Are 36 STU Paddles to big for S4/5?

Reece Pettersen

Reece Pettersen

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Title really says it all. We have two cars looking to go from 33s to 36s next season. I would like to get opinions here and maybe @Sean@Weddle can chime in. 

The first car is an alumicraft pre-runner with a danzio 418ci and S5 with some of the newer shift upgrades. I was thinking to run a 36-17 no. 2 on this car. 

The second is an alumicraft sand car with a stock ls6 and a S4. I was thinking to run a 36-17 no. 1 on this car.

I was always told to stick with the 33s with this gearbox, but see so many people making the jump. Both cars are stout enough to handle the bigger tire, just worried about wear and tear on the trans. 

 
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A car in our group wore out a brand new ring and pinion in four trips, but it also has a twin turbo 416 redline motor making 700-750 to the wheels so I’m sure that played a large part. 
 

im scared to go to 36’s at that same power level on my car but im sure Sean would say not to even run that much power on an s4/5 🤣

 
I’m by no means an expert or even qualified to comment but that hasn’t stopped me before, obviously the Trans / CVS are the weak links in a drive train. I’d think time in the dunes between trans servicing / repair would be shorter with the bigger donuts. The gearing should be slightly taller as well. Seems like wear could be mitigated a bit by eliminating hauling azz from a dead stop and going with a little more air pressure.

You definitely have the cool factor with the 36s though…

 
The S4/5 uses a 10” ring gear just like a 2d. I ran STU 35.5s with a #2 cut on my mid engine SU and it was always the R&P that would go bad. In theory there is less stress on the R&P with a mid engine car because it doesn’t squat as much as a rear engine car but it’s still the weak link. 
I think my last R&P had about 4 seasons on it. That would include a couple of EPOs and several trips to the sand drags plus lots of dunning. 

 
@Reece Pettersen thanks for including trans and motor, but do you know what HP these are putting down to the ground? The 36-17 is a monster of a tire compared to the 33. Not only is it taller but its way heavier due to the construction of the tire stepping up to a 6 ply compared to the 33 being a 4 ply. We (STU) give recommendation's based off WHP numbers and trans set up Primarily. With that said, unless someone is making north of 650 hp, I dont usually recommend that big of tire...  

 
HP.Habits said:
@Reece Pettersen thanks for including trans and motor, but do you know what HP these are putting down to the ground? The 36-17 is a monster of a tire compared to the 33. Not only is it taller but its way heavier due to the construction of the tire stepping up to a 6 ply compared to the 33 being a 4 ply. We (STU) give recommendation's based off WHP numbers and trans set up Primarily. With that said, unless someone is making north of 650 hp, I dont usually recommend that big of tire...  
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I was not too concerned with HP. My car is making 350 wheel horsepower and is amazing with the 36 no. 2. Turns them just fine for a 3,200lb car with a convertor. 

The Danzio car is ~500 to the tire. I assume the ls6 is ~300-330. 

 
I never broke the S4 in my SCU with a 600HP blower motor and 36’s. I broke my S4 every trip in my racer with a 632 big block and 36’s. I think that Danzio motor is perfect for S4 and 36’s. I think a LS6 is going to struggle to turn 36’s. 

 
I am a proponent of running the biggest effin tire possible. The more of you that do, the better schooling my daughters will get. Thanks.

Joking aside,

There are many factors that dictate wear and tear on any trans. Engine power/torque, tire size, how hard/fast it is driven, and how rough the terrain is are the 4 major factors (not in that particular order). The gear ratio can be factored into that equation as well, a lower ratio gear (5.14) is weaker compared to a taller ratio gear (4.63), but there inlays the conundrum of requiring a lower gear ratio to turn over a larger diameter tire at the expense of having the weaker gear. 

The larger the tire, the more stress will be put on the trans, that is a fact. But is it enough to dictate whether it will break the trans? The other 3 factors have to be considered in that equation, but it certainly raises the risk factor. 

I would not say that the 36 tires would kill a R&P in those particular cars if driven with moderate fervor. It would almost certainly accelerate the wear on the gears due to the increased torque load to get them to turn over. Your trans builder will probably see more surface tears and pitting in the gear teeth, possibly some cracking if you are running the cars hard over the whoops. 

Bottom line is be prepared to replace R&Ps more frequently than you would have with the smaller tires. 

 
Totally anecdotal, but when I went to 36"s on my Potter I started killing R&Ps.  I only had ~1.5 seasons on it before I went to the 36"s, but those were solid 90+ day seasons in G (take me back to that life, please).  That was a ~2600lbs ( @L.R.S. weighed it at some point and might still have the slip) car with a big-cube, NA LS that did mid-500s to the tire.  I had an Extreme DTD with a mild twin turbo LS1 (prob made about the same HP as my big cube NA motor in the Potter, but I assume more torque) that was on the Extreme 35"s that also killed a R&P but that was after a ton of seasons (mostly before I got it), so again nothing scientific here.  

-TJ

 
Markcsand said:
I thought the redesigned r&p was stronger?
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I am assuming you are referring to our new "finish ground" R&P sets? 

We don't sell them as being any stronger than the Klinglenberg Palloid design that we have had for years, it's simply another offering as the Klinglenberg tooling is getting scarce, and we needed to find an alternative that could hold up as best as possible to this type of use. 

We are happy with the wear life and strength of the new Finish Ground R&P sets. 

 
Reece Pettersen said:
I was not too concerned with HP. My car is making 350 wheel horsepower and is amazing with the 36 no. 2. Turns them just fine for a 3,200lb car with a convertor. 

The Danzio car is ~500 to the tire. I assume the ls6 is ~300-330. 
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If your not concerned with the HP, then sure, it will turn it and get through the dunes. As for the Trans, I know many S4/S5 cars with those tires. @Sean@Weddle's word is law on trans info. As for tire, The main reason I dont recommend that tire is due to how much driver performance is being left on the table. I would try a 14.50-17 dune sport before a 36-17, even though their the same weight, the Dunesport is designed for more tire spin and sliding. While it will still cause more stress on the trans, it will be a little more forgiving (and should be more fun through the dunes). The Dune Sport 14.50-17 measures out to 35" tall, and thats excluding paddles. Not sure if thats something you have considered before. Just a thought..

 
tjZ06 said:
Totally anecdotal, but when I went to 36"s on my Potter I started killing R&Ps.  I only had ~1.5 seasons on it before I went to the 36"s, but those were solid 90+ day seasons in G (take me back to that life, please).  That was a ~2600lbs ( @L.R.S. weighed it at some point and might still have the slip) car with a big-cube, NA LS that did mid-500s to the tire.  I had an Extreme DTD with a mild twin turbo LS1 (prob made about the same HP as my big cube NA motor in the Potter, but I assume more torque) that was on the Extreme 35"s that also killed a R&P but that was after a ton of seasons (mostly before I got it), so again nothing scientific here.  

-TJ
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FWIW McDowell in Santee - advice to me was no bigger than a 33 for the S4/5 - anything bigger he recommended the S4D / S5D

 
wesinls said:
FWIW McDowell in Santee - advice to me was no bigger than a 33 for the S4/5 - anything bigger he recommended the S4D / S5D
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Yes McDowell preaches that, he is a firm believer that bigger tires kill trans.

With that said, I ran a blown 416 stroker with an S5 and 36s and never had an issue with it. I think a lot of it has to do with driving style, I see a lot of guys out in the dunes that I wonder how their trans even makes it through a weekend and others that are easy and have some regard for parts so i think a good part of it comes down to that

 
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