I'm looking at replacing the tires on my 170. It's got 8.5's on there now, and I'm trying to figure out how much different 8.00 tires would be. I'm never going to land on anything that isn't an actual air strip. Is there much difference between the two sizes?

Come on Ravi you know the only answer on this forum is

BUSHWHEELS BUSHWHEELS BUSHWHEELS

Get the buffed down ones if you don't want to go with Big smooth fun ones

You didn't buy a 170 for anything but the cool factor anyway

You didn't buy a 170 for anything but the cool factor anyway

Truer words were never typed.

In all honesty I could afford the bushwheels, but I can't afford the mistakes inherent with landing places you need bushwheels to land. My personality does not accommodate mistakes with any grace what so ever...probably a good and bad trait for a pilot.

So really...8.00 or 8.5?

Stole this from somewhere (maybe here?) but here are the rolling
diameters of some common six inch tires.

600 x 6 =13.8"
800 x 6= 15"
8.50 x 6 = 16.8"

The 8.50s will no doubt be "fatter" than 800s in cross section too.

As far as speed, with a 170, expect maybe a couple of mph
difference (max) between 800s & 8.50s.

16.8 - 15 = 1.8 / 2 = 0.9 (8.50 is .9 inches taller than an 800).
If you keep banging your head into the trailing edge of the wings
of your airplane like I do, that .9 inches of extra height comes in
handy....

Well, they aren't my numbers (I kyped them off of a post
somewhere), but I have to admit, I didn't even look at the
numbers and mentally compare them in my head to what would
look/sound right!

In any event, a radius of 13.8" for a 600x6 doesn't sound right
(that would be 27.6" in diameter, which would be larger than
the main gear tires on a T-6 or P-51, which utilize a 27" tire).

When I get home, I'll measure the height of the 8.50s on my
180 and I'll post back here what the dimension is.

I still think the speed difference between the two (800 vs 850)
will be negligable....

Hammer wrote:I'm looking at replacing the tires on my 170. It's got 8.5's on there now, and I'm trying to figure out how much different 8.00 tires would be. I'm never going to land on anything that isn't an actual air strip. Is there much difference between the two sizes?

Price

My 8.50's were Goodyear recaps. The were 22" diameter. Sold for under 100 bucks. And I liked them a lot better than the 8.00's which were about 18".

shortfielder wrote:My 8.50's were Goodyear recaps. The were 22" diameter. Sold for under 100 bucks. And I liked them a lot better than the 8.00's which were about 18".

Hiya Shorty

Where'd ya get the recaps? Desser? Did you send in your carcasses or did they send you a set from stock? My Goodyears are getting thin but I only have one set and would rather not put the plane up on blocks in the front yard. Would add a certain "trailer park allure" to the place.

Larry Filener tells me you might come down for the RAF seminar next month. I've been enlisted to burn the burgers. Be advised: Park well away from the grill.

I bought them off ebay, but I have a spare set of carcasses if you want to get them recapped, and then just swap. If yours are Goodyears.
Gary

I've got 800's on my 170, mainly cuz they're on the TCDS & I didn't have to worry about any paper. They've been OK for most of what I do-- no true off-airport op's but plenty of (sometimes soft) grass strips. Your 180 horse might be enough heavier on the mains that 850's would be a good idea. Then again, being based in california, you might not be dealing with as much muddy terrain as I do in western washington. The 850's don't have as much cool factor as the BW's ( they don't cost 3 grand either!) but they do have more than 800's. If I had anything bigger/heavier than a 170 (like a 180), it'd have 850's.
I've had more trouble with the tailwheel sinking in on soft ground. A fat tailwheel (ABW or Gar) would be a nice mod.

Eric

The BW's look cooler than the 8.50's, which look cooler than the 8.00's...

But, for everyday plunking around, the 8.50's are cool enough. And if you're not gonna play in the dirt for real, then the BW's on pavement are gonna put you in the same class as the jacked up 4X4's that never leave the suburban streets.

Not cool.

Stick with 8.50's on that C170.

Gump

it's so funny you guys are so caught up in cool, what about cost and practicality??

Who gives a shit about that

GumpAir wrote:The BW's look cooler than the 8.50's, which look cooler than the 8.00's...

But, for everyday plunking around, the 8.50's are cool enough. And if you're not gonna play in the dirt for real, then the BW's on pavement are gonna put you in the same class as the jacked up 4X4's that never leave the suburban streets.

Not cool.

Stick with 8.50's on that C170.

Gump

Now there you go sounding like dad again, and being right again

it's so funny you guys are so caught up in cool, what about cost and practicality??

For cost and practicality you might as well go with 700s. You lose lots of cool points, but if you truly aren't going to operate off anything that isn't an established airstrip than why go big - they just cost more and up your drag index. I operated off of numerous (east coast) grass and dirt strips with 700s on my Stinson and never had a problem. I've gone to 800s now, but only because the STC for the 470 requires it. Just didn't see the need to go to the 850s. If I get to the point that I need some real bouncy bounce then I'll find some 26"ers or BWs.

mr scout wrote:Who gives a shit about that

Goddam... I like the way you think Sir...

Gump

I think the 8.50's (Goodyear recaps)are a good all-round tire, and maybe the cheapest, at around $100.00 each.

Finnally got around to measuring the height of the McCreary
8.50s on my 180. There's 24psi of air in them right now, and the
height of the tires is 19.5 inches.

My mechanic wouldn't install 850s on my 170 without also installing double-puck brakes. Parting out cleveland brake parts, it was a better deal just to get the whole wheel-brake kit. It got spendy fast. The only savings was that my friend gave me the 850s and tubes for free.

I like the 850s for most of what I do, which is 95% off-pavement. Also, the terrain I fly over would be much less forgiving in a forced-landing situation, than hay pastures, highway medians and golf courses. The difference between 800s and 850s isn't that huge, but it's a little added insurance in a forced landing. If I could rationalize BW's, that would be better insurance.

The other factor is wheel-skis, if you ever plan to install them. So far as I know, the common penetration skis and hydraulic skis are limited in terms of the size tire you can run. I believe 800s are the upper limit for most of them.

Goodyear 8.50's are significantly larger in diameter than McCreary's, by at least a couple inches. My 8.50's run about 21 to 22 inches in diameter, depending on inflation.

Be VERY careful using recaps on these small tires. Goodyear refuses to recap small tires, because in their opinion, the cost to do so PROPERLY is so close to the price of a new tire, that it's pointless to do so.

Save a little money on a cheap set of recaps, then have one turn loose on you during a landing or takeoff, and wreck the plane......

Makes sense to me .

I've used new Goodyear 8.50's and new tubes for as long as I've owned my plane. I'm on my second set, cant' tell you how many hours off the top of my head cause the plane's gone to floats at times.

Perhaps the more important thing is that Goodyears have MUCH more UV resistance, so when the plane is outside, those tires will last much longer than McCreary's or recaps.

As to 8.00 vs 8.50--pick what you like. There's a little difference in size, a bit more significant difference in weight if that's an issue to you, but drag in cruise at these speeds is minimally different.

Just remember, some of those nice grass strips have gopher holes, ground squirrel holes, etc, in them. Bigger tires can help there as well.

MTV