Register now to get rid of these ads!

Technical How low?

Discussion in 'The Hokey Ass Message Board' started by sgtlethargic, Jul 3, 2020.

  1. What are some rules of thumb for how low a car can be and be safe?

    What things factor in (wheelbase, for example)?
    chryslerfan55 likes this.
  2. Slopok
    Joined: Jan 30, 2012
    Posts: 2,559


    Everything should remain above the scrub line to be safe, many are not.
  3. Lloyd's paint & glass
    Joined: Nov 16, 2019
    Posts: 2,411

    Lloyd's paint & glass

    Scrub line is most important to me. And depending on what it is, how you plan on lowering it can destroy the ride quality.
    SlamIam, Elcohaulic, loudbang and 4 others like this.
  4. blowby
    Joined: Dec 27, 2012
    Posts: 6,722

    from Nicasio Ca

    And rim diameter is a factor in scrub line, since the rim is what you want hitting the ground. So a 15" rim with a lower profile tire of the same diameter as a higher profile 14" will allow a lower ride height.
    chryslerfan55 and SlamIam like this.
    Register now to get rid of these ads!

  5. arkiehotrods
    Joined: Mar 9, 2006
    Posts: 5,843


  6. The scrub line stuff is good, but I was thinking more about the frame rails. Using the underslung image as an example, how much ground clearance, and would you only need to consider the lowest point? I think the frame would be Z'd front and rear, so there'd be maybe six feet of low frame rail. 4, 5, 6 inches of clearance?

    Underslung- model t forum.jpg
    chryslerfan55 likes this.
  7. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,677

    jimmy six

    I thought if it didn't knock over a pack of Camels.. it was OK
  8. dan31
    Joined: Jul 3, 2011
    Posts: 1,047


    Really depends on how long the wheel base is , rear departure angle and what the terrain is like where you live. My 54' sits pretty low with a static drop and i live in South Jersey which is flat so it works, other regions maybe not so much.
  9. I think that scrub line is probably the most recognizable of all the best "safety" rules/tips.

    Here is something that I think a lot of people don't think about. I had an OT mini truck for a while in the '90s and it pretty much skimmed the road. It did not have a scrub line issue per se. But it was low enough to bang into a 12 pack box left in the road in Colorado. I was accustomed to driving real mud trucks at the time (just back from Mexico) and fortunately the box was empty.

    Whey is this important? People leave trash in the road, you cannot always miss is and a drop axle may not have a scrub issue but would have a junk issue.
  10. The37Kid
    Joined: Apr 30, 2004
    Posts: 27,232



    This looks about right for the 1910 era, started as a Buick if memory is correct. Bob
  11. fuzzface
    Joined: Dec 7, 2006
    Posts: 1,299


    a friend that build cars from the ground up like starting out by putting a 4x4 down in each corner and putting a 2x4 on top of that and builds his frame from there. that is the lowest he wants his frames. He doesn't mind going up but that is the lowest for him. so if I remember correctly that should be like 5" seeing lumber isn't true to the inch size.

    Must be something to this seeing him do this for years and then I saw one of those tv car shows(don't remember which one) last year or so and they did the same thing
  12. hemihotrod66
    Joined: May 5, 2019
    Posts: 192


    I think if you can't drive across speed bumps without damaging headers and oil pans the ride is to low...You also got to watch steep driveways and parking blocks too...I worry about that with my car and it isn't near as low as some cars are....
    VANDENPLAS and loudbang like this.
  13. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,262


    IMG_0812.JPG My 64 Biscayne with 2" drop spindles and cut coils in the rear is just a little too low. Speed bumps raise Hell with the pipes unless I crawl over them. With people in the rear seat and luggage in the trunk I have to be real careful on bumps as the drive shaft hits the floor. Not that we carry anyone that often. Otherwise it rides pretty good.
    Last edited: Jul 4, 2020
  14. Low enough to clear grates or cool road plates they use here........I would build it to go over the height of 2 road plates just in case. Had a friend take out part of his crossmember on a overlapped road plate going home one night. It was fun bending it back the next night. Early 90's, static drop (all coil), rode pretty decent 1960 Elco.....we were kids :). Mine was a little higher.

    Last edited: Jul 6, 2020
    chryslerfan55 and VANDENPLAS like this.
  15. fiftyv8
    Joined: Mar 11, 2007
    Posts: 5,072

    from CO & WA

    A beer can height for road clearance and noting to scrape on the road when you get a blow out.
    Obviously the longer the wheel base that can height may need to be raised slightly.
    Don't run yourself out of suspension travel when lowering your ride...
    53 hemi likes this.
  16. In my opinion, no low is too low. But when it comes to safety, keep everything clear of curb height.

    Sent from my iPhone using H.A.M.B.
    chryslerfan55 likes this.
  17. Have always sacrifice ride for cool. lol
  18. Mimilan
    Joined: Jun 13, 2019
    Posts: 593


    So you can drag it off the road with 4 flat tyres [this is what most sanctioning bodies mandate]

    For handling , you can never go "Too Low, Too Wide, or Too Light"
    chryslerfan55 and Ned Ludd like this.
  19. Hot Rods Ta Hell
    Joined: Apr 20, 2008
    Posts: 4,080

    Hot Rods Ta Hell

    The main factor is what car? Wheelbase and front/rear overhang is a huge factor. A Model A and a 51 Merc could both have a 5" frame clearance but the Merc will play hell in spots where the Model A will have no problems.

    For example a Model A has a relatively short wheelbase and almost zero front and rear overhangs, whereas the Merc has a much longer wheelbase and significant overhangs, especially in the rear. The Merc is much more prone to getting 'high centered' in humped driveways and will drag it's ass in and out of driveways cut steeply away from the street even when 'cutting an angle'.
    On super low cars, I try to keep everything within the wheelbase above the bottom of the frame so if it drags, the frame acts as a skid rather than a trans pan, bellhousing cover, exhaust pipes or headers taking the plunge. Block hugger style headers on a really low car are a must. Collector style headers 3" from the ground really suck and end up acting like bulldozer rippers.
    Tman, chryslerfan55, SlamIam and 2 others like this.
  20. Gotgas
    Joined: Jul 22, 2004
    Posts: 6,851

    from DFW USA

    If you're going for super-low, then make sure the frame is the lowest part of the car. Scraping the frame is preferable to dragging exhaust and transmission pans off the car.
  21. jnaki
    Joined: Jan 1, 2015
    Posts: 4,648


    cool looking, lowered to the max, but illegal...


    The purple Buick is a daily driver in So Cal. We have seen our share of lowered cars, cars on drastic Cal Rake angles and they look cool, but most of them can’t pass the simple test from the CHP. The test being, no body part can be lower than the lowest edge of the rims. It doesn’t matter if the tire is low profile or not, the rim is the important part. So, how do those lowered cars go over bumps? Sideways, or very slowly. Some have reverted to hydraulics or these days and air bags to raise the car for certain obstacles.

    It isn’t just hot rods or customs that are lowered. A normal teenage sedan with several friends inside will lower the car, depending on the size and weight of the occupants to very low, if not an illegal stance. Despite the air bag controversy, it does have some value, if that is the way to go on your lowered hot rod or custom car/truck. The gas tank is the main culprit on all non electric cars. It is usually the lowest part and that rim rule is based on gas tanks scrapping and offering bad results.
    This chopped Ford sedan is also a daily driver and the stance is very low, but legal if the rims are the lowest point of the measurement standard. Lowered cars give the stealthy attitude when cruising around. This Ford sedan has it in droves. Not only did it have a flat black satin sheen, but it just looked cool going down this So Cal street. If I were the CHP officer, I would not pull this car over for illegal vehicle checks. But, it is right on the edge and if more passengers were inside, it would be illegal for street driving. lowered So Cal daily driving…


    When I saw the purple Buick parked in the industrial area of this coastal beach town, it looked cool, just sitting there. But, upon closer inspection, it had to have air bags as I could not see it clearing the dip located a block back on the same road and ahead of the Buick about a ½ block.

    So, the conclusion was what the old lowriders used to do anytime we saw them in our Westside Long Beach neighborhood. The ride is in the normal height. Then when it is time, some parts are lowered for looks. By the time they park somewhere, the whole car is slammed down to the ground and now, the security lock is in place. It would be very difficult to steal any car that is lowered to the ground.

    So, I am assuming the daily driver, purple Buick has the modern day equivalent of hydraulics with an air bag system. Otherwise, he would be stuck where it is parked with the drastic drainage dips in front and back of the location. Those dips are even slow-downs for normal height and superior shock system cars/station wagons. If not, then a big noise comes inside of the cabin to surprise its occupants.

  22. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 1,029


    I like to enjoy the drive. I dont want to be holding my breath while going over things.... Cars look broke down to me when there real low.. Besides I drive the hills of Pittsburgh. I like the front a touch higher then the rear..
  23. The37Kid
    Joined: Apr 30, 2004
    Posts: 27,232


    Joined: Jun 3, 2005
    Posts: 8,048


    I think if you have to dig a hole to get in or out it's prolly too much...:eek:
  25. Ned Ludd
    Joined: May 15, 2009
    Posts: 4,033

    Ned Ludd

    The scrub-line principle is a sound one, but special care needs to be taken with the overhangs, which should not scrape when tyres are flat on only one axle. Suspension travel might go under the scrub line momentarily, as long as it comes back above in a steady state: another reason for decent damping. Static deflection plays a role also, especially if the car is very light and/or the suspension is very soft. It's no use violating the scrub-line rule the minute there is a passenger or any kind of payload in the car. Rising-rate springs with a rapid rate increase can help there.

    One of my first posts on the HAMB years ago concerned a way to get around the scrub-line rule safely. Unfortunately I was not yet au fait with the culture of the HAMB at the time and, not realizing the resemblance of many on here to Cornish sheep, who are "very dim; once they get an uydear in their heads, there's no shiftin' it," I made the mistake of describing my proposed auxiliary trolley wheels as of the same sort as those on casters. There was nothing I could do to dispel the impression that I was talking about actual casters pivoting about a vertical axis. I meant something more like the wheels on wheelie bars, or the additional axle on some semi-trailers whose wheels only contact the ground at a certain load, all of which are fixed in their rotational axes. I still believe that the idea has merit.

    It should be simple enough in the case of rear tyres whose sidewalls are taller than the scrub line to run a pair of trolley wheels inboard and/or slightly aft of the rear wheels, on which the car would fall if the rear or all four tyres were to blow out. Of course the trolley wheels would need to be selected for the necessary impact strength, etc. It would be harder at the front, as such auxiliary wheels would have to steer with the front wheels, and I suspect that the complexity wouldn't be worth it.

    I understand that solid tyres inside the pneumatic tyres are or were used in NASCAR for the same purpose? The problem with that approach is of course that you can't check on the solid tyres without removing the pneumatic tyres, so that's no good if you need to be able to demonstrate compliance. All I'm doing is taking the solid tyres outside the pneumatic tyres.

    I hope nobody decides that I'm talking about shopping-cart casters this time.
    Lone Star Mopar likes this.
  26. jnaki
    Joined: Jan 1, 2015
    Posts: 4,648



    The whole thing is "how low" in the question. So, if it is going to scrape something, it is too low. If it is against the law, it is too low. Even though a car is low, when a tire blows, the weight of the car will make something scrape. Hopefully it is not a gas tank.

    Ii wrote before that a normal height 4 door Chevy sedan is legal, but put in 4th of July beach stuff, picnic stuff, 4-5 people, now, the stock height sedan is too low for being legal. On our way home from our granddaughter's house a year or so, ago, a 1955 Chevy 4 door sedan was on fire from the rear seats, trunk and rear tires. Their stuff was on the sidewalk, the CHP was directing traffic and everyone slowed down to gawk.

    The family seemed to be OK as no EMT van was loading anyone. But, over stuffing any car, will make the idea of being "low" too harsh. In the other post, yes, HAMB is not air bag friendly, but something must be said about the safety of cars that are too low in any circumstance. Why spend hours and money to get a hot rod looking nice and then have it damaged by being too low? or worse?


    Luckily a fad that was back in the late 60s-early 70s was a skid plate welded below the gas tank up to the bumper. When the front went up, the skid plate hit the ground causing sparks galore. It was a hit with little kids, but others just shook their heads. The CHP did not like that and it was a vehicle violation with a removal order in place.

    There are other things to worry about these days, one should not be endangering your family for the sake of style or thinking your car looks cool. STAY SAFE...
    sgtlethargic likes this.
  27. goldmountain
    Joined: Jun 12, 2016
    Posts: 1,940


    I have a daily driver 2014 Focus that is low enough that I can't slide my floor jack under unless I drive it onto some ramps. It doesn't get hung up on anything. My dropped axle is about the same clearance so I am good to go.

    Sent from my SM-T350 using The H.A.M.B. mobile app
  28. Kevin Ardinger
    Joined: Aug 31, 2019
    Posts: 199

    Kevin Ardinger

    Filter or non filter?

    Sent from my iPhone using The H.A.M.B. mobile app
  29. jnaki likes this.
  30. jnaki
    Joined: Jan 1, 2015
    Posts: 4,648


    Hello S,

    I am sure it is a work in progress... I will try to see if I can get an update photo as soon as I see the Ford again. But, these days, not too many cars are out on the road. We don't go to outdoor events if they are open. Masks are necessary, but no one uses is not worth it. We do not want to be in the next upturn of cases. Age bracket and all that goes with that vulnerability. We are patient and will wait our turn to freely go out to see local hot rods, soon.

    So, once we all can go out without any problems, the hunt will be back on. I had seen that same Ford a month earlier in 2019. Then the moving film was taken just before Christmas in 2019. Daily drivers do get driven.
    Then as we all know, the stuff hit the worldwide fan...

    Sharp eye on your behalf. Those lowered cars usually got a scrape or two when trying to negotiate those steep So Cal drive-in theater hills between the rows, back when we were teenagers. Even the mild Cal Rake Chevy Sedans also had to go over those drive-in hills slowly with several friends in the cars.
    sgtlethargic likes this.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.