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130/80 rear tire

Started by MikeScoot, February 09, 2020, 03:52:34 AM

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MikeScoot

Looking into 130/80 rears at the moment. Have read a couple of posts here suggesting the 110/90's are a better way to go. But crikeys Steve, this is 2020!!!
  Most of the neg. comments about the 130's were that they have a slightly too large a radial (?) diameter. So, was thinking that going down to 130/80 instead of 130/90 might be OK.
  Anyway, the main purpose of this thread is to try to ascertain WHERE they might scrub IF they did.

  The only other neg. about such a tire would be that when cranked over the centre of gravity of the bike would be displaced (in relation to the contact patch on the road) a fair bit more than usual. But that's cool for me. Ever since owning an XS1 ("Hinge") I'm quite comfortable shifting my body weight around to compensate for this type of fun.

So, does anyone have actual real life info about exactly where they might scrub at speed? I mean, anyone actually fitted similar tire and really know?

Cheers :-)
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

auto

Went that route some years ago.Looked better,but I think they react faster with the smaller tire. Just don't think the rim is wide enough to control the larger tire.  We just mounted some Avons on my sons vision.They look good and the bike handles excellent with them.

fret not

The point about putting a large tire on a narrow rim is that it puts the beads of the tire too close together and that makes the tread portion of the carcass bend to a tighter arc and actually provide less contact area with the road surface.  Always use the recommended tire size for the rim size you have.  There are tire charts and motorcycle manufacturer's recommendations available for determining appropriate selection.  Safety and performance are the main criteria I use when choosing tires.  If you want wider tires then put wider rims on the bike.

You can get away with lots of things that are not recommended, but there are reasons for the recommendations. :police:
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

MikeScoot

Ah yes. Thanks, I overlooked that. The tire profile would be higher. So the only way to really do it would be with a wider rim.
Cheers,
Mike
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

injuhneer

I have a spare bike for parts. That means two rear wheels on hand. My intent (now that the electrical is sorted out) is to mount a tire on each. One OEM and one a size up (120/90) running a bit less pressure. Ride on each then decide.

My first reaction was to look for an XJ900 rear wheel but then isn't everyone?  I can wait while the prices come back down. Maybe I'll visit some of the XJ forums I used to frequent and ask around for a wheel.
- Mike O
1982 Yamaha XZ550RJ

MikeScoot

Yeah, the 900 wheel looks like the go.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

injuhneer

Today was tire day. 120/90 Kenda Challenger on the rear (have had good results with the Challenger on XJ Yamahas) and a Dunlop 100/90 D404 on the front.

Started off with 45psi/310kPa front and rear. Adjusted each down a bit after successive rides. Landed at 38psi/262kPa in front and 40psi/275kPa in the rear.

The front felt nervous until the pressure was lower. At first it felt like notchy bearings in the stem. It feels good now. Interesting steering transitions in this bike.
- Mike O
1982 Yamaha XZ550RJ

MikeScoot

Great to hear that you have it feeling the way you like and Interesting to hear that you started out at 45PSI and worked your way down. Sounds like a pretty sensible way to do things and I'll take a leaf from your book and do the same when I get around to tires myself. Not too far away.  :) :P :) :P
Put last coats of clear on the tank and front guard today. Been bloody miserable weather here for a few weeks so I was REALLY glad to get that done. Side covers and rear guard are already done and looking good, so now the only bits of serious painting are finishing off the strips under the seat.
A few days from now (when the clear has hardened-up a bit and been finely cut) and I'll mount the petcock (fuel tap) and stick the tank on. Really looking forward to that!!!
Great to hear your tires are feeling good.

Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

fret not

I am a bit envious of you guys that are riding your Visions, mine is a 'long term project' that I hope to ride maybe this year for the first time.  I would like to relate an experience I had resurrecting a CB500 Honda that I bought from an insurance company so many years ago.  It had been stripped and dumped in the San Francisco Bay, so when I got it there were tiny clams growing between the cylinder fins.  It smelled pretty bad for a while but did get cleaned up.  The point here is painting the tank; I was untrained for such a task, but I went ahead and did it anyway.  I recall putting more than one rattle can of (LubriTech) clear over the new paint, and it looked gorgeous.  I proudly rode the bike for about a year and traded it in on a new 750F at the dealership where I worked.  I saw the bike a couple years later and it looked horrible because it had been kept outside in the elements.  The thick clear coat was badly checked and discolored, looked more like a big scab flaking off bit by bit.  The lesson was made clear to me much later when I was busy applying finish to musical instruments: that thick finish has a tendency to crack and chip easily.  A thinner finish that seals the surface is a much longer lasting protection for the underlying surface (unless you choose powder coat or poly paint like Imron, which are much tougher but require special knowledge and equipment). 
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

MikeScoot

Holy Crustaceans! That must have been a mammoth job!

Yeah, I've leaned a huge amount about painting too. If I ever re-paint this bike I'll be doing it very differently to this time around. Have especially taken note of your advice about thinner being better. Will also use ONLY epoxies for heavy and medium prep. work and final paint.

I'm also not expecting to actually ride this bike for some time to come - perhaps except for a couple of short testing rides. Still plenty to do, but the list is getting shorter.

Good luck with yours. It's a buzz seeing them get better and better. :-)
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

injuhneer

Not only is thinner better but consistent thickness as well. Those areas that are varying thickness react at different rates to heat/cold/UV. The checking will start more quickly if the layers are uneven.
- Mike O
1982 Yamaha XZ550RJ

MikeScoot

Ah, that's handy to know too - but tricky to do in tight corners.
Both Luthers had their dreams,
But I've just got one Vision.
Theirs got them into strifes,
Mine just takes me fishin'.

fret not

It's easy for me to give advice to you because I am not the one doing the work.  8)
I try to get the hard to reach areas first, then put a smooth coat over everything. 
Retired, on the downhill slide. . . . . . . . still feels like going uphill!