Who’s running 315 with 5.29 gears (1 Viewer)

[mjeckell]

I would like some input and reviews with this combination. Happy? Regretting decision and should have went 4.88. 37” may be my future. Not sure though. I don’t speed around town. I drive 65 on highway but not for long distance unless I’m heading to the Sierras. Let’s hear your thoughts. Also let’s discuss mileage. I have heard difference of opinions regarding gearing. Some say improved mileage and some say not due to higher RPMS.

 

[coax]

I have one step down on both tires and gears so similar overall gearing (4.88's w/ 285's)....same as you don't do much highway driving too often and usually keep speed down at 65. Wouldn't go back to stock, and I love the gearing. Gets up and goes quicker, better at high elevation, gas mileage stays around 15 even when loaded up. More control on the trail, especially when weighed down with gear. Don't need to use low range as much for easy dirt roads where it bogged down with stock gears before. Better for more stop and go as well I feel because of the lower first gear requires less gas to get up and moving. Almost like I'm driving a 5spd tranny but without being able to use the highest gear I'd say go for it.

 

[Bludozer]

If your rig is a DD, I can't imagine this being a good idea honestly. If you are positive you are going to go to 37's some point soon, I definitely see the justification of putting up with it for a while, but since that is a "maybe", figure out what tires you are going to be running for sure and then regear at that point.

I am currently running 35's and 4.88's and while I love the feeling of being slightly over-geared, I cant imagine being that overgeared. Even at 65mph you are going to be spinning some pretty high rpm's.

 

[baldilocks]

So, you currently have 5.29’s with 35’s? That’s about 14% over geared. Firstly, your odometer will be accumulating many miles that you never actually drove. Secondly, the rpm gain won’t be enough to keep you from needing to down shift on tough mountain passs at higher elevations, especially when loaded or towing. When you are forced to downshift to maintain a decent speed your RPM’s will be higher than necessary and speed slower than if you simply ran the gear ratio that kept the tach and speedo as close to stock as possible.

I run 37’s with 4.88’s. I leave the ECT button selected “on” at all times which helps hold the shifts out for better acceleration. Once rolling, I can dip down into second gear and still maintain 45-50mph and never spin above 4000rpm. In third gear at 65-70 and 3200-3400rpm she can pull some good sized hills in the mountains on the interstate.

I just finished a 4000 mile road trip through CA, NV, ID,WY, UT, and AZ. Many miles we covered at elevations well above 5000ft. The 1fz makes decent power beginning in the low 3000rpm range and we don’t need to be afraid of running it at 4000rpm as many miles as necessary. It was built to rev smoothly, not to be driven like American big block V8.

If there is anything at all to be gained by running 5.29’s with 37’s, it’s probably negligible and certainly offset by the fact that your speedo is now about 8% off. If you really need to get there fast, you need more horse power which usually means an engine swap.

I would suggest a real time water temp gauge install if you plan to run the 1fz hard.

 

[-Spike-]

In my opinion, if you plan on 37's, 5.29's is one of the best mods to do. As far as climbing hills, I drop into third while my stock-geared friends on 37's are in second and screaming (RPM's and obscenities). However, my truck spends an inordinate amount of time off-road, so the gearing is more important to me. I can still do 90, and cruising at 75 the engine is at 3200rpm or so. My speedo is 10% off, which is easy to take into account, but I often run a GPS app on my phone or tablet as well, mostly because I'm a nerd that way. The off-road benefits cannot be overstated. The cost is high, so figure out what you want to do with your truck before you start spending. I would guess 5.29's would be a bit on the high side with 35's, but certainly doable, and again that will depend on your planned usage. If you haven't bought the tires yet, 37's fit pretty much anywhere 35's fit- other than cost I can't see a benefit to 35's if you are regearing the truck anyway.

 

[Broski]

5.29s and true 37's and I love it. For serious off road rock crawling you need all the gearing you can get including low range gears for the transfer case.

 

[Mandrake]

A friend has 5.29s and 315'315's and his only complaint is exhaust drone on the highway, buy attributes that to the Cherry Bomb he put in place of the oem muffler. I've driven it around town a few times and it seems a LOT more lively than mine with stock gears and 285's. There's a steep road we both drive up to get to a ski resort... I'm dropping down to 1st gear and about 20 mph in a few places where he stays in 2nd and keeps on trucking at around 35 mph.

 

[mjeckell]

Thanks for all the replies. This is exactly what I’m looking for. Anyone on the central coast and their experience on Cuesta grade or grapevine

 

[DavidinAZ]

5.29s and 35s here. Living at 5kft and with the pathetic power output of the ol 1fzfe it's needed. I don't find the rpm excessive the rare times this pig winds up to 75 on the highway.

 

[Qball]

5.29s and 35s here. Living at 5kft and with the pathetic power output of the ol 1fzfe it's needed. I don't find the rpm excessive the rare times this pig winds up to 75 on the highway.

What's your rpm at 70? I'm deciding between 529 and 488, still and probably will stay at 35

 

[Nay]

So, you currently have 5.29’s with 35’s? That’s about 14% over geared. Firstly, your odometer will be accumulating many miles that you never actually drove. Secondly, the rpm gain won’t be enough to keep you from needing to down shift on tough mountain passs at higher elevations, especially when loaded or towing. When you are forced to downshift to maintain a decent speed your RPM’s will be higher than necessary and speed slower than if you simply ran the gear ratio that kept the tach and speedo as close to stock as possible.

I run 37’s with 4.88’s. I leave the ECT button selected “on” at all times which helps hold the shifts out for better acceleration. Once rolling, I can dip down into second gear and still maintain 45-50mph and never spin above 4000rpm. In third gear at 65-70 and 3200-3400rpm she can pull some good sized hills in the mountains on the interstate.

I just finished a 4000 mile road trip through CA, NV, ID,WY, UT, and AZ. Many miles we covered at elevations well above 5000ft. The 1fz makes decent power beginning in the low 3000rpm range and we don’t need to be afraid of running it at 4000rpm as many miles as necessary. It was built to rev smoothly, not to be driven like American big block V8.

If there is anything at all to be gained by running 5.29’s with 37’s, it’s probably negligible and certainly offset by the fact that your speedo is now about 8% off. If you really need to get there fast, you need more horse power which usually means an engine swap.

I would suggest a real time water temp gauge install if you plan to run the 1fz hard.

It's more than 14% in the real world. My Yellow Box speedometer calibrator is set at 18% on 37's with 5.29's. Do that mod no matter what you ratio you pick - the shift points improve when you correct the input.

The gains of lower gearing are never negligible. With an auto transmission, the only major consideration is top speed headroom for highway cruising, with some nod to MPH vs. RPM with OD off and the occasional pull up a steeper grade in second.

If you will keep it at 65, 5.29 really has no drawbacks, and it feels pretty much the same on 35's as it does 37's with that ratio. In the real world, rolling radius doesn't change as much as tire charts suggest and most people will likely prefer the same diff ratio for both 35 and 37" tires. In other words, if you prefer 4:88 for 35's you'd likely retain that preference on 37's and vice versa. The gear change difference simply outweighs the tire change difference. That's why people feel stupid when they've held out on 35's for years and finally go 37" and realize that the truck is almost exactly the same in every regard except for how much better it wheels. And looks.

Anyway, I like to be a gear ratio low for an inline 6 and auto transmission, having done this before on a highly modded Jeep Cherokee. I get better fuel economy and I'm not driving a lifted pig at higher highway speeds so I don't need the upper speed limit headroom. That's why I did 5.29's when I had 35's with no plans to go 37" at the time.

I'd personally only do 4:88 if I had an V8 swap or forced induction, because the overgearing in those cases would work against the purpose of the engine mods. Stock engine with 65 mph top speeds? The 4:88 top speed headroom is left 100% on the table, and that was the primary benefit.

 

[Box Rocket]

I run Nitro 4.88s with 315's. I do a fair amount of long distance driving and personally I think 5.29's are too low and rpms too high for 35's unless its a truck that is primarily an offroad rig used mainly for crawling. Or is not used for long distances at highway speeds.

As you probably know the 5.29 is also a weaker gear set due to the smaller diameter pinion gears. 4.88's are the right 'fit' for 35's and will get you closest to stock performance.

 

[richardlillard1]

The argument that 5.29s are a weaker gear set is a pretty moot point.

By now enough people have run them and put them through a lot of abuse that bringing it up is really reaching for something to gripe about that isn’t there.

@gearinstalls.com do you still have that 5.29 strength article on your website that we could link here? I didn’t see it.

 

[LINUS]

I would occasionally swap my 315's from black 80 to the 5.29'ed LX450 when doing some random stupid thing. And vice versa my intercos from the 450 to my 4.88'ed black 80.

It was a barrel of monkeys the way you accelerate on 5.29/315's (comparatively, we are talking 1FZ world).

Flipside is the 4.88'ed / 37's isn't obscenely overgeared. At least not at sea level (me most the time), and esp not if you had a S/C.

I don't have hard numbers, a rpm calc will get you that - but 75-80 was absolutely as much constant rpms as I remember 5.29/315 being road 'happy' at.

I'd really decide personally which tires you think fit your use (35's great, 37's start getting into the rowdy world & using words like Moab)

However 17" rims are now getting more the common OR tire choice size, so a 17" / 35" sidewall may not float your boat.

Tough call, I geared my black 80 in 4.88 so I would just run 315's & let this 80 live a life of relative ease vs my 450 that came to me on 5.29's/37's & meant it was built to get a little rowdy, got treated that way, and the guy who bought it continued that.

Just my experience between the 2 configurations.

 

[Box Rocket]

The argument that 5.29s are a weaker gear set is a pretty moot point.

By now enough people have run them and put them through a lot of abuse that bringing it up is really reaching for something to gripe about that isn’t there.

@gearinstalls.com do you still have that 5.29 strength article on your website that we could link here? I didn’t see it.

I'm not saying there's a high failure rate, but it's factual that the pinion gear is smaller and therefore more likely to break compared to a larger diameter pinion gear. That's not moot or reaching, it's fact.

 

[-Spike-]

Any discussion of the weakness of the 5.29 pinion is moot if there are no examples of it breaking. The only broken pinions of any ratio on an 80 that I've seen were attributed to lack of preload and subsequent deflection, not any inherent weakness of the parts.

 

[Qball]

I'm not saying there's a high failure rate, but it's factual that the pinion gear is smaller and therefore more likely to break compared to a larger diameter pinion gear. That's not moot or reaching, it's fact.

Yes but enough people have put the 5.29 gear to good amount of stress and they almost always break the drive shaft first. Good testament to Toyota engineering....and nitro quality. Our rear third is massive for a passenger car!

 

[baldilocks]

The argument that 5.29s are a weaker gear set is a pretty moot point.

By now enough people have run them and put them through a lot of abuse that bringing it up is really reaching for something to gripe about that isn’t there.

@gearinstalls.com do you still have that 5.29 strength article on your website that we could link here? I didn’t see it.

Regardless, Adams point is true and that absolute truth means that fact is is not moot, especially when the differential involved has a smallish 8” ring gear.

Many good points have been made here but what we are doing here is splitting hairs.

My 80 has 4.88’s installed by the PO. It had 35’s when I bought it and I never intended to go to 37’s but one day I saw the light and made the switch to the larger tire. There was a perceived loss of power as compared to the 35’s if I drove it in the same manner but the benefits of the 37’s far outweigh any “perceived” disadvantage wih 4.88’s and I suspect that pairing 5.29’s with 37’s wouldn’t make a world of difference.

I would not purposely pair 5.29’s with 35’s unless my 80 would never see the highway. The only exception would be if I lived at high elevation and traveled mountain passes on a regular basis.

The 1FZ is no fireball but it doesn’t need to be geared like we would a 4 cylinder mini truck.

 

[LINUS]

@baldilocks - Aren't you boosted though?

Or has my senility struck again?

Either way, I agree on people who say 315's/5.29's fine IF you don't freeway it or expect to.

I had fun when my 315's were on the 450 - it does make it a real crawl type setup. If rockcrawling was a local terrain thing, that would be fun for the ratios.

Altitude would be a factor if it was me, OP did mention heading to Sierras, so not sure what elevation his norm drive is.

I'd really decide on my tires & use, let that dictate gears, worst case default to 4.88's since you can still freeway no matter what tire (within his range)-you're on.

 

[baldilocks]

@baldilocks - Aren't you boosted though?

Or has my senility struck again?

Either way, I agree on people who say 315's/5.29's fine IF you don't freeway it or expect to.

I had fun when my 315's were on the 450 - it does make it a real crawl type setup. If rockcrawling was a local terrain thing, that would be fun for the ratios.

Altitude would be a factor if it was me, OP did mention heading to Sierras, so not sure what elevation his norm drive is.

I'd really decide on my tires & use, let that dictate gears, worst case default to 4.88's since you can still freeway no matter what tire (within his range)-you're on.

Nope, I’m running around on a regular ole 1FZ.