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Pan car front kingpin shims tuning

Pan car front kingpin shims tuning

Old 04-07-2021, 02:01 PM
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Default Pan car front kingpin shims tuning

Hello. I have a Roche P10 WGTR with a typical front suspension as in it has upper control arms and dynamic caster. The manual doesn't say how to move around the shims on the front kingpins to tune the front suspension. I'm unable to find any information on this anywhere. All RC suspension tuning books and manuals I've read don't say how to work with this suspension. They only say what droop/caster/etc does.

My goal is to reduce droop by one shim, increase ride height by one shim and not add any preload to the springs while doing this.

I have added a shim under the steering block to reduce droop, but it preloads the spring at full suspension expansion. I've added a shim above the steering block and reduced droop and increased ride height, but again it preloads the spring. Is there another way? Does preloading the spring at full suspension expansion matter?

I already removed all the spacers under the front suspension plate to gain as much ride height as I can. This got me to the minimum allowed 5mm ride height only with new tires. Now that the tires are used a little, I'm under 5mm again.

I would post a picture of the front suspension, but this forum will not allow me to yet. Thank you for any info.
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Old 04-07-2021, 02:21 PM
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Preload matters, but not enough to care in this case. You're springs will just be a hair stiffer now. No big deal. Drop to a softer spring if you'd like. Of course, that might be preloaded even more for the same result.

What's worse is if the spring is too short, and doesn't extend all the way down for droop. Like using a short xray spring on a crc wgtr.

Basically, you can do whatever you want. Try everything, even stuff that makes no sense.
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Old 04-07-2021, 05:41 PM
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Maybe we can have a mod move this to the Pan Car thread.

Pro 10: 235mm Le Mans Prototype Pan Car Discussion
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Old 04-08-2021, 05:48 AM
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Shimming a pan car front end doesn't have a lot of "rules", you pretty much do whatever you need to do to get where you want.

Add or remove the total number of shims, put them wherever you want to get your droop, ride height and upper arm angle.

If it's an option, on 1/10 pan cars, a longer kingpin is sometimes needed to get where you want to be. But, if you can't get where you want with what you have and others are getting the car to work with the same parts, sometimes it's worth trying what you can get first, then worry about getting where you want to be after testing.
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Old 04-08-2021, 06:15 AM
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I have the Roche P10 Evo, not the WGTR, but have added the front graphite lower arms from a P12, like your WGTR has. You can get the car much, much higher. I recommend removing the four red standoffs and replacing them with either shorter standoffs or a stack of washers. Roche makes a nice set of wide Aluminum Height Adjust Spacers (parts# 310031, 310032, etc.) in different heights. For reference, I have a stack of about 8mm to 8.5mm of these washers under the graphite lower arm. I think the red standoffs are 12mm or 12.5mm+ so you can definitely get the car to higher ride heights.

Are you running on black carpet, grey carpet or asphalt? I run on black carpet. I would recommend that you test droop levels and ride heights. They seem to have a large effect on balancing turn in without traction rolling. I go between 5.2 to 5.6mm front height and have tested between zero droop and 2mm of droop. 2mm of droop seems outrageous, but it does have an affect on traction rolling. If you are on one of those other surfaces, I really don't have any experience with these cars on those.
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Old 04-08-2021, 06:25 AM
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The Aluminum Rear Wing Post from the Roche F1 might be short enough standoffs (#210054). On my Roche F1 Evo, they measure 6.75mm. I think a stack of wide washers works just as well, but if you wanted a more solid piece, a shorter standoff would work. The Associated F1 front end stand offs are shorter too; 10.75mm so maybe a bit too tall - and a bit too blue.
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Old 04-08-2021, 09:14 AM
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Thanks for the recommendations. The front standoffs are 10.8mm in height. They are too long for GT-R tires. XRay makes some that are 10.5mm (373075). That should do it. I also found some generic standoffs on eBay that are 10mm. I'm concerned about the quality.
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