Larger tires
- Thread starter Crusin
- Start date
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before anyone else slaps ya upside the head, your year is kind of imprtant here. also did you take a peek in the faq's???
welcome to the board but do a little search adn get your answers now.
oh and what part of wa are you in??
Dave
welcome to the board but do a little search adn get your answers now.
oh and what part of wa are you in??
Dave
Stress due to larger tires? hmmm. Uh-ho.
psssst, you may want to look at a few of the faqs and other threads
psssst, you may want to look at a few of the faqs and other threads
Cruisin,
Those are both approx 33" tyres with the 305's being a bit wider and heavier. The stock engine and gearing will handle both with ease though you will feel a loss of pep with the taller tyres and stock engine. If you're at high altitude you will really notice the difference. The tranny will easily handle larger tyres until you get to Christo's 40 inchers and probably even with those.
In another thread, NY posed basically the same question concerning 315's (~35") tyres and the answer is basically the same. With 35's most feel that regearing is necessary. 4.56:1 will get you back to stock and many recommend 4.88's for the additional low end torque.
-B-
Those are both approx 33" tyres with the 305's being a bit wider and heavier. The stock engine and gearing will handle both with ease though you will feel a loss of pep with the taller tyres and stock engine. If you're at high altitude you will really notice the difference. The tranny will easily handle larger tyres until you get to Christo's 40 inchers and probably even with those.
In another thread, NY posed basically the same question concerning 315's (~35") tyres and the answer is basically the same. With 35's most feel that regearing is necessary. 4.56:1 will get you back to stock and many recommend 4.88's for the additional low end torque.
-B-
- Thread starter
- #7
Beowulf said:
So 285's is a good choice for a stock engine with no regearing needed? And just regear the speedometer? There will still be a loss of pep, but its gonna look good, right?
How bout fuel economy, is there a big difference?
Thanks
MoJ
Moderator
Crusin said:So 285's is a good choice for a stock engine with no regearing needed? And just regear the speedometer? How bout fuel economy, is there a big difference?
Thanks
Yes - regear the spedometer - super easy to do.
Going from stock Michelins to 305/70 BFG I haven't noticed a measureable difference - possibly .5 mpg but that little of an amount could be due to lots of things. Physics tells us that there's gotta be a reduction in MPG when going to a larger tire.
I don't notice a mpg or "power" difference with my 285/75/16 MT/Rs and haven't re geared the speedometer, it's only a ~3% diferrence so I just keep that in mind. No worries about increased wear.
firetruck41 said:
The difference is more like 5.4%
275-70-16 is 31.2" diam
285-75-16 is 32.9" diam
After adjusting for this difference in the odo reading, the MPG is basically the same as stock size.
Acceleration is reduced but not significantly.
Crusin,
I'd just recently posted similar questions concerning gas mileage, etc. As has been restated here, maybe a .5mpg difference. Regarding the speedo recalibration, I wouldn't bother. I've driven my '94 thru countless radar trailers and am consistently reading faster on speedo than actual. This is very typical as far as I understand it. Porsche I owned was a flat 8% off (dyno tested) and Porche's response was that anything up to 10% variance, typically reading faster than you are actually moving is acceptable! When I'd originally suspected the Porsche speedo was off I just tracked it against the cruiser and they were the same, so a similar variance exists on my cruiser at least. There's a tire/speedo variance calculator out there that I think B had posted a link to awhile back and I checked it out - stock 275's vs 285's. Variance difference was just a couple % difference, actually bringing the speedo closer to actual speed as measured via a radar trailer. May also check against my GPS at some point as well.
Long winded answer to your question, but short story on the 285's as least IMHO is that it's not worth correcting the speedo.
I'd just recently posted similar questions concerning gas mileage, etc. As has been restated here, maybe a .5mpg difference. Regarding the speedo recalibration, I wouldn't bother. I've driven my '94 thru countless radar trailers and am consistently reading faster on speedo than actual. This is very typical as far as I understand it. Porsche I owned was a flat 8% off (dyno tested) and Porche's response was that anything up to 10% variance, typically reading faster than you are actually moving is acceptable! When I'd originally suspected the Porsche speedo was off I just tracked it against the cruiser and they were the same, so a similar variance exists on my cruiser at least. There's a tire/speedo variance calculator out there that I think B had posted a link to awhile back and I checked it out - stock 275's vs 285's. Variance difference was just a couple % difference, actually bringing the speedo closer to actual speed as measured via a radar trailer. May also check against my GPS at some point as well.
Long winded answer to your question, but short story on the 285's as least IMHO is that it's not worth correcting the speedo.
Modifying any real 4x4 for looks only will always be bad for it, because over time the gods will frown on your excess and punish you with an endless series of strange but seemingly disconnected series of problems that you can't really trace anywhere except to the day you said "but it will look good, won't it?".
Nay
Nay
Here's the tire/speedo calculator I referred to. Posted by Biff:
http://www.miata.net/garage/tirecalc.html
http://www.miata.net/garage/tirecalc.html
You're right, OEM Michelin = 31.3", 285/75/16 MT/R = 33.1". 5.7% difference.mtycruiser said:
With GPS I observed 62-63mph at a speedometer indicated 60mph.
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60 x 5% = 3; therefore your actual speed is 63 with an indicated 60MPH.
-B-
-B-
Ben - wow - Mine is the opposite based on my comparison of the LC and the Porsche being the same. I that case speedo at 65 actual about 61. If this is accurate and using the 5.4% difference the tire calculator has between the 275 and 285, that brings speedo and 'actual' very close. Now you've got my curiosity peaked to use the GPS on the way home tonight (if the batteries are any good in it - they've been sitting awhile). hehehe
When I used to wheel my Tacoma. The R&P didn't like going from the stock 31x10.5x15 tires to the 33x12.5x15 tires. A lot of guys ran into R&P problems. Especially when going to 35's. I think the only real difference between the 285 and the 305s will be additional wear. If you are looking for getting the diffs off of the dirt as your main concern. Go with the 285s. If you want a wider tire for looks or offcamber grip go with the 305s.
Just remember. If you run the 305s on the stock 8" rims. You will wear down the center of the tire quicker than the 285s. Unless you run a lower psi in the 305s which will drop your mpg (on pavement, that is)
Just remember. If you run the 305s on the stock 8" rims. You will wear down the center of the tire quicker than the 285s. Unless you run a lower psi in the 305s which will drop your mpg (on pavement, that is)
Crusin said:Deppends on the price and looks
Yup, that's all that matters.
Gee it's fun to follow Junk's thread posts. First the "sealer" comment and now "that's all that matters".
I get a real kick out of it and he's right.
Good fun.
I get a real kick out of it and he's right.
Good fun.
