Speed limiter delete

[swathdiver]

On 5/10/2025 at 3:32 PM, GETGONE said:

 

I've run mine to 112 countless times with zero issues. 31K miles and still going strong. Took it to a test and tune and ran about a dozen passes trying various launches, no issues. Best of 14.2 in the 1/4.

 

Nice time!  If memory serves, that 112 mph problem applied to K2 1500s.  I recently learned that my kids have been exceeding 112 with their GMT900s with 6.2s too!  

[redwngr]

Driveshaft seems to get a lot of the press, but tire speed rating should be looked at too. 

(yes, I realize that exceeding speed rating isn't likely to cause immediate failure...)

 

Do they know about tire speed ratings? 

 

Speed (and load) rating will also be on the tire.

Factory tires on my '21 were speed rating S.

 

 

 

 

S

An S speed rating indicates the tire has been approved for speeds up to 112 mph (180 km/h) under optimal conditions. Everyday passenger vehicle tires can be S speed rated, but S tires often prioritize specific performance or function. Many all-terrain LT tires are becoming available in an S rating as that’s the OE spec for many of these vehicles like the Ford Raptor. 

 

 

This is was on a set of Duratracs I used to have.

Load load rating 109, speed rating S

 

 

Current '23 has  275/60R20 115S 

So again, speed rating S 

 

My current winter tires are speed rating R.

 

Speed rating R allows for speeds up to 106 mph (170 km/h) under optimal conditions. Like Q, R tires generally prioritize a particular function or unique performance over maximum speed capability. R speed tires are rare but can be found on some heavy-duty light truck (LT) tires, as well as studdable and studless winter tires.

 

Edited June 4, 2025 by redwngr

[redwngr]

 

Speed Rating	Miles/Hour	KM/Hour	Typical Application(s)
L	75	120	Trailer tires
M	81	130	Spare tires
N	87	140	Spare tires
P	93	150
Q	99	160	Select winter tires
R	106	170	Passenger and light truck tires
S	112	180	Passenger and light truck tires
T	118	190	Passenger and light truck tires
U	124	200
H	130	210	Passenger sedans, coupes, SUV and CUV’s tires
V	149	240	Performance sedans, coupes, and sports cars tires
W	168	270	Performance sedans, coupes, SUV and CUV’s tires
Y	186	300	Exotic sports cars tires
Z	149+	240+	High-Performance vehicle tires

[GETGONE]

Trail Bosses with the 18" tires are electronically limited to 98mph due to tire rating. The 20" wheel option bumps the limiter up to 112mph because of the S speed rated tires.

[PunchT37]

3 hours ago, swathdiver said:

 

Nice time!  If memory serves, that 112 mph problem applied to K2 1500s.  I recently learned that my kids have been exceeding 112 with their GMT900s with 6.2s too!  

LOL. Busted.

 

My 2000, GMT800, that I still have, has a 128 limit. I have seen 4000 rpm`s in overdrive with 16 inch wheels and 3.73 gears. Poor 100 mph speedo.

[redwngr]

16 hours ago, PunchT37 said:

LOL. Busted.

 

My 2000, GMT800, that I still have, has a 128 limit. I have seen 4000 rpm`s in overdrive with 16 inch wheels and 3.73 gears. Poor 100 mph speedo.

I'm curious what the tire loading label on the doorpost lists as the speed rating?

Edited June 5, 2025 by redwngr

[PunchT37]

1 hour ago, redwngr said:

I'm curious what the tire loading label on the doorpost lists as the speed rating?

S. But, this truck has a whole new computer.

[redwngr]

4 hours ago, PunchT37 said:

S. But, this truck has a whole new computer.

 

Thanks.

 

So if they were installing S rated tires on (at least some) 2020's the original limiter was likely lower/

 

 

 

 

[PunchT37]

4 hours ago, redwngr said:

 

Thanks.

 

So if they were installing S rated tires on (at least some) 2020's the original limiter was likely lower/

 

 

 

 

 

4 hours ago, redwngr said:

 

Thanks.

 

So if they were installing S rated tires on (at least some) 2020's the original limiter was likely lower/

 

 

 

 

Factory limiter on that 2000 truck was 96 mph.

[Silveradgo]

I have yet to top mine out since I had it unlocked and then tuned it (High Country 6.2 10 spd), but my tires will limit me as I have a brain. But damn the ecm and tcm tune feels great. If anybody is on the fence, just do it. I'm still tweaking some of the shift times to get rid of the sluggish shifts on lower power shifts. mid power shifts are .200 seconds and full power are .100 seconds, tires chirp with only a small boost in pressure and reducing shift times.

Edited November 24, 2025 by Silveradgo

[johnnyquick]

10 hours ago, Silveradgo said:

I have yet to top mine out since I had it unlocked and then tuned it (High Country 6.2 10 spd), but my tires will limit me as I have a brain. But damn the ecm and tcm tune feels great. If anybody is on the fence, just do it. I'm still tweaking some of the shift times to get rid of the sluggish shifts on lower power shifts. mid power shifts are .200 seconds and full power are .100 seconds, tires chirp with only a small boost in pressure and reducing shift times.

Who tuned it and how much did it cost you?

Any mods beside the tune?

[Silveradgo]

I tuned it. Only have a K&N Blackhawk intake on it for the sound. Longtubes will be the next go-fast mod.

 

Edit: I'll have to get a video of the induction noise during the 1-2 shift at like 4.5k 

Edited November 24, 2025 by Silveradgo

[GETGONE]

How did you tune it since you have to send in the ECM last I knew to get it unlocked to be able to tune it.

[Silveradgo]

8 hours ago, GETGONE said:

How did you tune it since you have to send in the ECM last I knew to get it unlocked to be able to tune it.

See my earlier post

[GETGONE]

4 hours ago, Silveradgo said:

See my earlier post

You have 3 posts. You just said you had it unlocked and you tuned it. That tells me NOTHING. WHO unlocked it? WHAT are you using to tune it? New member sounds like a troll.