Rear Tire Wear

Aptera Community Aptera Discussions Rear Tire Wear

Aptera Community Aptera Discussions Rear Tire Wear

  • Rear Tire Wear

  • Steven G. Bueche

    Member
    February 9, 2022 at 5:00 am

    After viewing some of the current track testing I noticed the rear tire not tracking with any of the turns and taking a bit of drag on it’s lateral sides. Sure some of the turning in the videos is a bit hard due to that particular test. but How much lateral wear will come from every day driving? How it will effect the tires longevity. Will it wear out on the outsides before the middle.

    Any thoughts?

  • Steven G. Bueche

    Member
    February 9, 2022 at 5:06 am

    OK, how do you delete multiple posts?

    • Harry Parker

      Moderator
      February 9, 2022 at 10:25 am

      If you hover your cursor to the right of your name on the post you’ll see 3 vertical dots. They bring up a little menu and one of the options there is “Trash”. Click on it to delete your the post.

      I deleted one. I’ll leave the other for you to try to delete. Let me know if you have problems.

    • Thomas Bushaw

      Member
      February 9, 2022 at 11:02 am

      I believe the “Delete” option is only available to the author for a limited time (1 day? or until the first reply?).

      • kerbe2705

        Member
        February 9, 2022 at 8:30 pm

        Moderators, like our Harry, are granted special additional powers!

  • Guy SKEER

    Member
    February 9, 2022 at 5:19 am

    The tires are so lightly loaded, the interest in High Efficiency (thus at slightly elevated pressure), and opportunities for Driving at that level are so Rare in Day-to-Day driving, I believe that the Center of the tread will probably wear to the Warning Bars first. RANK CONJECTURE on My Part.

    • Lou Verner

      Member
      February 9, 2022 at 5:43 am

      Steven, How often are you planning to put your Aptera through the kind of slalom run seen on the video? I can remember doing such a quick maneuver perhaps 3-4 times in 50+ years of driving. I agree with Guy that the rear tire center wear will likely be comparable to that of the front tires. But that is RANK CONJECTURE on my part too 🙂

      • Steven G. Bueche

        Member
        February 10, 2022 at 4:17 am

        Hi Lou. I’m not so concerned about aggressive driving as I am about how the rear does or does not track with the turning radius of the front tires. It seems that no matter how you drive the rear tire with always encounter a bit of sideways drag.

  • Scott Price

    Member
    February 9, 2022 at 10:39 am

    Interesting points, everyone. Given the different suspension geometry and location of tires relative to center of vehicle mass between front and back tires, there will presumably be some different gradual wear patterns between front and back tires over time. Given the vehicle’s light weight, it could even be partially affected by whether most driving is by one driver on one side, or with driver + passenger, and/or with relatively heavy load in back.

    A likely solution, if needed, for most regular driving may end up being good ol’ periodic tire rotation. Unlike 4 wheel cars that rotate forward/aft + cross over left/right, perhaps the recommended rotation will be to pick a clockwise or counterclockwise direction and rotate the tires accordingly every X thousand miles. This may end up just being part of a recommended maintenance schedule in the Aptera user manual.

    • Guy SKEER

      Member
      February 9, 2022 at 12:33 pm

      Yeah, Scott…

      I am (Sigh – Still) a Big Boy, and have already planned for making an adjustable version of the vertical Link to the Anti-Sway Bar, such that I can “Tune Out” at least Half of the Markedly Port List that My Vehicle will exhibit whilst Porting My Lard Butt. ‘course, that will give rise to some Interesting Woggles when Going over a Speed Bump or suchlike!

      In the Days of Old, Bias Ply Tires could happily Reverse subsequent to a Tire Rotation, but These days the folks at My Tire Shop say it is not so good to ask a Radial Tire to Change Directions from Original Mounting…

      • Scott Price

        Member
        February 9, 2022 at 1:44 pm

        Guy, you should volunteer yourself to be a test driver then! You can use your “girth” as a data point to make the rest of us jealous and report back. 😉

        That is a really good point about modern rotation practices. I just did some quick online research after you pointed that out. Modern multidirectional radial tires can still be rotated both front and back plus left to right. However, modern unidirectional radial tires must be maintained on the same side of the vehicle though can be swapped front and back. The main issue for unidirectional is that it has a prescribed direction of forward rotation, so for the Aptera’s middle back tire it would be more about direction of rotation than which side of the vehicle it is on.

        So… in an Aptera, multidirectional should allow the rotation pattern I mentioned. Unidirectional radial tires would create some funky rotation pattern issues, though (example: first rotation could be swapping front left and back tire while leaving the front right where it is, but then you could not rotate the front right with the back tire on the next rotation since that back tire was previously the front left).

        Most of the sources I saw online said that unidirectional tires frequently provide better performance and wet/snow traction, though multidirectional tires have more flexibility on tire location and rotations. It will be interesting to see what Aptera determines for final tire type and their recommendation regarding rotations.

      • Vernon Michael Gardner

        Member
        February 11, 2022 at 12:04 am

        Hey Guy, unless you have directional tires, it’s okay to change direction of radials. 40 years ago this wasn’t the case and the belts had to seat, that’s no longer an issue. Your tire guys are probably too young and not educated enough in their tires. Don’t forget to hand torque the lug nuts to your vehicle specifications. For tire inflation I go about 3 PSI above manufacturer recommended spec, this reduces the shoulder wear for the type of driving I do.(I like roads with a lot of switchbacks)

  • Steven G. Bueche

    Member
    February 10, 2022 at 4:25 am

    With the current rear set up this seems impossible but maybe in the future iterations there could be a three wheel steer version? It would increase cost so maybe make it available as an option.

    I seem to think Chris said you could do the Tank Crawl. This must be with the three motor set up. Has anyone seen any video of this?

    • Vernon Michael Gardner

      Member
      February 11, 2022 at 12:11 am

      Have you ever tried driving a forklift with rear steering very quickly? Rear steering is a scary thing and should be designed into the suspension. Rear steering angles change with speed and load. Some vehicles had electronically controlled rear steering. Honda made several vehicles with rear steering. Mazda made some with rear steering that was controlled by load.

      • Steven G. Bueche

        Member
        February 14, 2022 at 3:49 am

        Hi Vernon, Yes I have driven forklifts and I completely agree that they can get away from you if not paying attention. I guess I should be asking about rear wheel tracking. The front would do the majority of the steering but the rear would pivot just enough to follow the directional curve. Does that help?

  • Michael Klensch

    Member
    February 12, 2022 at 4:30 pm

    Seems to me that maybe Aptera might want to use a rear tire with a similar profile to a motorcycle tire rather than a car tire. Especially since they are using a rear swing-arm suspension like a motorcycle. That tire will experience similar lateral forces to a motorcycle, so then why not use a tire intended for that purpose? It’ll be interesting to see if they end up going in that direction.

    • Paul Schultz

      Member
      February 13, 2022 at 10:31 am

      But will the rear tire experience lateral forces similar to a 2-wheel motorcycle? There will be much less lean during turns compared to a motorcycle in normal driving/riding scenarios the way I look at it. With the stability provided by the wide front wheel spacing, the rear wheel will not have the lateral forces similar to a motorcycle.

      • Michael Klensch

        Member
        February 13, 2022 at 12:32 pm

        Certainly not as much lateral force as a motorcycle, but as pointed out above, considerable more lateral force, (just on that rear tire), than a 4-wheeled car. That’s why I’m thinking maybe flat profile car tires up front, and a motorcycle U-shaped profile type tire in the rear. A bit of a U-shaped profile, (not extreme), on that rear might help it perform and wear better.

    • kerbe2705

      Member
      February 13, 2022 at 7:52 pm

      The swing-arm suspension has been replaced with a multi-link system that is currently being tested in the first Beta. We believe that this redesign was as a result of the Roush consultancy and it’s already showing benefits in ride and control of the vehicle. Anti-sway and anti-roll control are now part of the re-engineered front suspention, as well.

  • George Hughes

    Member
    February 13, 2022 at 5:07 pm

    Paul:

    I’m with you on this. As Steve and Chris point out, the loading on the inside rear wheel in a FWD 4-wheeled vehicle often lifts off the ground in aggressive driving. That is because the load shifts almost totally to the outboard tires.

    Then the question becomes, what have you gained by not having that second tire, wheel, frame, brake, spring, shock, etc. to add their weight to that outboard tire in addition to ‘its share’ of the burden.

    That simply means the main difference between a 3-4 wheel vehicle’s rear wheel setup is that on a 4-wheeler, the rears are basically deform their sidewall in only one lateral direction as weight largely shifts from one wheel to the other depending on the direction of the turn. On the Aptera 3-wheeler, the rear tire just flexes in both lateral directions.

    I’m not sure of the size but in the case of anti-roll bars, size matters. Attached to the front suspension members and work to level the sway by working to divert weight to the inside tire. Three-wheeler’s are seriously confronted by the natural roll or twist the rear end because of the point of contact with the road is the center of vehicle.

    Like a car unlike a motorcycle, Aptera compresses to the outside front wheel in a turn. On a motorcycle, the rider rotates his weight to the inside to ‘counter’ to the natural rotation. This means the normally balanced vertical ride, the rider offsets himself 20-30-40 degrees from vertical to keep balance in a turn.

    I tend to think the automotive built-up sidewall counters that automotive tilt while a motorcycle tire design would work to ‘tip’ or increase the automotive lean in the corner. If the Aptera’s lean were transferred to a motorcycle, you’d be well into a flying tip-over.

    Presumably a stout anti-roll bar will minimize the any variance from 90-degree vertical of the rear wheel geometry but it won’t counter-tip the vehicle. Given the center of gravity in the Aptera is by definition forward of the centerline – the weight distribution is something like 70-30 front/rear – means that you could use automotive profile tires because it leans like a car leans – to the outside of the turn.

    That said, I’m not sure a different rear tire design would improve handling but I suppose some design might be more optimal than an auto tire design for the demands of the rear wheel. That this ‘winning design’ might even appear counter-intuitive is more than a mere possibility.

    Handling is certainly a serious consideration but remember this vehicle prioritizes efficiency as its first principle.

    If Aptera gets into serious tire testing, I’d like them to report their findings in regard low/lowest rolling resistance.

Viewing 1 - 7 of 7 replies

or to reply.

Original Post
0 of 0 posts June 2018
Now