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Old 06-12-2013, 07:58 AM   #1
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Default Inboard rear suspension on a TC?

Why is this design so unpopular?

(I appreciate that this question has probably been answered before somewhere) but I remember owning one of the few chassis when it came out that had this feature, the tenth technology streetwise

http://www.tamiyaclub.com/getuserima...3725_2_350.jpg

I quite liked this car in its day, but never seen such a design recently....
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Old 06-12-2013, 08:22 AM   #2
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Originally Posted by tc3team View Post
Why is this design so unpopular?

(I appreciate that this question has probably been answered before somewhere) but I remember owning one of the few chassis when it came out that had this feature, the tenth technology streetwise

http://www.tamiyaclub.com/getuserima...3725_2_350.jpg

I quite liked this car in its day, but never seen such a design recently....
It creates more problems than it solves. It's more complicated, adds friction and slop, takes up space better used for other components, etc...
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Old 06-12-2013, 08:24 AM   #3
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Inboard suspensions are usually used to improve aerodynamics or lower the Center of Gravity (CG). Our cars don't use underbody aero tunnels, and the example you show doesn't look like it would lower the CG.

Many people also have the mistaken belief that inboard suspensions eliminate the shock parts and spring from the unsprung weight. That isn't true; if it moves when the wheel moves up and down, it's part of the unsprung weight. There can be some improvement in the unsprung weight if the inboard suspension causes less movement of the shock/spring than it would have otherwise. But then the weight of the pushrods, bellcranks, or other associated mechanisms must be added back in again.
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Old 06-12-2013, 08:51 AM   #4
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Interesting info, thanks guys

The streetwise was shaft driven too, a rare sight for todays TC, and hence why the suspension was high up.

I know a car has to be manufactured ideally to accomodate all grip levels for r/c, but I wonder if a rear inboard setup may work better in very high grip conditions, or simply offers no benefit and can only hinder laptimes for any type of rc racing.

The Tenth technology predator off road cars use fully inboard suspension and performed well in the UK.

But, I guess different environments suit different suspension layouts, or the guy wheeling the car can over compensate their ability to get performance from a "bad design" of chassis?
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Old 06-12-2013, 09:06 AM   #5
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The only sedan I can recall that ever used inboard rear suspension was one out of the UK. I don't believe it's still made, but they do have their 4wd offroad buggy the X11 predator.
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Old 06-12-2013, 09:26 AM   #6
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I agree with the other guys. No real point unless their is a body that needs it like the F1 car tamiya put out a few years ago. Neat idea but the car was a bit over engineered and Formula 1 isnt 4wd lol
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Old 06-12-2013, 09:44 AM   #7
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The only sedan I can recall that ever used inboard rear suspension was one out of the UK. I don't believe it's still made, but they do have their 4wd offroad buggy the X11 predator.
Yes, the streetwise was that car. Although there was a better version of it, but dont remember its name.

I havn't raced off road for ages now, but the X11 has been a reasonably popular off road car from what I have heard but is overshadowed more by other brands.
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Old 06-12-2013, 09:59 AM   #8
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Basically, the problems that inboard suspension solves are not problems for us. We use full fender bodies so the shocks are out of the airstream and we do not have ground effects and huge downforce levels. So why add tons of complexity to solve problems that are not problems?

That being said, there are inboard configurations that allow you to do some different things. Most F1 designs now have bounce and roll completely separated, both springing and damping. I would love to try something like a Reynard style monoshock front suspension with a F1 style floating, linked torsion bars or third spring rear set-up. But if you think a regular pushrod suspension is complex, that takes it to a whole new level
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Old 06-12-2013, 10:02 AM   #9
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If my memory serves me correctly , PTI had a prototype car which didn't come to fruition - it looked cool . They're no longer in business. Anyone else recall this or similar suspension set-ups...?
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Old 06-12-2013, 02:40 PM   #10
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The inboard shocks were inboard on the Predator buggies for better aerodynamics, everything tucked inside the streamlined body instead of two vertical shock mounts and shocks sticking up. The layout was transferred to the FTD wide tourer as it was the buggy converted to on road. The narrow DTM and Streetwise used inboard shocks as again they just kept the chassis and suspension layout from the buggy.
When Tenth technology developed the tourer into the T1 they went to standard vertical shocks as there is no need to keep them out of the airflow to the rear wing that the buggy used. It lowered the centre of gravity and made the rear more stable, so even TTech saw going outboard as an improvement in handling. The buggies have kept inboard because the airflow over the chassis is much more important than the trade off in the raised centre of gravity.
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Old 06-13-2013, 01:48 AM   #11
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The inboard shocks were inboard on the Predator buggies for better aerodynamics, everything tucked inside the streamlined body instead of two vertical shock mounts and shocks sticking up. The layout was transferred to the FTD wide tourer as it was the buggy converted to on road. The narrow DTM and Streetwise used inboard shocks as again they just kept the chassis and suspension layout from the buggy.
When Tenth technology developed the tourer into the T1 they went to standard vertical shocks as there is no need to keep them out of the airflow to the rear wing that the buggy used. It lowered the centre of gravity and made the rear more stable, so even TTech saw going outboard as an improvement in handling. The buggies have kept inboard because the airflow over the chassis is much more important than the trade off in the raised centre of gravity.
That answers everything for me, many thanks!
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Old 06-13-2013, 06:36 AM   #12
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Check out the new Awesomatrix car, not a pushrod suspension but a setup much different than anyone else right now.
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Old 06-14-2013, 04:28 AM   #13
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Check out the new Awesomatrix car, not a pushrod suspension but a setup much different than anyone else right now.
Hi, yes I did follow the build and what the developer said/did when the car was in its design and testing phase.

I think Ivan Laptov was/still is racing this car and IMO, it's a very nice car. Very well designed. Some would say overdesigned, but definately in a good way!

Unfortunately though, although I am sure for what the car "is" it is a good price, but was out of my budget.

I settled for an XRay T4.

Although its suspension is traditional in layout, it does use shorter shocks etc and I am looking forward to seeing how well it handles - and how well setup changes affect its drivability
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