Landracing Forum
Tech Information => Steering - Suspension - Rear End => Topic started by: Mr. Schimstock on April 15, 2015, 08:15:03 PM
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I've read some of the threads regarding having or not having a front suspension. For the purpose of this thread I'm talking about an XO lakester. I see the benefits of the rigidly mounted front axle (no suspension) but would have concerns about the increased loading from a complete lack of compliance and issues with stress concentration at the mounting points. Has anyone considered mounting a front axle on some high durometer rubber isolators. My thinking is that this would allow the absorption of some to the loads and vibration but limit movement of the axle to less than something like .25" It would be somewhere between a suspension and a rigid mount, or maybe a very high spring rate short travel suspension. There are different styles of isolators that could be used to change spring rate in different directions (fore-aft vs vertical). The isolators typically have some natural damping so I think it would bounce much.
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You might talk to Jack Costalla about this. Jack has used a similar deal.
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I chose solid but 1/4" to 1/2" would not bother me---I think this would make sense
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I've read some of the threads regarding having or not having a front suspension. For the purpose of this thread I'm talking about an XO lakester. I see the benefits of the rigidly mounted front axle (no suspension) but would have concerns about the increased loading from a complete lack of compliance and issues with stress concentration at the mounting points. Has anyone considered mounting a front axle on some high durometer rubber isolators. My thinking is that this would allow the absorption of some to the loads and vibration but limit movement of the axle to less than something like .25" It would be somewhere between a suspension and a rigid mount, or maybe a very high spring rate short travel suspension. There are different styles of isolators that could be used to change spring rate in different directions (fore-aft vs vertical). The isolators typically have some natural damping so I think it would bounce much.
Granted, it was independent, and operated through levers, but the original Mini Coopers used rubber cones with great success for 50 years.
As long as you can keep everything on the horizontal planes in check, all you'd really need would be what you're talking about, but the caution I have is this - Would the inspectors consider it a sprung suspension, which then requires shock absorbers on each wheel? :?
I think you could get by with it if you were to mount the axle with large diameter isolation bushings.
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Thats quite doable & has been done a few times. Thrust II had rubber cone suspension copied from the Mini. The Herbert Steen liner was suspended with a stack of Belleville Washers. SCTA would likely view it as suspended & require shocks. The rule doesn't say how effective they have to be! :roll:
Sid.
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Front ends suspended by rubber biscuits were used by dragsters in the late '50s early '60s. Chassis Research sold One
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We were going to run front suspension originally but ran out of time & room. Not saying it's right but our car has a solid mounted axle. Has run at El Mirage & Bonneville since 2008 with no problems. 175" Wheel base & 3500 lbs. 240+ mph
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I remember seeing a modified roadster with a suspension setup like you are talking about back in something like 1998, came back a couple of years later and he had made it solid. All I remember was the car was Toyota powered and blue in color.
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Thanks for the input. I think I'll give it a shot and build in some "friction shocks" in the locating arms. If it gives me any concern during any runs it will be easy to change the stiffness or just swap out the rubber for some metal and voila... solid mount.
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A successful car by the name of Speed Demon uses the 'hockey puck' style of front suspension.
Again, nothing new at the salt.
DW
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Do most of the above comments pertain to lakes running? If so, can anyone say whether suspension (front and/or rear) would be of more/less importance on the pavement of ECTA and/or LTA?
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Thanks for the input. I think I'll give it a shot and build in some "friction shocks" in the locating arms. If it gives me any concern during any runs it will be easy to change the stiffness or just swap out the rubber for some metal and voila... solid mount.
CAUTION - if you make a modification of that nature during a meet, run the car back to tech when you're done and make sure they're aware of it.
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A successful car by the name of Speed Demon uses the 'hockey puck' style of front suspension.
Again, nothing new at the salt.
DW
Figured it wasn't a new idea but had to ask. Do you know if they run dampeners or just the pucks?
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Thanks for the input. I think I'll give it a shot and build in some "friction shocks" in the locating arms. If it gives me any concern during any runs it will be easy to change the stiffness or just swap out the rubber for some metal and voila... solid mount.
CAUTION - if you make a modification of that nature during a meet, run the car back to tech when you're done and make sure they're aware of it.
Yep... I'm thinking pretty much any changes would need to be run through Tech or at least give them notification to they can accept/acknowledge it..... which likely means running through tech again.
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Since we're on the subject of front axles, I assume a decent street rod/gasser front axle would hold up OK on the salt. Most appear to be 2" OD 1/4 wall DOM. Thought's/concerns on this using one?
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One thing that I feel is important if you run a solid mount axle system, is that you do need some way of raising or lowering one or both ends of the axle if you are planning to scale the car to get the weight distribution even on all wheels, and some times you may find out that you want more weight on one or the other rear wheel. If you don't have a way to move one or both of the axles vertically you will only be able to change the tire loads by actually moving weight. I am using Strange Engineering funny car spindles on my lakester as they use a long king pin compared to the axle boss and this allows you to move the spindle vertically with relationship to the axle. The funny car guys use this to cross weight their cars. I am planning to use bellville washers instead of solid spacers to get a very small amount of "suspension" travel. The bellville washers have a very high internal friction when stacked and this provides dampening. Just a thought.
Rex
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Jack, Suspension is important if you are running in Loring and Ohio. Both tracks have bumps.
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most "Gasser axles are set up for radial tires--- will run on the out side of the tire---if that bothers you have one built to specs
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Recently spoke to a guy in Brisbane Aus. who is building a busa powered lakester, he has plans to use high frequency isolator bushes which I think he said are from mining equipment.
Our front axle is straight DOM 1&7/8 1/4 wall mounted narrowly under 3/8 rubber sandwich material.
Personally, I haven't tried the sandwiches.One thing that I feel is important if you run a solid mount axle system, is that you do need some way of raising or lowering one or both ends of the axle if you are planning to scale the car to get the weight distribution even on all wheels, and some times you may find out that you want more weight on one or the other rear wheel. If you don't have a way to move one or both of the axles vertically you will only be able to change the tire loads by actually moving weight. I am using Strange Engineering funny car spindles on my lakester as they use a long king pin compared to the axle boss and this allows you to move the spindle vertically with relationship to the axle. The funny car guys use this to cross weight their cars. I am planning to use bellville washers instead of solid spacers to get a very small amount of "suspension" travel. The bellville washers have a very high internal friction when stacked and this provides dampening. Just a thought.
Rex
Rex, I think you need to access the bias adjustment and dial in more building than thinking :wink:
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James,
Regretfully my list of projects with higher priority keep getting in the way. I just finished putting a V 8-60 in my neighbors T speedster, motor mounts, tranny mount, drive line, headers and exhaust, complete new pedal assembly new firewall and then I had a drunk pile into my lakes modified roadster last October and completely tore the rear end out, bent the frame, took out the right rear qtr panel so I have it completely apart, just finished fixing the frame, new qtr panel is next except I just bought a new (to me) Mori Seike lathe so I am presently cleaning it and prepping for paint and then I have to get it up and running. Plus I have "volunteered" to build the header for Steve Nelson's new F class motor and he wants to make Speed Week this summer! But I do have the lakester perimeter frame fabed and I bought an engine from Sumner last year so I have it setting in the frame, I just purchased a set of 17 x 3 aluminum wheels for the front so I can start on the front axle (Strange Eng spindles). So you can see that I am committed to the lakester project and I will get it done and out to the salt it just won't be this year.
Rex
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Rex, if I wasn't so far away, I would be such a smart ass.
Also if I could so accurately list what I was up to at the moment the way you just did I'd be way ahead of where I am.
Right now I'm thinking about a big cup of Margarita mix with a big shot of Don Julio in it instead of the million things I should be doing....... :roll:
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Right now I'm thinking about a big cup of Margarita mix with a big shot of Don Julio in it instead of the million things I should be doing....... rolleyes
Dr. G I just knew from "the Start" you are a displaced Texican.
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He seems to have that "Southwest Texas" drawl..... :cheers:
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Cactus juice induced no less
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Rex, if I wasn't so far away, I would be such a smart Acura.
I doubt location has anything to do with you being a smart ass. :roll:
Ok ok, I know, it takes one to know one. :-D
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... Suspension is important if you are running in Loring and Ohio. Both tracks have bumps...
Thanks Joe.
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I'm pretty sure I've only drunk tequila with Rex at the startline, for breakfast, and possibly afternoon tea........ Where the rest of you gathered the experience to make qualified comment is beyond me.
:roll:
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Well the old C&W song says it best ----"Jose Cuervo is a friend of mine."
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Joe Timney- are any lakesters at Wilmington running with just the front axle sprung?
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Jack,
A number of belly tanks use a single front spring...with dampeners! The concrete pads are smooth but there are a number of bumpy transitions from one pad to another.
j
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The very first place we drove our tank at speed was Mangalore airport here in Victoria. The transitions were enough that after about three runs to about 100mph I was done, I felt like I had been kicked by a horse and was worried another might injure my spine. Remember though that we have only an inch of clearance and the body was bottoming out. It was a sobering start, then the very first drive on the salt I got head shake.
Thankfully, once that was sorted it was a dream drive......be prepared for some disappointment before then though......
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Dr. G
How much suspension movement do you have?
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Hard at both ends Shimmy, bit of flex under the front, that , on the concrete was the problem because it allowed the body to bottom out on the transitions, I've bottomed out on the salt and had it airborne after hitting the creek that crosses the track at the six at Gairdner but nothing compared to the bottoming out on the concrete, that was nasty :oops:
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I have clearance of 2.75" in front and a little over 3.75" in the rear.