Baby bushwheel on 8.5 mains?

How to keep the Cessna 170 flying and airworthy.

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blennon29
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Baby bushwheel on 8.5 mains?

Post by blennon29 »

Hi everyone. My first post. I’ve owned my 170B a bit over a year after passing my check ride and have about 200 hours. I’ll post some pictures soon.

Anyway, My tail wheel tire is worn out and the rest of the 3200 is sloppy so I’m thinking about upgrading to a baby bushwheel. I play on Ohio grass strips regularly and hope for more adventurous mountain trips in the future. So slightly overkill now, but getting set up for the future. Any opinions if 8.5 desser mains are large enough to balance the 11” tail wheel? Looks, like the deck angle will still be slightly steeper than with original 6” mains and stock tail wheel.
N4494B 1955 170B O-300 A
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Vertical
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Re: Baby bushwheel on 8.5 mains?

Post by Vertical »

The only reasons to have a baby bushweel:
1. You will operate on very rough ground including bumps, rocks, ruts etc.
2. You will operate on soft ground, including sand, beaches, mud etc.
90% of the benefit is purely for taxiing in 1 or 2.

If those are in you future, then do it. “Baby” that tail as much as you can. It’s fragile. Also, get the 3400 with the bent control arms. If those ops aren't going to happen then just do standard 3200. It’s lighter and far less likely to shimmy (a very nasty but common issue with the BBW).

Alternately, and I can’t recall the cost difference, but if there is savings by staying 3200 (or rebuilding yours) then put the $$ into 26” Goodyears for the mains. -It’s the best tire for the $$ for light off airport ops.
hilltop170
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Re: Baby bushwheel on 8.5 mains?

Post by hilltop170 »

Desser Tire and Aircraft Spruce both sell Aero Classic 8.50-6 Smooth tread tires that are very light, not expensive, and work very well on a 170 on unimproved strips. They also look “right” on a 170 and will go well with a larger tailwheel tire.
Aero Classic 8.50-6 Smooth tread tires.
Aero Classic 8.50-6 Smooth tread tires.
5F60CCB5-41A5-4BAA-9632-2D7102E27F98.png (429.03 KiB) Viewed 77024 times
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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blennon29
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Re: Baby bushwheel on 8.5 mains?

Post by blennon29 »

Thanks for the input. I already have the Aero Classic 8.5s on the plane. Great tire. I just wasn’t sure if those we’re large enough to compliment the BBW. 26’s will be down the road.

I’ll look closer at the 3400. I hadn’t considered that.
N4494B 1955 170B O-300 A
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Vertical
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Re: Baby bushwheel on 8.5 mains?

Post by Vertical »

Whoops disregard the 3400. You want the 3200 with the wide fork..-memory failure.
There is also the Gar Aero wide fork for the 3200 if you can find one.

For either, you can also run the glider tire in the wide fork rather than the bushwheel tire to save $$. It’s a similar size.
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falco
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Re: Baby bushwheel on 8.5 mains?

Post by falco »

Vertical wrote:The only reasons to have a baby bushweel:
1. You will operate on very rough ground including bumps, rocks, ruts etc.
2. You will operate on soft ground, including sand, beaches, mud etc.
90% of the benefit is purely for taxiing in 1 or 2.

If those are in you future, then do it. “Baby” that tail as much as you can. It’s fragile. Also, get the 3400 with the bent control arms. If those ops aren't going to happen then just do standard 3200. It’s lighter and far less likely to shimmy (a very nasty but common issue with the BBW).

Alternately, and I can’t recall the cost difference, but if there is savings by staying 3200 (or rebuilding yours) then put the $$ into 26” Goodyears for the mains. -It’s the best tire for the $$ for light off airport ops.

Reason 3: You have a bigger engine and a constant speed prop and want to add 4 pounds as far aft as possible.
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Fishsticks
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Re: Baby bushwheel on 8.5 mains?

Post by Fishsticks »

Reason 3 is definitely a strong one. If you are really going for tailwheel bling there is also the T3 on a field approval.

Does anyone have a source of Desser 8.50-6 smooths? Everyone I have contacted about them is sold out. Desser doesn't know when they will have stock again and has a waiting list....
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Vertical
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Re: Baby bushwheel on 8.5 mains?

Post by Vertical »

I suppose the T3 would add even more weight back there if that's what you really want.

I would be more inclined to try to find ways to loose weight to correct CG issues then adding weight to correct CG. Especially if you don't actually need the benefits of the BBW or the bling of the T3. These planes like to be light. There are lots of options...lightweight battery, starter, alternator, prop, vacuum removal, obsolete instruments or consolidation to modern instruments, moving ELT farther bac, titanium firewall, etc.. Or on the other side, what about keeping your survival gear and tool kit in the back of the extended baggage (or adding an extended baggage) or adding tail pull handles. The baggage or pulls add weight, but add excellent functional benefits.

If you will be be in the rough/soft stuff..Then definitely do the BBW. If not, there are other fun ways to spend $$ for things you'll actually enjoy the benefits from. I would hedge that by saying that a BBW is a pretty inexpensive, easy mod (relative to many of the other things listed above).

On a side note, my understanding is that you can get the Lycoming 4 cylinder conversions to a reasonable CG. Although this might be mostly due to a Trailblazer or MT. Maybe someday I'll do it and find out for sure. I can't speak to the IO-360 cont. or Franklin options or how the CG works out for those.
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falco
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Re: Baby bushwheel on 8.5 mains?

Post by falco »

Vertical wrote:I suppose the T3 would add even more weight back there if that's what you really want.

I would be more inclined to try to find ways to loose weight to correct CG issues then adding weight to correct CG. Especially if you don't actually need the benefits of the BBW or the bling of the T3. These planes like to be light. There are lots of options...lightweight battery, starter, alternator, prop, vacuum removal, obsolete instruments or consolidation to modern instruments, moving ELT farther bac, titanium firewall, etc.. Or on the other side, what about keeping your survival gear and tool kit in the back of the extended baggage (or adding an extended baggage) or adding tail pull handles. The baggage or pulls add weight, but add excellent functional benefits.

If you will be be in the rough/soft stuff..Then definitely do the BBW. If not, there are other fun ways to spend $$ for things you'll actually enjoy the benefits from. I would hedge that by saying that a BBW is a pretty inexpensive, easy mod (relative to many of the other things listed above).

On a side note, my understanding is that you can get the Lycoming 4 cylinder conversions to a reasonable CG. Although this might be mostly due to a Trailblazer or MT. Maybe someday I'll do it and find out for sure. I can't speak to the IO-360 cont. or Franklin options or how the CG works out for those.

I added a bunch of weight to the front of the airplane when I did the XP Mods STC in 2000. Bigger Six Cyl and a constant speed prop. With vacuum pump, governor, etc. Added baggage door and moved battery aft at that time and weighed it. Empty CG moved forward enough so I had to add a 13# lead brick at STA 200 to bring it back to something reasonable -- where I could fly solo or with one passenger, no cargo, full fuel and not be forward of CG limit.

Hard to tell how much changed because the airplane had never actually been weighed before. (Factory weighed something like one in ten airplanes.) Calculated changes were included for most stuff, but there were also some things never added to the W&B calcs before I owned it. (e.g. Seats had been reupholstered with boat vinyl over the original upholstery - back seat was 36 pounds, should be 29. etc. )

Over a 20 year odyssey, I changed rear seat to BAS jumpseats, reupholstered with lighter materials, battery moved aft, lightweight alternator, starter, etc. Most of that weight reduction moved the CG further forward. The starter and alternator are lighter but don't shift CG much.
Result is with 1 front seat passenger (and me) some cargo weight is required to keep CG within limits. With one backseater this is never an issue. Added the carbon fiber extended baggage so now I can put my tool/survival kit further back. That helps.
Best thing I could do here is switch to an MT prop. That is also the most expensive option. Or lose the vacuum system and go electronic with G5s or similar. Also expensive.

The 'tailwheel bling' adds weight as far aft as you can get it. The BBW adds 4 pounds at STA 249. which means I could take 5# off the lead brick (at STA 200) maintaining current CG and losing a pound. T3 would have a similar effect. And I could do both for less than the cost of one G5 in the panel without so much as drilling a hole.

I am generally not big on bling, but I do like the look with Desser 850 slicks and the bigger tailwheel. And the T3 looks cool too. I would probably use the glider tire (for durability) rather than the BBW because I am based on asphalt runways, though I do venture into grass, dirt and gravel.

Best thing I did this year for the airplane W&B though was to lose 25# off my belly. Cost nothing, no 337 to file, no A&P required and feels good too.

Cheers,
Pete
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c170b53
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Re: Baby bushwheel on 8.5 mains?

Post by c170b53 »

You’re likely not alone (I’m working on weight reduction now as well as most of my life). I removed my AI to install the AV30 and I don’t think there’s much difference in weight between the instruments. Maybe removing the transponder with a tailbeacon x will drop a couple of lbs but being right on the datum point it’s not going to help with a heavy nose. Heaviest component is likely the pump, maybe 3 lbs, again not much of an arm.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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4583C
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Re: Baby bushwheel on 8.5 mains?

Post by 4583C »

Agree the personal weight loss would be the most efficient :roll: but I haven’t been to successful. I just changed out my Venturi vacuum system,AI,DG, Transponder and encoder for 2 AV-30s and the tailbeaconX and gained 14 lbs useful load!
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Vertical
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Re: Baby bushwheel on 8.5 mains?

Post by Vertical »

4583C wrote: I just changed out my Venturi vacuum system,AI,DG, Transponder and encoder for 2 AV-30s and the tailbeaconX and gained 14 lbs useful load!
That's a significant change. Nice work. How is the AV-30/xponder? -Have a friend considering it. My recently installed AV-30 DG drifts so aggressively it's unusable.-Still troubleshooting.
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cessna170bdriver
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Re: Baby bushwheel on 8.5 mains?

Post by cessna170bdriver »

c170b53 wrote:You’re likely not alone (I’m working on weight reduction now as well as most of my life). I removed my AI to install the AV30 and I don’t think there’s much difference in weight between the instruments. Maybe removing the transponder with a tailbeacon x will drop a couple of lbs but being right on the datum point it’s not going to help with a heavy nose. Heaviest component is likely the pump, maybe 3 lbs, again not much of an arm.
It doesn’t matter where any weight is relative to the DATUM (which can be anywhere the manufacturer wants it to be). What makes the difference is how far it is from the empty CG. For example, weight added to the firewall (the datum on a 170) will move the CG forward (though not by a huge amount).
Miles

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GAHorn
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Re: Baby bushwheel on 8.5 mains?

Post by GAHorn »

c170b53 wrote:You’re likely not alone (I’m working on weight reduction now as well as most of my life). I removed my AI to install the AV30 and I don’t think there’s much difference in weight between the instruments. Maybe removing the transponder with a tailbeacon x will drop a couple of lbs but being right on the datum point it’s not going to help with a heavy nose. Heaviest component is likely the pump, maybe 3 lbs, again not much of an arm.
Eat more calories…and S-L-I-D-E you seat farther back! :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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c170b53
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Re: Baby bushwheel on 8.5 mains?

Post by c170b53 »

Any opinions if 8.5 desser mains are large enough to balance the 11” tail wheel? Looks, like the deck angle will still be slightly steeper than with original 6” mains and stock tail wheel
Good question, would not the deck angle be less ? Also what about dampening ?
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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