Front-End, to Narrow or Not to Narrow?

[Vitamin K]

This question is broken out from a different thread, but I thought it was worthy of its own.

This past thread was the starting point.

Basically, I'm wondering if I don't need to narrow the front end of a rail-runner car. The referenced thread seems to indicate that if the DFW is canted enough (7+(!) degrees?), there's no need to narrow the DFW side to insure that your rears stay off of the track.

So, I'd like to hear from you pros:

- Do you still narrow your front ends?

- How much do you recommend canting your DFW axle?

- Any good way to test that the car is going to keep the rears off the rail with a given alignment? Without a test track, that is.

- Any 'gotchas' I should know about if I attempt to build a RR car without a narrowed front end?

It is particularly relevant to me, because our rules, if interpreted strictly and unfavorably, could prohibit a body width, at the axles, of less than 1.75". I could probably do it anyhow, and I doubt it would be an issue, but if I don't have to, I'd prefer not to.

 

[Kinser Racing]

So, I'd like to hear from you pros:

- Do you still narrow your front ends? I do but it's really not imperative.

- How much do you recommend canting your DFW axle? As much as you can to fit through the wheel bore, but only a little is necessary to get the job done. It's personal preference really.

- Any good way to test that the car is going to keep the rears off the rail with a given alignment? Without a test track, that is. If you take a 1/16" or less you'll be fine. It's when we try to narrow the whole car that you can take to much and the opposite rear wheel can hit the track.

- Any 'gotchas' I should know about if I attempt to build a RR car without a narrowed front end? If you've got a good steer bend in your DFA you'll be fine. The opposite cant's of those two wheels will keep you clear of the track. The main reason we try to get them optimized is to keep them both off of the track during drift (wiggle, wobble, ect.), because we run our cars on the edge.

 

[Chump Change Racing]

This EDGE you speak of.. Is it running the least amount of steer you can get away with and still be stable? Not trying to thread jack but I also saw where QT spoke of the same thing running on the edge. Or is there a lot more to it than that. Haha!!

Thanks Shane

 

[~JBD RACING~]

Yep .. Means could wiggle anytime..

 

[Kinser Racing]

Yep .. Means could wiggle anytime..

Exactly! /images/boards/smilies/thumb.gif

 

[Peerless Racing]

How much bend is too much (running pinecar solid axle from kit with caps so wheel doesn't have to fit over bend)?

 

[Kinser Racing]

How much bend is too much (running pinecar solid axle from kit with caps so wheel doesn't have to fit over bend)?

If you're running the pinecar solid axle you DO NOT want to bend it. Keep it as straight as possible. /images/boards/smilies/thumb.gif

 

[Crash Enburn]

Why is that, Kinser? Difficult to get accurate bend? The axle snaps before bending? Likelihood of marring the polished ends of the axle? I'm curious.

Thanks.

 

[Kinser Racing]

Why is that, Kinser? Difficult to get accurate bend? The axle snaps before bending? Likelihood of marring the polished ends of the axle? I'm curious.

Thanks.

It would be extremely difficult to get two accurate bends on the same piece of material. It would be a lot harder than just bending rear axles, which we recommend against because of the difficulty of getting them accurate and tuning.

 

[Crash Enburn]

So the DFW should be fine to bend then...

 

[Kinser Racing]

So the DFW should be fine to bend then...

Absolutely. I'd do it just like normal just leave the rear straight.

 

[Peerless Racing]

Agreed on the rears. I actually make nails from them as derby dad has stated. The one piece axle fit the wheel bores better. But the DFA can be bent quite easily and to whatever angle I chose. As usual I have made several cars with more n less bend on the DFA. So now I am trying to consider the different effects this will cause.

 

[~JBD RACING~]

Some cars like to be narrowed and some don't.. I had a car that was fast not narrowed. So I thought I would narrow it and gain some speed. The car slowed 6 thousands. So I took washers and shimmed the wheel back out and gain my speed right back.. Now I always start my cars narrowed and use washers to shine out for needed space..

 

[B_Regal Racing]

Some cars like to be narrowed and some don't.. I had a car that was fast not narrowed. So I thought I would narrow it and gain some speed. The car slowed 6 thousands. So I took washers and shimmed the wheel back out and gain my speed right back.. Now I always start my cars narrowed and use washers to shine out for needed space..

With all of the tidbits you post, I just have to wonder exactly how long does it take you to build a car? I know you send in a lot of them...

 

[~JBD RACING~]

Not long.... Built 2 last night.. Waiting on wheels and axles and fenders ..

 

[Guest]

Hi Vitamin K
This a a way that I was able to visualize it easily.
Build a small section of track (or cut off a piece of a Besttrack) about 8" long.
Put your car on this jig so that the clearance difference is split on the rears.
At this point you will know whether the DFW need to be pushed in or pulled out.
This is the reason 5K does his axle holder.
Without an axle holder you need to add/subtract washers to get the alignment right.
Good alignment consists of the rears off the rail and the DFW on the rail.
In addition to a good drill job of course.