I don't know that I have ever ridden on radial tires so I have zero knowledge/experience with them.  Is there a noticeable difference in either handling or tire life?  I am contemplating a front end and rear rim change and am wondering if it will be worth the investment.

As is true with many questions, the answer to yours is, "It depends."  
I believe radial tires are preferable due to the improvement in handling I perceive on my K1100LT.  I'm an old slowpoke of a rider, so don't take that to mean radial tires are only for the go-fast crowd. If your most important consideration is economy, they may not be the best choice for you.  I'm just on my first ever set (thanks for the recommendation, Duck) so I cannot speak to their longevity as compared to bias ply.  But, at this point I can't see me going back to bias ply designs.  I'm that impressed.

I have tried my K1100LT with both RS and LT wheels as I have both sets. I have however come to the conclusion that I prefer the LT wheels which means I stay with the BT45 which I like. 51 days my last set lasted......5,700 miles. Not complaining as the handling and turn in seems good enough with them. I found on the RS wheels there was a greater need to slide off the seat to go around corners. I am a little under 70kg.

I don't know that there is a right or wrong answer to that question.

In my case I put bias tires on my old bikes just because.

My modern K1600 gets radials because that is what it came with from BMW. I get about 10,000 km's out of a rear tire and 17,000 km's out of the front.

I'm on BT45's as well Olaf.  I just changed my rear at 18k kms and the front is still going strong.  I'm wondering now if my speedo/odometer is completely out to to lunch.  There's no question that it shows a much higher km/h reading than actual (+10km/h) and this has to inflate the odometer reading as well.  My front tire is still going strong and the rear was well past its due date.  Even if it is out by 15% that still is 15k kms, give or take.  I have no complaints whatsoever with the BT45's but I also have nothing else to compare them to.  A big part of the reason to change out the front and rear is to get the much improved breaking power with newer front end.  I have no complaints about the current performance of my brakes but more braking capacity is never a bad thing.

I just finished a 7300 mile trip around the U.S. and Canada.  I started with a pair of moderately worn Shinko Tourmasters which I have found to be reasonably good tires, especially so when cost is considered.  I completely wore them out at the 6000 mile mark and replaced them with a set of Metzler Marathons which were the only tires available where I was that fit my K75RT.

Having said that, bias ply tires seem to have a thing for following imperfections in the road surface, especially when they are half way worn or more.  It seems that everywhere I went the roads are being repaired with those machines that lay down a 3 foot wide strip of asphalt that is about a half to three quarter inches thick.  The edges of these strips are always in the part of the lane where motorcycles operate and no matter how I try, I am constantly riding over the edges causing annoying wobbles in the front end.  I have noticed that radials are able to totally ignore these edges along with most other imperfections in the pavement. 

That to me is the main advantage to having radial tires.

G'day Woodie , I did the rim swap on my bike ( 4.5x18 rear ) and am now running 110/80/18 front and 160/60/18 rear Michelin radials , not concerned about how long they will last coz I don't ride that hard or heavy . The radials are very neutral turning in with greater feel ( IMHO ) leaning over , wet / dry they are very consistent . I like the idea of having the latest carcass design available to me . Best mod I've ever done to my bike

John Re

Melbourne Australia

I dunno, I maybe don't ride much...


On my red RS I have the 18" three spoke wheels, front and rear, with the 4.5" out back. I've tried a set of Pirelli Angel GT, two sets of Continental Road Attack II, and now Michelin Pilot Road III, all radial tyres. Aside from the wider rear wheel & tyre combo being more difficult to remove from the bike due to calliper and exhaust mount clearance issues, these tyres have proven themselves in traction, ride comfort and relative longevity. I wouldn't go back, but I question doing the swap if you have yet to purchase the variety of items needed, modded centre stand, etc. Unless, of course, all you're going to do is mount the mixed brand set of radials, which we read about here being used successfully, to the original Y spoke wheels. Then, yeah, go for it. Radials improve the bike, IMHO.

Even if you're not riding hard radials do make a difference in my experience.

I switched my K1100LT from bias (Michelen Macadams) to radial (Avon Azaro) in the middle of a trip so after riding a little over 1,000 miles on bias the very next day I was riding on radials so it made it easier to compare.

One of the first big differences I noticed was that on sweepers doing about 60 MPH (not particularly aggressive riding IMO) that the rear end felt much more planted and stable.

YMMV.

I’m going to say no, they are not a must at all. The K100 2v was designed to wear non radials. It’s weight, power and stability are well matched to decent non radial rubber as is. I’m running Pirelli sport demons on my RS and it’s totally stable on sweepers, twistys and straights at speeds that can match plenty of faster bikes. The old style Metzelers that were on it before which I’ve used for years on R bikes are also strong performers on the K bikes. I’m sure that radials give perhaps a tiny bit more in the wet but I’m not cranking it over like im in F1 in the wet anyway. I have radials on my Dakar and it certainly corners nicely in the wet but ‘a must?’ definately not and dare I say it, with the wheel changing and brake swap ruin the original K100 old school look for me. Each to their own of course!

nobbylon wrote:I’m going to say no, they are not a must at all. The K100 2v was designed to wear non radials. It’s weight, power and stability are well matched to decent non radial rubber as is.

I would say rubbish, the tyres that were available then were not radials. They don't design bikes for tyres, but for riders and they will fit the best that has been invented.
Probably the reason that all new bikes use radials.
If you want to use tyres from 1983 because you think that they are within the design spec then be my guest, tyres have come a long way since then.

TT100 tyres got their name for a reason, lap speed 100mph on the TT course.

Modern bikes and modern technology tyres have brought that well above 130mph.

Not a bad improvement.

Thanks gentlemen for all the responses.  I like the fact that they are likely to add to the stability of the bike on the tar snakes, etc.  Changing my rear shock from the 33 year old OEM has helped a huge amount in that respect as well.  Would radials improve the stability on the open grating used on bridges?  I have never liked the feeling of the front end hunting all over the place.  What about longevity?  Do they last longer or not as long as a bias tire?

And yes Dazza, you really should try to make more of effort to get some miles on....

No guarantee on tar snakes.  I recently put some Pirelli Diablos (only thing I could get while touring) on a K1100LT and they really suck on warm tar snakes. Never had that issue with Bridgestone, Michelin or Avon radials though.

BobT wrote:

nobbylon wrote:I’m going to say no, they are not a must at all. The K100 2v was designed to wear non radials. It’s weight, power and stability are well matched to decent non radial rubber as is.

I would say rubbish, the tyres that were available then were not radials. They don't design bikes for tyres, but for riders and they will fit the best that has been invented.
Probably the reason that all new bikes use radials.
If you want to use tyres from 1983 because you think that they are within the design spec then be my guest, tyres have come a long way since then.

The available non radials today (latest technology and materials and not as you suggest 1983) are more than capable of tolerating anything a standard 2v does and most riders are capable of. If radial tyres are your requirement then a later bike could also be a solution instead of a chopped K100.

nobbylon wrote:

BobT wrote:

nobbylon wrote:I’m going to say no, they are not a must at all. The K100 2v was designed to wear non radials. It’s weight, power and stability are well matched to decent non radial rubber as is.

I would say rubbish, the tyres that were available then were not radials. They don't design bikes for tyres, but for riders and they will fit the best that has been invented.
Probably the reason that all new bikes use radials.
If you want to use tyres from 1983 because you think that they are within the design spec then be my guest, tyres have come a long way since then.

The available non radials today (latest technology and materials and not as you suggest 1983) are more than capable of tolerating anything a standard 2v does and most riders are capable of. If radial tyres are your requirement then a later bike could also be a solution instead of a chopped K100.

I'll take one of my Ducatis out then.

Don’t get it wet

nobbylon wrote:Don’t get it wet

Do you mean them? Why?

Off topic I know, sorry. You stated you were going to take one out so I replied don’t get IT wet. Don’t get wet because they rust! Cheap nuts and bolts, oil pipes and couplings etc. 14k kms sat outside for less than a year and rusting. Nice engines but the rusting makes a nice looking bike look cheap and nasty so they need to stay dry. Oh and while I’m Duke bashing that dry clutch on some of them sounds like a bag of spanners in a washing machine. I end up keeping the clutch in at traffic lights out of embarassment and I’m still trying to make this monster steer properly!

nobbylon wrote:Off topic I know, sorry and apologies for not acknowledging you have more than one, impressive. Don’t get wet because they rust! Cheap nuts and bolts, oil pipes and couplings etc. 14k kms sat outside for less than a year and rusting. Nice engines but the rusting makes a nice looking bike look cheap and nasty so they need to stay dry. Oh and while I’m Duke bashing that dry clutch on some of them sounds like a bag of spanners in a washing machine. I end up keeping the clutch in at traffic lights out of embarassment and I’m still trying to make this monster steer properly!

You are still living in the 1980's there mate. Dry clutch? None of my 3 Ducatis have a dry clutch. Rust? Audi own Ducati and have done for a few years, I doubt that they would put their name to something that rusts, none of mine are rusty or have cheap fasteners, but there again mine are 2018, 2017 and 1967 models.
What Ducatis have you owned that gives you so much knowledge?

You seem to want a pissing match for some reason? weird. 
I worked on my mates 95 monster for a few years and I was out on his 99 at the weekend. I personally wouldn’t buy one but you seem to like them so maybe the Ducati forum is a better place than here for these discussions.
I’d also remind you that this forum is called K100 forum. The bike was made in the 80’s and indeed the OP’s bike is from 85. Nope not living in the 80’s but still riding and enjoying BM’s from the 70’s on.

Radial tires aren't a must. They are an enhancement of a good riding machine.

When I was young I was told by my parents one doesn't discuss politics sex and religion.

They never mentioned oil and tyres........

oh go on....lets have an oil discussion

nobbylon wrote:oh go on....lets have an oil discussion

Go on then. Bet that the first thing you tell us is that the K100 was designed for mineral oil!
Can just imagine the BMW engineers sitting there saying that they have this oil and need to design a bike for it. 

I wouldn't add headlight relays either because Bosch didn't design the electrical system around them.

BobT wrote:

nobbylon wrote:oh go on....lets have an oil discussion

Go on then. Bet that the first thing you tell us is that the K100 was designed for mineral oil!
Can just imagine the BMW engineers sitting there saying that they have this oil and need to design a bike for it. 

 I think you need to read what I actually say and not what you’d like me to have said to give you something to chew on.
At no point have a said that the K100 was designed around anything or for anything. I said it was designed to USE said tyres and it was probably initially designed to use mineral oil. 
At least have the courtesy to not mis quote or invent stuff.
You just end up sounding sad and unknowledgeable and sniping at others for differing in opinion is easy when you’re sat behind your computer screen.
I come to this forum for the helpful discussion and hopefully am able to pass on some of my aquired tips and mechanical knowledge to others if I can. So far I’ve seen nothing constructive from you, just negativity which frankly I can’t be arsed with anymore.

Woodie wrote:I don't know that I have ever ridden on radial tires so I have zero knowledge/experience with them.  Is there a noticeable difference in either handling or tire life?  I am contemplating a front end and rear rim change and am wondering if it will be worth the investment.

So 27 posts later - what was the verdict of running radials on a K100? 

I also have zero experience of riding a K bike with radial tyres but also have no great problem with riding with non radial tyres. I have noted issues with the non radials tracking to various road imperfections and have noted how the ride characteristics change quite perceptibly once the non radial becomes worn close to the tread limit (especially the rear). If there was a distinct improvement in handling and reduced tyre wear, I would be sorely tempted to try out a set of radials (can you mix radial and non radial - front and back?)

One thing I do know is I tried re-mould tyres on my car once - and will never do that again!

On the tracking issue: If the front tire has a center groove then that will tend to track on grooved concrete.

Ummm,    uhhh,  .....   .....   I think I'll just put a radial on the front and leave the rear a it is ..... 

Woodie, tho' BMWs in the past have had a radial and bias ply they've been early GS models which are potentially subject to much lower speeds and significantly lower GVWR. I would not mix tyres on a big girl like a K.

If only one radial is used it should go on the rear but as EWB said dont mix them pairs are best.

Sorry, just trying to toss a little humour into a very serious topic    I wouldn't think of forcing big momma K into a mixed marriage of tires!

duck wrote:On the tracking issue: If the front tire has a center groove then that will tend to track on grooved concrete.

BT45 comes to mind....and I do use them. I run them at 38psi which seems to reduce the tendency. We don't have much by way of concrete roads here but we do get tramlining in blacktop joints.

RicK G wrote:If only one radial is used it should go on the rear but as EWB said dont mix them pairs are best.

I believe this will also pass an MOT (roadworthiness) test, but not the other way around..

I have a pair of part worn (actually scrubs!) ContiRoadAttack2 CRs to fit to the front, standard 100/90-18 fitment yet radial - when I finally wear out this Michelin Pilot Activ (bias ply but so so good, and still going at 7K) I'll let everyone know what the difference is like. And hope that the MOT man is a bit blind

I have to say I appreciated the profile of the radial Michie Pilot Roads as I bent and twisted through the corners - at speed - of the C521 'tween Whitfield & Mansfield and then Murchison Gap over both smooth and rough tarmac, today. I gave 'em a workout and they returned the favour with no slips, no stammers and my supreme confidence in them. I ate chicken strips for dinner in their honour.