base (its actually illegal on the left side measures 107 " or so), 72" set back and 78" wide, front, rear a bit narrower usually 76".

Handles good, and responsive.

Worked on a 112" car, wont own one.

Krom.

Back to the Archives