TYRE SIZE DEBATE

[MarkMod]

I have just purchased a 1982 LS which has a very old 110/90 Avon tyre on the rear. As there is a new 90/90 Avon Roadrider on the front it makes sense to match up. The debate is using the Avon Roadrider 120/90 18 65V  or change the front and rear tyres so I can use a 110/90 rear.

What tyre combinations you other people recommend as well as tube or non tube.

Sorry if I have repeated a previous post.

Thanks

Mark

[montmil]

I have just purchased a 1982 LS which has a very old 110/90 Avon tyre on the rear. As there is a new 90/90 Avon Roadrider on the front it makes sense to match up. The debate is using the Avon Roadrider 120/90 18 65V  or change the front and rear tyres so I can use a 110/90 rear.

What tyre combinations you other people recommend as well as tube or non tube.

Sorry if I have repeated a previous post. Thanks Mark

First off, welcome to the forum, Mark. Nice to have another R65er amongst us.

We usually put these tire threads in the "Rants, Tires and Oil" section as you are correct... this topic has been lashed many times on this forum and others. We'll give you a pass this time as long as you promise to learn how to scale your photos to fit the page format. Deal?

120 section tires may or may not rub the swingarm on R65s Much depends on the tire manufacturer's specific final dimensions. I had a 120 on my '81 R65 and it did buff off the paint. Also made it a PITA to remove the rear wheel for any service needs. Fitted new Bridgestone S11 Spitfires all around with a 110 on the rear. The Spits are fairly popular with R65ers.

The rims on both the R65 and LS models are designed to run tubes. Myself and a few others run our tires tubeless. I've done so for years with no problems whatsoever. Fact is, my tubeless tires hold air pressure better the the tubed tires I have on my '83 R65 with Avon tires. Tubes seem to leak down sooner than later. Weekly checks are mandatory in my shop.

Matched tires are always as good idea. Those tire engineers seem to know their business so I never run mix n' match rubber. Motorcycling is exciting enough without having to worry if your tires are going to play nice together when you're accelerating through a diminishing radius turn.

Wait for it... Other opinions will arrive shortly.

[Bob_Roller]

The tire size for the rear, is a 4.00x18 .

You can use a 110, or a120 width rear, depending on make and model of tire .

I know a 120 Metzeler Lazertec will work on the rear, I've had two of them, but they make tire/wheel removal a lot more difficult than it needs to be .

As far as using a tube, the LS  bikes came with tubes from the factory .

I have read that the bead area on the LS wheels, are for tubeless type tires, majority of owners use a tube even though they have tubeless tires mounted and they don't seem to have any problems

I guess it all depends on how comfortable you with it .

[MarkMod]

Sorry note taken regarding section and picture size. I have just put a post about stand springs with big pic attached, so apologise again.

Avon tyres website qutes 120/90 18 65V for the rear but does not mention tubes so I guess you can go tubeless. The cost fitted was £106.

They produce a 110/90 16 61V which is good for 257kg. The 65V is good for 257kg.

So I guess for me its Avon 120/90 on the rear to match up with the Avon already on the front or change both to say the Bridgestone Spitfires front and back at more cost.


Decisions, decisions.

[MarkMod]

The load rating could be another factor about all these tyres. 65 taking more weight than a 61. Does it matter?

Just visited the Bridgestone site and they recommend either the

120/90 18 65 V TL
4.00 18 64 H TT

The second one seems to match the original spec.

[MarkMod]

That Bridgestone tyre mentioned in my last post is a Battlax BT-45. Anyone used these?

[nhmaf]

Many folks use the Bridgestone BT45 tires on these - they work quite well and I've a pair on my bike.  I use the 110/90x18 rear.   The LS front wheel rim is a bit wider than the non-LS snowflake front wheel rim, so you could got to a 100/90x18 on the front instead of 90/90x18 - the steering/turning is slightly slower - but not much, IMHO- and highway stability is somewhat improved I think.
  

[tvrla]

Welcome to the forum Mark!

Just because the rear tire is old doesn't mean it's toast. If it's still soft (check with a durometer), wear it out!

I've used the bridgestones - S11 and the BT45. Like them both. And I run the 110 rather than the 120. The 120 gives sluggish handling, besides being a bitch to install, both on the rim and on the bike.

[Barry]

Welcome Mark

You will have gathered by now that tyre choice is anything but straightforward unless you stick to the original 4.00 and 3.25 sizes and even then there are some surprises. What I would do is carefully measure the width of your rear tyre and also the clearance you have  between the tyre and swinging arm. That will give you some idea of what will fit.  I suspect you won't want to exceed 120mm wide if that.  When I'm choosing a tyre I also look at the diameter because 110/90's tend to be smaller than the original 4.00 tyres which has a slight effect on gearing. Here's some data I gathered on rear tyre widths.

[Ed Miller]

The Roadriders, unlike many tires we use, come in 4.00 x 18 so there is no need to try for a close-enough metric approximation.  Too bad they don't make a 3 1/4 x 18 front, but nobody else does either.

Having said that, my tires never wear at the same rate so I just replace them as they wear.  I rarely have new tires front and back at the same time.

[MarkMod]

thanks go all you guys for your feedback. Lots of different views and thoughts.

I am going to phone Avon head office and ask them what they think between the 120/90 roadrider or the 4.00 18 roadrider.

Will let you know their thoughts asap.

[MarkMod]

I spoke the UK head of sales and his response was:

Use the 120/90 roadrider for more touring riding, due to its larger contact are and more grip and use the 4.00 18 for general riding, Sunday outings etc.

He says if the rim was originally designed to take a tube then keep a tube in it.

The height difference between the 90/90 18 front and the 4.00 18 rear was less than the 120/18 rear.

So I will probably use the 4.00 18 plus Michelin Tube, which he advises is the best tube to use.

Hope this post has been useful.

[Session101]

i have shinko's and they grip nice
running 100/90/18 front and 110/90/18 rear with tubes, they are rated up to 112MPH that's after including the effect that tubes drops the speed rating down

i wouldn't go any bigger in the rear or you will have to deflate the tire to get it in and out and also could have clearance issues on the driveshaft

[EGRG]

Too bad they don't make a 3 1/4 x 18 front, but nobody else does either.
 

I have a set of Heidenau that come in the original 3.25-18  front and 4:00-18 rear.
A little old school tread design but with modern construction and compounds.  Run great, much better than my old Macadam rear.
Front 3.25 looks a lot more beefier than the old 90/90-18 Conti that came with the LS when I bought it.

[Barry]

I heard Heidenau are good tires. They are available in the UK now at reasonable prices.

Being the original sizes I trust the rear fits OK.  Any chance you could measure the overall maximum width and diameter or circumference so I can add the data to my tire table ?