Kumho Solus 155/60R15

[exwinger]

Kumho rear tire disappointment

Try Discount Tire... :thumbup:.........................Took my bike back to Discount Tire today because it's almost to the wear bars and a little over 11,000 miles( 30,000 mile warranty ) .Wearing evenly across the tire .Nothing they will do about it other than to say "yep , it's about gone ". Won't honor warranty or make adjustment because the tire hasn't been rotated and being used for something other than it's intended use. When I bought the tire nothing was mentioned that using it on a motorcycle would void the warranty , all they said was that I should get 30,000 plus out of it . Makes me mad that they won't back it but I guess it's still cheaper than using the Kendas.

 

[sledmaster]

Front tire cupping

As for the front tire cupping, back to 2008 I have always been of the opinion this has been caused mostly by not enough front shock preload and not enough ride height. Back on the 2008s, when the front tires cup on the inside edges you crank up the preload to get the tire to ride flatter on the road, instead of carrying the weight on the inner portion of the tread.

Same thing on the 2013s & 2014s. This problem is magnified on units with no preload adjustability (big no-no in my book). After seeing how my front tires were starting to cup I dumped the OEM stock shocks on my 2013 ST-S and installed a set of the Fox Podium shocks with adjustable preload. Cranked up the preload to get the tire tread to sit flatter on the road surface, less cupping. You can actually feel the difference when you crank up the preload.

BRP has specifications as to what the shock length is supposed to be when loaded, and preload is supposed to be adjusted so the front end geometry sits right. This is not guess and miss, this is an actual Spyder specification on how much preload should be dialed in to achieve the specified shock length, thus the a-arms and tire sit properly. I think I posted this before, but here we go -

"The importance of properly adjusting the shock preload is to set the vehicle at a ride height at which the vehicle was designed to operate. Alignment values are determined at precise ride height values. Ride height is also the position at which the alignment is the most stable and less influenced by bump steer.

In order to properly adjust the vehicle’s ride height, have the customer sit on the unit and add approximately what the customer loads in the front cargo bin. Measure the distance between the front shock bolt centers. Adjust the preload in order to reach the desired value in the ride height chart. Remember to lift the vehicle to adjust the shock cams or rings in order to avoid damage to these components.

Preload does not influence stiffness nor softness of the ride, it only adjusts the ride height."


[TABLE="width: 500"]
[TR]
[TD="align: center"]Model Year
[/TD]
[TD="align: center"]Model
[/TD]
[TD="align: center"]Distance (± 2 mm, 0.08 in)
[/TD]
[/TR]
[TR]
[TD="align: center"]2008 - 2012
[/TD]
[TD="align: center"]GS/RS
[/TD]
[TD="align: center"]428 mm (16.850 in)
[/TD]
[/TR]
[TR]
[TD="align: center"]2010 - 2012
[/TD]
[TD="align: center"]RT
[/TD]
[TD="align: center"]428 mm (16.850 in)
[/TD]
[/TR]
[TR]
[TD="align: center"]2013 - 2014
[/TD]
[TD="align: center"]RS/ST
[/TD]
[TD="align: center"]420 mm (16.50 in)
[/TD]
[/TR]
[TR]
[TD="align: center"]2013 - 2014
[/TD]
[TD="align: center"]RT
[/TD]
[TD="align: center"]445 mm (17.50 in)
[/TD]
[/TR]
[/TABLE]


The Kumho front tires should work well, 10mm narrower is negligible, diameter increase is less than 1%. Main concern would be the LOW speed rating of 118 mph. Chances are this is what I will be installing next.

 

[Jim&Teresa]

Yup...Discount Tire

Where can I get Kumho 225/50-R15 ? I called tire rack and they don't have any, also none anywhere in Wichita ks. I have 8,200 miles on mine and it is bald. I have a michelin 215/60-R15 but the dealer in wichita told me that it would screw up the computer tack and speedometer .
Jaybird

I purchased mine from Discount Tire about a month ago for $85.70 total. Had to order it and it took about a week to get. It goes on next week.

 

[Bob Denman]

Sledmaster,
Thanks! :thumbup:
For those that don't know...
How'd you come across all of this very useful information?

 

[sledmaster]

Front tire cupping

Sledmaster,
Thanks! :thumbup:
For those that don't know...
How'd you come across all of this very useful information?

That info was in a technical document "Theory of Aligning a Roadster" regarding the proper alignment procedure of a Spyder. Roadsters have a unique wheel configuration that requires fundamental knowledge of alignment principles. The relationship between vehicle load and front wheel toe are important factors which influence handling and tire wear. While toe is really the only adjustable parameter on a Roadster, one has to have the proper vehicle ride height beforehand.

So when we start talking about tire cupping, we have to go over things like ride height and pre-load settings. When a dealer tells you there is nothing they can do for tire cupping, we know better. Gotta' have that tire sitting flat on the road or it will cup, regardless of tire type. Yes they are cheap OE tires, but you still have to get the proper ride height.

 

[Bob Denman]

I would assume that the ride height should be calculated with the bike carrying it's normal load...
How do use mee mortals, learn what the proper height should be? :dontknow:

 

[sledmaster]

I would assume that the ride height should be calculated with the bike carrying it's normal load...
How do use mee mortals, learn what the proper height should be? :dontknow:

Correct, that is why I felt it useful to share this information. Set the preload so your shock length (when loaded) is as specified, then the ride height is where it should be.

You now know more about this subject than some dealers do......

 

[BLUEKNIGHT911]

TIRE CUPPING

That info was in a technical document "Theory of Aligning a Roadster" regarding the proper alignment procedure of a Spyder. Roadsters have a unique wheel configuration that requires fundamental knowledge of alignment principles. The relationship between vehicle load and front wheel toe are important factors which influence handling and tire wear. While toe is really the only adjustable parameter on a Roadster, one has to have the proper vehicle ride height beforehand.

So when we start talking about tire cupping, we have to go over things like ride height and pre-load settings. When a dealer tells you there is nothing they can do for tire cupping, we know better. Gotta' have that tire sitting flat on the road or it will cup, regardless of tire type. Yes they are cheap OE tires, but you still have to get the proper ride height.

:gaah::gaah::gaah:...Dear Mr. Sledmaster....If your theory is even remotely correct ( and I don't think it is ) then we would have hundreds maybe thousands of Spyders with " CUPPING " tire issues.....and that is just not case .....at least I don't recall any hugh number of people reporting this here..........JMHO......Mikeguyver :thumbup:

 

[Bob Denman]

Mike,
He's more right than you could ever imagine; much less understand...
Send me an email... off-forum for this one...

 

[SpyRyd]

As for the front tire cupping, back to 2008 I have always been of the opinion this has been caused mostly by not enough front shock preload and not enough ride height. Back on the 2008s, when the front tires cup on the inside edges you crank up the preload to get the tire to ride flatter on the road, instead of carrying the weight on the inner portion of the tread.

Same thing on the 2013s & 2014s. This problem is magnified on units with no preload adjustability (big no-no in my book). After seeing how my front tires were starting to cup I dumped the OEM stock shocks on my 2013 ST-S and installed a set of the Fox Podium shocks with adjustable preload. Cranked up the preload to get the tire tread to sit flatter on the road surface, less cupping. You can actually feel the difference when you crank up the preload.

BRP has specifications as to what the shock length is supposed to be when loaded, and preload is supposed to be adjusted so the front end geometry sits right. This is not guess and miss, this is an actual Spyder specification on how much preload should be dialed in to achieve the specified shock length, thus the a-arms and tire sit properly. I think I posted this before, but here we go -
View attachment 93255
"The importance of properly adjusting the shock preload is to set the vehicle at a ride height at which the vehicle was designed to operate. Alignment values are determined at precise ride height values. Ride height is also the position at which the alignment is the most stable and less influenced by bump steer.

In order to properly adjust the vehicle’s ride height, have the customer sit on the unit and add approximately what the customer loads in the front cargo bin. Measure the distance between the front shock bolt centers. Adjust the preload in order to reach the desired value in the ride height chart. Remember to lift the vehicle to adjust the shock cams or rings in order to avoid damage to these components.

Preload does not influence stiffness nor softness of the ride, it only adjusts the ride height."


[TABLE="width: 500"]
[TR]
[TD="align: center"]Model Year[/TD]
[TD="align: center"]Model[/TD]
[TD="align: center"]Distance (± 2 mm, 0.08 in)[/TD]
[/TR]
[TR]
[TD="align: center"]2008 - 2012[/TD]
[TD="align: center"]GS/RS[/TD]
[TD="align: center"]428 mm (16.850 in)[/TD]
[/TR]
[TR]
[TD="align: center"]2010 - 2012[/TD]
[TD="align: center"]RT[/TD]
[TD="align: center"]428 mm (16.850 in)[/TD]
[/TR]
[TR]
[TD="align: center"]2013 - 2014[/TD]
[TD="align: center"]RS/ST[/TD]
[TD="align: center"]420 mm (16.50 in)[/TD]
[/TR]
[TR]
[TD="align: center"]2013 - 2014[/TD]
[TD="align: center"]RT[/TD]
[TD="align: center"]445 mm (17.50 in)[/TD]
[/TR]
[/TABLE]


The Kumho front tires should work well, 10mm narrower is negligible, diameter increase is less than 1%. Main concern would be the LOW speed rating of 118 mph. Chances are this is what I will be installing next.

No preload adjustment on the 14 RT-L shocks so how can BRP specify a loaded shock length "desired value" when it can't be achieved by all of varying weight (load)? Only option...replace the shocks?

 

[Bob Denman]

I suppose that we can either gain, or lose weight?? :dontknow:
I've got the "gaining" part figured out...
It sounds as if this information can be pretty important... Time to break out the rulers, and see what's going on up there... :thumbup:
Sled...
Thanks! :clap:


EDIT: Do you know if anyone is producing spacers for the front shocks of the 2013 & 2014 models? :dontknow:
Granted; they won't help if the loaded length is too long; but it'll at least help with the "saggy" front-ends! :thumbup:

 

[sledmaster]

This is why it is a no-no to be shipping units with no adjustable preload, IMO. Granted, they should be close for average riders of average weight carrying average loads, but when we get to riders that weigh more and/or carry more, the front end squats and the top of the spindles tilt in, and the load is carried on the inside portion of the tire. Proper alignment is based on a correct ride height.

This is why I installed the adjustable Fox Podium shocks, to regain preload adjustability and to tighten up the damping, but one should be able to install the rubber spring spacers into the springs to cheat a little. They were talking about them in the ST area, #0431-0260 from many vendors, Moose Racing or Parts Unlimited, for like $39. https://www.denniskirk.com/moose/shock-spring-wedge.p582794.prd/582794.sku They would help, especially to reduce bottoming of the belly pan. Cheap and easy. Several on the forum have installed them.

 

[Bob Denman]

Would you characterize this as a deficincy in execution; rather than a deficiency of design?

 

[sledmaster]

Would you characterize this as a deficincy in execution; rather than a deficiency of design?

Certainly. Typically an OEM will use the lesser shocks to a)save product cost and increase margin, b) to simplify the system for the end user.

Not having adjustments reduces the chance of an end user screwing it up, but also takes away from the ability to compensate for those outside of the normal parameters.

It can also be done to leave room for later model year improvements. For example, the 2013 ST-S has gas cell shocks w/o adjustable preload. The 2014s have Fox Podium shocks with adjustable preload. I would bet that was planned before people started to wear out front tires on the 2013s.

The amount of worn out tires with the 15" front wheels (new tire design and front suspension) has been far greater than what we saw on the 2008-2012 models, IMO. For sure that is what we have seen. On my Spyders alone the fronts went 22,000 miles on the 2008s, but I am going to have to replace them on my 2013 real quick, around 12,000 or so. Bummer.

 

[cyclelover63]

I have a stock shock 2012 RTL and I noticed quite a difference between my "bump skid to ground clearance" compared to the same year RTL that had Elka shocks on the front...The RT with the Elkas have quite a bit more clearance than mine...Do the Elka installers measure this when they install them?:dontknow:

 

[Highwayman2013]

Where can I get Kumho 225/50-R15 ? I called tire rack and they don't have any, also none anywhere in Wichita ks. I have 8,200 miles on mine and it is bald. I have a michelin 215/60-R15 but the dealer in wichita told me that it would screw up the computer tack and speedometer .
Jaybird

Well I have a 215/60/15 and it works fine.

 

[Bob Denman]

I have a stock shock 2012 RTL and I noticed quite a difference between my "bump skid to ground clearance" compared to the same year RTL that had Elka shocks on the front...The RT with the Elkas have quite a bit more clearance than mine...Do the Elka installers measure this when they install them?:dontknow:

I would guess that they don't...
But now that SledMaster has given you the specificztions for your bike; you can! :thumbup:

 

[bluep]

Where can I get Kumho 225/50-R15 ? I called tire rack and they don't have any, also none anywhere in Wichita ks. I have 8,200 miles on mine and it is bald. I have a michelin 215/60-R15 but the dealer in wichita told me that it would screw up the computer tack and speedometer .
Jaybird

The Michelin defender 215/60/15 will work fine. I have that tire on my 2014 RT-S No computer or speedometer problems. In fact any brand 215/60/15 tire will work fine.

 

[AeroPilot]

Kumhos on the Front and back of the wifes 15 RT- She Loves Them... I'm ecstatic!!

As to the "cupping" referenced from the OEM Kendas I can attest that both our 15 RT's exhibited this to some degree (I and Discount Tire call it "feathering") which I remediated to some extent by flipping or rotating the tires on the wheels at Discount Tires which were also able to spin balance them and improve the ride and get up to 20,000 miles out of the front Kendas. I ordered and had the Kumho Solus KH fronts in 155/60/15 put on the fronts and now have unidirectional tires/wheels that I can rotate anytime without remounting as required by the directional Kendas.

But, the best news is the wife is Happy, so I'm ecstatic. Just did the north Rim of the Black Canyon of the Gunnison this weekend and while we were blown off by the sport bikes, we were very pleased with their Performance. Hoping for 30,000 miles on the Kumhos similar to the service we seen with the Kumhos rears we've used (2 already mounted, 2- 2016 dated tires in the garage waiting for winter refresh maintenance time):yes::yes::yes:

 

[Bob Denman]

Thanks for a review of the Solus tires: they're on my radar, for when it's time to pull the Kendas. :thumbup: