Installed 37's on Gen3 35 Raptor - no issues.
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Speedo is all that is needed. I haven’t done it though. 37’s we’re put on at delivery may 22’
pnwobrigade
Full Access Member
Made the switch today from OEM Cast 35's to KMC Mesa Forged 17x8.5 +0 (23lbs) and OEM FP 37's. Suspension is stock 35 unmodified and no rubbing and fitment is spot on. Back is perfectly flush, front pokes maybe 1/2" which is slightly more than I'd like but manageable. Debating on 1.0" Front Stg.1 Eibach springs for extra clearance although I off-road it I likely wont ever get the tires off the ground. I have a dedicated UTV for those shenanigans.
Couple Notes:
OEM Cast 17's and 35's weighed ~94lbs on my scale.
KMC Forged Mesa and OEM FP 37's weighed 91lbs. I think BFG specs for their OEM 37's are off. KMC Mesa verified at 23lbs so these tires are closer to 67lbs not 63lbs. This also accounting for TPMS sensor and balancing weight (10-14oz).
Drivability is as expected thus far with the first 100 miles, I'll comment more once I have more miles on the setup. No major changes in ride, handling, or steering, if anything ride is slightly better in certain situations. However, low end acceleration and overall responsiveness of the transmission is definitely a notch lower. Clearly, the change in ratio is definitely noticeable so for the people that say "ah can't even tell" not sure I'd trust that. Stock 35 was noticeably snappier and accelerated faster, not a lot but clearly noticeable. I also used Forscan to update my speedometer/tire size to OEM 37PP and reset the PCM/TCU so all adaptations are where they should be. GPS verified to be within .1mph up to about 80mph so far. Overall, the slight decrease in acceleration/responsiveness is definitely worth the additional height and looks. 37's just "fit" better where the 35's just looked small on the vehicle, which is odd to say.
Couple Notes:
OEM Cast 17's and 35's weighed ~94lbs on my scale.
KMC Forged Mesa and OEM FP 37's weighed 91lbs. I think BFG specs for their OEM 37's are off. KMC Mesa verified at 23lbs so these tires are closer to 67lbs not 63lbs. This also accounting for TPMS sensor and balancing weight (10-14oz).
Drivability is as expected thus far with the first 100 miles, I'll comment more once I have more miles on the setup. No major changes in ride, handling, or steering, if anything ride is slightly better in certain situations. However, low end acceleration and overall responsiveness of the transmission is definitely a notch lower. Clearly, the change in ratio is definitely noticeable so for the people that say "ah can't even tell" not sure I'd trust that. Stock 35 was noticeably snappier and accelerated faster, not a lot but clearly noticeable. I also used Forscan to update my speedometer/tire size to OEM 37PP and reset the PCM/TCU so all adaptations are where they should be. GPS verified to be within .1mph up to about 80mph so far. Overall, the slight decrease in acceleration/responsiveness is definitely worth the additional height and looks. 37's just "fit" better where the 35's just looked small on the vehicle, which is odd to say.
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hyrepower
Full Access Member
I have the same wheels and tires on mine. I have the Eibach 1.0" springs as well and they ride much better than preload collars and a much better looking lift as it sits about 1/4"-1/2" lower in the front, providing a conservative "leveled" look.
Ill be selling my Live Valve struts and springs as I am putting on a set of Fox Race Series Coilovers next Friday. If anyone is interested, I dont have too much extra space in my garage so Ill be interested in selling them for a fair deal.
AustinRaptor512
Active Member
I just changed tire diameter via my Cobb Accessport. I also recommend @GooseTuned if you’re thinking about it!
Thanks man!!
WorldwideScales
Member
Because of you, I Just ordered the 2.25. I have 37 nitto trail graps in the garage waiting to be installed. ill hold off now until my 2.25 comes in!
If you plan on putting anything in the rear of the truck, I would do at least the 3/4 or 1” spacer. What I mean by anything is like a spare tire or even a loaded tool/cooler set up. You will see the rear springs settle and you will be very nose high.
FREEZE451
Active Member
I took some measurements of my fenders and their height so those wondering can know, or others can chime in.
- 2021, 35 package with 37x12.50x17 Ford Wheels.
- 36 PSI hot, just drove 20 miles
- Full tank of gas, less 10 miles (1 gallon)
- 1.5" RPG
Driver Front = 42 1/2"
Driver Rear 42 1/4"
Passenger Front 42 1/4"
Passenger Rear 41 3/4"
I'm taking out the RPG this week, so I'll get updated heights.
I tried to look as level as possible but even with that slight comparison I'd consider it "level" for my human margin of error.
Based on this thread I should be good with my 37s, so if I have rubbing I'll open that can of worms.
- 2021, 35 package with 37x12.50x17 Ford Wheels.
- 36 PSI hot, just drove 20 miles
- Full tank of gas, less 10 miles (1 gallon)
- 1.5" RPG
Driver Front = 42 1/2"
Driver Rear 42 1/4"
Passenger Front 42 1/4"
Passenger Rear 41 3/4"
I'm taking out the RPG this week, so I'll get updated heights.
I tried to look as level as possible but even with that slight comparison I'd consider it "level" for my human margin of error.
Based on this thread I should be good with my 37s, so if I have rubbing I'll open that can of worms.
pnwobrigade
Full Access Member
Thought I'd give a quick update on my thoughts having around 4k miles bone stock (35 Package) to now switching to a 37 setup pictured above last week. I recently did a 600 mile road trip and spent some time off-road in dried lake beds and FS Roads with around 12-16" of snow in places. I'll preface this by saying my experiences of this probably won't mirror the mass sentiment here. I spend a copious amount of time off-road and have raced anything with 2 or 4 wheels in that environment for many many years, needless to say I'm a picky SOB when it comes to change and vehicle dynamics.
First off, the general sentiment of adding 37's is no noticeable change I don't agree with. Is it a drastic change, not by any means. Is there definite drawbacks that can be noticed, absolutely 100% so don't trust the placebo effects from many of oh "it looks badass can't even tell". First off, the most apparent the MPG decrease is there for those that care. My anecdotal observation is I lost a solid 1.5mpg on average with a trip I frequently take which is inline with how Ford rates EPA of a 35 vs 37, so no surprise. The reason why though I feel is important. Adding 37's has a very noticeable impact on the final drive ratio and therefore really takes away the down low snappiness of the 10AT combined with 35's. It's now 200-300rpm lower in any given gear and almost always needs to be a gear lower than previous to have that same "take-off" and go. You start noticing things like turbo lag and torque converter slippage when it isn't locked in lower gears more than before. Once going at HWY speeds this is less noticeable however instead of 2,000k RPM at 70mph I'm now right at 1,700 RPM. So it will downshift to 8/9th more often all things being equal to stay in the correct TQ band. For reference, I also reset the PCM/TCU adaptations and reset my tire size per the Forscan instruction included on this forum. Oddly, I've also noticed much more clunking on downshifts from the 10AT after doing so but I don't believe this to be attributed to anything tire related...yet.
Although, my 37 wheel/tire combo is basically as light as you can buy currently I wouldn't say it rides better. OEM FP 37's although C rated have thicker sidewalls than the metric 315/70 (35") counterparts when I looked at both dismounted. I find under certain conditions 37's ride better but on broken or uneven pavement my 35's actually rode better and were less nervous traveling at FWY speeds of 70-80mph. The 37's I suppose from being skinnier actually tramline worse which is ironic given I thought they would less. Note: I run the same pressures for each at 38psi Cold. The biggest item to consider is off-road the 37's are less composed on moderately fast terrain. Think dry lake beds doing 40-60mph and hitting large dips at those speeds. The rebound dampening isn't quite there to support the larger tires overall. I would imagine this is where the 37pp is retuned to account for that. Changing to Sport or Baja mode helps this but doesn't fully mask it. Ultimately, any of the faster paced stuff 37's are a clear downgrade which again is to be realistically expected but was more than anticipated.
With that said, would I go back? I'm not 100% sure overall. Personally, I've never let looks generally dictate a modification given I "use" my vehicles for their intended purpose. However, I was woefully unimpressed with how pedestrian a stock 35 Raptor looks. To the point even with smaller tires my previous GMC AT4 almost had more presence. With the 37's the truck just looks right, fender proportions, how it sits, stance, etc. just fit the body lines of the truck perfectly. It has completely altered how I feel about the looks of the vehicle and I'm 100% pleased. From a performance perspective I'd being lying if it's not in the back of my head to go back to 35's though...
First off, the general sentiment of adding 37's is no noticeable change I don't agree with. Is it a drastic change, not by any means. Is there definite drawbacks that can be noticed, absolutely 100% so don't trust the placebo effects from many of oh "it looks badass can't even tell". First off, the most apparent the MPG decrease is there for those that care. My anecdotal observation is I lost a solid 1.5mpg on average with a trip I frequently take which is inline with how Ford rates EPA of a 35 vs 37, so no surprise. The reason why though I feel is important. Adding 37's has a very noticeable impact on the final drive ratio and therefore really takes away the down low snappiness of the 10AT combined with 35's. It's now 200-300rpm lower in any given gear and almost always needs to be a gear lower than previous to have that same "take-off" and go. You start noticing things like turbo lag and torque converter slippage when it isn't locked in lower gears more than before. Once going at HWY speeds this is less noticeable however instead of 2,000k RPM at 70mph I'm now right at 1,700 RPM. So it will downshift to 8/9th more often all things being equal to stay in the correct TQ band. For reference, I also reset the PCM/TCU adaptations and reset my tire size per the Forscan instruction included on this forum. Oddly, I've also noticed much more clunking on downshifts from the 10AT after doing so but I don't believe this to be attributed to anything tire related...yet.
Although, my 37 wheel/tire combo is basically as light as you can buy currently I wouldn't say it rides better. OEM FP 37's although C rated have thicker sidewalls than the metric 315/70 (35") counterparts when I looked at both dismounted. I find under certain conditions 37's ride better but on broken or uneven pavement my 35's actually rode better and were less nervous traveling at FWY speeds of 70-80mph. The 37's I suppose from being skinnier actually tramline worse which is ironic given I thought they would less. Note: I run the same pressures for each at 38psi Cold. The biggest item to consider is off-road the 37's are less composed on moderately fast terrain. Think dry lake beds doing 40-60mph and hitting large dips at those speeds. The rebound dampening isn't quite there to support the larger tires overall. I would imagine this is where the 37pp is retuned to account for that. Changing to Sport or Baja mode helps this but doesn't fully mask it. Ultimately, any of the faster paced stuff 37's are a clear downgrade which again is to be realistically expected but was more than anticipated.
With that said, would I go back? I'm not 100% sure overall. Personally, I've never let looks generally dictate a modification given I "use" my vehicles for their intended purpose. However, I was woefully unimpressed with how pedestrian a stock 35 Raptor looks. To the point even with smaller tires my previous GMC AT4 almost had more presence. With the 37's the truck just looks right, fender proportions, how it sits, stance, etc. just fit the body lines of the truck perfectly. It has completely altered how I feel about the looks of the vehicle and I'm 100% pleased. From a performance perspective I'd being lying if it's not in the back of my head to go back to 35's though...
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