Tires for my 89 K100rs

[harper]

Having a hard time getting tires for the ole girl. I found the front in a radial 110/80ZR-18 (stock: 100/90-18). The rear was a 150/70ZR-17 (stock: 140/80-17). Has anyone put radials on that were this size? I'm not worried about clearance but handling is my biggest concern. Would bias tires in V rating perform ok??
The bike is an 89 K100RS.

[Rick G]

You can get the Michlin Pilot Road 2 for them I just ordered 2 sets from Rocky Mountain ATV & MC for $524 and delivery in the 48 is free.
They have a real good reputation as a tyre, lots of guys in Oz ar getting 15,000 miles out of them.
I have noticed you say 89 K100RS but have you got the correct rims I think they had a 120 x 70zr x 17 on the front and an 16 x 60 x 18 on the rear.
Yours seem to be the tyres required for a K1100 LT which have the 3 spoke wheel but the same sizes as an early K100RS.
Maybe a previous owner changed the wheels.

[harper]

The correct sizes are the ones shown. Nothing has been changed on this bike.

[frankenduck]

The later K100RS, K100RT and K100LT models came with the 3x17 3-spokes used on the K1100LT rear.  It varies some by year and by country but sometimes they were standard, sometimes an option.

The "snowflake" rear wheels were 2.75x17.

[Rick G]

Not that this solves the tyre problem but has the bike got 3 spoke or Y spoke wheels because as far as I know the 1989 K100RS had the 3 spoke wheels and 17 front and 18 inch rear.

[harper]

Thanks for the replies. The 89 RS of mine has the Y spokes. I have a nice set of three spokers off a 96rs. Never gave it a thought that they could work. Will they??

[frankenduck]

Thanks for the replies. The 89 RS of mine has the Y spokes. I have a nice set of three spokers off a 96rs. Never gave it a thought that they could work. Will they??

I have not played with it myself _{(insert Anthony Weiner joke here)} but I've heard that a 96 RS rear will clear the mono swing arm but will hit the 2V center stand so you'd need to swap in a 4V center stand.

[Rick G]

I believe the rear would fit but the front is more of a problem in that you would need to change the brakes and calipers and then also the forks and triple clamps etc.

I was just looking at the info I have and the 89 models that came to Oz were all 3 spoke but the early 89 in the US were Y spoke.
I can see the problem with tyres that you want to run radials but the rim sizes dont really work in favour of that.
Any Ks I have had with the Y spoke all used the Bias tyres and did handle well and I never tried them with radials.
My current K100LT has 100 x 90 x 18 BH45? on the front and a Michilin Macadam 140 x 80 x 17 on the rear and I have found it to be a good combination but unfortunately I can no longer get that rear so I will have to go shopping again for something that works.

[frankenduck]

I believe the rear would fit but the front is more of a problem in that you would need to change the brakes and calipers and then also the forks and triple clamps etc.

And the master cylinder too.  That's what my K75 has.  Since the stem has a smaller diameter in the steering head you also give up the fluid block damper.  A little wobbly up to say 3 or 4 mph but fine after that.

[Rick G]

Thanks for the replies. The 89 RS of mine has the Y spokes. I have a nice set of three spokers off a 96rs. Never gave it a thought that they could work. Will they??

I have not played with it myself _{(insert Anthony Weiner joke here)} but I've heard that a 96 RS rear will clear the mono swing arm but will hit the 2V center stand so you'd need to swap in a 4V center stand.

I had a play round with it a while ago (laugh now) and decided they didnt fit but since have come across a few who have the wheel in and it depends on the tyre as to whether it touches the swingarm or not.
The whole front end virtually once the master cyl then comes the throttle and on and on.

[harper]

Back to my original post: Will those ZR oversize tires fit????
It amounts to 10mm oversize on each tire. That equates to .400 oversize which should only be .200 on a side. Also trying to figure out how far off the speedo will be with the different profile tire. Maybe a couple mph.
Get the mustard--the weiner's cooked!!

[frankenduck]

The Avon Azaro 46 comes in a 140 80 17 - why not just use that if you've got a 3x17 3 spoke rear?

[bosozoku]

Back to my original post: Will those ZR oversize tires fit????
It amounts to 10mm oversize on each tire. That equates to .400 oversize which should only be .200 on a side. Also trying to figure out how far off the speedo will be with the different profile tire. Maybe a couple mph.
Get the mustard--the weiner's cooked!!

Fitting the tire carcass into the available space isn't the issue.... but going to a larger tire on skinny old wheels almost always results in downgraded handling. The bigger tires also weigh more, cost more, and require more to energy to accelerate and slow down. 

Where's the gain?.   ???

A better approach to choosing your next set of tires would be to make the choice based on your wheel widths, referenced to the tire manufacturer's list of approved rim widths for whatever tires you're after. Fwiw, tires that have comparatively wide wheels work better than the usual big tire/stock rim combo, and unless you can mount wider wheels, that means going to a slightly narrower tire for crisper handling.


What diameter and width are both of your wheels?. I have a similar situation to what you're in: skinny wheels/older bike/limited choices that actually work. I've got a 1.85" front/2.15" rear, and found a few choices that work very nicely, at under $200 a set.  8)

[harper]

Bosozoku, I'm going with the standard size tire for the bike.
Front: 100/90v-18, and rear:130/90v-17.
Hard to find them . I'm running Pirelli's now and had good luck with them so I'm going to replace them again. The front was $93.99 and the rear was $115.99. I'll go ahead and mount them here in the shop and put them on my balancer after mounting. They're the street compound and I only get about 7-8K out of them. I still have lots of tread left but don't want to head out to the Natl. Rally with light tread. I do most of my riding in Western Pennsylvania and need the grip on the corners. I'm riding very conservative in my old age.

[bosozoku]

How wide are your wheels?.   ???

[harper]

Front: 2.50-18
 Rear: 2.75-17
I have a nice set of 3 spoke but I'm going to sell them. They're too wide and I don't need the hassle for a little extra rubber on the road. Some day I'll learn how to insert a picture on this website. :-\

[mystic red]

Front: 2.50-18
 Rear: 2.75-17
I have a nice set of 3 spoke but I'm going to sell them. They're too wide and I don't need the hassle for a little extra rubber on the road. Some day I'll learn how to insert a picture on this website. :-\

It's not tough, look here.

[mystic red]

Bosozoku, I'm going with the standard size tire for the bike.
Front: 100/90v-18, and rear:130/90v-17.
Hard to find them . I'm running Pirelli's now and had good luck with them so I'm going to replace them again. The front was $93.99 and the rear was $115.99. I'll go ahead and mount them here in the shop and put them on my balancer after mounting. They're the street compound and I only get about 7-8K out of them. I still have lots of tread left but don't want to head out to the Natl. Rally with light tread. I do most of my riding in Western Pennsylvania and need the grip on the corners. I'm riding very conservative in my old age.

Go with Duck's recommend. Diameter of the tire will change minimally. Radials rock.

[harper]

I checked the size of my rear 3 spoke. It has a 160/60-18 tire already mounted. My rear is a 17. No way can I use the 3 spoke on my bike. I ordered an Azaro 140/80zr-17 for my rear and a 110/80r-18 for the front. They'll be delivered next week and I'll let you know how they fit after I get them mounted. Thanks for the input..............