K Block Tires

Hi Doc,
The only old 2 wheel tire mixing complex I know of is the mixing of bias ply tires and radials on the bike in high performance situations. There may be others, but mixing tires on sidecar rigs is very common. Most sidehack outfits have three different sized tires and a mix of radial and bias ply tires is also common usage. While radials may maintain a flatter footprint (especially automotive tires), the sidewalls usually have less resistance to sideloading than bias ply tires. Sideloading isn't a problem with a single track vehicle that banks in the turns, but sidewall strength can enhance the handling of a rigid mounted sidecar rig.
As far as wear, the front bike tire usually lasts the longest and the rear bike tire goes first. The sidecar tire life depends on alignment, loading and whether it is a cycle, sidecar, or automobile tire (which will last the longest). For cycle tires I've had good wear and all-weather use with the Dunlop Elite II and Metzeler 88s up here in rain country.

Agree with Lonnie about mixing tires on an outfit..Not a problem.
Avons on the 19" wheels and the Block K on the 18 sounds like a natural to me.
If using bike Tires the Dunlop 491 has done well.

What are the Avon equivalent of the Metzler K Block tires called?

Thanks In Advance,
Jim Kelleher
AKA Dr. Raoul Duke
AKA The Circus Bear

Avon Triple Duty MKII Sidecar
It comes in 3.50 x 19.
If you punch 'Avon Triple Duty MKII' into Google you will be able to find a picture of one. I would have attached the picture here but do not know how to do it.
Or..click here:

A picture of a Metzeler Block 'K' sidecar tire can be seen by
clicking here:
http://www.us.metzelermoto.com/product_info/catalogo/scheda.asp?ID=136
4.00 X18 is only size available.

Jim,
I don't think this was mentioned before but one advantage to making all of the wheels 18" as you stated some have done would be that the rig would then have a common tire size. Hey, you could even rotate your tires to get the most milage out of them. A spare would look good on the back of that Ural too.
(no ... I am not getting comissions from Metzeler)
Claude

I have AVON MK II 4.0 x 18 on my guzzi and they work fine!
As stated above rear itres wear out faster so keep an eye out for premature wear, and don't judge tire wear by just examing the front tire.
Happy holidays

Lenny,
Is that an Avon 4.00 x 18 or a Metzler?? I always thought the AVOM MkII were only availble in 3.50x 19 and the Metzler Block K in 4.00x18.
If I am wrong it sure would not be the first time.

I've run a variety of different tires on a BMW airhead/Ural rig, similar to yours. In a nutshell, you can run just about any combination you have handy and it won't make much difference.

I had an 18" front wheel built for the R100(with Unit leading link) for offroad duty, primarily because of the wide availability of 18" motorcycle tires--street, knobbies, etc. Changing to 18" from 19" also has an effect on steering trail. If you use a flat profile "sidecar" (rear) tire on the front, you'll reduce tire OD slightly, decreasing trail and making steering slightly easier. But if you already have a reduced-trail front end, you can use a taller or fatter rear 18" tire on the front, either maintaining the same OD as the stocker, or even increasing OD--with a slight increase in steering effort. With a leading link, you can also adjust trail slightly by increasing or reducing shock preload or shock mount position. So, if you're running a stock front end, you'll probably get better steering with a low profile 18" front tire than the 3.25 x 19.

Personally, I prefer a round profile front tire, because it is less prone to tracking grooves than a square profile tire. Wear isn't a big problem for the front. If you do install a "rear" tire on the front, turn the tire around so the rotation arrow points backwards (to help keep the plies from separating).

pmdave

Claude:

I have an older 19" Ural Rig. Can I chahge that to an 18", if so what effect will it have on my setup (which I am happy with), or my handling. Sames goes for putting an 18" on the front. I am adding the Perry Bushong Triple Tree to reudce front front end "wobble" at low speeds. Thought if I put a K Block or Dunlop Square type tire on the front it would also improve steering? Now I am confused...where would you get the most benefit from a K block?square tire...on the front wheel or the rear?

Thanks in Advance,
Jim

Jim, I could be wrong [that should bolster your confience] but if you change ALL three wheels to 18" your set up should not be affected. Unless you've already got the triple tree mod, why not consider a set of LL forks from Ural? They're not cheap ~$650 new but it's a whole new front unit complete with new shocks. These are also commonly available used within the Ural community.While I run Block K's all around, I suspect that you'll get the most bang for you buck from putting a square profile tire in the rear first. You'll get better wear with the larger footprint. As a bonus, going from 19" to 18" your pick up off the line will improve because of the effectively lower final gear ratio.

I have a brand new leading link FE complete with steering damper for $575.00. It's listed in the want ads here.

al wrote:
>>As a bonus, going from 19" to 18" your pick up off the line will improve because of the effectively lower final gear ratio.<<

Be sure to check the actual diameter of the tire when mounted as it is not really wheel diameter that counts but rolling diameter of the whole assembly.
Claude

I do not think has been mentioned, but an advantage to all 18 "wheels as you said that some have is that the platform would have a standard size tire.

Maruti Swift