20 Silverado Higher speed requirements

wslr85 · January 1, 2023

Hi truckers

I have 2020 Silverado TB and raised the limiter to 200kmh, I have done 200 just for seconds and can go more but the issue is I heard many talks about the shaft or diffs couldn’t handle higher speeds!! Thats make me worry, Does anybody knows for sure?? And what parts other than the tires must be changed to be safe for higher speeds??

thanks guys…

fatwhiteboy · January 1, 2023

From what I have been told by the GM engineers, the speed limiter is restricted to tire speed ratings. Mine was set a 113MPH. There are many tools to raise it or turn it off. I am not advising it but the 6.2L will do over 140MPH "allegedly". Mine has a few suspension mods and is very stable at higher speeds. You will hear many stories of a friend's uncle's cousins' sister's boy friend had a drive shaft fly off. My stock drive shaft is still under the truck as it came from the factory. These aluminum shafts are very strong.

seamus2154 · January 2, 2023

The two main issues are the driveshaft and the tires. I have seen more than one aluminum driveshaft fall apart on the dyno and drag strip. Do I think it will fail from just speed like 140??? Probably not, but I would have a steel driveshaft and speed rated tires. Aluminum is just not as strong as steel in this application. There are really strong custom aluminum driveshafts that are much thicker gauge aluminum and arent ballooned and thin like the stock one is. That is a nice expensive option. The stock is very thin, and ballooned, good for stock use.

Edited January 2, 2023 by seamus2154

swathdiver · January 2, 2023

K2s with the single aluminum driveshaft have a sweet spot for twisting their tubes apart, 112 mph.

You could do the forum a service and find out what the limit is for your configuration and share with us the pictures of the aftermath.

Denali_1500 · January 2, 2023

My 2020 Chev High Country would only do 99MPH

My 2022 GMC SLT would do 112MPH

My 2023 GMC Denali will only do 106MPH

CamGTP · January 3, 2023

Are the factory driveshafts strong? Yes, but being strong doesn't mean it can handle the torture it will take past it's critical speed. They use a very thin aluminum that can't handle super high speeds, they will handle the maximum speed allowed by the tires and going past that is not advised. Also if the truck is lowered, lifted or anything of the sorts could change the speed at which things happens. Different driveshaft angles and u-joint angles could make the driveshaft vibrate differently at higher speed.

Edited January 3, 2023 by CamGTP

seamus2154 · January 3, 2023

They are great in stock form for stock use. Lightweight and strong enough. They dont fail under stock use. They are a weak point after that. Which means dangerous at high speed unless you want to put in a driveshaft loop and find the failure point. Because there will be a failure. Go under your truck and tap the side of the drive shaft.........then tell me how strong you think it is.

newdude · January 3, 2023

Limiter is there for a reason. 124mph is asking for trouble.

wslr85 · January 3, 2023

Thanks all for your replies & info🫶, thats why I posted this topic, I’ve heard & seen many videos of it failing specially on dyno and also many videos of it going fast with stock shaft, my self had 2011 Z71 and reached +137mph many times before knowing its unsafe, now on the new 2020 I reached 125mph and can go more but thats what I set the Pulsar LT to, and the stability was great, as I said I only do it on open highway far from other traffic, it’s a truck for sure it wont be safe to maneuver between cars or lanes at high speeds, are all truck trims have the same shaft?? Denali, TB, LTZ, …?? All years model same shafts 2008-2020??

I think the issue on the truck in youtube video is trying to do burnouts applying too much brake, the photo I sent is truck with some mods, exhaust, intake, stock shaft

Edited January 3, 2023 by wslr85

calgator73 · January 3, 2023

1 hour ago, wslr85 said:

Thanks all for your replies & info🫶, thats why I posted this topic, I’ve heard & seen many videos of it failing specially on dyno and also many videos of it going fast with stock shaft, my self had 2011 Z71 and reached +137mph many times before knowing its unsafe, now on the new 2020 I reached 125mph and can go more but thats what I set the Pulsar LT to, and the stability was great, as I said I only do it on open highway far from other traffic, it’s a truck for sure it wont be safe to maneuver between cars or lanes at high speeds, are all truck trims have the same shaft?? Denali, TB, LTZ, …?? All years model same shafts 2008-2020??

I think the issue on the truck in youtube video is trying to do burnouts applying too much brake, the photo I sent is truck with some mods, exhaust, intake, stock shaft

If you know the max speed of the shaft you can use this formula I found on another site:

MPH = (Driveshaft rpm * tire diameter in Inches ) / ( Gear Ratio * 336)

Using the gm accessory steel shaft as an example on my truck:

(4391*33.2)/(3.23*336)=134.32mph

usmcfiredog · January 4, 2023

On 1/1/2023 at 4:54 PM, wslr85 said:

Hi truckers

I have 2020 Silverado TB and raised the limiter to 200kmh, I have done 200 just for seconds and can go more but the issue is I heard many talks about the shaft or diffs couldn’t handle higher speeds!! Thats make me worry, Does anybody knows for sure?? And what parts other than the tires must be changed to be safe for higher speeds??

thanks guys…

How did you raise the speed limiter?

My 2021 Silverado LTZ Z71 was set to 112 or so, but my new 23 Sierra AT4X is set to 98 and would love to bump it up some. Not looking to break the bank to do it.

2016 Sierra Owner · January 4, 2023

3 hours ago, usmcfiredog said:

How did you raise the speed limiter?

My 2021 Silverado LTZ Z71 was set to 112 or so, but my new 23 Sierra AT4X is set to 98 and would love to bump it up some. Not looking to break the bank to do it.

According to his post above he's using the Pulsar LT to raise the limiter.

wslr85 · January 4, 2023

22 hours ago, usmcfiredog said:

How did you raise the speed limiter?

My 2021 Silverado LTZ Z71 was set to 112 or so, but my new 23 Sierra AT4X is set to 98 and would love to bump it up some. Not looking to break the bank to do it.

As the Sierra owner said by pulsar LT