Rail Riding - "How To Guide"

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.

Have you had success with a "rail rider"?

Yes
90
49%
No
8
4%
Somewhat
12
7%
Haven't tried yet
72
40%
 
Total votes: 182

Slalom
Journeyman
Journeyman
Posts: 30
Joined: Sat Feb 26, 2011 12:13 pm
Location: San Diego, CA

Positive camber on DFW

Post by Slalom » Thu Mar 29, 2012 6:34 pm

Hi, Quick question, maybe I am screwed up but have aligned rear wheels using sporty's graphite no front wheels technique, RUn bent axles with negative camber rear, and bent front dfw with Positive camber, The positive camber seems to "encourage" the DFW to ride against the car body, rather than the axle head, is there any way around this? Or is the nature of running DFW with + camber, thanks in advance. :mrgreen:



User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2646
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: Positive camber on DFW

Post by FatSebastian » Thu Mar 29, 2012 6:51 pm

Slalom wrote:The positive camber seems to "encourage" the DFW to ride against the car body, rather than the axle head, is there any way around this? Or is [that] the nature of running DFW with + camber
That is the expected behavior.



Slalom
Journeyman
Journeyman
Posts: 30
Joined: Sat Feb 26, 2011 12:13 pm
Location: San Diego, CA

Re: Positive camber on DFW

Post by Slalom » Thu Mar 29, 2012 7:10 pm

FatSebastian wrote:
Slalom wrote:The positive camber seems to "encourage" the DFW to ride against the car body, rather than the axle head, is there any way around this? Or is [that] the nature of running DFW with + camber
That is the expected behavior.
Thanks thought maybe speed would push it out, maybe the rail



User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2646
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: Positive camber on DFW

Post by FatSebastian » Thu Mar 29, 2012 7:23 pm

Slalom wrote:Thanks thought maybe speed would push it out, maybe the rail
Your description of seeming to "encourage" the DFW was actually right on. If the DFW hits a defect in the rail, it will slide a bit outward on the lubricated nail before it hits the nail head and jars the front of the car body. To help maintain that shock-absorbing effect, it is desirable that the wheel hub nominally rides against the body rather than the nail head. (And don't forget to indent the body ~1/16", if allowed.)



Slalom
Journeyman
Journeyman
Posts: 30
Joined: Sat Feb 26, 2011 12:13 pm
Location: San Diego, CA

Re: Positive camber on DFW

Post by Slalom » Thu Mar 29, 2012 7:28 pm

FatSebastian wrote:
Slalom wrote:Thanks thought maybe speed would push it out, maybe the rail
Your description of seeming to "encourage" the DFW was actually right on. If the DFW hits a defect in the rail, it will slide a bit outward on the lubricated nail before it hits the nail head and jars the front of the car body. To help maintain that shock-absorbing effect, it is desirable that the wheel hub nominally rides on the body rather than the nail head. (And don't forget to indent the body ~1/16", if allowed.)
Thanks, I just sanded sown that side of the body 1/16th rather than dent, the rear wheels seem to avoid the track. Thanks again!



User avatar
Noskills
Master Pine Head
Master Pine Head
Posts: 787
Joined: Tue Jan 31, 2012 1:37 pm
Location: Bellevue, WA

Re: Rail Riding - "How To Guide"

Post by Noskills » Fri Mar 30, 2012 10:11 am

shock-absorbing effect
I have conceptualized the RR effect and positve camber as the ying and yang of the DFW but I like the concept of the shock-absober!

Seth


"Nunchuk skills... bowhunting skills... pinewood derby skills... Girls only want boyfriends who have great skills!"
Napoleon Dynamite

Slalom
Journeyman
Journeyman
Posts: 30
Joined: Sat Feb 26, 2011 12:13 pm
Location: San Diego, CA

Re: Rail Riding - "How To Guide"

Post by Slalom » Thu Mar 14, 2013 4:09 pm

HI. So we have car built, looks really sharp good aggressive COG, aligned rear wheels using sporty's technique with front wheels off, some scotch tape and lube under the front. rear wheels aligned, ride on axle hub back and forth, sanded off 1/8th inch from DFW. Still even with DFW just kissing the rail, rear wheel does as well. So I did stan's technique of accomodating by toeing rear wheels. Once past threshold that brought rear wheel off the rail, the DFW had to be toed out in order to get even semi reasonable drift to rail. This seems to be not a good situation with the front and back fighting hard and twisting to maintain good alignment. SO I shaved another 16th inch or so off the DFW side, re aligned, and exact same thing....what am I missing?

Thanks in advance!



User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3355
Joined: Sun Feb 13, 2005 2:00 am
Location: rockfalls, Illinois

Re: Rail Riding - "How To Guide"

Post by sporty » Thu Mar 14, 2013 5:10 pm

Slalom wrote:HI. So we have car built, looks really sharp good aggressive COG, aligned rear wheels using sporty's technique with front wheels off, some scotch tape and lube under the front. rear wheels aligned, ride on axle hub back and forth, sanded off 1/8th inch from DFW. Still even with DFW just kissing the rail, rear wheel does as well. So I did stan's technique of accomodating by toeing rear wheels. Once past threshold that brought rear wheel off the rail, the DFW had to be toed out in order to get even semi reasonable drift to rail. This seems to be not a good situation with the front and back fighting hard and twisting to maintain good alignment. SO I shaved another 16th inch or so off the DFW side, re aligned, and exact same thing....what am I missing?

Thanks in advance!

A few clarifications. That process, That you mention, In regards to the rear wheels off and tape under the nose of the front end, with no wheels on, the wood does need to be true under the front end. untouched as i call it.
I also make sure the board is not all twisted and its level thru out the board.
And you have to use a 4 foot long board and raise it up enough for the car to run down it.

However, this is to check to see if the car is running strait and true. It is not how to correct or fix a issue. It only points out issues.

If it faiils the test, I toss the car and start over. I do not atempt to spend hours trying to resolve the problems. Just to much work and added frustration that is not needed.

Now, How you adjust and try and resolve the problem is mentioned on here from many people, but hard to grasp by reading and if the issues are to severe, then it's very difficult to resovle with bent axle tuning and so forth.

Perhaps you might post some good pictures and close ups, if you are really stumped for us to better help you.

So post some pictures. I cant recall if you drilled axle wholes or are using slots.

Sporty



User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3355
Joined: Sun Feb 13, 2005 2:00 am
Location: rockfalls, Illinois

Re: Rail Riding - "How To Guide"

Post by sporty » Thu Mar 14, 2013 5:12 pm

FYI, The rail rider guide should be a closed topic.

All the add on's and posting, detours from the guide, versus a serious of posts after the fact.

I recommend and ask, all future questions be posted elsewhere in the forum and let this info be a guide to read only.

Sporty



Post Reply